Y axis cuts inconsistant, progressively worse over course of job. Chinese Trocen cont

[andyeddy15]

Hello all!
I am rather new to CNC's, but have spent the last few months obsessively reading and upgrading my 50w Trocen controlled chinese blue machine 500x300mm.
The problem I am running into is that my machine is becoming very inaccurate along the y axis. when I cut a series of slots or holes moving down the y axis, the spacing becomes progressively inaccurate. as the job progresses, even the slots themselves do not end up where they began, as if the cutting head moves up less than it moved down. if I cut circular dials, the central holes become more and more off center. I have already spent a long time with laser alignment, and gantry squaring and it doesnt appear to be that. it is accurate at the beginning of a job, and becomes progressively worse, as if every time it tries to return to a given Y position it doesnt quite get there. I will attach some photos to show what I mean.(the photos are all rotated , not sure why. the gap in the circles is along the y axis) Raster engrave seems to work just fine, although there seem to be more pronounced ridges. Is this a stepper motor problem? thanks everyone.

Similar Threads:

• material sensor (amplifier) for Trocen TF-6225
• Need Help!- RECI W1 Low power with Trocen
• Which el-cheapo chinese milling machine is least worse for PCB
• Newbie- Can a 15 Amp cont. driver work with a 19A cont. motor?
• Progressively milling to final size

[Jim Dawson]

A slipping motor coupling or pulley perhaps?

[andyeddy15]

A slipping motor coupling or pulley perhaps?

Do you mean the belts? I have checked both y axis belts for same tension/enough tension. Can the pulleys themselves be slipping?

[Jim Dawson]

Yes, it's possible for the pulleys to slip on the shafts. Sometimes they come loose.

[andyeddy15]

Yes, it's possible for the pulleys to slip on the shafts. Sometimes they come loose.

I will check into that tonight, Thanks!

[Dean448]

On Y axis I would grasp both pulleys on the ends of each axis and gently twist the shaft. Tighten anything that allows it to move.
Also make sure the belt isn’t riding up on the pulley flange. Check that the belt tension doesn’t vary as the axis moves, which is unlikely unless something is bent.


Sent from my iPhone using Tapatalk

[andyeddy15]

I pulled the entire gantry and y axis motor and shaft. you were right, there is considerable play in one of the gears. I am not sure how these are fit on, there does not seem to be any sort of notch or keyway.. I am not sure how I would find a replacement spline gear for this belt. any ideas? thank you again for the help, half way there!
I can pull the spline about a mm off the shaft by hand, would you think it is simply press fit? the shaft itself is approx .3 in or 7.62mm, and covered in tiny ridges.

[andyeddy15]

I just got the spline off by pulling really hard there is some sort of grey dry stuff on the shaft, reminds me of graphite lubricant, but that doesnt make much sense. could I just locktite the spline on the shaft? I just need to fix it in place yes?

[Jim Dawson]

For this application I think red Loctite will work. Not the best, and normally I would not recommend this for a fix. Maybe JB Weld would be worth a look also, should be right next to the Loctite on the store shelf.