eBay Chinese CO2 Laser Cutter & Engraver - Squaring and Alignment

[@MileyonDisney]

I do not know, but I would think that aligning the second mirror close to the laser, then at the opposite end would be much more precise than measuring against the sheet metal. If the laser burns a hole in the tape in the same spot at both ends, it's aligned. It's all based on where that first mirror is pointing. I am only guessing.

[@greggjohnson621]

Actually, if that first order mirror points the beam parallel to the Y axis of the gantry, then it doesn't matter if it's square with the case. That second order mirror adjusts left and right so you can get it in the center of the beam once the beam is parallel to the Y axis. But the issue I'm having is that the anodized x axis bar that carries the laser head left and right, is not 90 degrees to the y axis bars. So far, I don't see an adjustment to square it. Of course I could skew my file to make a perfect part but I'd hate to have to do that for every part I cut. Do you know of a good way to get the x bar a perfect 90 degrees to the y bars?

[@DIY3DTECHcom]

Sort of as my gantry runs downhill and I had to shim it up as the metal case was not square. As this is the problem with these as the expensive units have a ridged substructure hold everthing square, however these, well they are different story :-)

[@johnm7727]

I just got a k40 and noticed that when I slide the y axis of the gantry it seems to have a lot of friction especially compared to the x axis. It seems to be from the metal rail on the left side. There is an audible grind when I move it. Would lubricating the rail fix this or could it be the belts?

[@DIY3DTECHcom]

Could be the wheels as I had to replace a set in one as thy were bad. You can get them from light objects...

[@jmpattillo]

Instead of worrying about the gantry being square to the sheet metal, couldn’t you reposition the first order mirror so that it casts the beam parallel to the y axis rail of the gantry?

[@jmpattillo]

Whoops. Never mind. I see that was addressed in another comment

[@DIY3DTECHcom]

:-)

[@RichardVowles]

This has to be the best video for metric measurement i have seen for a while. 1/28th? Thanks for the video though!

[@DIY3DTECHcom]

+Richard Vowles laser beams aren't very wide :-) Glad it was help and if you any questions feel free to ask ...

[@freebird1963]

Seems funny to be squaring to the side. How do you know that is level and square.?

[@DIY3DTECHcom]

Simple you are only using this as a reference point, as what is "square"? In short this becomes your point of origin to square off of...

[@donaldkerr1901]

I'm many hours into a confusing problem. On my 100W china laser, the X axis does not cut at a 90 degree to the Y axis. My gantry is true and square. When I move the head on the Y axis front to back it stays straight. When I move my X left to right, it measures a half inch different for left to right. In other words, from the front gantry rail to the X beam, it can be 5 inches from rail to beam, and on the other side it will be 5.5 inches. I don't see any adjustments? When I tied to shim the rail end it binds in the Y rails. It does a great job unless I need a square cut or a perfect circle, not other things you can't notice its off.

[@DIY3DTECHcom]

From what you explained it not square, I know that is an obvious statement however what many folks miss is must square both the beam and mechanics. In doing that neither might be truly square on its own so both might be off to come to a square result.

[@roncarpenter2984]

Okay I have a question, I have a k40 I updated the exhaust port and hade to take out the gantry and when I put it back in the mirrors won’t line up. The primary and secondary will until I move the secondary back to the other end and it’s so far off it’s. It even on a sheet of paper. I’ve tried everything and I’m so frustrated I want to just sell it. How can I fix this problem ? Please help.

[@DIY3DTECHcom]

Its because the gantry isn't square as it needs to be square in X, y and yes Z. If you look in my eBay/K40 playlist you will find a video where I had to design and 3d a print a shim for this....

[@GaryMcKinnonUFO]

Yes, bring out the Geekdom, laser-measure it ! This is very handy, i've ordered a set square now, thanks :)

[@bamabeeeze]

I've perfect Y axis alignment. I fight with X axis alignment of the 2nd mirror aligning with the laserhead along the X axis. What are the square mechanical actions to align the moving gantry's alignment? Thank you!

