xiphmont: (Default)

TD (@enginetankard) will concur--- I wouldn't shut up about it when he was here.

Chinese laser cutters often come with a little air pump; it's used to blow smoke away from the optics while cutting. You're supposed to set it up somewhere near the machine, and run an air tube in. It's a simple little AC coil/solenoid attached to a piston. It also vibrates enough that it will walk across a workbench under its own power unless you bolt it to something. I want my air pump internal to the cutter, and I want it automatically controlled to only be on when cutting. Vibration would be a major problem mounting it inside the case, so I took two of the little ones, machined a custom output valve housing/gasket and connected them in opposing orientation. Viola! No vibration.

xiphmont: (Default)

The radiator juuust sneaks in. And a big rad needs nice beefy fans, which double as smoke exhaust.

Also, it's nice of the vendor to use flimsy tack welds that snap right off with a little prying. I'm actually serious here. No reason to stupidly overbuild. This thing is made to be messed with.

Also also it's _really_ hard to nibble in a straight line.

xiphmont: (Default)

I've built up quite a pile of project pics I took meaning to post, then never got around to it.

OK, so, laser cutter.

China sells a lot of cheap cheap cheap "It's so cheap I can't believe that price covers shipping let alone materials" maker tools. Some are better than others, and many barely work for their intended purpose out of the box. Overall, plan to get what you pay for, and I mean that in both the good and bad senses.

Most of these tools make decent starting kits though! Research a bit, then choose the kit with the most parts you want to keep (or the fewest you plan to toss).

I bought a K40 variant (SL320) on AliExpress, and I'm building it into a complete cutter now. It has a decent X/Y stage, came with a good tube (which I promptly broke while being an idiot), a larger than normal case, tubing, flow sensor, air assist head, and a better than average power supply. It also came with an exhaust fan and aquarium pump I don't plan to use, a useless Z-stage, and an air pump that makes half of the ideal.

Others are already doing a good, detailed job of documenting their K40 builds. I've been referring to Dons Things and Tims Machines extensively for tips in my own build. So, I'm going to stick to pictures, terse captions, and the few things I've uncovered that I haven't seen solved elsewhere.

I don't want my water cooling tubing dangling out back to an open bucket and a failure-prone aquarium pump, and I'm pretty sure an external chiller is overkill. I want a fully internal, closed water cooling loop. Water cooling may be useless (if still cool) for PCs these days (ha ha, see what I did there), but it does mean nice cooling parts are cheap and plentiful for other uses.

So, step 1: shoehorn in the biggest possible radiator core. And by biggest possible, I mean, "move everything else as far out of the way as I can to make more room". That starts with lifting the laser tube tray up by about 2cm. The original mounting flange is just tack-welded on. It's easy to pop it right off.

The limitation to how much higher I can go is actually the clearance of the mirrors along the left side, and the XY stage fitting under the door opening lip in the front. You can see I also nibbled off about half the depth of the left side of the door opening lip.

Aside: freehand nibbling is really hard to get straight.

xiphmont: (Default)

It's an old pic at this point (taken while TD, aka, @enginetankard was still here in January) but I can't mention 'laser cutter progress' without following up at least a little.

This was one of the first test runs, and it revealed a problem with laser arc stability. More about that soon, because I think quite a number of K40/D40/SL3020 users are putting up with it, unaware of the cause or the fix.


xiphmont: (Default)


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