Product Corner: SME Sponsored Seminar and Webinar

It’s been quite a while since I’ve taught a seminar for the Society of Manufacturing Engineers. I’ve always considered it to be quite an honor to be asked to teach for the SME. I’ll be teaching a two-day “Introduction To CNC” seminar on May 28-29, 2009 at the Sandvik Productivity Center in Schaumburg, Illinois (Northwest suburb if Chicago). You can find more information about this session and register for it here:

• Introduction To CNC two-day seminar

To help promote the seminar, I’ll also be leading a webinar entitled “Getting More From Your CNC Machines” on May 5, 2009 at 2:00 PM EST. While information about this webinar has not yet been posted, it will be soon – and you will be able to find the webinar listed on this page as soon as it’s available:

• SME webinars

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Instructor Note: How solid is your school’s manufacturing program?

I received this email from an instructor in a community college a few weeks ago. I found it troubling – you probably will too.

Hello. I have taught several CNC courses in the past years and have thoroughly enjoyed it. Because of our local economy, my institution is proposing to eliminate the entire CNC program. I have one last chance to convince them otherwise. Do you have any material that I could use to show them the importance and necessity of continuing the CNC courses at my school? I need to convince them with a "wow" presentation. Thank you so much for your time and consideration.

While I have modified this email a bit to remove the writer’s name and school name, it remains pretty-much intact. Unfortunately, this isn’t the first time I’ve received such a correspondence – and it’s always pretty scary. My response is below. While I don’t have anything miraculous to say, I’m hoping it offers some food for thought should you ever find yourself in a similar position. And by the way – I’d be very interested in hearing your comments along these lines. So please email me (lynch@cncci.com) if you have thoughts you’d like to share. I’ll include your comments in the next issue of The Optional Stop newsletter.

I'm sorry to hear about your situation. I hope it is resolved in your favor.  I have some thoughts along these lines. I'm hoping they help with your presentation.

Support for local industry:

It is my feeling that technical courses from any school should be tailored first and foremost to the industry in its local area. Unfortunately, too many schools are too quick to give up on local industry at the first signs of dropping registrations when the economy takes a downturn.

The first place industry will turn for new people when business improves is, of course, the local technical school or community college. But if the school has dropped its technical programs, local industry will be left high and dry.

When a school eliminates a program, in essence, the school is saying "We don't think our local industry is going to survive, and we're not going to wait out this storm." Frankly speaking, it is exactly this thinking that eventually turns into a vicious circle for the school. With no one to train, they eliminate classes. When students try to come back, they have no classes to offer. Loyalty from the very people the school is trying to serve will suffer when people become aware of what the school has done. CNC is not the only curriculum that suffers when this thinking is applied.

Depending upon your current relationships with manufacturers in your area, you should solicit them to help in your quest to maintain the program. I'd suggest having at least one person from a local manufacturing company - preferably people who have been sending students to your school and/or hiring your graduates - participate in your presentation. Let your administrators meet face-to-face with the very people who will be hurt the most by the elimination of the CNC program.

Even if the school must temporarily cancel a few classes or even suspend a program – again, temporarily – they can still maintain the program for the time when things improve and students come back.

Support for students and potential students:

While it's a bit off the subject, I've been surprised at my company's recent sales to technical schools. With the bad economy, you'd think that people would be pulling back on taking classes. But we've actually had a small increase in sales when comparing the last few months to the same period last year. While I'm no expert in Human nature, I think it's because people see their own knowledge level as one of their most important possessions – especially in bad times. People seem to have no problem spending money to improve, especially when they see the need or potential for immediate improvement.

Since manufacturing took its "big hit" some time ago (when so much manufacturing moved out of the country), it actually seems to be currently holding its own better than other areas of the economy (again, I'm stating opinion - I'm not an expert here). People in many areas of the country actually see manufacturing as a growing field. What a change from the last few years! But again, when you compare how manufacturing is doing to – say – the real estate market or retail sales, manufacturing actually look pretty good right now. And people are going back to school to learn what it takes to get a job at a local manufacturing company.

