Hello Guest it is October 21, 2020, 05:35:45 PM

Author Topic: New Cutter Comp code and Examples  (Read 25821 times)

0 Members and 1 Guest are viewing this topic.

Re: New Cutter Comp code and Examples
« Reply #20 on: December 22, 2008, 09:36:47 PM »
Also did you see this message:

Quote
It will fit if you have your numbers right .. I would use R type programming so I can get a good center point  The IJK modes don't work so well with rounding errors..


That will fix your trouble...

Thanks
Brian
Fixing problems one post at a time ;)

www.newfangledsolutions.com
www.machsupport.com
Re: New Cutter Comp code and Examples
« Reply #21 on: December 22, 2008, 10:28:32 PM »
If you round your numbers in the cad system to the safe side (Make the arc bigger by where you place the arc center) I can be sure that I cut all the parts right..  I can not change Mach3 to round because the guys running micro machines will have trouble. You need to fix it on your side and I need to run many types of machines.

The following comp code is a simple square with 1 inch sides and .5 arc corners. If you look at the I and J words of the four corner arcs you will see they are all exactly .5000 or .0000 so there has been no rounding on the CAM side. These are the exact coordinates in the precise location and yet the new comp code will not work with it. If I change the G42 P.5000 line to G42 P.499999999999 it works fine. That would indicate the error is on the Mach side and not with the CAM as there would be no rounding I could do on the CAM side to fix this.

Using the R-word in place of an I and J is not really an option as it has its own problems with ambiguity of arcs greater than 180 degrees. 

G00 Z.3
G00 X0 Y0
G00 X1.5000 Y-.2500
G42 P.5000
G00 Z.1000
G01 Z-.1000 F10
G01 X.7500 Y-.2500 F20
G02 X.0000 Y.5000 I.0000 J.7500
G01 X.0000 Y1.0000
G02 X.5000 Y1.5000 I.5000 J.0000
G01 X1.5000 Y1.5000
G02 X2.0000 Y1.0000 I.0000 J-.5000
G01 X2.0000 Y.0000
G02 X1.5000 Y-.5000 I-.5000 J.0000
G01 X.5000 Y-.5000
G02 X.0000 Y.0000 I.0000 J.5000
G01 X.0000 Y.5000
G02 X.7500 Y1.2500 I.7500 J.0000
G40  (cancel cutter radius comp)
G01 X1.5000 Y1.2500
G00 Z.3

Graham

vmax549

*
Re: New Cutter Comp code and Examples
« Reply #22 on: December 22, 2008, 10:30:04 PM »
HOPEFULLY it will allow us to get closer than it did before(;-) I had stopped using comp in mach because of the large difference in allowed cutter sizes to the arc radius. Pretty nmuch you had to stay about .625 smaller with the cutter than the arc to be safe that MACH did not throw an error at you. You never really knew untill you tried to run it if it worked or not.

AND you don't always have controll over the radius used in a part drawing. (Customer supplied and a tight tolerance sheet). So I for one think a .500" cutter should cut a .250" radius(;-)

Thanks (;-) TP
Re: New Cutter Comp code and Examples
« Reply #23 on: December 22, 2008, 10:39:14 PM »
Well I will take you bitching into acount.. I think I have a pan in what I can do but IF it is going to hose ANY file that I test I am taking it out.. In the an error message is better then a scrap part..

Here is a Quote from Peter Smid's "CNC Programming Handbook" 3rd Edition

Pg 270 "Make sure you the cutter radius is always smaller than the smallest inside radius of the part countour"


Thanks for your support
Brian
« Last Edit: December 22, 2008, 10:46:04 PM by Brian Barker »
Fixing problems one post at a time ;)

www.newfangledsolutions.com
www.machsupport.com
Re: New Cutter Comp code and Examples
« Reply #24 on: December 22, 2008, 11:13:12 PM »
Hello Graham H. ,
Just a note if you are going to use the P for setting the offset amount. the P is the offset ammount not the DIA of the tool that you would like to run..

So G41 P.25 would be what you would put in for a .5 tool

Thanks
Brian
Fixing problems one post at a time ;)

www.newfangledsolutions.com
www.machsupport.com

vmax549

*
Re: New Cutter Comp code and Examples
« Reply #25 on: December 22, 2008, 11:38:52 PM »
OK I  guess I am dumb but why would a .500 NOT cut a .250 radius . It by all counts should not gouge. Now I agree that a .5001 cannot cut a .250 R. IS it the rounding factor of the numbers (.000011111=.0000 ) that we cannot see  the problem???

AND I agree a type c comp cannot gouge in any circumstance.

(;-) TP
Re: New Cutter Comp code and Examples
« Reply #26 on: December 23, 2008, 12:26:24 AM »
Okay it will now run the part.. I have tested it on as many files as I can find and they all work without killing the part.
I have changed the price of mach3 to reflect this enhancement LOL (there will be a 10% increase the first of the year and that is not a joke... )
Thanks
Brian
Fixing problems one post at a time ;)

www.newfangledsolutions.com
www.machsupport.com

Offline vlmarshall

*
  •  23 23
  • G28 G91 X0 Y0
    • View Profile
Re: New Cutter Comp code and Examples
« Reply #27 on: December 23, 2008, 12:42:04 AM »
Ah, well... even a new carbide endmill isn't exactly onsize. A little cutter diameter tweaking is nothing new, it's why we have tool offset and diameter tables. :)

Great work on these improvements!
Re: New Cutter Comp code and Examples
« Reply #28 on: December 23, 2008, 01:02:20 AM »
Hello Graham H. ,
Just a note if you are going to use the P for setting the offset amount. the P is the offset ammount not the DIA of the tool that you would like to run..

So G41 P.25 would be what you would put in for a .5 tool

Yes that is correct. in my example above you will see I was using .5 radius arcs with a 1 inch diameter cutter (.5 radius hence P.5000). I could have used .25 arcs with a P word of .2500 or .125 arcs with a P word of .1250, its all the same thing. None of those will work.

I agree that any cutter less than .5 will work with .5 arcs....  What we discussing is if the arc is the same as the cutter radius.

Graham
Re: New Cutter Comp code and Examples
« Reply #29 on: December 23, 2008, 01:06:44 AM »
Okay it will now run the part.. I have tested it on as many files as I can find and they all work without killing the part.
I have changed the price of mach3 to reflect this enhancement LOL (there will be a 10% increase the first of the year and that is not a joke... )

Sounds good Brian, I knew the bitching would pay off. :)   Let me know when I can give it a run...

Graham