Feedrate and RPM for a Plexiglass mold

[gabi68]

Hi to all,

I have a Taig CNC and I want to make some molds from Plexiglas. I need to know what are best specification (feedrate and RPM) to do that.
I need to use coolant (I prefer not to)?
I also need to know if I can use my old metal bits or I should order some bits made for plastic milling.

Thank you in advance
GB

[MrMold]

If you have a mister or can faricate an air gun for cooling and removing chips that would be the way to go. RPM can be as fast as it will go as long as you can keep the tool cool and the chips out. I use carbide 2 flute, single flute even better. I wouldn't worry about braking any records with the feed rate. Typically you could cut as fast as you want. However with your set-up and machine I'd be real conservative with the feed rate. Figure .001-.002 chip load. This isn't a production job and you'll want the best finish you can get. The material is prone to melting and really gumming up the works so be careful about letting things get out of hand.

[gabi68]

Hi Mark,

Anyway, with my machine what are the best configuration for milling Plexi.
Feedrate?
Rpm?

TIA
GB

[MadPickinSkills]

Originally Posted by gabi68 Hi Mark, Anyway, with my machine what are the best configuration for milling Plexi. Feedrate? Rpm? TIA GB

Feedrate=100ipm
RPM=18000
These are CNC router params. Adjust the feedrate according to your max spindle speed.
Carbide single O-flute spirals work the best. The longer the flute length, the more the tool diameter should be for a good cut. Coolant will make the cut look the best, but not neccessary.

[bkobernus]

GB,
I'm with Mark on the feedrate. My best results cutting Lexan, and /or any plastic for that matter, have been with 2 flute HSS endmils and flood coolant. Plastic tends to melt to the flutes so top priority is to have chip clearance.
Not knowing the size and complexity of your project makes it challenging to suggest speeds and feeds.

Good Luck,

Bill

[draughted]

ive read that using cast acrylic helps with the tool guming-up