G2/G3 Spiral Interpolation?
05 Sep 2011 22:19 #12995
by zarthcode
G2/G3 Spiral Interpolation? was created by zarthcode
Is there a command in EMC2 that would allow for spiral interpolation? I'd like to make planar spirals, tapered holes, etc. My CAM software supports it, but I'm unsure of if EMC2 does (Circles, and helixes work just fine!)
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06 Sep 2011 00:47 #12996
by andypugh
Replied by andypugh on topic Re:G2/G3 Spiral Interpolation?
zarthcode wrote:
As far as I know, there is no such command. EMC2 recently gained multi-turn arcs. Multi-turn, variable-radius arcs would be a step further.
What does the Gcode command that your CAM produces look like?
Is there a command in EMC2 that would allow for spiral interpolation? I'd like to make planar spirals, tapered holes, etc. My CAM software supports it, but I'm unsure of if EMC2 does (Circles, and helixes work just fine!)
As far as I know, there is no such command. EMC2 recently gained multi-turn arcs. Multi-turn, variable-radius arcs would be a step further.
What does the Gcode command that your CAM produces look like?
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06 Sep 2011 23:55 #13013
by zarthcode
Replied by zarthcode on topic Re:G2/G3 Spiral Interpolation?
Here is a sample program that seems to produce a spiral output. (To get it to work properly w/EMC2, I have to output as linear segments) It's meant to pocket a hole using a planar spiral pattern.
The complaint will occur on line 12:
Radius to end of arc differs from radius to start:
start=(X0.1250, Y0.0000)
center=(X0.2500, Y0.2165)
end=(X0.1250, Y0.2165)
r1=0.2500 r2=0.1250
I haven't played with the feature enough yet to completely understand how the format is supposed to work. I'm also unsure if my postprocessor is outputting a common way to mill a spiral (I could dig through some posts to compare.) But the post processor goes to a lot of trouble to make a distinction between a circle, a helix, and a spiral - thus allowing different syntax/formats/commands for each.
%
G17 G20 G40 G90
(Hole Pocketing)
(TTS Holder)
T10 M06
G43 H10
S780 M3
G0 Z0.25
X-0.07352 Y-0.10105
G1 Z0.025 F5.
G17 G03 X0.125 Y0. Z-0.0625 I0.07352 J0.10105 F1.5
X0.125 Y0.21651 I0.125 J0.21651
X-0.125 Y-0.21651 I-0.125 J-0.21651
G1 X0.125 Y0.
X-0.00006 Y-0.12489
G03 X0.125 Y0. Z-0.125 I0.00006 J0.12489
X0.125 Y0.21651 I0.125 J0.21651
X-0.125 Y-0.21651 I-0.125 J-0.21651
G1 X0.125 Y0.
X-0.00006 Y-0.12489
G03 X0.125 Y0. Z-0.1875 I0.00006 J0.12489
X0.125 Y0.21651 I0.125 J0.21651
X-0.125 Y-0.21651 I-0.125 J-0.21651
G1 X0.125 Y0.
X-0.00006 Y-0.12489
G03 X0.125 Y0. Z-0.25 I0.00006 J0.12489
X0.125 Y0.21651 I0.125 J0.21651
X-0.125 Y-0.21651 I-0.125 J-0.21651
G1 X0.125 Y0.
X-0.00006 Y-0.12489
G03 X0.125 Y0. Z-0.3125 I0.00006 J0.12489
X0.125 Y0.21651 I0.125 J0.21651
X-0.125 Y-0.21651 I-0.125 J-0.21651
G1 X0.125 Y0.
X-0.00006 Y-0.12489
G03 X0.125 Y0. Z-0.375 I0.00006 J0.12489
X0.125 Y0.21651 I0.125 J0.21651
X-0.125 Y-0.21651 I-0.125 J-0.21651
G1 X0.125 Y0.
X0.
G0 Z0.25
M30
%The complaint will occur on line 12:
Radius to end of arc differs from radius to start:
start=(X0.1250, Y0.0000)
center=(X0.2500, Y0.2165)
end=(X0.1250, Y0.2165)
r1=0.2500 r2=0.1250
I haven't played with the feature enough yet to completely understand how the format is supposed to work. I'm also unsure if my postprocessor is outputting a common way to mill a spiral (I could dig through some posts to compare.) But the post processor goes to a lot of trouble to make a distinction between a circle, a helix, and a spiral - thus allowing different syntax/formats/commands for each.
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07 Sep 2011 00:08 #13014
by andypugh
Replied by andypugh on topic Re:G2/G3 Spiral Interpolation?
It is possible that the code is using absolute centre arcs rather than relative centre arcs, but it is a bit too late for me to think that hard.
You could try an experiment with G90.1 and G91.1 at the beginning of the file:
linuxcnc.org/docs/html/gcode_main.html#sec:G90.1,-G91.1
You could try an experiment with G90.1 and G91.1 at the beginning of the file:
linuxcnc.org/docs/html/gcode_main.html#sec:G90.1,-G91.1
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07 Sep 2011 12:03 #13023
by BigJohnT
Replied by BigJohnT on topic Re:G2/G3 Spiral Interpolation?
It is definitely either a bad start point, bad end point, bad offset for a circle. You might check into your post processor to see if it has some options for a helix.
John
John
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07 Sep 2011 17:26 #13033
by jmelson
Replied by jmelson on topic Re:G2/G3 Spiral Interpolation?
zarthcode wrote:
pico-systems.com/gcode.html
You can download C language source for this program and modify it to do what you want. Or, maybe
the quadrant arcs are already close enough for what you want.
Jon
I have a program posted online that makes a round pocket by spiraling out in quadrants. See the first program at :Is there a command in EMC2 that would allow for spiral interpolation? I'd like to make planar spirals, tapered holes, etc. My CAM software supports it, but I'm unsure of if EMC2 does (Circles, and helixes work just fine!)
pico-systems.com/gcode.html
You can download C language source for this program and modify it to do what you want. Or, maybe
the quadrant arcs are already close enough for what you want.
Jon
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