Not cutting square

[Mcclure3]

Hello there, I have been on this site for a few months now and I can not thank everyone of you enough for all the information and knowledge you guys share. Thank You! I have searched everywhere to find this problem but no luck. I have a Precision Plasma 8020 4x8 HD, home built table, Candcnc software. So my problem is when I cut out a fairly large oval piece my edges are not to size at all. I have only noticed it on oval pieces but I'm sure it's with everything I cut. It seems that it is not cutting square. I have cut out many things so far and all measurements are very close. I have checked measurements with a marker and made sure my motors are tuned right and it is right on there. All of my gears seem tight and everything seems to be square on the table. I am thinking that it has something to do with my x axis but not sure. The picture will probably make more sense. I just don't really know what to do from here. Any suggestions?

[sphurley]

Which CandCNC system is it? Windows or Linux? There are some changes to the Linux system if that is what you have.
Is the gantry racking to one side? If your oval should have the same size trim around it then it is really noticeble.

[Mcclure3]

Linux with bladerunner, command cnc, and sheetcam. I got the system in may of this year. The trim on the oval should all be even. Its about a 1/4 inch on one side and 3/4 on the other. As far as racking to one side it does not seem to pull one way or the other. How could i be absolute sure that it doesn't?

[sphurley]

From Tom at CandCNC
1. Make sure you are upgraded on CommandCNC to at least 0.8.5 or later
2. Set the MOTORS tab of the Configurator for the running config: Set the Step Pulse up to 3.5 and the Step Space up to 3.5
3. Set the STEP ACTIVE LOW on X and Y motors to checked (ON)
4. Save and then exit the configuration . Open it back up and make sure the settings are changed. (If not you are on an older release and need to upgrade)
5. Load CommandCNC and your issues should vanish

[WyoGreen]

Looking at your picture, it appears the proportions are ok, it just looks like when you change operations from the inside cuts to the outside cut, that the outside cut is offset about a 1/4" to the right. Now all we have to figure out is what would cause that offset. I sure hope sphurley's suggestions pan out, because right now I have no idea.

Steve

[Mcclure3]

sphurley, you are correct I must have the older version. I will give this a try and see how it turns out. Thank you.

[Mcclure3]

Okay I did the update and configuration of the motors. Now I am getting a Axis Following Error on all axis. It will make a few cuts and then the error will occur.

[sphurley]

That usually means you are pushing the motors too hard. Did you increase the velocity or acceleration at the same time?
What are those numbers.

[sphurley]

Also read the PDF with 8.5 there are some changes in how you set the Z offset.

[Mcclure3]

I didn't change any of those settings. But from reading a little bit that sounds like that is the problem. X and Y max velocity is 350, acceleration is at 25.
Z max velocity is 120 and acceleration is 25. All homing velocity's are 20.

[sphurley]

Those settings sound fine.

[sphurley]

8020 HD Motor Tuning Information.pdf

(52.92 KiB) Downloaded 112 times

8020 HD Motor Tuning Information.pdf

(52.92 KiB) Downloaded 112 times

Not sure if you have 620oz motors or not and direct or belt drive

[tcaudle]

Following errors are not from motor tuning. Its an internal (PC) timing error. Its IMPORTANT that when you update and before you start making changes you open the Configurator to each working CONFIG then save and exit it. Updates include updates to the Configurator and the associated files for each CONFIG have to be updated . Once you save it then you can open. Note that any offset (like the swtich offset) is now negative number.

Make sure the configurator then opens to the new tab menu interface Newer Configurator has extensive HELP files on each page

Make sure that when you open CommandCNC and HELP/About it shows the correct REV number

[Mcclure3]

That seemed to have worked. Thank you guys so much.

[sphurley]

Now lets see if it cuts right and let us know.