I’ve been doing a fair amount of cutting of Aluminium on the Carvey recently, and I’ve noticed that sheet aluminium is difficulty to hold down sufficiently well to get a good cut. You’re using an up-cut bit, because Aluminium, which exacerbates the issue… In most cases, solving this comes down to
Make sure the clamps are equally spaced and there are sufficient of them (ie: as many as possible)
When placing the sheet onto the wasteboard, look along the edge of the metal. If there is a natural bend upwards of the sheet, turn it over so that the natural bend is pushing the metal into the wasteboard, not out from it.
Try using double-sided sticky tape to keep the metal attached to the wasteboard. This is a method of last resort because cutting through the metal will inevitably cut through the tape, leaving you with lots of small islands of tape to try and remove from the wasteboard after the cut. This can be surprisingly difficult to do with a bumpy wasteboard…
However, making life more difficult is that on one part of the wasteboard, (the vertical edge between the back of the wasteboard and the smart clamp), there are no clamp holes. I get that there’s not much space there, but I think it’d be possible to put one or two holes there for clamps, even if the clamps themselves had to be angled to prevent them hitting the side of the case.
See here for an illustration of the problem. Fortunately I was present (in hour 5 of a 5-hour carve) and could e-stop the machine as it started to try and cut 0.8mm of aluminium in a single pass. Taping down the metal was the best I could do at the time, and it worked reasonably well, but tape isn’t reliable either.
So, any chance of more holes in the wasteboard in future ?