Re: ATM Plastics for machining

[Dominic-Luc Webb molmed <Dominic.Luc-Webb@molmed.ki.se>]

On Tue, 30 Oct 2001, Anthony Stillman wrote:

   > >You CAN cut threads in acrylic
   >
   > Jerry,
   >
   > How?  Every time I've tried, they've chiped out or the tap jams.  Is there
   > a trick?  Please, I'm begging, tell me how?


I will check this with our machine shop. We are a
medical laboratory, and use threaded clear plastics
routinely for many applications. My coworker tells
me it is polymethyl-something-or-another-acrylate,
and it is same as is used for hocky fields, also
called plexiglass. This material is what we are
using to make decent precision perifusion columns
etc. The construction is virtually identical in
size and dimensions & threading & quality as FPLC
or HPLC columns, if you have seen these (lots of
pictures on the internet). I cannot recommend our
machine shop to do such work, due to fantastic
fees, but I have managed to tap threads into plastic
and have made threads on plastic rod. I think
standard tap and dies would work. This is how I
constructed parts of my motion control system. I
have typically worked slowly with taps and dies,
because I think the plastic can get hot and melt
rather than cut.


Dominic