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Sharp Corner on Angles using Cutter Comp

dalt.deuel

Plastic
Joined
Apr 19, 2018
I am having trouble getting sharp corners when I am programming angles. The larger the angle the bigger the chamfer on the corner.

I've also hand written program with G-Code as well as used Opticam and got the same result.

Below is a picture of what is happening and also the program that I ran to get the result.


P.S. if I take G41 out of the program i get a sharp angle.


Picture should be rotated 90 Degrees clockwise. I want the angle to be sharp and I do not know what is causing it to have a notch in it.

Practical.jpg



G20 g80 g49 g40 g90;
;
t7 m06;
;
g00 g54 g49 z0. M05;
;
;
s1030 m03;
g00 g90 x-0.38 y0.38;
g43 z0.17 h07 m08;
g01 z-0.1 f18.;
g01 g41 x0. Y0. D07;
y1.;
y-1. X1.5;
y-1.;
x0.5;
y0. X0.;
g40 x-0.5 y0.5;
m30;
 
Off the top of my head, I can see the following:
G00 G90 X0. Y0.
G43 Z0.2 H07 M08
G01 Z-0.25 F18.
G01 G41 X0.5 Y-0.385 D07
X1.5
X2.5 (missing Y value?)
Y-2.385 X2.7
X0.5
Y-0.385
G01 G40 X0. Y0.
G00 Z0.2

Do you not need at least the radius of the end mill to start and cancel comp?

I tried to draw up your part, based on your coordinates, but the X2.5 must be wrong (or missing a Y value) as the path looks NOTHING like you posted a picture of.

Got a print????
 
G20 g80 g49 g40 g90;
;
t7 m06;
;
g00 g54 g49 z0. M05;
;
;
s1030 m03;
g00 g90 x-0.38 y0.38;
g43 z0.17 h07 m08;
g01 z-0.1 f18.;
g01 g41 x0. Y0. D07;
y1.;
y-1. X1.5;
y-1.;
x0.5;
y0. X0.;
g40 x-0.5 y0.5;
m30;
 
Off the top of my head, I can see the following:
G00 G90 X0. Y0.
G43 Z0.2 H07 M08
G01 Z-0.25 F18.
G01 G41 X0.5 Y-0.385 D07
X1.5
X2.5 (missing Y value?)
Y-2.385 X2.7
X0.5
Y-0.385
G01 G40 X0. Y0.
G00 Z0.2

Do you not need at least the radius of the end mill to start and cancel comp?

I tried to draw up your part, based on your coordinates, but the X2.5 must be wrong (or missing a Y value) as the path looks NOTHING like you posted a picture of.

Got a print????

Sorry. I replied with the program to match the picture. This is not to match a print i simply gave the picture to show the problem. It happens with every angle i program unless its a 90 degree angle or straight line.
 
Off the top of my head, I can see the following:
G00 G90 X0. Y0.
G43 Z0.2 H07 M08
G01 Z-0.25 F18.
G01 G41 X0.5 Y-0.385 D07
X1.5
X2.5 (missing Y value?)
Y-2.385 X2.7
X0.5
Y-0.385
G01 G40 X0. Y0.
G00 Z0.2

Do you not need at least the radius of the end mill to start and cancel comp?

I tried to draw up your part, based on your coordinates, but the X2.5 must be wrong (or missing a Y value) as the path looks NOTHING like you posted a picture of.

Got a print????

Also if you wouldn't mind posting the G-Code for a parallelogram with any degree using G41 cutter comp so I can reference what a correct program should like?

Thanks again for all your help.
 
Here is a program using a 3/4 em, and running G41 around the part in a climb cut.
The right rear corner is X0,Y0
The cutter path is green.

