Brian's "my wife isn't sure about this contraption" build

[quadmasta]

I put in MakerSlide for the Y ways and got the gantry back on. I really wish I had a manual mill to remove the profile where I had to put support angles. I can probably have it up and running again in 6 hours or so.

[quadmasta]

So far, the alignment with makerslide and the re-squared gantry is way better than the last time. While aligning my mirrors, I can't get one corner to hit. If you number them clockwise starting in the rear left corner, I can't get mirror 1 aligned; 2, 3, and 4 are aligned perfectly. The mirror at the laser and the mirror on the gantry are both the same distance from the side frame member. The laser mirror mount is perpendicular to the rear frame member and parallel to the side frame member. The frame members are as close to square as I can get them. Anybody have any pointers on aiming for me?

[BenJackson]

I doubt I would have gotten my laser aligned if I had not started with the red laser that let me see what was going on. If you are truly stuck you could always remove the real tube (try backing out only one alignment screw so you can repeat the tube position) and insert a jig with a red laser. Your setup sounds like it is already working well enough that you could laser cut a front disc with a pinhole (for aiming) and a rear disc with a hole large enough to hold a laser pointer. The OD of the discs should match the tube (50mm in my case).

However, to diagnose from your current setup we need to know how the beam is moving as you move the gantry and carriage around. If you put a test target in front of the final 45 degree mirror assembly, where does the beam hit as you move to those 4 corners?

Given your description I can guess that the beam is too high or too low at the tube and your setup has the beam angled downward (or upward) enough that once sufficiently far from the tube (note your failing position is the shortest beam path) it is back in alignment. At this point you have to give up your success on 2,3,4 and get that position 1 to work first.

[quadmasta]

Should I do 1, 4, 2, 3?

[BenJackson]

Should I do 1, 4, 2, 3?

Yes. After you have adjusted the tube and the first mirror to hit the the gantry mirror in the center at position 1, move to position 4 and ensure it still hits the center (or even part way to 4). If adjustments of the first mirror can't center the beam at 1 and 4 then you will have to adjust the tube until you can. After that you should not touch the tube or first mirror while you use the gantry mirror to center the beam on the carriage in position 1, then 2. At that point you should be hitting at 4 and 3.

I think this is all spelled out in the build doc linked from the drawings page (near the end).

[quadmasta]

I've checked that everything is within the same plane vertically. I've checked parallelism of the laser and gantry mirror. I adjusted the gantry belts so it's tracking evenly. If I align the laser to fire on the first mirror dead center and then dead center on the second mirror it's fine at position 1. If I move to position 4, the laser is off to the inside of the machine. As I move from position 1 to position 2 the laser goes further toward the front of the machine and up. By the time the carriage is about an inch and a half away the laser no longer is hitting the mirror on the final optic.

What do I need to check?

[StigOE]

First you need to adjust the mirror by the laser so that you hit the same spot on the gantry mirror in both position 1 and 4, then leave the mirror by the laser alone. Next step is to make sure you hit the same spot in the laser head opening for both position 1 and 2. If it's correctly adjusted, you should hit the same spot in postion 3 and 4 as well. If the spot in the laser head opening that you hit is to the side of the center, you need to move the laser plate to the side until you hit it in the center. If you hit too high or too low, you need to adjust the height of the laser tube, or at least, where you hit the first mirror. Then, make sure you hit the mirror in the laser head at precisely 90 degrees when you look at it from above. The final step is to adjust the last mirror so that the beam exits out the air assist nozzle in the middle of the opening. You may have to use some paper or something to adjust the angle of the last mirror for this.

Good luck.

[quadmasta]

I had a few issues. The laser wasn't perpendicular to the end of the machine. The stupid adjustment screw that adjusts in both directions on the mirrors were both causing issues. I've got a good focus at all 4 positions now

[quadmasta]

I finally got something thick enough that I could check edge sqareness. When the carriage is closer to the mirror on the gantry, everything's relatively plumb. The further it gets away from the mirror, the more the slant is noticeable. Since it's not off at both ends of travel it leads me to believe that the issue is with the focus mirror being not centered within its holder. Is this correct?

[BenJackson]

Which way is the slant?