Cutting 1/4" and 3/4" Acrylic Cast Sheet

[bjwat@comcast.net]

OK guys...I searched on the topic but am not sure I found the info that I need. My Acrylite dealer gave me a 'Working with acrlic" booklet by the manufacturer, but the routing section is short and just says "...run 10,000 to 20,000 RPM quickly through the material..." You can bet I rolled my eyes at that.

So my questions are feeds and speeds, conventional vs climb and material hold down. I am working with a new product called Exotic Edge which is $1200 a sheet...(Yikes!) It is .706 thick and I need to cut 17" squares out of it. How many passes? What size bit? What bit geometry do you recommend?

The bugger is going to be cuting 1/4" thick squares that measure 2" (120 of them) and 1" squares (1500 of them!) My initial thought on this is to make a vac jig AND tab them to hold them together. I'd like to keep the tabs to a minimum because that's 1500 more steps I have to finish per tab. Same deal, what speeds, RPM, depth per pass, conv/climb, geometry, diameter bit.

Any and ALL replies are appreciated...I'd like to hear from you guys that routinely cut acrylic. You can imagine my gingerly approach to cutting $2700+ worth of material...

Thanks!
Brady

[beacon14]

um, table saw?

[nehdad]

Brady,

I do not know if this will help but we cut on acrylics, aluminums and carbon fibers. I would suggest trying what we use. We use 3M repoistionable 75 spray adhesive and spray a particle board substrate and "adhere" the material to the board. I use the word adhere loosely since you can heat up the product and it becomes easy to ply off the finished parts. Of course we use a tradition method to hold down the particle board. In the short time that we have been using this machine and technique the results have been accurate and consistent.

If you have any questions please feel free to email me.

Good Luck,

Rich

[artisan]

Hi Brady. That is an interesting new product you've got there. I was reading up on it and it says the edges can be flame polished....a good thing, because it apparently has the tendencies of cast acrylic. I cut acrylic with a double fluted straight carbon bit most of the time. I have also had success with a spiral bit on some plastics where chip removal is crucial. HEAT is your enemy. The acrylic will fuse the chips if you overheat and will ultimately attach to the bit if you begin to burn material....making a sticky mess. This is why the manufacturer says move quickly through the material. I find however, that .5 setting on the Bot works well for me. It's trial and error and you need some scrap to test on. I also reccomend a spray bottle of water with some murphy's oil soap in it to spritz your bit with occasionally. Having said all of that....I agree with David....ummm Tablesaw?....D

[kerrazy]

Onsrud has come out with a great searchable guide for plastic routing, where you can input the manufacturer of the material as well as the type of material and it will kick back a table of suitable bits.

It is a great referance available at www.plasticrouting.com

My concern is the size of pieces, it will be hard to hold them all in place with out machining off existing tabs....hmmm Table saw does look good to me as well.
Dale

[bjwat@comcast.net]

Looks like the table saw is the way to go...I completely overlooked it. I think I will rip strips of it on the table saw and then jig up the chop saw.

Thanks for the ideas,
-Brady

[artisans@chdc.org]

Brady -
Keep in mind that the same problems that you could encounter with chip welding with a router bit would occur with a table saw blade, especially at that thickness. If you are serious about cutting on the table saw, invest in something that will help you do the job correctly - there are several manufacturers out there with baldes that cross over from solid surface cutting to plastics / acrylics / pvc - here is an example:
http://store.yahoo.com/freud-tools/freudlu9inpl.html

I would also think long and hard about how you are going to feed the stock - you may be interested in "borrowing time" on a sliding panel saw from a friend with a cabinet shop - i can't imagine handling a 4' x 8' x 2" sheet of anything- no wonder that you were shooting for the 'bot. Careful how you cut this stock - not forgiving if the table saw is underpowered (no contractor saws!).

I am certain that there are many, many 'botters (cabinet makers) that could recommend how to approach cutting plastics on a sliding panel / table saw.

A table saw option is smart, because of a much thinner kerf, resulting in less waste (you would need to use a 3/16 - 1/2" cutter (a 1/8 cutter in four passes would flex like crazy, i suppose).

Another option is band saw - very thin kerf, cool cutting (if you use compressed air, or a coarser blade, 5 - 10 TPI)- not the best finished edge, but if these are to be flame polished, is it a possibility?

Thanks for the great presentation at Camp Shop Bot! Inspiring show and tell! You prove that 'botters can fabricate anything!

Matt Barinholtz
Covenant House Washington, D.C.
Covenant House Washington

[gerald_d]

All our suppliers of plastic sheet stock, are set up with their own saws (and blades/experience) for straight cuts. Have you asked your supplier if they would do the cutting for you?

[bjwat@comcast.net]

Matt,
I am cutting 3/4 and 1/4...not 2". Thanks for the saw blade info. I had one around years ago for cutting acrylic...but looks like I need a new one. I'm going to be spending some time tuning up the table saw and fence because the cuts need to be dead on.

Thanks,
Brady