UMS Used Machinery Sales LLC.
Jack Mendenhall, CEA John F. Roedel, CEA Brenda Daleki
19131 Industrial Blvd Suite 2 Elk River, Minnesota 55330
Tel:(800) 726-7167 (763) 441-5152 Fax:(763) 441-5075
CNC Machining Centers, Vertical & Horizontal, CNC Lathes
Boring Mills, CNC Presss Brakes, Shears, Punches and Lasers
Opportunities in the used CNC market
A Presentation For The MDNA
By Pete Nagel (847) 981-0704
Mike Lynch (847) 639-8847
A sales person that markets any product must possess a broad range of attributes. Highly important attributes include people skills, like charisma and communication skills. In fact, many successful sales people get by quite nicely armed with only these attributes. However, most sales people want more. At the very least, most want to possess good knowledge of the sales process. Though the most successful sales people have a natural aptitude in this regard, many do need some help in this regard. Among other things, salespeople must possess the ability to make initial inquiries, sort out the qualified buyers, make the sales presentation, and handle objections. And all the while, experienced salespeople work to close the order. There are any number of books, publications, and courses available that relate basic selling skills that can be applied to almost any product that can be sold.
Though the skills and attributes mentioned thus far are among the most important a salesperson should possess, most successful sales people will agree that product knowledge is also highly important. The better a sales person's working knowledge of the product being sold, the better they can communicate with perspective buyers. More importantly, product knowledge will help during every step of the sales process, from making the initial inquiry through closing the sale. This is especially true with CNC machine tool sales.
When compared to the vast resources available for learning sales and marketing, there sources for gaining specific product knowledge about CNC machine tool sales is harshly limited. Since you are commonly selling a product that is (well) under ten year sold, arid since that product was at the cutting edge of technology when it was originally sold, it can be very difficult indeed to find resources to help you understand the products you sell. This is especially true for sales people selling used CNC machine tools. While a new machine sales person working for a machine tool builder or distributor will have people available to help (applications, service, and design people), the used machine salesperson may have nowhere to turn for help.
It is the intention of this paper and presentation to help you extend your current knowledge of CNC machine tools and CNC users. Though CNC machines have been around for over thirty years, and though there are several generalities with which you are probably familiar, our primary objective will be to discuss the current state-of-the-art for CNC technology. You may be surprised to see that several technology changes are now occurring that will make it necessary for you to rethink your current methods in order to keep up with the times.
How CNC technology adapts to the times:
In the thirty-five plus years since the first numerically controlled (NC) machine was developed in Traverse City, Michigan and used to machine the elaborate contours on templates required for helicopter blades, manufacturing has seen a tremendous improvement in usage, serviceability, and capacity from this exciting technology. Admittedly, machine tool sales people need not have a complete understanding of every historical event that contributed to the evolution of current day CNC machine tools. However, understanding where we have been always offers insight into where we are going.
While people that have worked with CNC for many years may disagree with our methods, for the purpose of this presentation, we offer and discuss four major periods in CNC's evolution. It is not our intention to list every significant event that occurred in each period. Instead we simply list the periods, offering descriptions of the machine tool types produced during each period as well as their most basic applications.
Stage one - Early NC machines - Late 1950s through late 1960s:
The dinosaurs of CNC machine tools were extremely crude and difficult to work with. In fact, about the only kind of user willing to live with the poor reliability, difficult usage, and in general, extremely cumbersome functions was a user producing work pieces that could not be produced in any other manner and could afford the expenditure in money, time, and personnel needed to keep the NC machines running. Generally speaking, the aerospace industry (most companies at least partially sponsored by the US government)was about the only industry willing and capable to deal with this very narrow application focus.
Stage two - The advent of the computer- late 1960s through late 1970s:
Though it is somewhat ironic, CNC machine tools were the first devices in most companies to incorporate a computer. Though this is the case, computer technology has grown at a much faster rate for almost every other computer application than it has for CNC technology. This is evidenced by how inexpensive personal computers are found in just about every company in existence today. And problems we're still struggling with in CNC technology (shortages of program storage memory, communications protocol, and user friendliness) have been much better handled with computers having other applications.
Though evolving at a slower pace, computers in CNC machine tools can be credited with the expansion in feasible applications. The most substantial contributions from computer technology in CNC machine tools include improved reliability, improved usability, and lower costs. With CNC machines, many more companies could afford to purchase them, it didn't take a rocket scientist to use and maintain them, and they could be depended upon to stay running. This meant that more and more companies could afford to purchase them, even for less sophisticated applications. While a great deal of controversy still exists about how CNC machine tools are best applied, the computer within the CNC control made it feasible to perform all kinds of machining operations.
Stage three- Brute force rules - Mid 1970s through 1980s:
CNC related technologies are constantly leapfrogging one another. One classic example that was in evidence during this period relates to cutting tools. Machine tool builders design a CNC machine tool that can handle the most powerful machining operations current cutting tools can handle. In essence, the cutting tool is the weak link in the manufacturing process. Then cutting tool manufacturers improve their cuffing tools, making the CNC machine tool the weak link. This leapfrogging continues, and with every step, the CNC machine tool becomes much more powerful.
Keep in mind that manufacturing processes have also been constantly evolving. During this period, methods of producing raw materials (castings, forgings, slugs, etc.) were poor. Stock removal amounts were high, meaning the more powerful the machine tool, and the more material a cutting tool/machine tool could remove, the faster work pieces could be produced.
Stage four - Let's get technical - Late 1980s through present:
Current trends in manufacturing have been completely rethinking how work pieces are produced. Buzz words that evidence this trend include just-in-time, near-net-shape, ecologically sound, and ISO 9000. The focus has switched from removing a great deal of material as quickly as possible from a crude piece of raw material to removing a small amount of material from a piece of raw material that is closer to its intended shape.
While there is still a need for powerful machine tools capable of heavy stock removal, the bulk of machines sold today do not need these capabilities. Instead of accomplishing tasks with brute force, machine tool technology is now trending toward highly sophisticated functions. Machine tool functions that show evidence of this include very high spindle speeds, linear guide ways, lower horse power, and compact design.
We cannot stress enough the importance of a machine tool salesman having a good working knowledge of the CNC technologies currently evolving. While in the past you may have been able to get away with a minimum of knowledge in this regard, now more than ever, to compete you must be versed in this technology. To help keep up to date, subscribe to some of the excellent manufacturing-related trade journals like Modern Machine Shop, Manufacturing Engineering, Cuffing Tool Engineering, And Modern Application News.
Know your customer:
In order to have the largest potential to sell a CNC machine tool, you must know the needs of the people with whom you are dealing. The more you know, the easier it will be to customize your presentation/s to suit their needs. Here we introduce the four company types and show you how to evaluate a company's profile. For informed buyers, all purchasing decisions begin with these basic principles.
The four company types:
Though CNC machine tools are applied to a wide variety of applications, and though almost any company that manufactures anything uses CNC machine tools of one kind or another, there are only four categories of CNC users. This means that you can divide all companies using CNC machine tools into four basic types. Though there may be some overlap, knowing the basic company types should help you begin to size-up the company you're dealing with early on in the sales process. Here we list the four company types, giving a brief description of each.
Companies that manufacture a product:
As the name implies, product producing companies get their revenue from the sale of a product they sell. While this may sound like a basic statement; you must understand that it has fantastic implications when it comes to machine tool sales. Since profit is one step removed from the manufacturing process, the product producing company tends to work on the largest profit margins. They tend to adequately engineer production work pieces, they tool their CNC machines accordingly, and they staff their CNC environments with as many people as it takes to ensure maximum up-time. When it comes to CNC machine purchases, while they may be cost conscious, cost will not be the primary factor that dictates which machine they will buy. This offers the machine tool sales person a great potential for profit.
