Start/Stop point issues

Axeman
Posts: 118
Joined: Thu May 09, 2013 7:52 pm

Start/Stop point issues

Postby Axeman » Mon May 28, 2018 7:21 am

Hey folks...

Got another issue that I've stumbled on and I've exhausted all my ideas.

I recently replaced my v-groove bearings, rails, pulleys, and belts. The belts are now upgraded to GT-2 belts (SO much better).

Problem:

Occasionally on a curved line if the start/stop point is on there, it will do this offset. I have ruled out using "Manual order" to change the start/stop point to different area since it happens only sometimes with only certain vectors (not all curved surfaces which I initially thought). It's not the X/Y axis because everything else is 100% accurate without oblong shapes or inaccuracies. It's not all curved surfaces since they all cut very nicely. I just re-calibrated my steps which ended up being I believe 12.43 uM to be spot on. It's not speed dependent...I cut out a square and it's within less than 0.5mm square.

This is using LaserCad 7.98 with the latest firmware (as per the software dev's website). I'm at a loss here...any of you know how to fix this?

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Techgraphix
Posts: 484
Joined: Fri Jan 20, 2012 1:39 pm
Location: Appelscha, the Netherlands
Contact:

Re: Start/Stop point issues

Postby Techgraphix » Sun Jun 03, 2018 3:27 am

A few things can cause this:
Backlash: Belt tension of Y is insufficient or/and one or more timingwheels (beltgears) are not tightened enough so they can rotate around the axis

Steploss: the acceleration or speed is set too high for your machine, a small dent the guideways or dirt on or in the bearings can cause a "heavy"point which causes a loss of steps. Esspecialy the Y-axis as it has to move the entire bridge, laserhead and motors..

Vibration or moving of the object: If the object is not fixed to the bed (normaly the weight of it is enough) or the bed-structure is weak or even loose, it can move due to vibrations during the laserjob.
Dont underestimate those forces.. My machine can move 2m/sec and accelerate with 5G! but when i use this settings my entire machien of approx 120 kilo's will travel quite a distance.. I reduced it to 1m/sec and 3G's which is still breathtaking fast..
Kees

Tech_Marco
Posts: 4347
Joined: Mon Jun 15, 2009 3:00 pm

Re: Start/Stop point issues

Postby Tech_Marco » Sun Jun 03, 2018 9:44 am

Please post the specifications of your laser machine
Then, post screenshot for both user parameters manufacturer parameters for review.

Pay attention to the belt tension on your axis. Make sure that both side is balanced. Double check the bearing see if it runs smooth.

Marco


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