Simulation runs are a key step before running your CAM program for real

I believe that as time goes by CAM programs, like many other things, will get easier to use. Until then, for a beginner like myself, pushing the “Emergency Stops" will remain a common occurrence. I know I’ve had to use that button a few times.

If you have ever seen CNC code, specifically G&M code as a list of commands, it can look rather scary. But there are ways to make your life easier.

Last month I discussed making a coffee cup coaster for ENGINEERING.com’s  President John Hayes. Now I will discuss the G&M code needed to produce the design.

Here we see the tool path and the actual G & M Code in the left hand column. It is this code that tells the machine where and how to cut out the letters that are at the heart of this model. The Backplot Screen shot illustrates the paths that a 1/16 inch or (1.588mm) ball nose router bit will trace.

It isn’t cost effective to rush a job and break an expensive bit. Therefore, to ease the stress on the small bit, the tool cuts about four step downs into the material. 

There is a lot of trial and error learning CNC programming. However, there is also a lot of help inside of the program.

The nice thing about CAM programs is that they can simulate the actual cutting of the part. This is a key step to perform before you send it to your expensive machine. The simulation will allow you to correct mistakes you might have made while programming the various steps.

In the simulation code you can adjust the speeds, feeds, sequential order of steps and the type or size of tool. Some CAM programs will stop the simulation when there is a problem; others will give an error message in a message box.

Let's take one more look at another contouring step, the trace around the plaque with those dark blue lines. The cut needs about five step downs to make the lip just before the outer lower lip.

 Looking at the Backplot for these particular tool paths you can see once again the G & M codes that were done in order to cut this contour. Notice also that the sliding scroll bar is a lot bigger than the one you saw with the lettering. My experience says that there are a lot more commands needed to cut the letters than this contouring operation. 

If you are a beginner or expert in programming a CNC cut, it pays to make sure your simulation of the job at hand is going to do exactly what you want.  If it is right in the simulation you can be pretty sure it will be right on the cutting table.  It is a step that should not be overlooked.  Bye for now,