And More - Interactive Article:

by Mike Lynch, CNC Concepts, Inc.

First published in the August 1997 issue of Cutting Tool Engineering magazine.

Inspire Aggressive Awareness

Any continuous improvement program requires aggressive awareness. Aggressive awareness is that attribute within us that causes us to search out potential improvements – and it begins with the realization and acceptance that there is room for improvement in every area of your CNC environment. As human beings, we must fight our natural tendency to leave well enough alone. You know the saying, "if it isn’t broke, don’t fix it." Always remember that just because your CNC machines seem to be running smoothly (they are not broke and seem to be running well enough) does not mean they are running at optimum levels.

Ignorance will keep you from being fully aware of potential improvements. Of course you cannot begin to apply a technique unless you know (or suspect) it is possible to do so. How do you keep your people from being ignorant? This is a very basic question with an obvious answer. Only education can overcome ignorance.

Scour your manuals

Your machine tool builders and control manufacturers, of course, publish usage manuals to help you understand their machines. While these manuals are an obvious resource to help you learn more about your machine tools, too many CNC users treat them solely as reference material, referring to them only when faced with a specific problem. In addition to supplying reference information, your machine tool usage manuals contain a great deal of information about usage alternatives. Admittedly, some are difficult to read and absorb (especially those translated to English), but to ignore them as a CNC utilization improving resource can be an expensive mistake. What follows are a few specific suggestions for topics you should study including specific examples of how companies have improved utilization through a better understanding of information included in the manuals

Confirm your understanding of all M codes - All too often, important M codes get ignored. Example: One company wanted to reduce program execution time. They noticed that whenever a spindle orientation was programmed (M19) during the machine’s return to the tool change position on their machining center, this machine would still wait until the motion was completed before the spindle orientation occurred. Upon further study, they found that two other M codes control whether a motion must be completed before M codes begin activation. By including a simple M code in the program, the spindle orientation now occurs during the tool’s motion to the tool change position, saving precious cycle time.

As you study each machine’s M code list, be ready for some pretty obscure functions that may not be very well described in the machine tool builder’s manual. You may have to contact your builder to learn more about how certain M codes function. Doing so may expose a potential improvement that you have never considered.

Learn all standard features of your machine/s - If you have depended upon your initial training (commonly supplied by the machine tool supplier) to supply everything you know about your machines, you’ll likely find many additional features and functions in you machine tool manuals. These additional features may make it possible to do things you never thought possible. Example: One company wanted to reduce setup time. They wanted to eliminate the tasks related to assigning program zero during setup. Since they make qualified setups (locate fixtures from key slots on their machining center), the program zero location remains the same from one time the setup is made to the next. By studying the programming manual, they learned that program zero setting with fixture offsets can be programmed. This not only eliminated the program zero measurements, it eliminated their entry as well.

Even if you find you have little current need of certain features, at least you’ll be able to recognize applications for the feature if and when they present themselves. And again, you’ll likely find some features you do not understand (the builders’ manuals often neglect to show you why certain features are important). Be ready to contact your machine tool builder to get explanations of features that are new to you.

Learn about available options - Your machine manuals also include documentation on additional options that are available for your equipment. While these features must be purchased, knowing that a feature is available is the first step to using it. Example: One turning center user has a three axis turning center (X, Z, and C) with live tools. The C axis is a rotary axis within the spindle. This feature allows secondary operations not commonly considered turning operations (milling, drilling, slotting, etc.). This company was constantly struggling whenever this machine had to mill flats or contours on the face of their workpieces. An elaborate computer aided manufacturing (CAM) system was used that generated a very lengthy CNC program for the machining of the face contours and flats. Upon further study, this company learned that an optional feature called polar coordinate interpolation makes the programming of face contours and flats as easy as any other motion. Based upon the amount of face work, polar coordinate interpolation was very easy for this CNC user to justify.

