I was having a TON of problems cutting acrylic. I used all of the tips from this thread and still, the cut was not weldable and required prep after.
A few things I figured out while wasting a TON of acrylic lol…
- make sure spindle is going in the proper direction when using a spindle/vfd combo!
- cast vs extruded, there is a noticeable difference
- BIT - I tried some cheap single o flute bits and had decent success on both extruded and cast. I ordered an Onsrud 63-515 made specifically for acrylic and WOW! No longer are the chips partially melted and slung all over the place. This bit is amazing and worth the money. You get what you pay for. My cuts with a .001 finishing pass are weldable with no further prep.
I know tip #1 seems pretty obvious but being new to this hobby, I thought I had it wired correctly to the VFD and it turns out when I slowed it down to 1 RPM, you could see that FWD on the VFD was running the bit in reverse. I rewired the VFD and it now runs in the correct direction.
I let VCarve determine the feed rate, and I am running at 17,000RPM with a .021 depth of cut per pass. The feed rate is pretty decent though, I would guess over 100ipm closer to 130ipm.