John, sorry that you haven't received an answer yet. I can't help you either. You are already further along than I am since you have taken a class on it. I have been teaching myself, although I do want to take the online course. Haven't gotten the nerve to sign up yet.
Have you visited the Parametric Programming section yet? It is under G-Code Programming. You might get some answers there. You will also find some examples of Parametric programming.
Do you have any specific questions? We all like to help when we can. Best advice I can give is to just start doing it. I only program for lathes, so am limited in my use of parametric programming.
I started off by writing a master program for each thread size (from 10-32 to 1/2-20) for a family of studs we make for a sister company. It required changing one variable to start machining another part. Diameters were all controlled by 500 series macros. No longer had to go out and modify a program because of taper or because one diameter was on size while another was a few tenths off. Also saved me a ton of programming.
I then put my Barfeed and Cut-off operations into a subprogram. At first I used 500 series macros, but when we got a new family of studs, I started running out of unused variables, and so went to the 100 series variables. Then I learned how to use the G65 Macro call. Now both of these operations are not only called by one block, but all the variables are also set in that block. It eliminated several blocks from my programs. I picked letters that made it easy for the operators to understand which had to be changed when necessary. T for station number (Tool) being used. F for feedrate, X for X-starting position, etc. Course not every variable works out that way.
I got tired of writing the same part program for the same lathe just because a different size stock was being used. First I switched to a G71 canned cycle to make my life easier. Then I added a variable for the stock size. Problem was that I still needed to change the DOC manually for best results. Then I asked myself why a WHILE statement couldn't be written to handle that. So I did. It will also change the feedrate based on the DOC.
Guess what I am saying (in a rather long way
) is that you will learn more ways of using variable/parametric programming as you use it. You will also come to understand it better as you use it.
I have a parametric program (sent to me by a person posting here, and never used yet) that will do grooves based on the assigned variables. My next project is to write my own. His puts 45 degree chamfers on it, but I always swing radii to avoid any burrs being pushed back. Talking about on the 45 degree chamfer moves. Sometimes I only need a radius at the OD/ID, no 45 degree. This will require a little more complicated routine.
Most of the guys posting here are so far ahead of me that it isn't funny. I blame a lot of it on only having worked for this company, and not being able to program for mills. Working at different companies will give you the opportunity to learn more things, but I have never been one to jump from company to company. Fear, I guess.
06-26-2008, 09:32 PM
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