Companies that produce production work pieces for other companies:
Commonly known as job shops or contract shops, this kind of company gets its revenue from producing production work pieces for product producing companies. While there are exceptions, work piece producing companies tend to be quite small, the vast majority employing fewer than 50 people. In this kind of company, there is a direct correlation between manufacturing and profit. Most contract shops will quote their jobs based upon each CNC machine's shop rate (the dollars per hour rate for machine usage). When it comes to expenditures of any kind (including machine tool purchases), the contract shop will commonly be on the constant lookout for the best value. While this means you must be ready to sharpen your pencil for negotiations, most contract shop owners do perceive used CNC machine too/s as being better values than new machine tools, assuming they can find a used machine tool suitable for their purposes.
Companies that produce tooling:
This kind of company gets its revenue from the production of tooling for other companies. Though most tooling producing companies do tend to specialize in but one or two types of tooling, jigs, fixtures, cutting tools, dies, molds, and gages are among the kinds of tooling produced. Like contract shops, tooling producing companies tend to be quite small. And like contract shops, owners tend to see the value in purchasing used equipment.
Companies that produce prototypes:
This kind of company gets its revenue from producing test work pieces for product producing companies. In fact, an entire industry is currently evolving that surrounds this field (surely you have heard of rapid prototyping). While the technology surrounding this field tends to be the newest and most sophisticated, this field does involve some common CNC machine types. Examples include elaborate 3d shapes machined on a CNC machining center that were previously made by hand by model and pattern makers. Again prototype producing companies tend to be small, and when suitable used CNC equipment is available, owners recognize the improved value over new CNC machine purchases.
Again, watch out for overlap - Product producing companies tend to have the most overlap in this regard. It is not uncommon, for example, for a product producing company to have a tool room or research & development department. And as mentioned, CNC machines are commonly used in the production of tooling and prototypes. When involved with a CNC machine sale to a product producing company, you must qualify whether the machine is to be used in production or in the making of tooling or prototypes.
Evaluating a company's profile:
As you have seen, it should be quite easy to determine the type of company with which you are dealing. Assuming you do not already know, a simple question or two will provide you with this information. However, there are several more factors that will help you fine tune your understanding of your customer; factors that play a major role in determining which CNC machine tool will best suit their needs.
Any process engineer will tell you that the most important factor that dictates how a given work piece will be processed (including the decision as to which machine tool/s will be used) is production quantities. Production quantities, which we also refer to as lot sizes, are the number of work pieces to be made during a production run. We cannot overstress the importance understanding the implications lot sizes have on determining the appropriateness of a given CNC machine tool's ability to handle the job.
For the purpose of CNC machine tool usage, you can divide lot sizes into five categories.
Ultra low quantities, 1-10
Low quantities, 11-100
Medium quantities, 101-500
High quantities, 501-1,000
Ultra high quantities, over 1,000
Company type by itself will commonly imply the size of production quantities. Though there are exceptions, tooling and prototype producing companies have ultra low or low production quantities. Work piece producing companies commonly have quantities from ultra low through high. And product producing companies commonly have quantities from low through ultra high. Note again that we are talking about work pieces that are run on CNC machine tools. Since some CNC machine types are better suited to higher (and lower) quantities than others, it is mandatory that you know the production quantities expected of your proposed machine tool. For example, if you know that your customer has ultra low production quantities, programming will likely be done during setup. In this case, offering a machine with a conversational control (which can be easily programmed on the shop floor) will be to your advantage.
Amount of repeat business:
General purpose CNC machine tools (machining centers, turning centers, turret punch presses, etc.) are, by nature, designed to provide fast change over times. However, the more repeat business a company does, the more important it will be to minimize setup time. And some CNC machines, as well as factory installed accessories make it easier than others to minimize setup time. Features like quick change chuck and quick change tooling on turning centers, and pallet changers on machining centers facilitate quick change-over. Even something as simple as amount of control memory capacity has implications in this regard. If the CNC control has enough capacity to hold all programs a company runs, no time will be wasted during setup for the transfer of CNC programs.
Other factors contributing to a company profile:
As stated, the better you know your customer, the more likely it will be that you can meet his needs. While we have shown but two important factors, there are many that affect their buying decision. Though you don't have to be an expert in this regard (most buyers may know what they are looking for), understanding how to evaluate their needs will be very helpful in setting up a good rapport and will help you to communicate intelligently. Here we will simply list each additional factor and offer a few implications of when it will affect the buying decision.
Materials machined - Harder materials generally require more powerful machining operations, meaning the customer will be interested in more rigid and powerful machine tools. Softer materials do not require powerful machining and can be machined by lower cost machine tools. Dangerous materials like magnesium and titanium (not to mention nuclear materials) will require machines with special safety considerations. Dusty materials, like cast iron, require special venting.
Tolerances held - Extremely tight tolerances (say under 0.0005 in) commonly require machines designed to hold this close tolerance. The typical CNC user will be skeptical about (or may discount all together) a used machine's ability to hold such a tolerance.
Available personnel - Some companies, especially product producing companies, staff their CNC environment with adequate personnel. In these companies, programming is commonly done off line, meaning just about any conventional CNC control will suffice. However, other companies (commonly contract shops), have but one person doing everything, including the programming- These companies commonly prefer conversational controls to minimize on-line programming time.
Company location - CNC machines are found everywhere, from the most rural of communities to large urban areas. All customers will be looking for local service and support, and of course, if they purchase new machine tools, they will receive some kind of warrantee. However, you will likely find that companies in rural America (having no local machine tool builders) have become quite self sufficient when it comes to maintaining and repairing their own CNC machine tools. This kind of company will be more likely to purchase used equipment, since they know they have the ability to maintain and repair.
Your customer's need for training and support:
Part of knowing your customer is understanding the importance of training. You may, at first, think that as a used equipment salesperson, you are at a disadvantage to your new equipment counterparts. However, by understanding the availability of after market training suppliers and service people, you can in many cases equal, if not improve upon the services offered when new machine tools are sold. When it comes to training for machine tool usage, remember that several suppliers offer video courses, books, and in-plant training. When it comes to service, many machine tool companies and control manufacturers offer extended service agreements. All of this means you can offer your customers the same service and support alternatives granted by machine tool companies as new machines are sold!
Know what you have to sell:
Every week, trade publications come through your office listing the various CNC machine tool offerings currently available for sale. And we all keep tabs on the machine type/s our customers are looking for (and the price they are willing to pay) in order to match them with the offerings we find. If you truly understand your customers, you should be able to go further, and offer you customers alternatives based on the selection of machines currently available. In order to do this, you must additionally understand the capabilities of the machines currently available. In this discussion we list the most common CNC machine types and offer descriptions of their most common accessories.
Here we explore the various components of metal cutting machine tools for the purpose of comparison. This should help you relate important sales points to your customers. We'll begin with components that apply to all forms of CNC machine tools. Then we'll get specific about those components that apply to only one type of CNC machine tool. Keep in mind that it is our intention to speak in generalities and offer many opinions. Admittedly, machine designers may disagree with some of the statements we make. However, you should be able to get a good idea about the quality of CNC machine tools from the statements we make.
Common CNC machine components:
Here we describe those machine components that apply to all forms of CNC machine tools.