%
O0000
N10 (WEDNESDAY, FEBRUARY 20, 2019 15:14);
N20 (NONE);
N30 (T7 H7 D7 - PROFILE 3/4" 3FL STREAKER LONG);
N40 T7 M06 (PROFILE 3/4" 3FL STREAKER LONG);
N50 G90 G80 G40;
N60 G54;
N70 F50.;
N80 S7639 M03;
N90 G43 H7;
N100 G00 X0.218 Y0.875;
N110 Z1.;
N120 Z0.;
N130 G01 Z-0.25 F25.;
N140 G41 X-0.157 Y0.375 D7 F50.;
N150 G03 X0.2181 Y0. I0.375 J0.;
N160 G01 X2. Y0.;
N170 X3. Y-2.;
N180 X1.;
N190 X0. Y0.;
N200 X0.2181;
N210 G03 X0.5931 Y0.375 I0. J0.375;
N220 G01 G40 X0.2181 Y0.875;
N230 G00;
N240 Z1.;
N250 M09;
N260 M01;
N270 M09;
N280 G53 G00 Z0.;
N290 G53 G00 Y-.5;
N300 M30;
%

TEST G41.jpg
 
Most CAM like what doug925 posted will roll the corners because that’s the shortest toolpath. His code will give you a sharp corner.

On your code you need to extend the start element and the end element of the profile so your tool is in the cut before X0Y0 and ends past X0Y0. What you’re getting is tool pressure at X0Y0.
 
I replied in the cad/cam forum. Next time only create one post. Makes things easier for everyone.
 
OK, first, I am an idiot and misunderstood the OP's question and answered something non-germane in the CAD/CAM section.

Yes, it appears to be a Haas, and the code ( however ugly ) is fine, so is the CAM output.

Your screenshot is also correct!!! That is the actual path the tool will follow, and you will still get a perfectly sharp edge!
That is how it supposed to work on a Haas depending on which type of mode is selected ( Fanuc or Yasnac, Type A or B ).
On a Fanuc or Mits you may have some more control over how acute angles are vectored, but it will still be odd looking on the graph screen, and yet, the final product will be fine.
On EDM controls that shit gets even more weird, but the product will still be as intended.

Don't know if the newer Haas manuals include images of how cutter comped toolpaths are handled, the old ones did show various scenarios.
 
OK, first, I am an idiot and misunderstood the OP's question and answered something non-germane in the CAD/CAM section.

Yes, it appears to be a Haas, and the code ( however ugly ) is fine, so is the CAM output.

Your screenshot is also correct!!! That is the actual path the tool will follow, and you will still get a perfectly sharp edge!
That is how it supposed to work on a Haas depending on which type of mode is selected ( Fanuc or Yasnac, Type A or B ).
On a Fanuc or Mits you may have some more control over how acute angles are vectored, but it will still be odd looking on the graph screen, and yet, the final product will be fine.
On EDM controls that shit gets even more weird, but the product will still be as intended.

Don't know if the newer Haas manuals include images of how cutter comped toolpaths are handled, the old ones did show various scenarios.

20190221_095258.jpg

I have ran the program. This is the result of the said program. I have no idea what else to do. Obviously i can program with no cutter comp and it will be fine but that defeats the whole entire purpose of what i am trying to do. If you have anymore ideas let me know! Really appreciate all the input i can get!
 
Delete Y-1 block.
There seems to be some typo in the program. Please verify and post again.
 
Obviously i can program with no cutter comp and it will be fine but that defeats the whole entire purpose of what i am trying to do.
Try putting a tiny little .001" radius on the sharp corner. That should make the control figure out how to comp around it properly. Might need to be bigger than a thou, I don't know the internal accuracy of that control. .002" probably wouldn't hurt :D
 
One can play around with comps/accs/decs, exact stops.
Or you can just do what is sometimes called a "Fanuc corner".
Here you go off of side one and then circle around out in the air to the path for side two.
Some CAD/CAM systems support such, on others you have to draw a weird profile to follow.
Sharp corner guaranteed even if dia. comp or acc/dec/servo lag not quite right.
Bob
 
Ok let’s back up. Post the code that ran that part.
What is the “whole entire purpose “ of what you are trying to do?
 








 
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