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DoESLiverpool / somebody-should

A place to document practices on the wiki and collect issues/suggestions/to-do items for the physical space at DoES Liverpool
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Gerald is out of alignment #1942

Open amcewen opened 2 months ago

amcewen commented 2 months ago

Brian reported that the alignment on Gerald is way off when he came in tonight. It's not cutting through in the further side of the bed and he spotted that the red targetting laser dot was straying onto the metal surround for the mirror.

/cc @DoESLiverpool/laser-maintenance

Sean-anotherone commented 2 months ago

Had a quick look this evening and as someone is in the middle of a big job opted to not try any fix right now, but there are 2 elements to the problem and both need time to fix :

  1. The cutting axes are currently trapezoidal - this normally happens when someone runs the output piece into a job. The fix needs some careful measuring and 2 people. By my reckoning the RH Y slide needs to be ~2mm toward the front of the machine.

  2. The beam alignment is fundamentally out. This is not from hitting a work piece though as the tube itself seems to be out of line, plus the splitter and primary mirror block ( red dot is out of line too, but by a different amount !!). This will take a while to fix, it needs a full machine realign.

Have left it for now as it works after a fashion and I'm not able to fix it all this eve.

DaveBenji commented 1 month ago

Hi Sean. Is the beam alignment affecting the consistency of the cut? I found that Gerald's power was stronger on the x axis than the y axis and that, across a circular cut the depth of cut varied. What's the plan to rectify the machine faults please?

Sean-anotherone commented 1 month ago

It can, because it affects how the beam hits the final mirror and lens, which has an impact on spot shape. I'm hoping to make it this Thursday eve, and can make a start then

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On Tue, 1 Oct 2024 at 15:47, @.***> wrote:

Hi Sean. Is the beam alignment affecting the consistency of the cut? I found that Gerald's power was stronger on the x axis than the y axis and that, across a circular cut the depth of cut varied. What's the plan to rectify the machine faults please?

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JackiePease commented 1 month ago

Callum has finished his island model, so it should be ok to change the calibration now. @Sean-anotherone @magman2112 are you likely to be able to take a look on Thursday? @DaveBenji this is a large model and Callum doesn't seem to have had any issue with some parts cutting through and others not

DaveBenji commented 1 month ago

Hi Jackie. The machine cuts but for me the quality of the cut is poorer than it has been. Regards

JackiePease commented 1 month ago

Hi Jackie. The machine cuts but for me the quality of the cut is poorer than it has been. Regards

@Sean-anotherone is looking at this on Thursday evening - let's see where we are after that.

magman2112 commented 1 month ago

I managed to have a look at Gerald with JR on Maker Night and made a number of adjustments. We didn’t have the time for a full alignment (Maker Night was quite busy), but we did make quite a few adjustments.

The trapezoid misalignment was corrected, this was out by 9mm across the bed. The laser was then adjusted fully across the bed using the old fashioned masking tape method. There is a slight difference between the red spot and the actual laser beam, hence the tape method.

The lens was particularly dirty, spreading the beam size slightly. This was cleaned along with the key mirrors, which improved the cutting spot size significantly.

The fact that the spotter laser is not in the centre of the mirror on the left side is not critical I believe, not ideal but not critical. The beam maintains the same aspect along the full travel, so in other words it is parallel and consistent, which is the main criteria for this axis. This can be adjusted when we have time for a full alignment.

Subsequent test cuts showed consistent cutting in all axes and over most of the bed. In fact, it is cutting better in the top corner than it has in a while. We did notice a difference in the kerf on vertical compared to horizontal cuts, but this is at the level of 10ths or 100ths of a mm. This is likely because the beam isn’t circular, but an ellipse shape, with the narrow aspect being horizontal (x-axis), this has been the same since the last time the tube was changed.

There is also a 2mm difference in bed height on the right side of the bed that we ran out of time to fix, which can affect the focus slightly on longer cuts.

So it’s over to our regular users now to see if these improvements are good enough.

amcewen commented 1 month ago

Cutting some cardboard on Gerald today and it seems to be cutting nicely. Sizes match what the SVG says (within a mm) and the 90° corners seem to be right.

JackiePease commented 1 month ago

I cut some black cardboard on Monday. The output was fine (it wasn't something I needed to be a specific size), but in retrospect, the settings I used (20/50) seem a bit slow. I'll try cutting the engraved block I had issues with sometime tomorrow if Gerald is free.

amcewen commented 1 month ago

A further update after more of the cutting we were doing this afternoon - although the length and squareness seemed good, and the cut was decent across most of the bed, in the top left corner it wasn't cutting through very well.

JackiePease commented 1 month ago

I cut my woodblock again with engraving at 0 then 90 degrees. It was still misaligned, but I'm wondering if this is a separate problem. Will discuss with @magman2112 or @Sean-anotherone on Saturday before raising a new issues. 2 passes at 15/100 wasn't enough to cut through 5mm ply.