The control selection is among the most important buying decisions a CNC user will make. While the choices may be much more limited when it comes to purchasing used CNC equipment than when buying new, a user must know what they are getting when it comes to control technology. Of course, many informed buyers already know the various controls (possibly they already have many CNC machines). However, you will have ample opportunity to steer your customer in the proper direction by knowing but a few basic principles.
Here we will use the Fanuc product line to emphasize the evolution of control technology. Note that while Fanuc is the most popular control in the industry, most of the points made here can be applied to any control manufacturer. We will categorize in two ways.
Programming method - There are three popular methods of programming CNC machine tools. First, in companies that expect their CNC people to perform all CNC related tasks, like many job shops, programming is done right at the CNC machine tool. In this kind of company, maybe there is hardly any repeat business, lot sizes are small, and cycle times are short. In this case, programming actually becomes a function of setup. That is, the machine tool is down during the time it takes to develop the CNC program. In this kind of company, anything that can be done to shorten programming time will effectively reduce setup time. For this kind of application, conversational controls (also called shop floor programmed controls) make the best choice. Mazak's Mazatrol controls have made this kind of programming famous. In Fanuc's product line, turning center conversational controls include (from earliest to most recent) 3TD, 3TF, 10TF, 11TTF (four axis), and 15TF, and l6TF. Machining center conversational controls in Fanuc's product line include 6MB level up (not just the standard 6MB), 11MF, 1SMF, and l6MF. With all of Fanuc's conversational controls, the user can program the machine using the conversational functions or by more standard programming methods. In this sense, the user has the best of both worlds, and this kind of control should reap the best resale value.
Second, many CNC users have relatively simple work that requires very little in the way of programming effort. Additionally, many companies run a fixed number of CNC programs. Once the program/s are developed, there is little need of additional programming. For these kinds of companies, manual programming makes the wisest choice. Of interest to this kind of user will be special programming features that are built into the control, like canned cycles, parametric programming, axis rotation, and mirror image. Virtually all of the models in Fanuc's product line can be equipped with these features. However, many machine tool builders keep the cost of their machines down by not including them. And determining which of these features a used machine has can be difficult. It may take some leg-work with the previous owner to ensure that your perspective customer's needs will be met.
Third, many companies do work that require highly complex programs. Or possibly, one person must program for many different machines. Computer aided manufacturing (CAM) systems are required to help with the programming for these kinds of companies. Note that with a CAM system, very little in the way of special programming features is required in the control itself, since the CAM system does all the work.
Note that there is an application for CNC machining that demands the use of a CAM system. If your user will be machining three dimensional shapes (3d machining), it is virtually impossible to develop CNC programs without a CAM system. And by the way, the control technology related to 3d machining has changed a great deal, even in the last three years. If you know that your customer will be exclusively machining 3d shapes, you must know that controls over about three years old will have some dramatic limitations over new controls designed for 3d work. The limitations have to do with program transfer method (older controls require slow direct numerical control [DNC] transfer), memory capacity (older controls have very limited capacity in this regard), and something called look-ahead (with 3d machining, the control must look into the program a great distance to determine what is coming up even the next few inches of motion). Controls designed to overcome these limitations are called high speed machining controls. If your customer is buying a machine over 5 years old, they will not be able to compete with competitors using this kind of control. Note that there is one company producing high speed machining controls that will gladly retrofit a high speed machining control to an older machine. (Talk to Todd Schuet at Creative Technology at 847-818-0055.)
Control level - Almost all control manufacturers, including Fanuc, simultaneously have at least two current control models. One model is the low-cost, somewhat stripped down model while the other is the deluxe model. This thinking goes back about 15 years. At the time of the 6 series (6M or 6T), for example, Fanuc also had a lower level control, the 3 series (3M and 3T). The 6 series is the more powerful, and more desirable control, and obviously worth more in the used market. In similar fashion, the O series (OT or OM), is the lower end model during the time when the 11 series was produced (though the O series is still a current control model while the 11 series is not). The 10 series is the lower end model to the 15 series. And the 18 series is the current lower end model to the 16 series. While all of this is a little confusing, it does help to know which controls have the higher value to your customers.
Keep in mind that certain higher level functions (even something as basic as helical interpolation needed for thread milling) cannot be equipped with some of the lower end controls. In addition, Fanuc confuses the issue further by introducing their controls (even in a series) by level. For example, the O series has evolved through three levels, labeled with A, B, and C, with the OTA or OMA being the first and weakest of the O series. It is important to know the complete control designation in order to determine a control model's true value.
Axis drive systems:
The axis drive system refers to the electrical and mechanical components that actually cause axis motion. An axis drive is composed of the axis drive motor, the ball screw, and the feedback system which confirms a commanded motion has taken place properly.
Digital versus analog - More and more CNC machines are incorporating digital axis drives, which offer faster response times than analog drives. For general purpose CNC machines, analog drives are quite adequate. However, with the increased rapid rates of today's faster machines, digital drives require less response time for acceleration and deceleration. Additionally, digital drives offer better position detection whenever probing systems are used. The length of time that is required to determine the machine's position after probing is called lag time.
AC versus DC servo motors - A servo motor actually powers each axis of motion. Until relatively recently (about 7 years ago) it was not (feasibly) possible to precisely control the rotation of AC motors to the level required for CNC servo motor use. This limitation has been overcome, and to gain the additional power and reduced maintenance required of AC motors, most CNC users prefer the AC type.
Ball screw support - For a linear axis, the ball screw actually transfers the motion from the rotation of the servo motor to the moving component of the axis (table, turret, head stock, etc.). Some machines utilize support only on the drive motor end of the ball screw. Believe it or not, the other end of the ball screw is just hanging in space. Higher quality machines provide support at both ends of the ball screw.
Encoder feedback versus induction scale feedback - When a CNC control issues a command to move an axis, say three inches, it must have some way of confirming that the actual motion equals the commanded motion. Two popular methods are used to confirm feedback. Encoder feedback uses a simple encoder (commonly mounted right on the servo motor to determine whether the proper amount of motor rotation has been accomplished to equal the programmed movement. In essence, this kind of system is assuming that everything from the servo motor out is perfect (ball screw coupling, ball screw, coupling to the moving member, etc.). By far, the induction scale feedback is more positive. Instead of monitoring the rotation of the servo motor (and hoping everything else is all right), induction scales monitor the motion of the moving member. The higher the expected accuracy, the more induction scale feedback is required.
A machine's ways actually provide the path for axis motion, and can be compared to the tracks used for a railroad. Different ways systems are appropriate for different applications. If high rigidity is of primary concern, most experts would agree that box ways are best. As the name implies, square (or rectangular) box ways incorporate a solid way structure. The moving member slides right on top of the way itself.
Dovetail ways, though not as popular today as they once were are used when rigidity is not of primary concern. They provide a less expensive path along a linear axis.
A way style that has grown dramatically in popularity is the linear guide way. Research and development in this type of way has resulted in a highly rigid, inexpensive, and replaceable way system. And these way systems allow much faster traverse rates (rapid rate) than any other form of way. Due to their reduced friction, they make an excellent way of choice for smaller, high speed, and lighter duty CNC machine tools.
Spindle drive Systems:
The spindle drive motor can be AC or DC type. Generally speaking, the same advantages of AC type mentioned during the discussion of servo drive motors applies to spindle drive motors. Additionally, there is a relatively new bread of AC spindle drive motor (the high torque type) that has so much power at lower RPM's that it virtually eliminates the need for a spindle transmission. This is especially true of motors up to 30 hp.
Depending upon the machine's application, a transmission may also be required. Like the transmission of an automobile, this transmission helps provide high power at low spindle speeds and high speed at higher speeds. Keep in mind that if speed is of the utmost concern (as is the case with machining centers having 10,000 or more RPM), there may be no transmission. Instead a direct belt drive is used.
