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Thread: Cutting acrylic/ Feeds n Speeds
07-01-2005, 01:24 PM #1
Can anyone help me out. I need to figure out how to compute the proper speeds and feeds for cutting with a .25, HSS, One flute EM. We are looking for a good rough cutting speed, and also a finnish cutting speed. The work is done on a vacuum table, So im not to sure about multiple opperations. I am new to the company that is doing this work, and i dont quite know yet if this CNC should do more than one pass operations, because only the biggest peices wouldnt move. Im debating using a two flute cutter, with slower feed, so we can get much better edges. Can anyone help, or suggest someting?
07-01-2005, 02:25 PM #2
for most acrylic or lexan use speeds and feeds for brass. leave .020" per side to finish and use an air jet to evacuate the chips.
if you want a optical finish (clear) use either industrial diamond or CBN and apply heat with a torch playing it ever so lightly to melt the machined surface only...jim
07-02-2005, 10:51 AM #3
gotta' move the tool when cutting acrylic. if you can't keep up healthy feeds, you'll melt it ,and
it will stick to the tool and gum up.
07-02-2005, 07:50 PM #4
You can contact the manufacturers of acrylic for machining information.
Plexiglas is made by Rohm & Haas, and Polycast is another brand name. I remember seeing some manufacturer's printed information about machining cast acrylic a while back.
You should modify your endmill so that it has zero rake angle. I believe water based lubricants are recommended for acrylic (I think these are sometimes called "soluble oil").
It is not too hard to machine. If you want an optimal endmill, maybe you can consult with a cnc router supply person.
07-04-2005, 04:07 AM #5
Thanks for your time. I will look into your suggestions.
Also, the work table is a vacuum table, so we arent able to use any kind of fluid coolant. It has a secondary vacuum for evacuating the chips.
It is a new machine to me but easy to run and get to know. I just havent worked with the softer materials before.