fuzz when milling polypropylene

[DanielG]

We make some milled parts out of polypropylene. One of the issues we're having on the latest batch is a lot of fuzzy residue left behind on the pocket walls. Cleaning up the walls when we deburr is taking a lot of time.

• We are using new, sharp tools, mostly with an aluminum grind.
• The fuzzy residue is attached to the wall, you can't wipe it off, but need to use a deburring tool
• I think the problem is worse with this batch of material than previous batches.
• Our finish pass is .015", 5000rpm, 40ipm with a 3/8" 3-flute YG-1 Alupower HPC endmill

Any suggestions?

 

[gargamel]

I can't help on the milling & tooling side, but you could look into using a CO2 ice gun to save time on deburring. I use them for cleaning critical surfaces but the manufacturers also claim that they will deburr plastic parts with no damage. google "dry ice deburring" or similar to learn more.

 

[guythatbrews]

Maybe try one fonish pass about half or third sfm same chip load.

 

[???]

Try changing cut direction. Climb to conventional or vice versa.

 

[aandabooks]

.015 finish does seem like enough. Have the endmill skimming by without good engagement. Try is around .030 and see what you get.

 

[Limy Sami]

If (note if) the cutter's been used for anythng other than plastic, it will not leave a good finish !!!

Try using ''down cut'' wood router cutters, I can't remember the big US name in router cutters but I'm sure they do specials for plastics.

GOT IT ;- ONSRUD

 

[boslab]

Cool the plastic before machining, the fuzz is brittle when cold and breaks off, spot cooler on the cutter even
Mark

 

[garyhlucas]

When my grandson got busted in 8th grade for selling fidgit spinners he was making on our homebuilt CNC the deburring was a quick pass with a propane torch and the fuzz went poof. A torch with a flame spreader nozzle is better. Flame polishing is also done on the edges of plexiglass to get clear edge.

 

[DanielG]

Thanks everyone. Switching to conventional for the finish pass makes a big difference.

I've been trying to convince the customer they should buy a dry ice blaster, but no luck yet.

 

[CAMasochism]

You might try using one of Harvey's plastic specific endmills. We use them here for cutting Delrin and they work great.

Plastics

www.harveytool.com

 

[MwTech Inc]

As you found out, conventional worked better.
Now you need to play with the speed and feed.........
Once we did, almost perfect finish.

 

[DanielG]

You might try using one of Harvey's plastic specific endmills. We use them here for cutting Delrin and they work great.

Plastics

www.harveytool.com

I used them on a previous polypropylene job. I didn't find that much of a difference from the YG-1's. We also run some bullnose sizes that aren't available from Harvey.

 

[Davewitt]

Been several years since I machined polypro but it seems to me, we used WD40 as a lubricant with good success.