Promoting your classes

I'm not sure how actively you've pursued local industry and local high schools to recruit supporters and students. This may be something to include in your presentation – launching a more active campaign to bring in more students. When it comes to attracting people from manufacturing companies, this article may help:

http://www.cncci.com/resources/articles/train%20now.htm

Also, we maintain a free Schools page on our web site. I'm amazed at how many calls we get from people wondering if there is a CNC course in their area. It sure wouldn't hurt to post a free listing. Here is the link to our Schools Page:

http://www.cncci.com/resources/cnc%20schools.htm

Here is another article that addresses shrinking class sizes. I'm thinking it may help with promoting your classes:

http://www.cncci.com/resources/articles/dwindling%20class%20size.htm

Again, I hope you find these thoughts to be helpful. Please let me know how things work out.

Mike Lynch
CNC Concepts, Inc.

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Manager's Insight: The Ten Commandments of CNC

Suggested by Rick Lucchetti of TC Industries in Crystal Lake, Illinois

People strive to obey the Ten Commandments – indeed, almost everyone knows most of them – and you would be hard-pressed to find a person that isn’t at least aware of their significance. When it comes to stimulating a desired behavior, nothing creates a lasting impression like the Ten Commandments.

Many manufacturing companies have rules – both written and unwritten – that they expect their people to adhere to. You can add punch to the importance of these rules by picking your ten most important rules and naming them the ten commandments of your company.

Post them in the lunch room and conference rooms. Make a poster for entry-ways. Place them in locations that everyone will notice. The idea is to ensure that everyone knows what you – and your company’s management – feel are the ten most important rules that everyone in the company must obey.
You, and you alone, are best able to determine what your ten commandments should be. You can be as general or specific as you like. Just remember that the goal is to let people know, in no uncertain terms, the dos and don’ts of your manufacturing environment.

When coming up with your list, be ready to explain each “commandment”, as well as the consequences of breaking each of them. Don’t assume everyone will automatically know the consequences. With a safety-related commandment, for example, be ready to explain the potential danger/s. In essence, be sure people understand the logic about why the commandment exists.

Here are some examples. Admittedly, they are probably a bit more generic than you’ll want, but they should give you the general idea.

• Thou shall adhere to all safety-related methods as described in our list of safety precautions.

• Thou shall put things back where you found them and keep your work area clean.

• Thou shall not change programs to make sizing adjustments.

• Thou shall keep your machine/s clean and perform all assigned preventive maintenance tasks.

• Thou shall ask for help when you are confused or unsure.

• Thou shall not engage in horse-play or practical jokes.

• Thou shall check the condition of inserts at the beginning of your shift.

• Thou shall inform the programmer when you make program changes.

• Thou shall report machine mishaps (like crashes) to your supervisor.

• Thou shall not leave a machine that is running.

Again, pick those problems, considerations, and concerns that are of the most importance to you and your company. Then develop the wording as appropriate. The idea must be to ensure that everyone knows what is important. This kind of list should make it very clear.

By the way, I’d love to hear what you come up with. And, with your permission, I’d be happy to publish your company’s ten commandments in the next issue of The Optional Stop newsletter. It should make for some interesting reading!

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G Code Primer: Understanding the “common” fixture offset

As you know, Fanuc-controlled machining centers come with at least six fixture offsets, invoked in a program by G54 through G59 respectively. When the machine executes a G54, for example, it knows to look at the registers in fixture offset number one to find the program zero assignment values for the current coordinate system. (G59, of course, tells the machine to look in fixture offset number six.)

During setup – by one means or another – program zero assignment values are placed into each needed fixture offset. They could be entered by the setup person – or they could be more automatically entered by G10 commands in the program. But again, before the program can be run, the machine must be told the location of each program zero point (origin) used by the program.

You may not know that the point of reference for program zero assignment values that are placed into fixture offsets is related to the common fixture offset (fixture offset number zero on the first fixture offset display screen page). When the registers for the common fixture offset are set to zero, as they commonly are, the point of reference for program zero assignment values is the machine’s zero return position.

