I am attempting to cut some control horns with .080 plastic sheet.
Using a 1/32" bit and a pocketed out piece of FFF.
Will post results when done.

 

Looks like it will work
10 cut, 15 to go. I am keeping my fingers and toes crossed. Attached files

 

Update. I should have run them thru with the plastic underneath the foam.
The 1/32" bit has a plastic ring around it and foam collected there and eventually melted to the bottom of my cuts, so even though they look good from the top the underside is a flippin mess.
I will run to the hobby store and grab another sheet or 2 and run the sheets under the bottom side this time (it will let me reuse the carrier)
If I can get it worked out I will have Control horns 25 for $2 vs. 2 for $3.
Bleh $700 camera won't let me take a good close up. Guess I need to actually read the manual on it. Attached files

 

Very nice!

 

It's almost 1/16"

 

Ok, complete failure. The topside of the cut looks fine, the bottom side is a melted mess no matter what I try to do.
Going to give up and just cut them on 1/16" ply

 

I tried it with a foam backing and without, I guess with a 1/32" bit it just doesn't have the flute depth to chase the chips away and it gathers on the the bit that doesn't cut.
Without a backing of the foam the plastic started warping under the heat of cutting it.
I ran it again with 1/16th light ply and they cut perfectly. (after i peeled melted plastic off the bit)

So, unless there is a way to really slow down the bit I doubt plastic would be a viable alternative to light ply.
An overhead gantry machine would prob be the ideal platform to cut them out of plastic.

Below is a shot of the attempt with the foam backing. Attached files

 

I'm going to try and find someplace to buy some pcb board without holes, I think that would be the best. Stay tuned.

I figured that my Rotozip runs at 15,000 rpm (on slow) with an 1/8" bit, so a 1/32" bit should actually be turning alot slower (at the bit) being a smaller diameter and all. I don't know the math to figure it out. since it is 1/4 the size maybe it turns at a quarter the speed

 

I use the router control Mark posted and it works fine for a chopper style controller. I have been cutting FFF at about 1/3 power and don't get any of the melting foam vapors and the cuts are clean.

I am using a 1/8" bit. I haven't tried any other materials yet but have some O flutes on order for cutting plexi. The bits I have now won't chuck in the flex shaft.

 

Hi guys... SkyCraft in Orlando has some sheets of phonelic for $4 that works great for making control horns.

These were cut on JohnB's table top router, but I have cut them on my MKI.

The phonelic, if you want to get some, is in the first row as you come in the store, all the way to the back on the right side. You can call Skycraft and I am sure they will know what it is. It is about 1/16" thick and makes a very sturdy light weight control horn. Attached files

 

Yep, that's the stuff i went looking for today. Ran across some Formica chips at lowes and grabbed some.
They work great except I broke 2 bits making just 3 usable ones. Formica is just too hard, I even tried cutting at 1 ipm on the Formica.

I tried the multi pass method once, it still melted the plastic so I gave up on them

 

Update, I ran across some 1/16ths HDPE so I thought I would try this again.
I had just received my new .030 bits from
http://www.american-carbide.com/MicroEn ... ecimal.php

Results with dremel set at lowest speed with speed controller from Harbor Freight and not using mult-pass with feed rates set at 20ipm worked perfectly!!!!!

The picture is right out of the sheet with NO cleanup at all. Attached files

 

HDPE is pretty slick. I wonder if you will have problems getting glue to stick to it.

 

Jeff

Made sure your plastic is "cast acrylic" and not "extruded". I have cut a lot of cast acrylic with great results, cnc'ing extruded is hit or miss on how it comes out, mostly miss.

I have never see cast acrylic in places like HD or Lowes, I had to go to a store dealing in acrylic or order it on line.

george

 

As far as glue holding on the HDPE it seems to hold just fine, it may just be the glue filling the holes where it goes into the foam, Hopefully our field will be dried out enough by tomorrow to check how the hold really is.
I got the plastic for another project that never panned out, I got it from http://www.usplastic.com/
You will find alot of stuff that you can use on the Phlatformer also there