# I searched for this in the forums, but couldn't find it. Acrylic buildup on bit **URL:** \ **Category:** Troubleshooting\ **Created:** [August 6, 2015, 6:24pm UTC](https://community.inventables.com/t/i-searched-for-this-in-the-forums-but-couldnt-find-it-acrylic-buildup-on-bit/11596 "2015-08-06T18:24:02Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![CharlesDearing](https://avatars.discourse-cdn.com/v4/letter/c/4da419/32.png) [@CharlesDearing](https://community.inventables.com/u/CharlesDearing)\ **Post date:** [August 6, 2015, 6:24pm UTC](https://community.inventables.com/t/i-searched-for-this-in-the-forums-but-couldnt-find-it-acrylic-buildup-on-bit/11596/1 "2015-08-06T18:24:02Z")
I broke yet another bit trying to cut acrylic. It was going fine but the acrylic kept building up on the bit. Then the bit broke 😕 Is this just going to happen or is there a way to safely get the acrylic buildup off of it while in operation? The bit I used was a 1/16 fish tail 2 flute. ---
**Author:** ![ErikJenkins](https://yyz1.discourse-cdn.com/flex009/user_avatar/community.inventables.com/erikjenkins/32/84368_2.png) [@ErikJenkins](https://community.inventables.com/u/ErikJenkins)\ **Post date:** [August 6, 2015, 6:32pm UTC](https://community.inventables.com/t/i-searched-for-this-in-the-forums-but-couldnt-find-it-acrylic-buildup-on-bit/11596/2 "2015-08-06T18:32:16Z")
The build-up could be caused my melted acrylic, faster feed rates and shallower cuts will not allow so much heat to build up and melt the acrylic. That being said, I have not cut much acrylic…just a few pieces. ---
**Author:** ![CharlesDearing](https://avatars.discourse-cdn.com/v4/letter/c/4da419/32.png) [@CharlesDearing](https://community.inventables.com/u/CharlesDearing)\ **Post date:** [August 6, 2015, 6:36pm UTC](https://community.inventables.com/t/i-searched-for-this-in-the-forums-but-couldnt-find-it-acrylic-buildup-on-bit/11596/3 "2015-08-06T18:36:30Z")
There’s no doubt in my mind that friction is the culprit. I messed up a good sheet of mirrored acrylic trying this ☹ I went with the default depth per pass and should have made it more shallow. I wonder if the bit I chose played into enabling the buildup. The design had fine detail so I tried to go with a small-ish bit. Ugh, I can’t afford to keep breaking all these bits (and acrylic) while I learn things the hard way 😛 Thanks Erik. ---
**Author:** ![IanWatkins](https://yyz1.discourse-cdn.com/flex009/user_avatar/community.inventables.com/ianwatkins/32/58532_2.png) [@IanWatkins](https://community.inventables.com/u/IanWatkins)\ **Post date:** [August 6, 2015, 8:17pm UTC](https://community.inventables.com/t/i-searched-for-this-in-the-forums-but-couldnt-find-it-acrylic-buildup-on-bit/11596/4 "2015-08-06T20:17:02Z")
Bring the spindle speed down, increase the feed rate and do shallow cuts with a bit that can produce big chips. The build up is purely heat melting the material onto the bit. ---
**Author:** ![AlanDavis](https://yyz1.discourse-cdn.com/flex009/user_avatar/community.inventables.com/alandavis/32/4710_2.png) [@AlanDavis](https://community.inventables.com/u/AlanDavis)\ **Post date:** [August 6, 2015, 8:17pm UTC](https://community.inventables.com/t/i-searched-for-this-in-the-forums-but-couldnt-find-it-acrylic-buildup-on-bit/11596/5 "2015-08-06T20:17:37Z")
You may switch to down cut bits. That’s what I did for any Plastics. Lot better results. [http://www.ebay.com/itm/381313362014?\_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT](http://www.ebay.com/itm/381313362014?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT) ---
**Author:** ![Bill](https://avatars.discourse-cdn.com/v4/letter/b/ac91a4/32.png) [@Bill](https://community.inventables.com/u/Bill)\ **Post date:** [August 7, 2015, 3:32am UTC](https://community.inventables.com/t/i-searched-for-this-in-the-forums-but-couldnt-find-it-acrylic-buildup-on-bit/11596/6 "2015-08-07T03:32:40Z")
You might also try cast acrylic. I’ve been cutting it without a problem - it is much more tolerant of the heat and melting issues than extruded acrylic. ---
**Author:** ![StevenPaxman](https://avatars.discourse-cdn.com/v4/letter/s/b2d939/32.png) [@StevenPaxman](https://community.inventables.com/u/StevenPaxman)\ **Post date:** [August 7, 2015, 3:22pm UTC](https://community.inventables.com/t/i-searched-for-this-in-the-forums-but-couldnt-find-it-acrylic-buildup-on-bit/11596/7 "2015-08-07T15:22:44Z")
Thanks for that link. I just bought that, and a 1/16" one as well.