Product Corner: We've updated our on-line CNC classes!

I have been conducting on-line CNC classes since 2005. Until now, UniveralClass.com has been the hosting website. But as of February 1, 2011, they will no longer be allowing “third party” instructors (like me) to use their system. This means I had to find another website to host my classes. The selected site is eLearningZoom.com.

Four of the on-line classes have been dramatically updated, including:

• Machining Center Setup And Operation (going from six lessons to twelve)

• Turning Center Setup And Operation (going from six lessons to twelve)

• Machining Center Programming (going from ten lessons to thirteen)

• Turning Center Programming (going from seven lessons to fourteen)

Along with an increase in number of lessons, the course materials have been improved and expanded. Lesson text and PowerPoint presentations have been upgraded.

We’ve also maintained the pricing structure – the setup and operation classes are just $89.00 including (upon successful completion) a certificate and letter of recommendation. The programming classes are $109.00 – again – including certificate and letter of recommendation.

We have also moved the Advanced Techniques With Basic CNC Features and the Parametric Programming For CNC Machine Tools classes to the new training platform.

• Learn more about our on-line classes!

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Instructor Note: Prepare students for hiring interviews

As educators, we spend most of our allotted training time making sure students understand presented material. We want them, of course, to pass their courses and/or get their degree or certificate. Among many other teaching responsibilities, we make presentations, we assign homework, we help with lab exercises, and we go over assignments if mistakes have been made.

One topic that goes largely overlooked, however, is related to what students will do once they complete our courses and get their degrees. In order to get a job, students must be able to relate what they have learned in your school to the people doing the hiring. Unfortunately, many – even older – students tend to struggle in this regard.

If you doubt this, take a moment in class and ask a student what they have learned from you. If they hesitate and/or have to think much about it, it should be taken as a signal that they need to get more prepared in order to interview for a CNC-related position. And you can help.

Be sure students can communicate intelligently about their accomplishments. While there is no need to brag – or sound arrogant – students should be able to show a quiet confidence in their new-found abilities. As an assignment, have them make an outline of bullet-points that summarize what they feel are the most important goals they have achieved – and see if you agree.

If you come from a manufacturing background (as many CNC instructors do), you should know the ins-and-outs of manufacturing companies. You know that there are some pretty tough-minded people in this industry – maybe as in any industry – that won’t have much patience for or interest in people who cannot concisely explain what they will be able to do for the company.

To me, motivation is a key component. People that are self-motivated and eager to do whatever it takes to get a job done are highly valued, even over more experienced people that are less interested. So make sure your students know how to show their enthusiasm for what they’ve learned – and help them show perspective employers that they are motivated.

Relate your own success and failure stories. If you’ve gleaned an insight into what it takes to impress an employer, by all means relate it to your students. You can even conduct practice interviews. Take the role of an employer and have students interview for a job.

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Manager's Insight: What is included in your setup documentation?

In most companies, the programmer/s will provide – for every job – a setup sheet that tells the setup person how to make the setup for the job. But programmers vary with regard to just how much documentation they provide.

Admittedly, the amount and quality of setup documentation that is required is dependent upon the skill level of your setup people. If you have highly qualified and experienced people, your programmers don’t need to provide much. Indeed, a highly skilled setup person may be able to make some setups without any documentation at all. But as skill levels drop – possibly due to hiring new people – good setup documentation becomes more critical.

One easy way to judge the quality of your company’s setup documentation involves walking the shop floor when setups are being made. Look for times when machines sit idle because the setup person is unsure how to proceed. Maybe they have contacted a programmer or another engineer to help. Or maybe they’re spending excessive time studying – or asking other setup people what to do.

Some items that should be documented are pretty obvious. The location and description of cutting tool components, fixtures, and other needed components should be spelled out. Placement on/in the machine (tool station numbers and workholding device placement) should be documented. Again, the physical items used to make setups are pretty easy to spot.

But again, look for things that your programmer has missed that can cause wasted time during setup:

What offsets are used for each tool or workpiece attribute? In many cases offset selection is pretty basic. The offset number is usually tied to the tool station number in some way. But when secondary offsets are used, it can be difficult for setup people to determine which offsets are related to a given tool.

Are there any valves to set? With turning centers, for example, the chuck pressure may be changed from setup to setup. The documentation for every setup should spell out the chuck pressure to be used.

Is it necessary to change any control parameters? With major change-overs – like placing a rotary axis on a vertical machining center or changing a chuck on a turning center – there may be some parameters that must be changed. Be sure they’re spelled out in the setup documentation.
 

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G Code Primer: Help for manual programmers

Computer aided manufacturing (CAM) systems are extremely helpful (if not mandatory) for generating complex programs. With a CAM system, you can import geometry that has been drawn in a computer aided design (CAD) system and create the entire program (including tool paths) for machining the shape/s of your workpiece.

But CAM systems can be expensive – and difficult to initially set up. With simple work, a good manual programmer can often outperform even a good CAM system programmer. For these reasons, there are still many CNC programmers who elect to create their programs manually – at G code level – at least for some of the jobs they program.

The most difficult part of manual programming is calculating coordinates needed in the program. Again, for simple work, these coordinates are often specified right on the drawing. If machining a series of holes on a machining center, for example, hole locations are usually specified right on the print.

It becomes more complicated for manual programmers when coordinates needed in the program are difficult to calculate. Possibly a contour must be milled or turned that requires right angle trigonometry to be used in order to come up with program coordinates.

If a manual programmer has access to the CAD system drawing file (often a .dxf file), it is possible to create G code without having to buy an expensive CAM system. There are many inexpensive dxf-to-G-code software programs available to do just that. Some are even available as free-ware programs. A search in Google for “dxf to G code” will expose many of them. By the way, the tool path plotting program we sell ( NCPlot ) also has this ability.

A dxf-to-G-code converter will automatically create the tool path (in G code of course) needed to program even the most complicated two axis contour. This portion of the program can be copied and pasted into the actual program that will be used to machine the workpiece. This is not, of course, a CAM system. Only the tool path (typically for only one of the tools) is generated. The manual programmer must still write the commands needed for other tools.

If the programmer does not have access to the CAD drawing file (or the .dxf file), there is still inexpensive help available to minimize the effort needed to program tool path for complicated contours. There are many inexpensive CAD software programs available. Delta CAD (www.deltacad.com), for example, sells for only $39.00 (at the time of this publishing) and will allow a manual programmer to easily draw the complicated shape in need of machining. Many others are out there – as a search in Google will quickly confirm.

Once drawn in the CAD system, the shape can be exported to a .dxf file – or the programmer can use the CAD system’s dimensioning capabilities to determine the coordinates needed within the G code level program. Either way, this eliminates the need to manually calculate any coordinates.

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