Chinese laser engraving double image

[James Neathery]

i got a chinese 60w c02 laser not too long ago, set up beam alignment and focus, and it's working as expected, but engraving double. i thought it may have been a beam alignment issue (my tube is slightly out of alignment and not adjustable unless i get some new mounts) but i've gotten the beam centered pretty well. then i thought it might be a mechanical issue, but when i slowed down the gantry it still did it.

i had a concern though. when i unboxed it and tried to power it on, nothing happened. when i took the panel off where the electronics are, i noticed the back of the AC inlet plug had wires coming from ground, and two more on the left post. I thought maybe there was supposed to be a wire on each one, so i put one wire that was on the left post on the right.
well the laser still didn't power on, but it was because the emergency stop was pushed in and turned. when i released it, everything powered on. I didn't change the AC inlet wires back.

so, is it possible that having an AC wire on the left and right post, instead of having them both on the left post as they were originally, is causing this issue? like, causing a double polarity thing (please excuse my lack of electronics experience). as i said, everything else is working as expected. if pics would help, i can take some when i get home.

[Kev Williams]

if the double image is side-to-side, it's likely just a backlash alignment issue, meaning the engraving during the left to right sweep isn't lining up to the right to left sweep engraving. Should be adjustable in your software...

If your engraving menu has a "unilateral" setting, try that and see if the double image goes away. Unilateral means it will only engrave in direction, usually left to right.

[Matt McCoy]

I would not attempt to rewire the laser without a good understanding of what you are doing. If the E-stop was depressed, that is likely why the machine would not power on.

A pic would be helpful, but if the engraving trouble persists at slow speed, it is unlikely that it is a mechanical issue.

[James Neathery]

does this look like it might be it? it was set to bi-directional.
Screenshot (6).jpg

[Bill George]

does this look like it might be it? it was set to bi-directional.
Screenshot (6).jpg

Did you read the documentation that came with the machine? Also wonder why you have your rulers reading out to 3 decimal points?
Free advice from a old electrician, don't change wiring unless you know what you are doing. I would put it back the way it was, IF you can remember what wire went where.

[James Neathery]

this is RDWorks software. the manual was translated from Chinese and i don't see anything about this in it. it's almost unintelligible.
i can put the wire back where it was. i'll let you know what happens.

[Doug Fisher]

You can also change the direction function in the settings for a particular layer under the work tab at the Scan Mode setting.

I would try it without bidirectional scanning as Kev suggested. If that solves your problem then do as Kev suggested and work with your backlash settings.

[Doug Fisher]

The simplest backlash setting to start with is to check the "backlash reapy optim" setting on the Output tab. Your issue may need more complex adjustment in user tab.

[Kev Williams]

Just for the record, the first engraving I ever did on my Triumph was some Tin Cup font on a piece of wood-- I may still have it... anyway, the text was 1/2" high, and with the backlash set at the default, I got 2 completely different sets of words that were nearly a full 1/4" apart! A video clip that came with showed how to adjust for backlash, which I did-- and it got worse. Turns out I had to enter NEGATIVE numbers-

Another 'feature' of my software is I can (and must) adjust backlash for different speeds- I brag about great this machine engraves but it was up to me to make it so-- I spent many hours tweaking my settings; I have a different backlash setting from 50 to 800mm/sec in 50mm/sec increments. I don't know if other Chinese software has such provisions... I can also enter maximum vector speeds for any size circle I choose (but that's another story)

[James Neathery]

20170527_164912-min.jpg
the offset is definitely during engraving, x axis. i've tried selecting the "backlash reapy optim" option to no effect. i've tried changing bi-dir array to single to no effect. i've tried manually inputting backlash parameters to no effect.
i have painstakingly aligned my beam and cleaned all optics. i tweaked the tube alignment so that my beam geometry is nigh perfect. i tightned all mount points on the final mirror gantry in case it was wobbling.
20170527_170253-min.jpg
i noticed that when the lens is in, even if the beam is dead center, it skews to the left (see pic). changing the final mirror seems to have no effect for whatever reason. the lens is convex side up, flat side down.
20170527_165210-min.jpg
if i hold pulse, it looks like there is some sort of reflection happening at the nozzle (see semicircle burn in pic)
i don't know if this has anything to do with getting the double engrave since this only happens when i hold pulse down for a half second or more.
i'm at the end of my patience with this contraption.

[John Noell]

The semicircle says that you are not completely aligned. If you can feel the cone getting warm after a long pulse, it clearly is hitting the inside of the cone. Assuming the beam hits near the center of your final mirror, adjust that mirror to send the beam down he center of the tube. Also, you definitely want the nicely translated (non-chinglish) manual from RD Works Lab.

[James Neathery]

that's what i don't get. with the lens off, the beam hits the work surface dead center. is it possible my optics are messed up? and if the beam is hitting the inside of the cone, would that cause the double image while engraving?

[Bill George]

that's what i don't get. with the lens off, the beam hits the work surface dead center. is it possible my optics are messed up? and if the beam is hitting the inside of the cone, would that cause the double image while engraving?

See Johns answer, yes.

[Bert Kemp]

can you remove the cone and still have the lens in?

that's what i don't get. with the lens off, the beam hits the work surface dead center. is it possible my optics are messed up? and if the beam is hitting the inside of the cone, would that cause the double image while engraving?

[James Neathery]

no, not that i can see