Also of critical importance in the spindle drive system are the spindle bearings. And again, application should drive the design, and should dictate the user's buying decisions. Machines designed for powerful machining operations must have spindle bearings designed to take a great deal of punishment. Machines designed for high speed will not have durable spindle bearings for powerful machining operations.
As an applications salesperson, you can often alert your user to potential mistakes with machine selection based on spindle configuration. If you know your customer will be performing powerful operations, direct them away from the high RPM machines that are becoming more and more popular.
Other important CNC machine characteristics:
CNC chip cutting machine tools, ie. lathes, vertical MACHINING centers, and horizontal machining centers all share certain common characteristics. They all posses work size capacities, axis of motion travel lengths, work holding devices, automatic tool changing devices, spindles, and the electronic systems comprising spindle motor and servo, axis servo motors and drives, axis encoders, and a CNC control. Following are some descriptions and comments regarding each of the above characteristics. Thinking Of and evaluating, CNC machine tools in terms of characteristics, elements, or modules such as these will greatly assist you in gaining a clear understanding of the "hybrid" machines you will encounter.
Capacities and travels:
X, Y, and Z designate the primary axis of travel on all CNC machine tools. On a vertical machining center X represents the left to right table motion, Y the front to back table motion, and Z up and down motion of the spindle. Horizontal machining centers are similar, except Y and Z are reversed ( as if a vertical machining center were laying on it's back). Most CNC turning centers employ only two axis of travel, X expressed as a diameter, and Z which controls work piece length (usually a left to right motion). When discussing machine tool capacity in quotes, for example, it is always advisable to speak in terms of axis travel. This provides your customer with the information which he truly requires to determine if your offering is of sufficient capacity. Although useful, specifications such as swing, and distance between centers on a lathe, and table or pallet size on mills can be very misleading, and seldom present a true picture of actual work piece capacity. "Ball screws" are the long precision screws which provide both motion and accurate positioning, (throughout the travels), of machining center tables and lathe turrets. As with most things, the bigger in diameter that they are the better, stronger and more expensive they become. On "traditional" machines ball screws increase in diameter as machine model and size increase. On SOME "commodity" machines the same diameter ball screws are employed throughout many model sizes! This is one of the areas where "used" traditional designs can compete against commodity designs. Other important CONSIDERATIONS regarding ball screws are bearing supports and lubrication. The best and most desirable way to support a ball screw is with a bearing at each end. Many of the commodity machines do this, but be warned that some foreign and domestic machines exist where the end of the ball screw which isn't connected to the motor is left to hang and whip in free space (not good). The presence of the end bearing support can usually be determined visually, and lack thereof is good grounds for negotiation. The axis travels which appear to enjoy the most popularity in the marketplace are: Lathes 10" X (diameter) by 29" Z (Cut Length), Vertical Machining Centers X 40", Y 20" Z 20", and Horizontal Machining Centers 20" Cube (X 20" Y 20"Z 20")
All CNC machine tools have spindles, which apply the power which accomplishes the actual machining or cutting of the work piece. On machining centers the spindle holds a revolving tool to which a (prismatic) work piece is applied; on lathes the spindle holds a revolving (round) work piece to which stationary tools are applied. The most commonly encountered spindle configurations are multiple range geared units, and single or multiple range belt driven units (many times incorrectly referred to as direct drive). A third type of spindle drive exists which is a true direct drive ie. the motor shaft actually comprises the rotating spindle element supporting the tool holder or chuck. This design is of fairly recent manufacture, and only occasionally appears on the current used market. The most expensive spindles are gear driven and contain either spur or clutched helical gears in a minimum of two ranges. These spindles are essential for heavy high material removal type machining because of their ability to transmit great amounts of power at low spindle speeds. Belt driven spindles are far less expensive as power is transmitted from the motor to the spindle by simple toothed or "V" type rubber belts. They are generally capable of attaining higher spindle speeds than geared spindles, and find their greatest applications in light machining of steels, and non ferrous metals. Most belt driven spindles are single range and lack significant power at low spindle speeds. As with all things, exceptions exist, and it is worth noting that one of the commodity manufacturers offers dual range timing belt driven spindles (with a high torque motor option) capable of some very impressive and efficient cutting of steel at relatively low spindle speeds! Whether gear or belt driven, many builders incorporate the rotating spindle element and precision spindle bearings into a field replaceable "cartridge". when trouble occurs, the savings to the owner in the time and simplicity necessary to accomplish repairs is significant. This feature is a definite plus. Machining centers incorporate a taper within the spindle to accept a variety of tool holders presented to the spindle by the automatic tool changer. This taper is most commonly specified as a "Cat V flange" 40 or 50 taper. The 40 taper accommodates lighter tools and cutting. The 50 taper is most commonly found on large mills of 20 Hp. and up. A "BT V flange" taper is occasionally encountered and refers to the tool flange style by which the ATC arm grips the tool. The 40 or 50 taper associated with the holder is the same. This flange configuration is a European and Japanese standard and is less frequently used in the U.S. than CAT. If you purchase the machine this is a point of negotiation, and if at all possible try to have a fill compliment of tools supplied with the machine. For the record: CAT and BT tools ARE NOT interchangeable! The Tapers will seat correctly if they are manually placed into the spindle (and the pull studs are correct), however, at the very least, interchanging these tool holders will damage and bend the delicate gripper fingers of the ATC arm, and the possibility exists that a tool may actually be thrown from the gripper during arm rotation! Concerning turning centers, a word about "through hole" capacity is in order. Be aware that the spindle bore inside diameter (as stated in the machine tool literature) is exactly that, not the bar capacity size (which is what your customer asked you to check on). The spindle bore is always reduced (except when using a self contained air chuck) by twice the wall thickness of the actuator or draw tube which runs through it. This tube is the member which mechanically connects (and moves) the chuck or collet at the front of the spindle, by the motion of the hydraulic actuator at the back of the spindle. Coarse large tubes may reduce a spindle bore by .500", small high tensile alloy tubes may only cause a .062" reduction. Either measure the tube itself, or call the builder; anything else is guess work. Both lathe and mill spindles are frequently equipped with "Chiller" units to dissipate the heat build-up caused by running at high spindle speeds. Failure to provide such cooling results in machining in accuracy caused by thermal expansion, and occasionally also causes the tool holders to "stick" in mill spindles, for the same reason. Do not confuse these chiller units with the pumps and fans used to cool the oil in gear driven head stocks. Chillers usually incorporate a refrigeration unit to cool re-circulated cooling oil, and are essential above 6000 RPM.
Work holding and tool changing:
Chucks and collet noses:
Three jaw hydraulic power chucks are the most common form of work holding device supplied on CNC turning centers. They operate, ie. open and close through the pushing and pulling action of the hydraulic actuator cylinder mounted on the rear of the spindle housing. The actuator cylinder is activated by "M" codes to open and close it, as well a by a foot pedal. The codes and foot pedal action can be reversed, by a switch, for I.D. gripping. Cheap, and some high production lathes require you to switch hoses to accomplish the reversal.
