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Troubleshooting

PostPosted: Sun Aug 23, 2015 4:51 pm
by rsm5178
I would like some help improving the quality of my laser cutting on my 2.X. (2) issues that I would like to improve. I have a feeling they are related to the motor tuning. I know this is just a homebrew hobby laser, so if I'm expecting too much, please let me know. I am using the X7 DSP in a standard Laser 2.X. My LaserCad work parameters are attached as a screenshot.

(1)

Text: When I try to engrave anodized aluminum, I get horizontal lines in my engraving. I have tried scan gaps of .1mm to .05mm. Also it seems pixelated more than I'd like. Samples are on a black anodized tag. Samples show different directions of rastering on the x axis. 3.5mm tall letters.

(2)

Gear: It seems like my laser will not follow straight lines. Each diagonal line is a bunch of horizontal and vertical lines (see acrylic gear). .1" thick acrylic

Re: Troubleshooting

PostPosted: Sun Aug 23, 2015 6:59 pm
by Techgraphix
A few things you can try:
First: check the belt-tension.. Maybe the tension is too high.
Then: What type of belt is it? Belttypes with rounder teeth have less "blocking"
Then: Set your stepperdrivers to a higher microstep and reduce the Um/step accordingly.. When you have a UM/Step of 1-2 it gives you better resolution.
Then: Horizontal lines can be reduced by reducing the Scangap to 0.08 or less OR try a little off-focus

Kees

Re: Troubleshooting

PostPosted: Mon Aug 24, 2015 4:53 pm
by rsm5178
Thank you Kees,

I will try different belt tensions. The Y-axis is a bit tighter than the X. Belts are GT2 I believe.

Initially when I was setting up the cutter, I tried 1/16th microsteps and had issues with torque. I have been using 1/8th. I will try it again and adjust the accelerations to see if anything improves.

I can also try off focusing it. I do this with cork engravings.

Would a smaller scan gap be worth it if the beam size is about .1mm? I'll still try it, but that seems like it would just be a "band-aid" to the real issue.

Also, I am using some inexpensive Sainsamart TB6560 drivers. I didn't

http://www.sainsmart.com/cnc-router-sin ... pid=188_en

Thank you,

Rich

Re: Troubleshooting

PostPosted: Thu Aug 27, 2015 4:32 pm
by rsm5178
I went to 1/16th resolution on the steppers. Now it is better. Better, but still not great. I can still see the laser head move in jagged motions at low speed.

Are the TB6560 stepper drivers just junk in general? I had an issue with my all-in-one TB6560 CNC router board before I bought a G540.

Thanks for those that helped,

Rich

Re: Troubleshooting

PostPosted: Thu Aug 27, 2015 4:43 pm
by Techgraphix
All TB65XX drivers are definitely JUNK (imho).. I should have no doubt for a second to ditch them and replace them for something decent, like Leadshines (or clones)
These are not very expensive (think of 40-50$ each) and perform great..
The G540 you mention is a good drive too but as far as I know they are very limited in microstepping or any other setting. above that they are quite priced..

Kees

Re: Troubleshooting

PostPosted: Thu Aug 27, 2015 5:53 pm
by Halfdead
Seems like a software issue.

Re: Troubleshooting

PostPosted: Fri Aug 28, 2015 3:56 pm
by rsm5178
What settings would you recommend checking/changing.

I may also just get better drivers for the X & Y, but I'm willing to to try a software setting change.

Thanks,

Rich

Re: Troubleshooting

PostPosted: Fri Aug 28, 2015 4:39 pm
by Techgraphix
When you place new drives, set the microstep high (1/256 or higher).. This will make the movements smoother. But remember that the micrometers per step must be bigger than 1.
High acceleration can give you some beltstretch, torsion-distortion, lag etc.. reduce the acceleration to 5000 and see if you notice any difference..
Kees

Re: Troubleshooting

PostPosted: Sun Jan 24, 2016 2:17 pm
by bloq
Hey!

did you get that solved? I have a very similar issue on my laser (i made a posting here: viewtopic.php?f=32&t=2817) which i cannot solve

Thank you very much,

tm

Re: Troubleshooting

PostPosted: Sun Jan 24, 2016 5:12 pm
by rsm5178
Please look in your posting. Replied there first.

I used 1/128th step with success. Loss of speed to 150-200mm/s.

Really helps with the engraving.

Kees has Nema 23 motors and precision bearing blocks so his speeds are probably not as affected by the higher step resolution.

Rich