Hi there. So it was only matter of time until I ran the drill into those badly designed (IMO) clamps. (I think I will toss them away and find other system). Anyway, original SM flat end bit is gone, and I replaced it. Now I notice that it picks up the plastic I’m cutting; supposedly it’s acrylic, and I had used acrylic without problems before.
What causes this, is this a different software settings, is the bit not good (looks the same as the original and wasn’t cheap)…? And most of all, how can I remove the plastic to use the bit again. It’s hard as a rock.
After breaking that bit, and the next one immediately gathering very hard plastic again, I now believe I picked the wrong plastic sheet, and this is not actually acrylic but some other unusable material.
You are most likely correct on your guess.
This happens due to heat build up on the bit, it starts melting instead of cutting. Potentially reducing the speeds (spindle or feed rate) could help win this material over.
The plastic blob suggests that the plastic gets so hot that it melts and then accumulates around the bit. This may either be that the bit is not suitable for plastic, or that RPM and feed rates are too high (too much friction, not enough time to cool down. So if you verfied that the bit is good for plastic, try getting slower.
The problem with the clamps evade me - I actually like the Snapmaker clamps very much! Admittedly, the can protrude quite a bit an then there’s a risk that the head runs into the clamps, but this will hold true to some extent for any clamp. If you have a bit of material to spare, you could think about drilling screws into it down into the wasteboard - that will fixate the workpiece, but the screws will sit flat with the surface.
I did another run now with a plastic that is for sure acrylic. It went a bit better, but still had the blob problem. So I conclude that the original Snapmaker flat end mill bit was particularly well suited for acrylic, and the replacement bits were very bad suited, even though they were quite expensive.
Can anyone recommend 1 to 1.5mm bits (preferably via amazon.de) that clearly work with acrylic glass without creating the blobs? Of course, I could also buy the original SM ones, but then I’d like to buy a larger set and different diameters.
I have not yet worked with Acrylic, so I have no first hand suggestion. I (being Germany based) source my CNC bits from HC Maschinentechnik, and they have bits specifically for plastic:
That’s perhaps something to realize: The bits you linked are not really expensive. They (10 pieces) cost what a single bit at HC Maschinentechnik costs, and those from HC Maschinentechnik are not even the expensive ones. However, my take is that it is a good idea to invest in quality - faster working speeds, better results, less frustrations.
There are two types of acrylic - cast and extruded.
Cast is what you want. Mills better and melts less.
Usually if it’s not indicated, then it’s extruded. The cheaper stuff at Lowes or Home Depot is usually extruded.
Thanks! I also noticed that slowing down the travelling speed didn’t actually help but builds up around the same amount across the same distance. I ordered two different bits now both of which say they are optimised for acrylic glass and plastic. I’ll report back.
The plastic may be dissolvable in acetone or MEK. I use a product from BerryMan called B-12 (fuel injector cleaner) and it may help remove or at least soften the hard ball enough that you can remove it. The stuff turns PVC into mush.
New Snapmaker user - Having the same issues - will try some of the suggestions in the chat. However, I’ve been using a heatgun to melt the blob - pausing every 20-30 seconds, removing it, resuming… Very annoying, but the results are pretty good.
Acetone is likely somewhere in my household already. For now, those bits had been broken, but next time.