Laser Focus Fine but has side reflection

Laser
1

Some member left a note that the laser was out of focus. I went to check and a member that is currently cutting a piece is showing a blackening of the paper masking parallel to the cut to the right.

I guess the head has been bumped and the beam is impacting the side of the lens holder.

Someone from the laser committee needs to check the laser.

2

It looks like the upper left hand corner of the cutting bed is lower than the other three corners.

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I noticed something similar as well yesterday. When cutting at super low power we would get nice fine cut lines, but when we increased the power the cutting dot became a blob. I may have something to do with power as well as focus.

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It could also be that the head is dirty, or maybe one of the mirrors. I noticed last Thursday that the CO2 tube, that I had cleaned just a month ago, was filthy, again.

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I experienced the same issue as well, on Saturday night.
Haley figured the mirrors were quite dirty and was kind enough to clean them.
(Thanks again Haley).

I did not try it after the cleaning, though.

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I used the laser last night and can confirm that the issue is still present. It definitely becomes more noticeable at higher power settings.

7

My guess is the parasitic beam always is present, but it isn’t noticeable until reaching higher power levels.

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I had lunch with Matt Smithers and Lampy, They were guessing that the most likely issue is dirt and grime. Matt has a 150 watt laser that he draws his knowledge from, and ken has had extensive use of our laser at DMS. So they do have a bit of knowledge.

The laser is being used more than ever right now, especially for engraving which is messy. It may be that the laser is just getting dirty.

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Oh, I can say definitely that the laser is getting dirty! I mentioned in another thread that I found the CO2 tube was filthy last Thursday evening, which surprised me, because I had just cleaned it a month earlier.

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I think that perhaps we should set up a planned maintenance schedule so that we at least look at things like cleaning and lubing regularly. Hopefully by being diligent and keeping it clean and maintained we can head off any unnecessary failures.

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Perhaps... however everything is done on a as-needed basis.

Most things only need to be done like once per month.

However it is a select few users that continually ram the laser head. IF they would just email or tell us, we could get things done faster.

Most of this will be solved when the access controls are implemented.

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Regarding cleaning & maintenance…

I’ve mentioned this particular thread a couple times in the past, as it’s the one that keeps popping up when I try to research best practices for cleaning / maintenance for a heavily used laser (like ours).

http://www.fullspectrumengineering.com/forums/viewtopic.php?f=3&t=29694

Info from the posts:

From TLHarrell (South San Francisco Bay Area - Sales and Support Representative for Full Spectrum Engineering)

  • I’d say routine maintenance should be done a little more religiously.
  • I’d also consider placing a small whiteboard on the wall behind the machine with [Aligned], [Lenses and Mirrors], [Lubrication] tasks and a space for a date and initials. This way you know who did what and when.
  • I’d say clean the lens and mirrors a couple times a week in your situation. You never know how others will treat the equipment. Did someone touch it? Were they working on sanding MDF right on top of the machine yesterday?
  • Lubrication, probably twice a month. Give the rails a good wipe down, then relubricate. Again, if this were in your house you probably wouldn’t do this much maintenance, but since it’s in a shared common area more is better and certainly won’t hurt anything.
  • I rarely clean my honeycomb bed. Occasionally I’ll drop it into a bucket of hot water and dish soap and let it soak for a few hours. Kind of depends on what you’re cutting. If you start getting a lot of flare up from deposits, or deposits are starting to leave marks on your finished pieces, then clean it.
  • Note the amount of time between cleanings there, and adjust to the routine or shorten by a week or so.

From RGInCanada

Our lasers are production machine, in a shop like environment. We cut 3/8" hardwood at 100% power day in, day out, 6-7 days a week, as many as 18 hours a day. I doubt many people run their machines as hard as we do. We are in the third year with our 12x20 80W, and a few months in with the 18x20 ProLF 80W.

  • We clean the rails whenever they look yellowed, or the servos complain when homing.
  • The honeycomb gets cleaned once or twice a week using an Orange based cleaner in tub of hot water. A few times a year we bring it to the manual car wash and hose it down with soap and the pressure washer. Both are black and scorched, but work just fine. :slight_smile:
  • The older machine requires optics cleaning once a day at least with a camera lens wipe, as the lenses and all mirrors are exposed. The new machine with its shrouded optics has yet to need cleaning.
  • We check alignment a couple times a month, or if performance degrades, or there is a noticeable “slant” to the cuts.
  • We have yet to swap out a laser tube, although we have a spare on hand. We have had two power supplies fail, and the air assist tubing on the first machine degraded severely and required replacement.
  • As a side note, both machines are attached to a 1200cfm exhaust fan. This and the air assist are the biggest factors in maintaining clean parts.
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I doubt our air-handling system is fully effective, especially when someone cuts really smoky material.

I’d be curious how many hours of cutting the machine actually gets. I wonder if we (by which I mean, someone other than me) could install a time usage meter on the power switch?

I’m curious how that shrouded optics system works.

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I might be up for the challenge of adding a usage meter. Surely it would be easy to put one on the main supply. But it seems it would be even more interesting to (also) have one slaved to laser firing operations. Does anybody know if there are suitable schematics anywhere? Are there any warranty considerations to keep in mind?

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I was going to clean the lens yesterday, but caught up in business stuff. I will clean it tonight if no one else has done it before then.

2 Likes
16

Thanks Haley for cleaning the lenses. Next time I run into you at the space, could you give me a run down on what to do to clean the lenses without messing anything up?

@cottjr you should probably talk directly with William a bit before you jump into modifying the machine. Not that I doubt your ability, it would just help keep from having anyone one blow up for no good reason. Once you have a plan, just send a PM to william_petefish and I hope he is willing to help you add the meter.

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What’s a side reflection and how does that affect the way the laser works?

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If the laser beam is not centered on the bounce mirrors or through the center of the lens, the beam can impact the side of the lens holder a make a secondary beam. Usually it is much weaker. You can also get weird beam shapes if the lens is not seated properly in the holder.

I’ve seen the laser being used were it was cutting a line. Made interesting kerf shape in the cut!

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@Nick - thanks & you bet. That was just newbie brainstorming on my part. I’ll reach out as you suggest - maybe at tonights member meeting…

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Cool, I hope to see you at the space tonight to introduce myself.