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3 Attachment(s)
Extruded Acrylic
The artwork panel is cast acrylic but the base is extruded. This current base extruded Acrylic (Evonik Ind. by Cyro Ind.)cuts like chewing gum! I have tried from 3 flute, low helix to "O flute" sytle tools, even from different tooling suppliers. I have tried a variety of feeds and speeds. Normal machining for this part is about 6 min. and with the tool gumming (with just THIS BRAND NAME) I have to stop and clean the tool and contimue resulting in the machining time to >25 min. I have 7 5'x8' sheets of this stuff to be cut into a BUNCH of 2.5"x10" project pieces OR sit and cry in my beer for weeks on end! The supplier is no help and the mfg. will not talk unless you are a whlse buyer.
Problem: 1/8" tooling gums up (big time) and will snap the tool off. 1/4" tool gums and mars the edge where the tool needs to slow down.
P L E A S E help!
Attachment 5174
Attachment 5175
Attachment 5176
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Is gumming up not caused from the plastic melting?
Is melting not from too much heat? I would suggest going faster and turning down the router speed.
Also directing a jet of air at the bit might help as well.
Are you actually getting chips before it gums ups?
RIB
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Melting, without a doubt. With the cutting depth @0.1" tried combinations of 10Krpm (slow as I can go) thru 19Krpm with feeds from, 0.5ips to 2.0ips. Yes... I do get chips (better at the lower rpm) and cuts well but then all of the sudden the evil acrylic witch makes it start to wrap up. I'll hook up some air and try that. Thanks.
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I feel your frustration...been there, done that.
It has been so long since I tackled that challenge that I forget the feeds/speeds that began to approach acceptable quality. The reason it has been so long is that I gave up on extruded plastic altogether for cutting on the CNC.
Good luck!
Donn
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I was going to mention as well there are different types of plastic...
If you have the wrong type can you exchange or return what you have?
RIB
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Agree... extruded is not the best but this brand name is the worst! The new "Optix" by Plaskolite, Inc. brand extruded seems to machine very much like cast but with the extruded price.
Must keep in mind, I am woodworking oriented. This acrylic stuff is all new to me. It's just that when the jobber sends me the material for the task I need to be able to bid and deal with it. This job, thinking extruded was extruded, I unknowingly estimated @3.5hr while actual ended up @11.5hr.! No fun.
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This might be way out there but would spraying a mist of water while cutting relieve the problem?
I am thinking enough water to sort of pool on the top surface as well to keep the bit cool and wet...
RIB
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Euew... don't know abut the water thing, with UDF vacuum and all. Have contacted Vortex and have ordered a few 2 straigh flute "O" flute tools. They feel due to cutting producing chips and then start gumming up as inconsistant mixing in the (inexpensive) material. Probably just this jobber trying to save a few bucks. All-in-all is a good learning tho somewhat expensive and frustrating.
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Thanks for the heads-up Bill! I do most of my acrylic on my laser but with a 12 x 24 size limitation I have been tempted to try it on the Bot. Now I know what to look out for!!
Mike
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I think that I'd try cooling the bit with cold air guns like these: http://www.airtxinternational.com/ai...FYNX2god_GUvSQ
http://www.vortec.com/cold_air_guns.php
And, there's a forum discussion on air cooling bits, with a cheaper option by Gary Campbell, at http://www.talkshopbot.com/forum/mes...tml?1208916270
BTW, that's great looking work that you've posted.