17 November 2025

Bit of fun over the weekend ... pulled a car load of damp kit from the garage and have it drying in the hall at the moment. But still managed to progress a few things such as cutting the remaining parts for the third section of the marble run setup from FreeLaserFiles.

I had used up all of the original MDF building the first two units, and ordered a larger batch to continue, and while the new larger batch of stock was a lot cheaper than the original, it's also more problematic cutting. I had a problem initially which turned out to be that the laser had slid down a little too close to the surface and out of focus. Having corrected that, I found that even with the 'air assist', the nozzle was a little blocked so needed a clean out. Running the cut test showed something curious. While 2 passes at 240mm/min cut cleanly, one pass at 120mm/min did not, in fact even 80mm/min was struggling to cut through. I opted for 200mm/min with 2 passes and on the whole the results are clean, but a few small areas had not cut through fully. Craft knife managed to sort the gaps, but I still ended up running extra parts to get a full clean set. In addition to not cutting properly, the MDF does not seem to be as strong as the earlier batch and I've actually snapped a couple of parts while building. Perhaps I need a switch to plywood which while even more expensive, should cut cleaner and be stronger.

At the same time as I was running the laser cutter, the 3D printer was running another pair of spool roller sides. What I had not initially appreciated is that the Spanish filament spools has 175mm disk on one side and 160mm on the other! You do not notice until you put them onto the rollers and they are cak-handed. At least the new batch of filament has narrower spools with the same diameter on each side. Adding a bit of packing at least allows me to use up the older stock and the black is currently running down nicely as I try printing a more ridged mount for the z axis supports. Still waiting on the second pulley, and now have some linear bearings to augment the front to back rigidity. The part currently printing is diagonally across the bed, and apart from a little variation on the first layer, it's printing nicely ... and will finish tomorrow ... I need to print a small flange to connect the motor to the ball lift next. I should have watched the full video before ordering the latest little batch of parts as they also stock a metal one. Making my own will be useful practice. I'm also looking at combining the laser printer with a plastic core to make small spools for the 16x0.7 and 32x0.7 wire along the same size as the 7x0.7 spools. I can then build a plywood rack to keep them all tidy. Not sure if it's worth keeping the left over wire on the large drums. Will sort that later, but to have all three sizes ready above the bench will be progress. I've ended up with extra rolls of wire where I've not been able to locate the originals when rushing to finish jobs! Adding a friction slide to hold the ends of the wire will just be icing on the cake. I've printed an all plastic spool, but I think 1.5mm ply with the plastic core will be easier, and a nice little project to draw up in FreeCAD.

I took the opportunity to pick up some flat head M5 bolts. Not sure they will be much lower than the shallow dome on the existing ones on the gantry of the laser cutter, but they may give me another 2mm on the X axis which will tidy the remaining niggle there. I've picked up a couple of longer jst stepper motor cables for the 3D printer, but no one seem to do longer 2 or 3pin ones for the sensors, so I'll have to manually extend those. There SHOULD be some empty shells and crimp pins in stock here somewhere so I can probably make my own ... if I can find them ...