I have no idea what “bad as a laser” means. When I suggested you post your bit issues as a separate question, I was hoping someone with extensive plastic milling experience would respond. I’m confident you can find a recipe and bit combo that would cut your material down to 1.5mm, and it possible you can go smaller. You may need a specialty plastics bit, but I would start with standard flat endmills with 1 or 2 flutes, and I would try some burr engraving bits as well. Based on some acrylics cutting done by others on the Shapeoko, I’d start with this recipe:
- 1 or 2 flute endmills
- 1.0 to 1.5 (8,500 rpm to 10,000 rpm) setting on the Makita
- Cutting feedrate of 1100 to 1800 mm/min
- Start with 0.5 mm depth of cut
V-bits are a different item. The angle of the v-bits and the depth it cuts determines the top width of the cut. You can make fine shallow lines with high-quality large v-bits as long as you have your machine and spoil board tuned so that the depth of the cut remains constant. Without knowing what you are trying to make with your MPCNC, it is hard to make specific v-bit recommendations.
I’m curious enough about cutting plastic that when my current project is off the machine (likely tomorrow) , I’ll toss a piece of extruded scrap acrylic on the machine and try to machine it with some smaller bits. It won’t be your specific plastic, but it will give you and idea.