Need Help!- Routing Acrylic for Overflow boxes on aquariums

[prcdslnc13]

I finally found a way to combine my hobbyies of fish keeping and CNC. Ill make some overflow boxes and maybe some sumps, I thought. Well so fair that's been a massive, massive failure lol.

Shattered plexi, melted goop and burnt fingers (melting stuck acrylic off haha oh ya thats hot!) are what Ive got. Im cutting 1/8" Lexan, and so far Ive tried a 2 flute upspiral bit from Onsrud and a 2 flute straight flute bit from lowes. With both of them Ive tried many different combos of feeds and speeds from 15 IPM and the bottom of the RPM rate of my Bosch router (about 8k) to 55 IPM and about 20k. The spiral flute's had a really bad time pulling my part off of the table, but the straight flutes did better. Either way I had terrible scalloping on my edges which need to be nice and clean so I can glue and make a water tight seal.

Any ideas?

[neilw20]

If you HAVE to run that rpm then use a smaller cutter.
I don't know what surface speed you need, but way slower than melting the stuff.
If you want to melt it, use a laser!

[prcdslnc13]

Originally Posted by neilw20 If you HAVE to run that rpm then use a smaller cutter. I don't know what surface speed you need, but way slower than melting the stuff. If you want to melt it, use a laser!

Not sure I understand your reply. Im using an 1/8" cutter so going smaller is going to be difficult. My router will run 8-24000 rpm. At the 55 ipm and somewhere in between 12-15k Im guessing (between 2 and 3 on my bosch 1617 haha) with a .1 DOC I was getting perfect chips but this cuts all the way through the piece and was causing me to lift up with the up-spiral.

[Boltz]

My recommendation would be a single straight o-flute bit. Two flutes create more friction and heat.

-Jim Hart

[Geof]

Find out what type of acrylic you are getting. There is extruded acrylic which is the most common, and which is probably what you have, and cast acrylic which is the most expensive. Doing anything with extruded acrylic, drilling, routing, sawing does not give results that are as good as cast acrylic. Most times the extruded acrylic will melt and gum up cutters no matter what you try.

[prcdslnc13]

haha its most likely extruded, because it seems like no matter what i do i cant cut this stuff worth anything. I will probably look into some cast acrylic this week. I have some 1/4" that I cut great with this bit and the same feeds and speeds so I but that is cast. It was really expensive, so thats probably what it is.

[Boltz]

I'm tellin' ya... straight single edge o-flute.

Routing & Trimming Acrylics | | LMT Onsrud

-Jim Hart

[ger21]

Use a 1/4" O flute, 8,000 rpm and 100ipm or faster. I've used this bit with excellent results.
cnctoybox

[Boltz]

That's a nice bit, Gerry, but the OP said he had trouble with upspirals lifting the work off the table. He needs a straight bit.

Follow the link, or better yet spend an hour or 2 soaking up all the great info Onsrud has online.

Plastic Routing | LMT Onsrud | Plasticrouting.com

-Jim Hart

[prcdslnc13]

Wow theres alot of good info there. I ordered a Downspiral O-flute from Onsrud, from what I read it seems to be the way to go. Do you guys have any recommendations on work holding? Im using clamps now but the piece itself pulls up. I was thinking of getting some carpet tape tonight to try.

[Boltz]

Carpet tape is pretty strong, you might have trouble getting your work up when done. Some people put masking tape or carton tape on the work, and then double stick between that and the spoilboard. Running about a .003 skim cut on the spoilboard will show you where to place the tape.

-Jim Hart

[ger21]

but the OP said he had trouble with upspirals lifting the work off the table.

I stopped reading right before that line.

You can get straight as well as downcut O Flute bits from Vortex Tool: Solid Carbide Bits (plastics)