Announcement

Collapse
No announcement yet.

Milling 3mm Perspex (Plexiglass, Acrylic) Disc

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Georgineer
    replied
    Ed,

    I'm currently working on a job which involves cutting some pretty complicated shapes in black acrylic. (Evan, Ed's not entirely wrong about Perspex being 'clear black' - when you mill it to less than 1 mm thickness and hold it up to the light, it's actually dark green and translucent!)

    I did it on a much less powerful machine than yours and went for very conservative feed. I used a 2 mm 2-flute carbide endmill at 12 000 RPM without coolant, with 0.5 mm depth of cut and 8 mm/sec feed. The edges come out very smooth, 'semi-polished', without any hint of chipping. I agree with Evan about the importance of robust workholding.

    My next challenge is to fake up a line bender with some nichrome wire and a power supply, to put an accurate 90 degree fold in it.

    George

    Leave a comment:


  • Evan
    replied
    but I cheated and used a laser
    You SUCK John.

    If cutting dry I would also go lower than 5k rpm. With water it will work fine.

    Leave a comment:


  • John Stevenson
    replied
    Whoa, those speeds are way too high, Even is closer but to be honest I'd veer to a bit lower than that.
    Can you use 2 flute or even a single flute router bit ?

    Secret to milling plastic is to get rid of the chips, recutting chips causes heat and rewelding.

    Just done three small machine windows today in 3mm clear perspex, ran at 20mm / sec but I cheated and used a laser, came out perfect with polished edges - sorry

    Leave a comment:


  • Evan
    replied
    Keep the rpm at the very low end like around 5000 rpm. Feed consistent with less than maximum chip load. If it is at all flexible make sure it cannot climb the cutter or it will. Lube with soapy water for cooling. BTW, I am having difficulty imagining "clear black" plastic.

    Leave a comment:


  • The Doctor
    started a topic Milling 3mm Perspex (Plexiglass, Acrylic) Disc

    Milling 3mm Perspex (Plexiglass, Acrylic) Disc

    I need to make essentially a very large washer (~3" OX x ~1.25 ID) out of clear black acrylic sheet (Perspex 962 Black).

    I'll be using a CNC mill, with a spindle speed range of 80-30,000 RPM and feed to 147 IPM. Cutter will be a new, high quality 1/8" 4FL carbide end mill.

    I would appreciate some advice on speeds, feeds, and techniques to do this without melting or excessive chipping. GWizard suggests ~20,000 RPM & ~147 IPM (.0019" per tooth). Feed per tooth stays the same at lower speeds. If I choose "conservative" on the slider, it drops to .0012 per tooth, but still 18,000 RPM+.

    The recommended speeds seem likely to cause melting (no coolant) & the feed seems likely to chip. I'll probably use 3 passes to get through the full thickness, but not really sure about the rest. It's not a part where perfection is required, but I'm kinda picky.


    Thanks
    Ed
Working...
X