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Can't set rapid clearance to over .5" possible sheetcam question?

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plasmartist
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Joined: Mon Aug 07, 2017 1:31 pm

Can't set rapid clearance to over .5" possible sheetcam question?

Postby plasmartist » Tue Feb 20, 2018 6:21 pm

I have been using my table for a little over a year now, but it has never been able to have the rapid clearance set to less than .5". For example if I set the rapid clearance in sheetcam to .4", then run the postprocessor and load it into commandCNC the rapid clearance defaults out to .78", but when it is set to .5" or higher the rapid speed follow suit correctly. This isn't a deal breaker, but it would be nice to be able to speed up my touchoffs on certain jobs that have a ton of pierces with no chance of tip ups. In other words, everything seems to be correct in sheetcam, as seen in the pictures, but when I load the gcode in commandcnc anything less than .5" jumps back up to .78" or so.

I am running a basic setup from candcnc ie bladerunner, mini lunux pc, sheetcam, drawing in inkscape, ohmic sensor, pmx 85 unit with machine torch. However, for convenience I do all my drawing and sheetcam on a laptop because it is much more powerful than the little PC (and it increases the amount of work I can do from my recliner).

I am sure there is some setting somewhere that specifies a minimum rapid height. Any help is greatly appreciated, especially since my z lead screw is 12 tpi and my z speed is only 55 ipm.

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motoguy
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Location: Central MO, USA

Re: Can't set rapid clearance to over .5" possible sheetcam question?

Postby motoguy » Tue Feb 20, 2018 7:39 pm

I believe the posts 24C and 24D are coded to prevent any rapids at less than .5". You can click the "edit" button where you load the post processor, and see if it has these minimum settings.

I believe Tom/CandCNC was having issues with people setting their rapid and touch-off heights too low, and crashing torches. So, they set minimums in the post processor. If that's the case, you should be able to edit the minimum in the post, but I'd be careful of changing anything there if you don't know what you are doing.

ETA: Yup. I see you are running post 24D. That's why.
Bulltear 6x12 w/ Proton Z axis & watertable
CommandCNC/Linux w/ Ohmic & HyT options
Hypertherm Powermax 85 w/ machine torch
Solidworks, Coreldraw X7, Inkscape, Sheetcam

motoguy
Elite Contributing Member
Elite Contributing Member
Posts: 1073
Joined: Tue Aug 25, 2015 12:05 pm
Location: Central MO, USA

Re: Can't set rapid clearance to over .5" possible sheetcam question?

Postby motoguy » Tue Feb 20, 2018 8:06 pm

Here's where Tom mentions it (Rev 23, and any rev after that):

https://www.candcnc.com/supportforum/vi ... =24&t=1647

"Re: LINUX CommandCNC Post Processor Rev. 23

Postby admin13o5 » Wed Feb 15, 2017 5:50 pm
23 is for persons that have missed the admonition to set their Plunge safety clearance to .5" and their Rapid Clearance to about double that. It forces the right numbers so they don't get the G38,2 error on a touch off"
Bulltear 6x12 w/ Proton Z axis & watertable
CommandCNC/Linux w/ Ohmic & HyT options
Hypertherm Powermax 85 w/ machine torch
Solidworks, Coreldraw X7, Inkscape, Sheetcam

motoguy
Elite Contributing Member
Elite Contributing Member
Posts: 1073
Joined: Tue Aug 25, 2015 12:05 pm
Location: Central MO, USA

Re: Can't set rapid clearance to over .5" possible sheetcam question?

Postby motoguy » Tue Feb 20, 2018 8:09 pm

Just found this one, which explains your .78" situation:

https://www.candcnc.com/supportforum/vi ... 830#p10471

"Re: Pierce Height Delay Issues

Postby admin13o5 » Wed Jul 05, 2017 10:24 am
All you have to do is look at the code . A delay is a G4 P#. If its there it should delay. There is a Red HOLD led on the DTHC front and an LED on the screen. You also need to make you either have the Plunge Safety Clearance set in SheetCAm set to .5 in or more and Rapid Clearance of .75 or more OR use the rev23 post that sets those values automatically if they are too low. The Plunge Safety Clearance sets the point above Z zero where the torch changes from full rapid to touch-off speed (typically about 20IPM. If you do not see that actual slowdown on a touch off you need to check the settings"
Bulltear 6x12 w/ Proton Z axis & watertable
CommandCNC/Linux w/ Ohmic & HyT options
Hypertherm Powermax 85 w/ machine torch
Solidworks, Coreldraw X7, Inkscape, Sheetcam


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