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Author Topic: Randomly started getting curved corners instead of 90 degree corners???  (Read 250 times)

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Just found this forum, and hopefully this is the right section to post this in. I am a self taught CNC "operator" so I know just enough to get me in trouble. That said, I have been running my two Techno LC 4896 machines for over 10 years, mostly for cabinet making type projects. With the upgraded Mach 4 software, they have been running great for about 3 years now. Just a few weeks ago, one of my computers had a heck of a time starting up (took about 4 restarts). I finally got it up and running, and when I opened the software, I noticed the preview area background color had changed from blue to orange. Didn't think much of it, but then noticed some of the grooves I cut into my material no longer had "sharp" 90 degree corners, but rather "curved" corners (not taking into account the radius from the bit itself). This makes it really hard to put pieces into the grooves. Here are the facts as I know them:

1 - I have tested multiple different speeds and cut paths, and the faster the IPM, the more pronounced the curve is.
2 - I ran the same file on both of my machines (verified the G-code line by line), but only Machine 1 is having the issue, while Machine 2 is working as it always has.
3 - Under advice from ArtSoft, I went into the Mach4 configure/control screen, and changed the G64 (constant motion) setting to G61 (exact stop), thinking this may have accidentally been changed somehow, since it happened at the same time as the color change. This did correct the problem on Machine 1 as far as getting the 90 degree corners on my rectangular grooves, but now when it cuts circles, it is very "jumpy", like it is making hundreds of small straight lines, instead of a smooth curve.
4 - When I checked the G61/G64 setting on Machine 2, which is working properly, it had G64 (constant motion) selected, which contradicts me needing to change to G61 on Machine 1.
5 - I did revert a Windows Update that was done recently, thinking it may have initially had some affect on the software settings, since I have no idea how the background/preview area color changed from blue to orange.

I did have Techno CNC take a look remotely, thinking it was a hardware/mechanical issue, and although they noticed the color change setting and changed it back to blue, they did not notice any other setting differences between my two machines. I am at a total loss, and didn't know if anyone else has experienced something like this. Am I missing another setting somewhere? Is there a way to set the sensitivity of the "constant motion" setting? I am happy to get more information/pictures/video, but please remember where I mentioned I am self taught, so go easy on me and please explain everything to me like I am a 5 year old, haha! Thanks!!!

Pictures are how it is actually cutting, the design showing 90 degree corners, and another comparison of a single groove between Machine 1 and Machine 2, running the same exact program file.
« Last Edit: November 01, 2022, 05:11:12 PM by PlastixPlus »

Offline Tweakie.CNC

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Re: Randomly started getting curved corners instead of 90 degree corners???
« Reply #1 on: November 02, 2022, 04:00:06 AM »
On your problem machine try reducing your Velocity and increase your Acceleration settings for both the X and Y axis in Motor Tuning then save the changes. Do this in small increments testing the results each time. Referring to the manual ( the section relating to Motor Tuning ) may help.