Most of these chucks and actuators are of the "through hole" type, meaning that their design incorporates the largest possible hole through their center. The purpose of the hole is to allow the feeding of bar stock from the back of the spindle, and to allow long rod shaped parts (such as axle shafts) to be "swallowed" into the spindle during machining of the end journals. The chuck and the actuator are coupled or connected to one another by a "draw tube", which is a hollow tube mounted concentric to the spindle I.D. and threaded into both the chuck, and actuator. The smallest hole, whether it be in the chuck, actuator, or draw tube is what limits the maximum size of the bar stock which may be fed through the spindle (see "capacities and travels). Sometimes slightly larger bar capacity may be obtained by boring out the chuck and actuator, or by fabricating a thin walled draw tube of a high tensile strength steel (to compensate for the thinner wall). The easiest way to obtain the maximum bar size, approaching the fill diameter of the spindle bore, is to install a "self contained air chuck". These chucks are truly self contained, requiring no actuator or draw tube, thereby allowing fill spindle bar capacity. Such chucks are seldom encountered as standard equipment, and are not inexpensive, but can many times make a sale which would have otherwise been impossible. One of the best air chucks available is the 5MW brand. Just different sizes and types of chucks can be installed on any given spindle (provided that you correctly specify the "spindle nose" taper and bolt hole pattern) so also can "collet nose adapters" be affixed to spindles. These adapters take the place of the chuck, and can be purchased in styles accommodating a wide variety of collet types and sizes. They are actuated by the existing actuator and draw tube, and require a small adapter which threads onto both the draw tube an collet. One of the best collet nose adapters is the ATS brand. In addition to the foregoing, used lathes are sometimes purchased with a variety of special work holding units including expanding mandrels, face drivers, and faceplate fixtures, all of these are specialized and subject to negotiation. When purchasing a used CNC lathe always inspect the hardened "master jaws" in the chuck for cracks. This type of damage is common in the event of a severe crash, and is extremely dangerous! Fatal accidents occur when a cracked master jaw finally lets go and comes flying at the operator propelled by 3000 RPM of centrifugal force! All chucks have a maximum safe operating speed expressed in maximum RPM. This is seldom a problem with original equipment chucks supplied by the builder, but as a used buyer you must verify that the package you are buying is safe. If in doubt call the chuck manufacturer and check your model. Also, beware of large chucks (installed on lathes for special jobs)way out of proportion to the rest of the machine.
These chucks probably have a maximum RPM limit far lower than what the machine is capable of delivering, and can literally explode if run too fast (Product liability, negotiate a standard chuck). An additional problem created by oversize chucks is turret tooling interference. Frequently drills and boring bars must be installed one or more stations apart to "clear" the chuck, vastly limiting the tooling flexibility of the machine. Chucks accommodate three types of "top jaws" (always in sets of 3). Hard Jaws incorporate hard steel serrated gripping surfaces for holding rough irregular parts such as iron castings. Soft Jaws which are custom bored by the user to accommodate each of his work pieces, but are useful to your used buyer because he can re-cut them. Pie jaws which are a form of soft jaw but having a full 120 degrees of contact for delicate work pieces requiring light gripping pressure over a large surface. As a used buyer ask for any and all chuck jaws used on the lathe which you contemplate purchasing.
Turrets and tool stations:
All CNC turning centers Incorporate a "turret" to hold the tools necessary for a particular job, and quickly position each tool into the cutting position when commanded to do so by the program. Turrets are either good or bad relative to these two capabilities. The more tools held, and the quicker they can be indexed into cutting position, the better. Commonly turrets have 6, 8, 10, or 12 positions to which they can be indexed. To each position is bolted a tool block or tool holder capable of holding one or more cutting tools. The tool holders are specially configured to hold either O. D. tools such as turning, threading, grooving/cut-off tools, or I.D. tools such as drills, boring bars, and reamers. Each machine tool builder has his own design for tooling blocks; some makers provide blocks only for I.D. tools, mounting the O. D. tools in slots cut directly into the turret. Tooling blocks are frequently designed for a specific model of machine and turret, and are not interchangeable with other models of machinery from the same builder. Tooling blocks are also expensive costing from $200.00 to $500.00 each! In purchasing used, always try to determine what blocks were supplied by the manufacturer as standard original equipment, and include them, as well as any additional blocks purchased for the lathe. As mentioned, some configurations of tool blocks are designed to hold two tools, some two O. D., some two I.D., and some one O. D. and one I'D.. Many used quotes mention turret stations or positions only, and totally neglect to mention tool stations! A 6 position turret may be capable of providing 12 tool stations, certainly a more attractive offering to your customer. Three axis, hybrid, lathes, capable of milling as well as turning incorporate a "driven" or "live" station in every other turret position.
As you might expect, these tool holders are complex containing moving parts, some even incorporate right angle drives, and many accommodate and are supplied with collet systems. Live tool holders are almost never supplied as standard equipment, and are ordered as needed for given projects. They are of two basic styles, X axis and Y axis, indicating the attitude in which the rotating tool is positioned. Other types exist, usually called off-center holders for special overhead milling applications. Live tool holders are very expensive costing between $1,500.00 and $5,000.00, depending on the complexity and accessories such as collets. Be sure to obtain all of them available when purchasing a used hybrid lathe. Another type of tooling block that you may encounter is the "quick change" type. The purpose of this tooling is to allow the operator to install or change tools in a matter of seconds, as opposed to minutes, to facilitate setup and production. Some machine tool builders offer optional turrets specifically designed to accept quick change tools only! In this case make sure the seller supplies at least a fill compliment of tool holders, or you will be looking at purchasing some very expensive tooling to make your offering palatable. More commonly, you will encounter special tooling blocks, which conventionally bolt to turret positions, which accept quick change holders. By this method both conventional and quick change tooling may be employed on the same turret giving great flexibility and cost savings, but sacrificing rigidity over the turret dedicated to quick change only. The speed with which a turret can index a tool to cutting position is of great importance in minimizing cycle time. This speed is governed by three factors, the actual speed of rotation, the direction of rotation ( uni or Bi directional), and the continuity of rotation (must the turret pause or hesitate at intermediate stations between the one it is at, and the next one commanded). Older CNC lathes had turrets driven by a hydraulic motor and positions mechanically dictated by geneva cams and/or electromagnetic sensors. At worst this meant revolving in only one direction (unidirectional), and a hesitation at each turret position. If the turret was at station 1 and you wanted to index to station 12, you had to pass and briefly hesitate at stations 2, 3, 4, 5, 6, 7, 8, 9, 10, and 11. Time consuming! Many new CNC lathes incorporate electronic servo-motor driven, bi-directional, skip station turrets. These turrets are driven by single axis servo system, with continuous feedback, similar to the cutting axis of the machine tool. When the control reads and executes a tool station command, the turret indexes at full maximum speed, taking the shortest path to the commanded tool, which "it knows" and therefore chooses it's own direction of rotation, and skips all non commanded stations, as it is acting by absolute program command without the need to sense intermediate points.
Tables and pallets:
In contrast to lathes which hold their work piece in a rotating chuck, the work pieces to be machined on vertical and horizontal machining centers are mounted on flat tables called movable pallets on horizontal machining centers, due to their capability of being automatically moved in and out of the work zone) which move along the directions of the machines axis of motion. Tables are straightforward, but should conform to the following: Vertical machining center tables should be at least 10" (5"/side) longer than the axis travel in the "X" direction to allow room for work holding clamps and fixtures. "Y" axis table is usually only slightly longer than the travel. Horizontal machining center pallets are usually only two inches longer than the travels due to clearance problems arising during pallet changes. All tables must be flat! Lack of flatness, or camber, will induce distortion in any work piece or fixture clamped to the table, and spoil any subsequent machining. Table flatness is generated by the manufacturer, and seldom degrades through use, except for small nicks, which can be stoned off. Traditionally machine tables were ground on large water grinders to produce a uniformly flat surface, however some contemporary engineers believe that a still flatter surface can be generated by single point machining with a diamond cutter (the single point cut produces less heat than the grinding operation). So, don't be too quick to condemn a table because it is machined instead of ground. The thickness of a table is of significant importance in" retaining" flatness, as with use, repeated improper or excessively tight clamping of fixtures or work pieces may distort the entire table. Some inexpensive imports have this problem, which can sometimes be detected by sighting the table with a good 24"steel straight edge ruler. Be aware that the "T" slots machined into tables and sometimes into pallets can be to either inch, or metric size standards. Imported machinery will have metric "T" slots. A very helpful feature found on some horizontal machining center pallets are the inclusion of hardened, ground, and doweled edge plates on adjacent sides of the pallet. These enable the operator to easily and accurately install and align a fixture while the pallet is in the accessible "pallet change" position. Similarly, the ability to manually rotate the pallet at this position greatly facilitates the installation and removal of work pieces and fixtures. This capability will be apparent if the pallet change station is equipped with a foot pedal, which releases a shot pin, allowing the pallet to turn.