[@DIY3DTECHcom]

If your having issues in X you likely do not have "perfect Y axis alignment" as it is "all" or "nothing". Most folks struggle with this as I did for a while as I cover it in many videos, in high end lasers the optical train is "suspended" so it exists in its own common "mechanical" plane which is one of the things that make them so expensive. As you should be able (i.e. need to) set all optical surfaces to a perfect 90deg angle and it should work, if it doesn't you need to adjust the mechanics and not the optics...

[@1taiyab]

After getting mirror 1,2 and 3 perfectly aligned, i perform the test at all four corners to see if they all hit the same place. However, only the top right hand corner of the machine is not aligned, all three other corners are perfectly aligned. Any idea what could be causing this problem?

[@DIY3DTECHcom]

All mirrors should be at perfect 45 deg angles, if you have to adjust them then the optical train itself is off and this very common as the high end lasers have a ridge inter-frame for this reason and one of the reason they cost so much more. Also keep in mind that the laser tube itself MUST be square too. Note as you will see my other videos, you might have to shim the optical train...

[@1taiyab]

Really appreciate your response. Can you please link me to your video that shows how to shim the optical train? I believe that is my only problem. May have been caused by the mishandling of the machine when it was being set up.

[@DIY3DTECHcom]

Its been a while so I don't have episode off the top of my head, however take a look at the "eBay Chinese CO2 Laser Cutter & Engraver" playlist...

[@LittleBullseye]

apparently the huge waste of a vent that sticks out half way into the bed area is so wide that I cant get the gantry far enough over to align it square with the laser. I'm a woodworker and this is out of my element. Wish you were near as I would pay you to fix this...

[@DIY3DTECHcom]

Its easy to fix, place a metal cutting blade in your band-saw and cut it off, that what I did....

[@LittleBullseye]

DIY3DTECH.com My vent is welded in 2 spots onto the back of the box. I have had the k40 for over a month now and just finally aligned the mirrors and the rails. I want to test it out a bit on cardboard over the next few days. Then I will start adding and taking away. From what I hear, forced air is a must, which means I will be ordering an air assist nozzle after I make sure the laser operates properly. I have been scouring your videos like crazy!

[@DIY3DTECHcom]

BIG YES on the air assist especially with cardboard! Welded, Hmm can you pop the welds and replace with screws? Also any question just feel free to hit me up :-)

[@DIY3DTECHcom]

Ah hope all has been going well as YT notifications was a little slow in showing me this :-)

[@mauritzbotha4422]

wouldn't it help just to get Adjustable brackets for the tube and alignm the tube with the rail? surely non of them rest should matter then should it? if you can align the tube parallel with the direction the x rail moves.

[@DIY3DTECHcom]

No and Yes, if you watch the laser play list I do design and 3D print a set of adjustable tube holders so that is the "yes" part but the "no" part is that is only "part" of the solution. If you look at high end laser the the entire optical train "floats" as if you tie any portion of the "train" down you also tie yourself to some form of drift as nothing is square...

[@mauritzbotha4422]

but if the tube is parallel with the rail, I dont see how it would matter? All the mirrors are adjustable, so you can get 90 degrees on each mirror regardless of how skew the rails are. As long as they move consistently in the same skew direction. I have an alignment problem with my machine, and I have made adjustable brackets for the tube and a special jig to line everything up perfectly. My alignment is still out doesnt matter how hard I try, but I noticed that the end of my tube isnt actually in line with the rest of the tube. So I am planning on realigning everything again to compensate for the tube itself. The problem with the tubes are, they are hand made. Are you sure this is not your problem as well?

[@DIY3DTECHcom]

Let me explain it this way, unless everything is not at a perfect 45deg angle you have an issue if you have "to adjust" anything you have an issue. This is why in expensive systems the optical train "floats" which mean its not 45deg to the chassis but to the optical train it is. Again if you look at the expensive lasers (10k and up) they have an inter-frame to float the optics. As any adjustment means at some point there will be run out.

[@sotm6078]

My K40 gantry is spot welded to the bottom sheet metal at the 4 corners, not bolted. :(

[@DIY3DTECHcom]

Wow that is different!

