[Donkey Hotey]

I've got a problem with my Mastercam post. Before I can try to fix it, I have to figure out what a helical move should look like.

This is a simple, helical bore with a 0.5" endmill. It's basically opening up a counterbore for a SHCS.

Here is the output:

%
O0000 (Helical Bore)
N100 G20
N110 G0 G17 G40 G49 G80 G90
( TOOL - 3  DIA. OFF. - 3  LEN. - 3  DIA. - .5 )
N120 T3 M6
N130 G0 G90 G55 X-.1237 Y-.1237 S10000 M3
N140 G43 H3 Z.7 M8

N150 G3 Z.62 R.1749 F40.
N160 Z.54 R.1749
N170 Z.46 R.1749
N180 Z.38 R.1749
N190 Z.3 R.1749
N200 X0. Y.175 Z.25 R.1749
N210 R.175 F12.
N220 Y0. R.0875

N230 G0 Z.7 M9 N240 G91 G28 Z0.
N250 G28 Y0.
N260 M30
%

I know that the Haas wants a negative R value if it's going to track a 360 degree arc. If I read the manual correctly, to use the XYZ method, one of the values has to change. In this case, the move is ending at the same XY but different Z. I get the following error:

Invalid X, Y OR

I changed all of the moves above to be negative R. It still gives the same error. What should the output look like for those helical moves? I'm stumped.

[PBMW]

Send me the file and I'll have a look at it...Emails in the profile

[JROM]

first off all your z values are positive......that's not right
And I think you need an end point for the arcs in x&y.
Just my two cents Good luck

[littlerobb]

You are way brighter than I am but, I have done this before. Move your tool to the center of the pocket, and use a g12 or g13.

Example (maybe)
G0 x0 y0 z.1
G1 Z-.1
G91(incremental)
G12 X0 R Q L(loops) D F
G90(absolute)
g1 z.i

[Andre' B]

You can not do a full 360 degrees with a radius specified arc. The start and end points are the same so there is no way for the control to calculate the center of the arc.
You need to us I J type arcs.

[Geof]

N130 G0 G90 G55 X-.1237 Y-.1237 S10000 M3
N140 G43 H3 Z.7 M8

N150 G91 G3 I-.1237 J0.1237 Z-.08 F40. L5
N170 G90 G3 I-.1237 J.1237 Z-.45 F40. L2

N230 G0 Z.7 M9
N240 G91 G28 Z0

[Donkey Hotey]

From the look of things, it's safe to say that I have to rewrite that portion of the post to output IJ moves. I'll see if I can figure it out. Maybe a post in the MC post forum will net some answers.

I don't know if Mastercam posts all arcs the same way or if there is a special case for doing helical pocketing. My fear is that all arc moves will have to be changed to IJ and I'll hate trying to read the output at the control.

Thanks for all the suggestions guys. I knew this bunch would have an answer.

[littlerobb]

Andre b is correct we can cut 359.999 degrees with an R command but it will leave a little mark.

[Geof]

If you insist on doing it the hard way see if you can configure it to output sequential semicircles.