Automatic tool changers (ATC):
Cutting tools for both vertical and horizontal machining centers are automatically placed into, and removed from the spindle by the ATC.
Quantities of tools from 20, up into the hundreds are stored in tooling "pots" or positions, awaiting automatic retrieval for the current, or subsequent job being machined. ATC's come in a variety of designs, vertical magazine, horizontal magazine, direct spindle or "double arm" tool exchange, and sequential or random bi-directional in operation. In a similar fashion to lathe turrets, the criteria for a good ATC is how many tools it can hold (the more the better), and how fast it can change tools (the faster the better). Unlike lathe turrets, the ATC itself does not hold the tool during cutting, it retrieves it from a magazine, and places it into the spindle. This situation presents opportunities and problems. The opportunity lies in the fact that since the magazine is independent and removed from the cutting operation it can be made very large and elaborate, storing almost any number of tools the customer wishes (these are usually found on horizontal machining centers, as an option). Problems occur at the point of the tool change motion itself. If you stop and think of all of the numerous, and intricate motions necessary to remove one tool from the spindle and place it in the magazine, then retrieve the next desired tool from the magazine and place it in the spindle, you will quickly appreciate the complexity of this "robotic" mechanism. It is for this reason that the most common problems and "jam-ups" on machining centers are caused by ATC malfunctions. When inspecting a used machine be sure to have the ATC thoroughly demonstrated. If it jams be sure that tool length, weight, and flange criteria are correct before condemning the ATC. The fastest tool changes are accomplished by a "double arm" gripper which simultaneously grabs both the tool in the spindle and the tool in the magazine, rotates 180 degrees, and exchanges them. For this to take place the magazine will have to have rotated to present the next desired tool to the tool change position (this occurring while the machine was cutting with the existing tool in the spindle), and the position, or tool pot, of the new tool must be automatically "re-numbered" to the number of the tool being changed out of the spindle. The re-numbering and subsequent tracking for all tools is accomplished and monitored by the CNC control, or the machines PC interface. The slowest tool changes occur sequentially, where the spindle stops, places the last tool into it's fixed position in the magazine, the magazine then rotates in one direction to the next tools fixed position, the spindle then retrieves the next tool and begins cutting. Notice that putting away the tool, and retrieving the next one were two separate motions (not one as with the "double arm"), and that uni-directional magazine rotation was part of the actual tool change cycle (it didn't occur while the spindle was cutting). This rotation time could involve a complete magazine revolution, depending upon the tool selected. Interestingly, most "commodity" machining centers employ the slower method just discussed for reasons of manufacturing cost. If criticized, they simply point out that you can buy two of their machines for the cost of one competitor's machine, with a faster tool change time, and thereby cut their tool change time in half, as well as accruing other obvious benefits. This situation is not true with a quality "used" offering, and is another area where we can compete with these machines. Before leaving ATC's, it is very Important to know how to differentiate between "tool change time" and "chip to chip" time. These terms are often confused, and can be very misleading. The key thing to remember here, is that unlike a lathe turret, the spindle of a mill must "orient" and travel to the extreme of the "Z" or "Y" axis to reach the ATC, and exchange tools. In some cases other axis will require movement as well to avoid tool interference. The time required for the spindle nose to move the distance from the extreme end of the travel to the tool change position, plus the tool change time, plus the time required to move back to the extreme end of the travel, is the "chip to chip" time. This is the figure one has to work with when quoting cycle times, and can be as much as twice the actual tool change time. Chip to chip time takes into account all kinds of machine dynamics such as rapid travel speed (size of axis servo motors), accel. speed, decel. speed (digital AC, or DC servo motors), and spindle orientation type and method of operation (electronic or mechanical, can orientation take place during axis travel to ATC position?) Simple "tool change time" is just that, an indication of the time (and sophistication) of the tool change mechanism.
Machine frame construction and weight:
Rigidity in a machine tool is a very difficult element to quantify. It can be subjective, as for a light application the machine may be extremely ridged, but for a heavy application the same machine may be flimsy. Traditional machine design mandates that rigidity and mass increase with machine tool horsepower (stock removal capability, expressed in cubic inches per minute), and physical size. The benefits of rigidity lie in the machines ability to deliver and maintain accuracy, and to absorb and dissipate the vibration and impact of machining, without detrimental effect to the machine itself, the work piece, or the tooling. Lack of rigidity results in the inability to hold close work piece tolerances and surface finish, and tool cuffing edge deterioration, resulting from un dampened vibration, coupled with twisting, springing, torsion and thermal displacement of the machine frame. The repeatable accuracies of such a machine may only last for a year or two, and cutting tool life will be significantly less from the day it begins running. A significant part of rigidity is a function of the material from which the machine bed, table, columns, and housings are constructed. The geometric proportions (overhang), distributed mass, and weight engineered into these elements also plays a large part. Normalized, aged, low tensile strength cast iron elements with large mounting flanges where they bolt together constitute the most ridged and expensive method of construction. The least stable, and prone to induced vibration are machine frames produced from fabricated and stress relieved steel weldments. Thermal expansion is also a problem with steel framed machines, due to the much greater coefficient of expansion of that material. Steel weldment type frames represent the least expensive form of construction. In comparing cast iron frames, the best castings are always produced in foundries directly owned, or subject to a high degree of control by the machine tool builder. Many inexpensive Asian machine tools are poured in commercial foundries with little to no regard for quality. Good castings are well finished, free from flaws, and are thick and heavily ribbed in appearance. Quick comparisons of machine tools can be made by comparing overall machine weights. Some controversy exists over the use of "fillers" in machine tool castings. Fillers, such as core sand left in the casting, or engineered materials specifically placed there serve the purpose of increased dampening of vibration. Vibration travels best through hardened high tensile strength materials such as hardened linear guide rails, and the hardened surfaces of induction hardened integral ways. With proper design and spacing, vibration from the hardened way surfaces is transmitted to the much lower tensile strength cast iron frame, where it is further dampened and absorbed. At this stage, any remaining vibration is transmitted and absorbed by the air within the cavities of the machine tool castings. The inclusion of casting fillers provides an additional stage of yet lower tensile strength dampening and improves the machine tools vibration absorption characteristics.
