Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: TunerTom on January 25, 2009, 06:25:44 PM

Title: Help with G-Code?
Post by: TunerTom on January 25, 2009, 06:25:44 PM
I am haiving difficulty tracing arcs with G2 and G3. It seems that these arc commands are tracing the portion of the circle I don't want instead of the short arc I wish to follow. This is a turning profile for a lathe.

Here are the two examples I have tried...
G02 Z-2.23 X18.28 R9.400 F150.0
or...
G03 Z-2.23 X18.28 R9.400 F150.0

I am attaching two JPGs to show the results.  The blue lines are my "hogging out" cuts
The arcs are obvious.

Am I missing something?
Title: Re: Help with G-Code?
Post by: Overloaded on January 25, 2009, 06:59:07 PM
Tom,
  Check or uncheck this guy and see what you end up with.
RC
Title: Re: Help with G-Code?
Post by: Chip on January 26, 2009, 12:30:38 AM
Hi, Tom

It's under this Tab.

Chip
Title: Re: Help with G-Code?
Post by: jimpinder on January 26, 2009, 04:35:52 AM
The problem is the R command in the line.

This can be positive or negative. If you make it positive it will trace one way, if you make it negative, it will trace the other way. I see yours are positive, try and make it negative. If you do, you will see the toolpath alter to give you what you want.

Don't ask me what the rule is, I don't know. I always have this difficulty. Put it in as positive, look at the toolpath display - if it is wrong, change it to negative - thats what I do.
Title: Re: Help with G-Code?
Post by: WoodyCam on January 26, 2009, 04:16:09 PM
TurnerTom - how do you get your display to be so smooth? Mine is always jagged and not quite following the path? Sorry its off topic.

Thanks!
Title: Re: Help with G-Code?
Post by: Hood on January 26, 2009, 04:50:16 PM
TurnerTom - how do you get your display to be so smooth? Mine is always jagged and not quite following the path? Sorry its off topic.

Thanks!

What version are you using?
Hood
Title: Re: Help with G-Code?
Post by: TunerTom on January 27, 2009, 04:45:25 AM
First, I must say thanks to everybody here, who has been so generous to help me out. I have learned a lot over the past few days, and I'm sure I will have more questions to ask.

In answer to WoodyCam and to Hood...
The version I am using is... Version R3.042.020
Title: Re: Help with G-Code?
Post by: WoodyCam on January 27, 2009, 05:06:37 AM
I'm using the same - see attached. This is 14mm dia and 100mm long.
(http://)

Thanks!
Title: Re: Help with G-Code?
Post by: Hood on January 27, 2009, 05:12:32 AM
WoodyCam
 can you attach the code please, if its not the code then could be your graphics card.
Hood
Title: Re: Help with G-Code?
Post by: WoodyCam on January 27, 2009, 07:38:55 AM
Yep, thats what I thought, but I've tried it on three machines now with similar response. I think it may be the zoom level. But you can also see it's got the end of the work wrong, it should be a flat face. How does it look on yours? I'm in Diameter mode by the way.

Also, the G2 G3 info in this post is very helpful as Tom says!

Thanks for looking.

G21 G18 G61 G90 G95 G40
T0101 M06
M03 S1400
(Rough out with 0.4mm deep cuts with 0.4mm nose rad tip)
G0 X20.0 Z1.0
G0 X18.8 Z0.0
G1 Z-79.0 F0.15
G0 X19.0 Z0.0
X18.0 Z0.0
G1 Z-64.8 F0.15
G0 X18.5 Z0.0
X17.2
G1 Z-48.8 F0.15
G0 X17.7 Z0.0
X16.4
G1 Z-32.8 F0.15
G0 X16.9 Z0.0
X15.6
G1 Z-16.8 F0.15
G0 X16.1 Z0.0
X14.8
G1 Z-10.8 F0.15
G0 X15.3 Z0.0
X14.0
G1 Z-10.4 F0.15
G0 X14.5 Z0.0
X13.2
G1 Z-10 F0.15
G0 X13.7 Z0.0
X12.4
G1 Z-9.6 F0.15
G0 X12.9 Z0.0
X11.6
G1 Z-9.6 F0.15
G0 X12.1 Z0.0
X10.8
G1 Z-9.6 F0.15
G0 X11.3 Z0.0
X9.7
G1 X10.8 Z-0.55 F0.15
G0 X11 Z0.0

(Rough Profile 1)
X8.57
G1 X10.8 Z-1.1 F0.15
Z-9.6
X12.39
X15.3 Z-11
X18.6 Z-76.4
X18.6 Z-78.9
X19.1 Z-79.2
G0 Z0.0

(Rough Profile 2 0.4MM Deep)
X7.72
G1 X10.2 Z-1.24 F0.15
Z-9.90
X12.14
X14.72 Z-11.19
X17.98 Z-76.45
Z-79.01
X19.04 Z-79.56
G0 X20 Z0.0

(Cut final profile 0.1MM Deep)
G1 X7.44 Z0.0 F0.11
X10.0 Z-1.28
Z-10
X12.06
X14.52 Z-11.23
X17.78 Z-76.46
Z-79.06
X19.0 Z-79.67
Z-97.0 (end of profile)
G0 X20
Z1
M05
M30
Title: Re: Help with G-Code?
Post by: Hood on January 27, 2009, 09:40:40 AM
It does show the same on mine, think you have it that its the length versus dia that is causing it (long and thin) , I have just turned a taper for a boats prop shaft and when I zoom in I am seeing similar.
Hood
Title: Re: Help with G-Code?
Post by: WoodyCam on January 27, 2009, 10:51:12 AM
OK, thanks Hood.

The fact that I've got threading working well more than outweighs it :D

Any idea on G41 and G42 - I'm assuming they are not working any time soon in Turn?

Cheers.
Title: Re: Help with G-Code?
Post by: Hood on January 27, 2009, 11:34:26 AM
Brian is suypposed to be looking at turn in the next month or twelve ;D
Hood