That is, the X axis program zero assignment value is the distance from the X axis zero return position to the X axis program zero surface in the setup. The Y axis program zero assignment value is the distance from the Y axis zero return position to the Y axis program zero surface in the setup. And the Z axis program zero assignment value is the distance from the spindle nose (while the Z axis is resting at its zero return position) to the Z axis program zero surface in the setup (though the Z axis program zero assignment value will vary based upon how tool length compensation offsets are determined).

In essence, when common fixture offset registers are set to zero, the machine is being told that the point of reference for program zero assignment values is nothing from the machine’s zero return position. Again, this is a very common method of applying fixture offsets. The vast majority of CNC users do so in this manner.

When might you want to change the point of reference for program zero assignment values?  Let’s look at some times when the common fixture offset can be helpful.

During program verification

Though this may not be the best application, it should help you understand how the common fixture offset works. Say you have a vertical machining center and have just made a new setup. You’ve entered all fixture offset in the normal manner. With the method just discussed, the common fixture offset registers are all set to zero and there will be very large negative values in each fixture offset register.

Before running the actual workpiece, you may want to do some testing. Maybe you want to see how the program will run, but not allow each tool to come all the way down to its final Z axis position. Instead, you’d like to run all tools, say, five inches above the work surface.

This is easy to do with the common offset. Simply increase the value of the Z register by five inches. If it is currently zero – as it probably is – set the Z register to a positive five inches. This will tell the machine that the point of reference for all fixture offset entries is five inches above the Z axis zero return position. When each tool runs, it will stay five inches higher than it will when a workpiece is actually run. Once you confirm that the motions, of course, you will need to set the Z axis register of the common fixture offset back to its initial value (probably zero).

When using sub-plates

If you have a sub-plate on the table of your vertical machining center, it may be possible to simplify – or eliminate – the task of program zero assignment. That is, you may be able to keep the setup person from having to do anything during setup that has to do with program zero assignment.

As long as the sub-plate is accurately made – and as long as the component workholding tooling is also predictable, setups will be qualified and predictable. In this case, you can have the program zero assignment values be the distance from one of the location surfaces or holes on the sub-plate. In essence, this will make them easier to predict.

The common fixture offset can be used to shift the point of reference for program zero assignment values from the zero return position to the location surface/s on the sub-plate. Say we shift in XY to the lower left hole on a sub-plate that uses a series of clamping and location holes. If the zero return position is at the machine’s plus over-travel limit in each axis, the values placed in the common offset will be negative.

From this point, all program zero assignment values in XY can be specified from the lower left hole to the program zero surface on the workpiece. And again, since the location holes on the sub-plate are in known positions, the program zero assignment values will be easily predictable. The programmer can include G10 commands to specify them so the setup person need not do anything relative to program zero assignment.

After a mishap

If you’ve been using G10 commands to assign program zero in your program, you know that the zero return position better not change in any axis. If it does, the G10 commands will not be correct. So after a mishap (crash), the person fixing the machine must get the zero return position perfectly reset.

You can use the common fixture offset to allow for any deviations in this regard. With the sub-plate example just described, you can simply re-measure the location of the lower left hole after the crash and place the new values in the common fixture offset’s X and Y registers.

But even if you’re not using a sub-plate, you can use the common fixture offset for this purpose. Simply determine how far the new zero return position is from its old position and enter these values into the common fixture offset.

Consistent tool length compensation offset values

One last application for the common fixture offset that I’ll mention has to do with companies that use the same cutting tools from one machine to another. Possibly multiple identical cutting tools – say for a very common roughing tool – are setup to be used by the first machine that needs one. Even with identical machines, there may be a slight difference in the spindle taper. A cutting tool placed in one machine may “rise up” higher into the spindle than it does in another. This requires a different tool length compensation offset value for each machine. Allowing for spindle differences can be a headache if cutting tools are shared from machine to machine.

If the Z axis common fixture offset is set to the deviation from one machine to another, the same tool length compensation value can be used for both machines. Again, this will simplify the task of coming up with tool length compensation values for tools used in multiple machines.

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