Axis way systems:
The most ridged, long lasting, and costly method of way construction is the use of hardened and ground rectangular cross section steel ways, bolted and doweled to the machine frame. Equally as good are the rectangular steel ways integrally cast onto the cast iron frame by at least one Japanese builder. Following these are the intregally cast dovetail and rectangular ways, induction hardened, ground, and Turcite (low stick/slip material) coated, commonly found on machines of traditional design. In addition to providing a means of motion, the way system serves to couple the movable elements, table/turret, to the main frame of the machine. The more surface area and strength inherent in this coupling, the greater the machine tools ability to absorb and dissipate the vibration and impact of machining. Rectangular Box and dovetail ways, incorporating tapered gib adjustment to eliminate play, have always, and continue to be the most ridged and costly form of construction. For many years the rapid positioning speed of virtually all CNC machine tools employing box and/or dovetail ways was a maximum of 400 inches per minute. It was also thought that the limiting factor was the was the friction produced by the large contact area of these ways. While this was true as long as motor/servo size remained fixed, with the advent of more inexpensive larger digital servomotors, we are now seeing rapid positioning speeds in the area of 900 IPM on steel box ways. The other type of way commonly encountered is the linear ball bearing, or "guide" way. Due to their mis-application by a number of machine builders, at the time of their introduction in the mid 80's, much controversy still surrounds them. In a nutshell, most early mid 80's machines employing linear guide ways were no good! Most current production Machines employing them are fine. The fixed element of these ways consists of a heavy solid hardened and ultra precision ground grooved steel rail which is bolted and pinned to a qualified surface on the machine casting. The movable element consists of a rectangular bearing pack containing a large number of precision ball bearings, which re-circulate in the force lubricated pack, and ride (preloaded) in the ground grooves of the fixed rail. The advantage of these linear guide ways is that they are inexpensive relative to integral box ways. They are mass produced by specialty bearing manufacturers, and purchased by builders for installation on their machines. Additional advantages are that they can operate at very fast rapid speeds (1,000 1PM) with small servo motors (as long as the table load is not too great), they are field replaceable, and they are extremely accurate because they are pre-loaded (no backlash). The disadvantage to these ways is that the point contact of the ball bearings on the hardened steel rails affords a smaller path for the transmission of machining vibration, traveling through the table on it's way to the main machine frame where it will be dampened and absorbed. If the linear guide way rails have a thin "I" beam type cross section and a small "footprint" and are improperly located on the machine frame through unsound engineering, the entire table will break into resonant vibration during machining, with all the attendant problems. This is exactly what occurred with several vertical machining centers manufactured by prominent Japanese builders during the mid 80's. These machines should still be purchased with limited applications in mind. I wish to once again stress that problems like this are no longer the case in the 90's both American and Japanese builders are employing linear guide ways solely, or in combination with box ways with great success. However, ample applications still exist for the traditional box way designs, and some applications are impractical by any other configuration. In the final analysis, careful evaluation of the intended use of the machine is the only reliable guide for selection.
The state of the used CNC chip cutting machine tool market today:
Two broad application categories, or markets, for CNC machine tools have existed since the late 1970's, and continue to the present time.
The first (and smaller) market is comprised of sophisticated applications and users employing CNC for the purposes for which it was initially developed. That is to produce extremely complex, intricate, and close tolerance shapes, unattainable by conventional methods.
The second (and larger) market is comprised of simple unsophisticated applications and users employing the power of CNC, instead of (or because of a lack of) the skilled labor necessary to set up and operate the conventional machines suited to their applications. (Note: Some very simple applications, but in high volume and/or close tolerance circumstances actually belong to the first category or market.)
For the period of time from the late 1970's to the early 1990's these market distinctions were of little importance as, no matter what your what your application was, you had three choices; one of them good, and two of them bad. You either purchased an expensive Japanese CNC with quick delivery, state of the art control, and good service support, or you bought an expensive American CNC usually good iron, but a primitive control and servo system, and the worst applications and service support imaginable. In the mid to late 1980's the Taiwanese and Koreans entered the CNC market featuring quality Fanuc controls but cheap iron of radically varying quality, and service varying from mediocre to nonexistent. Some of these machines had Japanese names, but generally the price buyer thought all Asian machines were the same; to his later regret and embarrassment.
This CNC machine tool "status quo" was great for used CNC machinery sales! There was really only one type of CNC and that was the EXPENSIVE type. The majority of the market was dominated by the Japanese (EXPENSIVE), the remainder of the market was American (ALSO EXPENSIVE), and the odd European or Asian CNC was bought at a steal, or left for the brokers! All that the used CNC machine tool dealer had to do was market the builder, model, control, year, and some basic specs. If he bought right, success was virtually assured.
In the early 1990's all of this changed. The sophisticated high-tech CNC market became even more technical, applications oriented and expensive; while the unsophisticated low-tech CNC market expanded radically due to the appearance of LOW COST, HIGHQUALITY, AMERICAN CNC MACHINE TOOLS (FEATURING FANUC CONTROL COMPATIBILITY, AND EXCELLENT SERVICE/ SUPPORT).
The price differences are so great that a user can literally buy two new American spindles for the cost of one new Japanese spindle! (Always with the caveat: If the application warrants such a decision.). If you think this is tough on the "new" machine tool dealer, consider that his "used" counterpart may be asking the same price for a five year old Japanese CNC, as the cost of a "new" American CNC of equivalent size (not necessarily the equivalent quality). If the used dealer tries to remedy this situation by attempting to purchase the used Japanese CNC based upon the replacement value of a new, inexpensive, American CNC of similar capacity he may be laughed out of the sellers shop!
What has occurred, is that two, small, privately owned, American CNC machine tool builders, barely known of five years ago, are currently in the process of taking back the entire "stand alone" CNC machine tool market from the Japanese, and other foreign competition! This represents an exact reversal of the trend started by the Japanese in the late 1970's!
The American builders are achieving this success through sound engineering, and clever marketing innovation, at a time when the rising value of the Japanese Yen, and other foreign currency is making imported machine tools far more expensive.
Very briefly, these astonishing American CNC machines share the following characteristics: They are inexpensive, and are primarily consumed by the "second" CNC machine tool market discussed earlier. They are mass produced by the thousands, in the sizes most in demand by this market. Manufacturing costs are maintained at a competitive level, and the mass production needed to sustain profitability and growth is achieved through employing state of the art, high tech, Japanese, lights out, FMS systems, and design engineering incorporating EXTENSIVE use of interchangeable systems, modules, and machine parts. They are equipped with sound, inexpensive, domestically produced, CNC controls which program identically to Japanese FANUC controls, ( which currently enjoy domination of the world CNC market!)
THEY REPRESENT A BREAK WITH BOTH DOMESTIC AND FOREIGN MACHINE DESIGN TRADITION, IN THAT AS MACHINE MODEL CAPACITY (WORKPIECE SIZE) INCREASES, THE SIZE AND HORSEPOWER OF THE SPINDLE, AXIS SERVOS, AND THE RELATED MECHANICAL CUTTING POWER APPLICATIONS SYSTEMS REMAINS THE SAME AS THOSE APPLIED TO AND OFFERED ON MUCH SMALLER MACHINES, (this, a consequence of the great savings garnered by interchangeability, with attendant purchasing and stocking of items in large quantities and limited sizes.)
This break with tradition has created an entirely new and unique type of CNC machine tool; one whose place in the market is already unquestionably established, and whose presence has been long overdue. New manufacturing trends such as "near net shape" (die castings, impact extrusions, sintered metal shapes, etc. all incorporate minimal machining of selected elements to produce a finished part), cutting tool improvements such as "micro-grain carbide" (very sharp high-positive cutting tools requiring far less horsepower and producing far less cuffing vibration), and the use of CNC wire and ram type EDM in the production of dies and molds (most of the heavy cuffing done by spark erosion, with light cutting of graphite electrodes done by CNC mills) ; all speak favorably to the machine design concept of large travel capacities with relatively light spindle and servo requirements.