[@sotm6078]

Minor correction. After removal of the cutting bed I found that the gantry was bolted to sheet metal stand offs that were spot welded to the case. Couldn't see anything but the spot welds until I removed the cutting bed. It's even slotted for adjustment if needed. Four bolts, two on the back rail and two on the front rail. Not quite like your pictures.

[@jamienoel]

You aren't going to believe this, I didn't at first and I saw it with my own eyes. I destroyed the second mirror while realigning because I apparently had the tape touching while doing the test fires and ended up noticeably scuffing it, plus it had a black mark in one spot that wouldn't come off. While searching for the best type of mirrors, (Si,Mo etc.) I saw a post that mentioned using metal (not the glass or ceramic) hard drive platters because of their mirror finish. I had a few bad drives waiting to be scrapped, so I said what the hell and tried it. I placed tape on the platter to protect it from scuffing and used my Harbor Freight hole punch (3/4") and my press as the first try, but it looked slightly concave to me, so I used a hole saw on the second one and it looked perfectly flat. I swapped the mirror in the head with the second mirror and proceeded to test the platter cutout from the hole saw in the head at 4ma. I grabbed a wood ruler for a quick test and it left a burn mark about as good as the original lens. Just for the hell of it, I thought I would try the piece I punched out AND ABOUT FREAKED OUT! It left a much smaller hole that punched right through the wood ruler and out the other side! I repeated the test to be sure and was in shock at this point. I wanted to see how each mirror performed at 5ma, 10mm/s with 1/4" cast acrylic. The punched out platter mirror went just past the midway point while both the flat and original mirror were just under the midway point. I haven't added air assist yet and can cut 1/4" acrylic clean through at 16-17ma at 5mm/s. Not sure if that's good or not since I'm new to this.

[@DIY3DTECHcom]

Must say the hard drive is a first and interesting also you should avoid touching the (which are basically metal) as they can have a level of toxicity so I use nitrial gloves. Cutting 6.35mm at 5mm @ 17ma is pretty normal for a new tube (typically up around 19ma) and will depend too on the type of acrylic too. Keep in mind the laser will decay with use as the CO2 will break down into Nitrogen over time so new tube should perform very well. Please keep me posted on mirror adventures, sounds interesting as have heard of people making their own mirror from polished copper...

[@jamienoel]

Update on hard drive platter mirrors: I fried my lens! I used the HF tool and made a few more mirrors to test and of course using this method instead of the hole saw method makes them slightly concave. I had the lens out while aligning everything because I didn't want to chance burning the masking tape to it and noticed the beam was coming through the tape in a smaller diameter than usual. After screwing the lens back in, I took a piece of 1" x 2" solid wood, put it in place and hit the test button (it was still on 8 ma) and it punched right through the wood and out the other side with a hole so small, I couldn't believe it. The weird thing was that I could swear I saw the beam, but I don't have air assist yet, so it I assumed it was just smoke coming straight back up. It made the weirdest sound when it punched through the wood, like a high pitched, but flat sound. I checked the lens because I wanted to make sure it wasn't covered in smoke and it was burnt where the beam went through. S at this point, I said the hell with it and will mess with it tomorrow. Also, having a hell of a time trying to get it lined up in the upper right corner (original mirrors or HD mirrors) with the lower right corner. Trying different shim methods tomorrow. I can do that after ordering a new lens. lol

[@MarkSchuster-ym3iy]

I say that because I’ve got a 100 watt 3500 dollar Chinese laser and the metal box is not square with itself

[@DIY3DTECHcom]

Correct, how do you like I am considering picking one up...

[@donaldkerr1901]

@@DIY3DTECHcom I like my 100W, except for the problem I posted about in this feed - my x axis doesnt seem to be square 90 degrees to the Y, my x beam is not straight?

[@MarkSchuster-ym3iy]

It’s not as important that the carriage is square to the box just the frame

[@DIY3DTECHcom]

but the box persay is part of the frame...

[@BillyBob-si2db]

Squaring to flimsy sheet metal is a joke in itself. Majoring in minor things.

[@DIY3DTECHcom]

Well its better then nothing isn't it?