Cut speed is not consistent??

[Mr Patches]

Hey guys! Hope everyone had a great 4th!

Well lets see. Im running a candcnc setup. Cutmaster 82. Im having some issues with my cut speeds and not sure where to fix it...

Last night i was cutting some 14g mild steel sheets. 40 amp settings. My feed set in mach to 180ipm. From the start the torch is fine. It moves quick touches fires and then its super slow. For about 15 seconds then it takes off and cuts rapidly. Then slows down again. I have no snippet codes enabled... i noticed if im cutting an image with many short jaged lines its cutting those as well as small images very quickly. However any lines that are long and straight it seems to crawl... Which while cutting 14g is warping the metal and making a messy cut... I have also tried overriding the speed in mach while it is cutting slowly. This doesnt help because when the machine decides to speed up i end up cutting way to fast and loose penetration...

Is there a code i need for long straight cuts to boost the speed to what i have set in the cut settings page? Any help would be awesome!! Thanks and have a great day..

[sphurley]

A couple of questions. What does the screen show you feed speed is while cutting? What model of CandCNC do you have? If it slows that much the DTHC must be off or the height control would go nuts. Have you changed your CV settings in Mach recently?

[acourtjester]

You say you did not have snippets in the G-code I found many time that I did not put any in the tool setting while planning an operation. But there were cut rules in the G-code when I cut. What I found was if you go to the Tool drop down at the top and click on cut rules it was set to put rules in there. This over rules what was in the tool setting below. It seems like when SheetCam does an update things may get set to different setting. I now check both locations after any updates as I plan a new operation. This may also happen when an older job is call in for an new plan.

[Mr Patches]

Thanks guys. Steve. Im running the Candnc esp2 bladerunner. As far as my speed percentage and DTHC they are all over the board. So when the torch is crawling its at 20% when it takes off its at 190%. And the DTHV is all over the place meaning its on and off at many different times thru the cut. When its crawling it is off. When it takes off its on and off..

As far as CV settings ? Is that Cut Voltage? Ive had to set all of my cut parameters up so im thinking acourtjester may have knailed it.....

Acourtjester i will look at that. Seems like this problem is something new. Meaning before i copied all of the code snippets it was cutting fine. Now its doing this even though i have no codes enabled. Ill check the tool selection and see if its doing this on its own.

Also it seems to only do this on thin material.. if im cutting 1/4 " the speed stays the same...

Thank you guys for the info!!! I will see here in a few if we nailed it.

[Mr Patches]

Sphurley. CV. For constant Velocity.. i have not touched any of those settings.. Sorry still learning as ive only had this setup since February 16.

[tcaudle]

Do not drift down into the CV settings unless you what to spend a LOT of time in the section making it work. Look at your G-Code Feedrates are set using an "F" command. They are "Modal" meaning for a given type of G code they stay the same until they are reset.. There is no setting in the software (MACH or CommandCNC) that lets you change feedrates randomly . Get more specific help on the CandCNC Support Forum .

[Mr Patches]

Tcaudle. Thank you. Im firing it up here in a few min. Im not going to mess with the CV settings. Im hoping what acourtjester mentioned with my code snippets fixes the issues... So i went and checked my added codes and they where set to run all the time... I changed them to none on sheetcam. So im hoping it works here.

The only adjustment i was able to use was in Mach while cutting using the speed override box. In the lower left corner. The torch speed was only 20% so i ramped it uo to 100% while cutting which increased my speed a bit. The only issue i have with that is when the machine decides to go to 90% speed i loose my cutting all together... which at 190% should be expected i guess...

[Mr Patches]

Well i ran a dry run thru and my cut speed stayed at 190ipm by turning the code snippets to none. I noticed it installed a F190.0 into Gcode.

[Mr Patches]

Now if i can just get rid of this pause after each touch off id be doing backflips!!! Lol. Its bearable so i just hit run after each touch off. However if im cutting 1000 gussets id not be doing backflips anymore..... lol

[Mr Patches]

Thank you guys very much for the Help!! Very much appriciated!!

[tcaudle]

Now if i can just get rid of this pause after each touch off id be doing backflips!!! Lol. Its bearable so i just hit run after each touch off. However if im cutting 1000 gussets id not be doing backflips anymore..... lol

See the post on the support forum. Covered how to do that and a link to send your code to.

[Mr Patches]

Thank you Tcaudle. I recieved help from Tom on the Candcnc forum and its fixed. The issue was in the post processor on pausing for a tool change before each cut. I ended up just going into edit post processor and changed the True to false at the warning line to turn off the pause for toolchange selection. Seems to work good now. So now im going to reapply my rule snippets one at a time and see if incan keep everything communicating and getting along. Lmao.