Distance from end of the laser tube

Community Laser Talk
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to the first mirror “housing”. I think I’ve heard somewhere that you want around 1" from the end of the tube to the 1st mirror. I that pretty much common spacing? I have mine at 3/4 of an inch from the mirror housing, allowing another 1/4 into the housing.

A good friend of mine mentioned to me that this distance is pretty critical, or you can get what looks like double engraving “kind of”…

I know about the tape test to make sure your hitting pretty much in the middle.

I put my laser finally on a table to get me off the floor. :slight_smile:

Thoughts on proper distances from the end of tube to mirror housing?

TIA

2

You only need enough clearance to be able to clean the optics, and avoid touching the laser, but that end should be grounded anyways.

This isn’t going to matter. Beam divergence over 1" is insignificant.

What DOES matter is, if you use a combiner, install a black anodized beam stop 90 deg from the beamline. That is, a small % of the beam can reflect off a combiner plate when it’s supposed to pass through. That energy is enough to be dangerous.

One laser I’ve worked with had no beamstop, AND the plate is angled outwards. So, with the hatch open, part of the beam escaped and burned a hole in the drywall.

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Thanks for that info D

Here is the business end of my tube. I do not have it grounded, nor not sure how to go about that to be honest.

You’ll also notice some small air bubbles. I’ve got to get a chiller, which probably has nothing to do with bubbles, but put in a drop or two of dawn, and I get these everything now and then. Pinching the inlet hose does break them up some and they release into the return, but the only way I can rid of them, is to pull the tube out of the braces, and tilt it while the pump is on.

Tube End
https://drive.google.com/file/d/15MRacoEWIQzFiLT7b0ToPeOVG5SLS4vE/view?usp=sharing

4

The black wire leaving that end of the tube (cathode) is grounded or it wouldn’t work… It may go through a mA meter, but it should be at ground potential.

You should rotate your tube so the coolant will take any bubbles out of the tube… So the outlet should go up…

tube-up-crop
tube-up-crop1460×1224 112 KB

:smile_cat:

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Thanks. Jack. Hope all is well with you.

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Still up to my neck in alligators with the new fiber laser… Guess I’m really a masochist… :face_with_spiral_eyes:

:smile_cat:

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Yeah, I really thought that I would just buy a rotary, and I’d be off and running. Least did I know it would be 2 months in the process. Some of it me, Some of Monport. Ugggggg

I actually engraved a sample for some folks Sat. No problem. Yesterday, opening up the same file, and got what I would call weird results. Same file too. I haven’t found the right combo yet with regard to speed / pwr. Right now I “think” its fine at 50mm/30pwr

https://drive.google.com/file/d/1h2BkREDvBgmWBOI7tuk2LcSAc0Q6eOR1/view?usp=sharing

I guess it will all fall in place soon. I’m ordering a chiller today. This bucket of water thing isn’t working out either. Good news is, I finally got a table built, and the laser sit’s up nicely off the ground.

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Alleluia Alleluia

Man, I don’t want to jinx myself, but I want to pass this on.

OK, so I’ve been struggling with getting good engraving on these tumblers. Laser wise. Not the rotary. That’s another whole soap story.

So yesterday a.m. I decided to clean my mirrors. They in fact were “dirty”, So clean them all up. Since I’m yanking my tube in and out because I’ve changed water, and yes I’m ordering a chiller this week, I always put some tape on mirror 1. Great almost dead center.

For giggles I decided to tape 2 and then 3. 2 was off somewhat. The tape on 2 burn hole was off some. I adjusted mirror 1 to correct that. Fine, for what ever reason I didn’t check how mirror 2 was sending that to the final mirror.

I throw on a tumbler, feeling all cocky, and nohting. What? Nothing?
So I put a piece of tape over 3. The one at the tube. Damn laser was just barely hitting it.

I put tape over it, and made the adjustments needed to damn near hit the center. OH, btw, the thumb screw nut on UP/DOWN was loose. Of course this on the gantry.

I center her up, lock her down, burned a 10mm x 10mm square on my sacrificial tumbler. Clean as a whistle. I mean CLEAN !

I’ve never cleaned my mirrors and / or checked them. I’ve had this laser for 8 months, and it probably has 10 hours of run time on it.

Anyhooooooo, thought I would share this. Maybe someone can find it of use.

Cocktail time… .I mean Supper time.

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I’d say you have a mechanical issue also…

Squares

:smile_cat: