ABS Finish issues

[strabe]

Hi all,

 

I'm machining some ABS for a control box and one of the flag notes specifies that the outside surfaces are to be free of machine marks.

 

Does anyone have any experience in plastics that has a suggestion to polish or remove machining tool marks??

 

The engineer is calling the plastic supplier for their input as well.

 

Thanks for any help.

 

Ken

[Mark V.]

Sand Paper will take care of it. You can probably start with 280 grit if the marks arent too bad.

[strabe]

I tried a test piece with 600 grit and it left a cloudy finish which is okay but as soon as you drag yor fingernail on it, it leaves a highly visible scratch that only goes away with more sanding.

 

The engineer definately didn't like that.

[Thee Starry™]

After sanding it you can use a little rubbing compound on a cloth then wipe clean with a mix of 50/50 water and denatured alcohol.

 

if you use a fine enough rubbing compound and a little alcohol mix it will shine up nicely.

[dgriffiths]

Take a look at this. I used this quite often on acrylic and ABS. It might give you what you are looking for. Brillanize

[strabe]

Looks like sanding and polishing is the way to go.

Thanks for the help guys.

[MACHINEMASTERG]

we cut alot of plastics here usally they mean marks from the bottom of the cutters on the floor of a pocket or step down you might have to polish there, but ive never seen a problum from a fine finish side milled on a abs part around a countor of the part from the side of a sharp cutter

[strabe]

That's exactly the problem Greg, the floor of pockets.

[MACHINEMASTERG]

one thing i tell the guys here with plastics is to take at least .05 of a cut no little skim cuts also stone the corners on the tool or use tooling with a .01 corner radius no sharp corners

[strabe]

Thanks again Greg. I will stone the endmill.

[Matthew Hajicek - Singularity]

Ultra sharp cutters with corner radius. Edge prep for aluminum works well. Make sure your RPM isn't too high or it can melt bits of plastic back onto the part.

[#Rekd™]

Hi,

 

Single flute endmills work well on plastics.

 

John

[Mike Gates from Barefoot CNC]

Actually on contour cuts and cutouts o-flute tooling seems to work best IMO, they are specially made for plastic applications. A good source is from Onrud Cutter. I have used them a good bit in trimming out 5-axis thermoformed parts and they make better chips and leave a very nice finish.