Learn about power curves - Another commonly ignored topic discussed in your machine tool builders operation manuals is related to spindle and axis horsepower. Only by knowing when your machine reaches full horsepower (at what spindle rpm) can you confirm that you are programming the machine efficiently. Example: One machining center user noticed several undesirable pauses during tool changes. Upon further study, they found that their machining center has two spindle ranges (the programmer didn’t even know this) and that the machine automatically selects the spindle range based upon the programmed spindle speed (S word). If the speed requires the high range, the machine automatically makes the range change, if required. What this user found was that absolutely no consideration was being given to range changing. By grouping their tool operations in such a way that all operations requiring each range were done together, program execution time was reduced.

Learn all buttons and switches - As your CNC people look at your machine’s control panel, can everyone readily identify every button and switch? (Be sure to include all display soft keys in this question.) If they cannot, there may be some helpful function available of which your people are unaware. Example: One programmer was constantly having to make mass changes to CNC programs at the machine. He would always go back to the PC-based text editor to make these massive program changes. Upon further study of the control manual, he not only found that the control had a "cut-and-paste" ability, it worked in much the same way as the off-line text editor!

Learn what else applies to your specific application/s - Machine tool suppliers tend to teach you safe, easy, and convenient methods of CNC machine usage. The easiest way to handle a problem is seldom the most efficient. Only by studying everything can you determine what might provide a special benefit to your company. As you come across a feature that makes little sense, ask yourself "What could this feature do for me?" Example: One programmer works for a company that machined 300 workpieces in a very close family. While studying the programming manual, this programmer learned that parametric programming could handle all parts in the family with one CNC program, eliminating the need to maintain 300 hard-and-fixed CNC programs.

Take advantage of free or inexpensive resources

Being aggressively aware extends beyond understanding what is included in you machine tool manuals. And some resources for improvement ideas are free (or close to it), yet they go largely overlooked.

Read trade journals -There are several trade journals related to manufacturing, and several place a strong emphasis on CNC technology. Surely several people in your company receive them. However, you must confirm that they are they being read by the people who can use them the most. Since they often contain information about most recent developments in CNC technology, why not make them required reading? Example: One CNC user was able to completely create a distributive numerical control (DNC) system by using information supplied in a trade journal article.

Visit your local library - If you’ve never visited the manufacturing section of your local library, you might be quite surprised at the number and quality of books related to manufacturing. Note that most have excellent computer-based indexing capabilities, making it possible to research almost any topic. Example: One machining center programmer was faced with the need to do thread milling for the first time. In his local library, he had the reference librarian do a search on "thread milling". As a result, he found every book and article ever written about thread milling.

Log on to the Internet -More and more CNC resources are becoming available on the Internet that can help CNC users. There is even a newsgroup (alt.machine.cnc) that provides a forum for CNC users. Example: Would you like another user’s opinion of some CNC accessory you intend to purchase? Pose the question to this newsgroup. It is likely that someone in the group has experience with the accessory and will be willing to give their frank opinion.

Talk to accessory device sales people -Although you must be critical when judging the quality of their information (since they have a vested interest, most are very good at making their products sound right for everyone), sales people can relate the benefits of CNC accessories that can help improve CNC utilization. Examples include sales people working for computer aided manufacturing (CAM) system providers, distributive and direct numerical control (DNC) system providers, probe manufacturers, bar feed manufacturers, pallet changer manufacturers, and tooling & fixturing suppliers.

Look for outside help

Though most of the suggestions made to this point place the emphasis on self-learning, there are excellent outside resources that can provide you with ideas for improvement. Again, being aware of what is available is the first step to improvement.

Attend seminars and clinics - Many seminars and clinics (sponsored by organizations such as The Society Of Manufacturing Engineers) are aimed at keeping you abreast of the latest developments in manufacturing. Topics include setup & cycle time reduction, high speed machining, rapid prototyping, and parametric programming (among many others). While these sessions do tend to be somewhat generic (aimed at a wide variety of CNC users), they do make an excellent way to keep up with changes in this field.

View training videos - A number of suppliers offer the same kind of material presented in seminars and clinics on video tape.

Attend tool shows - Machine tool builders are always anxious to show off their latest developments at tool shows and you’ll have specialists available to answer your questions.

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