Machsupport Forum
G-Code, CAD, and CAM => G-Code, CAD, and CAM discussions => Topic started by: alanbredbury on December 31, 2009, 11:42:00 PM
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I used mastercam 9.1 to program a 2 inch diameter circle offset to the outside with a 1/2" diameter endmill. It cuts 1.75" diameter.
I have checked the machine calibration on 10 inch moves x and y axis it moves 10 inches on each axis when told to.
It makes a round circle.
I am using the demo version of Mach3 I know this is limited to a few lines of code is it also disabled on cutter comp?
Possibly the post I am using is off? I got it from a link on this forum and it stated it was for mastercam 9.x
I would not be suprised to get a 1.5" circle which would mean the cutter comp was not working at all. Here is the G code generated by mastercam.
I read G code, sort of, circles and radius are difficult for me
Thanks for any help
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O0000 (TESTM)
(MASTERCAM - V9.)
(MC9 FILE - E:\ROCKING HORSE\TESTM.MC9)
(POST - C:\MCAM9\MILL\POSTS\_MACH3B.PST)
(MATERIAL - ALUMINUM INCH - 2024)
(PROGRAM - TESTM.NC)
(DATE - DEC-31-09)
(TIME - 23:39)
(POST DEV - NovaLab)
(NWDTOOL N"UNDEFINED" T1 D.5 F.5 L1. A45. CD1. CL.5 SD1. C0)
(NWDSTOCK X0. Y0. Z0. OTC OX0. OY0. OZ0.)
N100 G00 G17 G20 G40 G49 G80 G90
N102 (WCS: TOP)
N104 T1 M06 (UNDEFINED)
N106 (MAX - Z.1)
N108 (MIN - Z-.1)
N110 G00 Z.1
N112 G00 X-2.25 Y.5 S1069 M03
N114 G01 Z-.1 F30.
N116 X-1.75
N118 G02 X-1.25 Y0. I0. J-.5
N120 G03 I1.25 J0.
N122 G02 X-1.75 Y-.5 I-.5 J0.
N124 G01 X-2.25
N126 Z0.
N128 M05
N130 G90
N132 M30
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Yes, I do believe cutter comp is turned off in the demo version. In mastercam, make sure that your cutter comp is set to 'computer', and not 'control'. That should solve your issue.
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I am still testing the machine and software so have not bought Mach3. can someone please confirm that cutter comp is not just disabled but skewed in the demo version before I buy? If cutter comp was simply disabled I should have gotten a 1.5" circle 2" less .25" on each side of the diameter. I did not I got a 1.75" circle. Thank you for the response Sam, I am familiar with Mastercam and have chosen computer as my offset source.
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You are correct, you should get a 1.5" circle if you programmed a 2" circle and cut it with a .5" cutter. Lets take out the comments in the file to have an easier look at it. There is not a cutter comp called in the code. The circle is 2.5" as coded , not 2" with comp on. If you cut it with a .5" cutter, you should get a 2" circle. You say that your getting a 1.75" circle though, so something is still wrong. You say that your steps are set correctly and the machine does truly move the commanded distance when told.The only thing I can think of that might give you a 1.75" circle would be that your using a larger cutter instead of a .5" cutter. Maybe someone else can chime in with a better explanation, and enlighten both of us. As for a note on the cutter comp...It is being modified in the newer version of Mach. I do not know the specifics on the changes, I'm sure there is a post somewhere here going into detail about comp. Sorry I can't be of any more help to you in that regard.
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O0000
N100 G00 G17 G20 G40 G49 G80 G90
N104 T1 M06
N110 G00 Z.1
N112 G00 X-2.25 Y.5 S1069 M03
N114 G01 Z-.1 F30.
N116 X-1.75
N118 G02 X-1.25 Y0. I0. J-.5
N120 G03 I1.25 J0.
N122 G02 X-1.75 Y-.5 I-.5 J0.
N124 G01 X-2.25
N126 Z0.
N128 M05
N130 G90
N132 M30
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Sam, right on all counts as far as I know, like I said I read Gcode sort of the line
N120 G03 I1.25 J0.
is the circle and it should define a 2.5" circle which should result in the machine cutting a 2" circle.
I am sure that Mastercam handles the cutter comp and therefore I am quite sure the G code is right.
I am using a 1/2" diameter cutter.
Once again I have told the machine to move 10 inches (on both x and Y axes0 in the input area on the MIDI screen code such as
G0 X10 Y0 and it moves 10 inches close as I can measure.
So where can the problem be? only thing I can think is maybe mach 3 is trying to do a cutter comp too? for a smaller cutter the other direction?
I don't know but I don't want to buy the program if I can't get it to cut proper dimensions.
On the run screen there is a tool information area it shows all 000s
fustrating
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only thing I can think is maybe mach 3 is trying to do a cutter comp too?
No. There is no cutter comp in the code.
for a smaller cutter the other direction?
I know what your saying. Comped to the inside instead of the outside. Not possible, because there is no cutter comp in the code.
If you do a single step through the code, you can see that Mach is telling the machine the correct points to go to. The circle starts at X -1.25, and 180 degrees later is indeed at X +1.25. This is what your seeing too, correct?
If you say that your machine travels 10 inches when you tell it to, and your using a half inch cutter, the only other option that I can think of that would cause the problem is that you have it scaled down in Mach. The "scale" LED's are not flashing, are they?
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Cutter Comp works fine in demo mode. I've used it extensively over the years testing before my machine was running.
But, as Sam said, you're code is not using comp.
I just ran your original code, and the toolpath did indeed make a 2.5" circle. If your seeing 1.75, something else is wrong.
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Thanks for the help. I did not realize mach3 supported scaling but I don't think I had it on. I will have to play with the machine more, it must be something simple that I am missing. I need to put a newer computer on the machine as the one I have on it is too slow. I am going to try cutting a rectangle next time I got to the shop. That mayh tell me something. Thanks again.
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I figured it out, my fault. I checked my 10 inch move with a tape measure on the table, new machine, just starting so I will dial in accuracy later. I started at 1" on the tape measure for accuracy and moved 10 inches and ended up at 10 inches. Then I checked 1" travel with a dial indicator and it ended up at 0. My problem was I should have ended up at 11 inches on the tape measure and the dial indicator was only moving .9 inches this was causing my 2 inch circle to be off by 10%. oops
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been there, done that.
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Just bought myself a licence now I need to make some money with it.