Machsupport Forum

G-Code, CAD, and CAM => G-Code, CAD, and CAM discussions => Topic started by: ta1dr on March 05, 2009, 02:18:43 AM

Title: how the engavring for plastic
Post by: ta1dr on March 05, 2009, 02:18:43 AM

Hi I want to engavring text on plastic or plexiglass  I can do it but metarial is melting  first letter is good but other are bed
do you have any idea ?

my cnc:
http://www.ta1dr.com/router_cnc.html

programs:
mach3
lazycam
sheetcam
coppercam
simplecam

Title: Re: how the engavring for plastic
Post by: RICH on March 05, 2009, 07:14:00 AM

Just got to keep it cool. And every material will be different. Also watch out for stress cracking. Can happen
after you are all done and an hour later.
RICH

Title: Re: how the engavring for plastic
Post by: Graham Waterworth on March 05, 2009, 12:14:09 PM

It could also be that you are not feeding fast enough and the tool is rubbing and melting onto the cutting edge.

Graham

Title: Re: how the engavring for plastic
Post by: ta1dr on March 05, 2009, 12:26:33 PM

RICH and Graham thanks for idea
 I will try increase feed

Title: Re: how the engavring for plastic
Post by: melcat on April 01, 2009, 05:17:02 PM

Hi there,

I done quite a bit of engraving on various materials.

The main problem people have is that the spindle speed is too fast.
Whist engraving material such as mild steel, aluminium and brass the key is to have a medium to high spindle speed with plenty of coolant to flush out swarf.
On acrylics, acetals and PVC the melting point of this material is very low. Just imagine the heat generated from the tool friction itself. it gets hot quite quickly and then this heat is transfered to the plastic surface. This then only melts the material instead of cutting it.

On acrylics and acetal plastics I run a speed of approx 1500 rpm to 2000 rpm with coolant.
While on PVC plastic I reduce this speed to about 750 rpm also with coolant.
Feed rates vary on the complexity of engraving. I usaully run at about 60 to 100 mm/min.

Also tooling counts too. You could spend alot of money for bespoke engaving tools or use small ball nose cutters along with small spot drills.
I use dia 1mm to 2mm ball noses or use up to dia 3mm spot drills. It saves alot of money on tooling and results are very good to excellent.

Try it out, see what results you get. You will be pleased.
If you need any more info, be my guest and contact me.

Mel

Title: Re: how the engavring for plastic
Post by: Sam on April 01, 2009, 08:22:16 PM

If your using something like a 4 flute endmill, switching to a 2 flute or single flute would help out, if your unable to slow the spindle speed.

Title: Re: how the engavring for plastic
Post by: ta1dr on April 02, 2009, 01:22:14 AM

@Mel  many thanks for help  I will try :-)

@Sam thanks for you but I can't understand 4 flute 2flute do you have any picture or drawing ?

Ahmet