With this transformation of the CNC machine tool industry taking place, you may be wondering what the Japanese CNC machine tool builders are doing? Many are specializing in very high tech "value added" CNC machinery, and doing quite well. Several years ago the Japanese government recognized the trends in increased Pacific rim competition, and the increasing value of the Yen, as being detrimental to all competition in the production of common trade products. This led to special incentives to develop sophisticated high tech versions of existing products, and to entirely abandon domestic manufacturing in some markets. In the area of CNC chip cutting machine tools, this led some companies to attempt production of "stand alone" CNC's in third world Asian countries; (be sure to check country of origin even on some well established brand names, as there are some real lemons out in the field). Most of these attempts were futile insofar as quality control was concerned, and were abandoned. Other Japanese manufacturers began manufacturing their high volume stand-alone CNC's here in the U.S. with excellent results( some machines have 60% to 80% U.S. content), and a substantial savings in cost over domestic production. The primary focus today of the Japanese CNC machine tool industry is on very expensive, ultra high quality, specialized machinery, primarily intended for the first market category, discussed earlier.
These machines include lathes with milling capability, mills with turning capability, large capacity tool changers on both lathes and mills, multiple axis turning centers which can produce a part from bar stock in one machine comprising first and second turning operations, and all subsequent mill secondary operations, auto loaders to handle all types of near net shape parts for both turning and milling, lathes which can turn hardened work pieces to grinding tolerances and finishes, multiple pallet pool FMS horizontal machining centers with electronically coded tooling, ultra high pressure coolant systems, automatic tool and work probing, integrated post process gauging, various levels of adaptive control, etc., etc., the list is endless!
Based upon the foregoing, I believe the following statements to be true:
* Currently, both the new and used CNC chip cutting machine tool markets are undergoing the greatest change that they have experienced in twenty years.
* A large part of the change has been brought about by the introduction of very reasonably priced American "commodity" type CNC machine tools, (mostly vertical machining centers), and the rising value of the Japanese Yen against the American Dollar.
* The change brought about by the introduction of these "commodity" machine tools will be permanent. Never again can a buyer or seller casually refer to a 40" vertical machining center, or a 10" chucker without examining the application of it's intended use. To do so might result in the purchase of a $50,000.00 apple, instead of a required $100,000.00 orange.
* The change brought about by technological advancements and demands in manufacturing, coupled with the rise in the value of the Japanese Yen has resulted in, and will continue to produce, highly complex and costly CNC machine tool hybrids, loaded with accessories (traditionally considered a detriment on the used CNC machine tool market) difficult, time consuming, and applications intensive to sell, both new and used.
* The confusion currently existing in both the new and used CNC machine tool markets will eventually abate, when buyers come to understand the "commodity" and "traditional" machine tools for what they are, and when the "commodity" machines saturate the market sufficiently to become part of the stock and trade of the used machinery dealers (the numbers of commodity machines over five years old is few, and at this point no one knows how well they will hold up in terms of usable lifetime, compared to "traditional" designs).
* The current resistance to "used" complex "hybrid" CNC's, and machines equipped with a variety of expensive options will eventually diminish as these machines become more commonplace, and their benefits become better understood. In the proper application such machines can produce far greater profits and parts of higher accuracy. Importers of this machinery must broaden and expand their service and support capabilities as this equipment becomes their principal source of revenue.
Recommendations for staying and remaining competitive in used CNC:
As used CNC machine tool dealers it is not unreasonable for us to be expected to expand our commitment in time, and money, to this segment of our business. After all, our customers requirements, and the machine tools themselves have both changed! Following are some suggestions, of how the information outlined in this presentation may be applied.
* KNOW YOUR CUSTOMER:
Traditionally, in used machinery sales, detailed information concerning our existing and potential customers is given little consideration. This is a serious oversight. Broad media advertising such as listings in the Locator, and mass mailings of lists and/or catalogues are common practice. Telemarketing also occupies a significant part of our time, but, as commonly implemented, is highly underutilized. While nothing is wrong with the foregoing; suppose that you are confronted with a "buy for stock" situation involving a four axis sub-spindle CNC turning center hybrid, complete with live tool milling/drilling capability, automatic magazine bar feeder, and parts unloading conveyor! The purchase price could be fantastically low, relative to the replacement value, but, with this package, it could well exceed $100,000.00! After purchase, how long will your investment and floor space be tied up knowing that this is a highly specialized machine usable only in high volume production quantities, to produce parts from a very limited size of bar stock, to efficiently produce only parts with the correct balance of A/B operations and milling, and probably appealing only to mid size or larger product manufacturers?
Your decision would be much simpler if you could search your customer data base for manufacturer, application category, turning, avg. part size, avg. lot/run size, etc. This information, along with other customer aspects mentioned earlier can be collected by your Tele-marketers and be directly and quickly entered into a computer template during the solicitation. You will have to train your Tele-marketers, and won't get as many calls per day, but approaching tough decisions, such as this offering, will be quick and decisive. Even if you decide to decline the offer, you will have some very good reasons for your actions. As these profiles are costly to develop, initially dealers could concentrate on their local areas, and expand by networking through other MDNA dealers with a similar commitment. Some MDNA members invest large sums of money, great effort, and a considerable amount of time in creative thought to enhance the image of their company with their clients. Developing such "uniqueness" appears to pay dividends. Consider your appearance to a prospective client when your desire to serve his needs and meet his requirements as discussed in the meticulous and intelligent manner suggested.
* KNOW WHAT YOU HAVE TO SELL:
As discussed earlier, the sale of both new and used CNC no longer occurs on a level playing field. Now, more than ever before, we, as sales people, must be conversant with the differences in design, modules and components comprising CNC machinery. In selling a used machine of "traditional" design against a new unit of the "commodity" type our only cost justification, and possibility of closing the sale, lies in stressing the rigidity, strength, and proven longevity of the "traditional" design (if warranted by the application). Until a sufficient passage of time eventually brings quantities of these "commodity" machines" to the used market, we will, more often than not, be selling against them. It is important to remember that the high-tech "hybrid" machines are not at all as complicated as they may seem at first. Those most commonly encountered on the used market, at this time, are turning centers, barfed, chucker, and universal, which incorporate milling and cross drilling capabilities, to various extents. The least expensive of these utilize an indexing mechanism which engages the lathe chuck and can present the work piece to the turret for milling and drilling, in increments of 5 degrees, for example. The more expensive and complex versions of these machines couple the lathe chuck to a true rotary servo drive (C axis) identical to those encountered on milling machines. In this case extremely complex shapes can be milled, or holes drilled to positions designated to one thousandth of a degree. The thing to bear in mind is that you are not encountering totally new machine elements and terminology, rather you are seeing a mixture of established and standard milling terminology mixed with standard CNC turning center terminology. You will encounter different builders applying different definitions to axis of motion, when applied to milling performed on a turning center, however, no rigid standards are observed in this area, so don't worry about any confusion which arises. The definitions, and descriptions of basic CNC machine tool elements presented in this paper will provide you with an adequate foundation to intelligently discuss all forms of CNC chip cutting machinery.
It has been a pleasure delivering this presentation, and for the remaining time available we welcome your questions, and specific inquiries. This offer extends past today. If you should like to contact us for any reason in the future, we can be contacted at:
CNC CONCEPTS, INC.
44 LITTLE CAHILL RD.
CARY,IL. 600130318: 0319:
Ph: (847) 639-8847 fax: (847) 639-8857
2406 S. GOEBBERT RD. SUITE 1016
ARLINGTON HEIGHTS, IL 60005
Ph/Fax: (847) 981-0704
0336: 0337: 0350: 0351: