Re: [CAD_CAM_EDM_DRO] routing acrylic/plexiglass

In a message dated 26-Oct-01 20:34:16 Central Daylight Time,
carlcnc@... writes:

> anyone have suggestions or rule of thumb for sfm,type of cutters
> -O-flute?]
>

Carl: I have made "dust shrouds" for several of my own CNC wood-turning
lathes of ¼" acrylic (Lexan, Plexiglas, whadever). First, it is NOT ¼", but
that is beside the point! If your router-bits are properly SHARP (i.e.,
"fresh"), they can be run at "full speed" (for a woodworking router, that is
about 25,000 RPM). "Stopping" might cause galling or a "gouge". Keep the
tool moving steadily, but not faster than, say, 0.005" per turn (if you can
"guess" that closely! I can, after years of "doing that"!). It works just
fine!

Same with PVC and Delrin. I have NO clue about routing UHMW, but I would
GUESS it is same or better than Delrin. Stopping, so that the spinning bit
is "at one place" for longer than a dozen milliseconds generates heat which
can SOMEtimes (no, not "always"! Depends on phases of the moon!) cause a
smear. and USUALLY causes a quite-perceptible "dent" in the cut, right where
you stopped moving.

Use ball-bearing-tipped cutters, running against a metal straight-edge,
clamped nicely to STILL-PAPERED plastic. NEVER expect "nice" results,
running even a clean router on a "bare" plexiglas surface!

Lotsa luck! Be careful! A "harmless-looking" router can do untoward things
to components of the human body with which it was never intended to have
contact!

Jan Rowland, Troll


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