Thread: Help with Acrylic

1" seems very thick, how deep you going?

Originally Posted by echnidna

1" seems very thick, how deep you going?

Well it's a rectangular piece that has to be cut into an 8" diameter circle, so for one cut, actually 2(rough and finish cut) I'm going all the way through. The recessed cutout for the monitor I'm probably going to go about 3/8" deep. One hole 0.377" I'm going all the way through and not sure on the rest of the holes for tapping I have to check the lengths of the screws. So this is a fairly complicated program, at least for me. I've got enough material to make 2 ports but hopefully the first one will turn out correct and I'll have the 2nd as a spare.

Billy

Hi Billy,
I'm not sure what you are making but the following might work. Make it out of 2 pieces, one say 3mm (1/8") thick and the other 19mm (3/4")thick. Cut the hole in the thick piece and then glue the thin piece onto it. If you mix fine sandings of the acrylic with a solvent, possibly MEK, and spread it onto the surface to be glued, then 'wriggle' the thin piece around until it grabs, you can end up with a trasparent joint. That way you dont have to polish the base of the hole as it will be the clean surface of the 3mm piece.
good luck, remember that practice makes perfect ...
Fletty

Think of it like this, I've got an 8" Diameter PVC tube that needs to have one end covered with a 1" thick piece of acrylic. In that end you need to be able to view a 5" lcd monitor that's inside the tube facing out(esetially looking through the acrylic). I've got a 1" thick rectangular piece of acrylic that's big enough to make 2 of these, just in case I screw up the first one. I need to know what router bits and any type of drill bits to use with what speeds and feed rates so I don't crack or melt the acrylic.

If that doesn't make sense let me know and I'll try to provide pictures.

Thanks!

Billy

Billy what is your spindle? Router? What speed range do you have?

I cut acrylic with a CNC mill at max rpm which is 3000. 1/4" upcut two flute end mill. About 500mm/min. At 1 to 2 mm depth of cut.

If you have a high speed spindle (router) you probably need to use the slowest rpm you can at a fairly high feed rate.

Have a go on a piece of scrap.

Getting a finish you can view the LCD through will be a problem. I think I would try to leave it 1" thick.

Greg

Originally Posted by Greolt

Billy what is your spindle? Router? What speed range do you have?

I cut acrylic with a CNC mill at max rpm which is 3000. 1/4" upcut two flute end mill. About 500mm/min. At 1 to 2 mm depth of cut.

If you have a high speed spindle (router) you probably need to use the slowest rpm you can at a fairly high feed rate.

Have a go on a piece of scrap.

Getting a finish you can view the LCD through will be a problem. I think I would try to leave it 1" thick.

Greg

Thanks for the reply Greg. Unfortunately the monitor has to be recessed 1/2" (basically flush) in order for the camera to fit into the housing properly. It's just going to take a lot of polishing to get it to where it needs to be.

What thickness acrylic are you using with that setup? I'm not sure on our router's settings I'm not drawing up the program for this piece. It is a $150K router so I'm guessing that it can do everything I need it to do.

What about drilling a straight hole in it. I've already got the drill bit (V-0.377) and we're going to perform a counter sync with a 1/4" router bit which was specified by the original housing manufacturer.

Unfortunately this stuff is not cheap to buy I think this one cost me about $75 and I bought it just for this so there really isn't any scrap that I can test on. I guess if this gets screwed up it'll just cost me another $70.

Thanks again for the help!

Billy

Originally Posted by oocpromo

Hey everyone i have a few questions. I've got a C&C and need to route a 1" thick piece of clear acrylic. I need to:
1. re-cut it to the correct shape
2. drill pilot holes that don't penetrate all the way through for tapping later
2. drill a single hole all the way through
4. route a recess in it for a 5" LCD monitor which will need to be visible through the other side(heavy polishing I'm guessing).

Has anyone worked with acrylic this thick? If so, what did you use for cutters, feed rate, rotation speed all that good stuff.

Thanks in advance for all of your help. The piece that I'm making is for a port for an underwater housing for a professional video camera. just so you have an idea of how perfect everything has to be, If this housing floods due to a failure in the acrylic (or any other error) I lose a $5K camera.

Billy

I cut arcrylic at work but nothing that thick. The most we use is 16mm thick. I use a downspiral cutter and going at a slow feed rate (50mm/sec) and about 10000rpm.

Hope that helps

Originally Posted by oocpromo

Hey everyone i have a few questions. I've got a C&C and need to route a 1" thick piece of clear acrylic. I need to:
1. re-cut it to the correct shape
2. drill pilot holes that don't penetrate all the way through for tapping later
2. drill a single hole all the way through
4. route a recess in it for a 5" LCD monitor which will need to be visible through the other side(heavy polishing I'm guessing).

Has anyone worked with acrylic this thick? If so, what did you use for cutters, feed rate, rotation speed all that good stuff.

Thanks in advance for all of your help. The piece that I'm making is for a port for an underwater housing for a professional video camera. just so you have an idea of how perfect everything has to be, If this housing floods due to a failure in the acrylic (or any other error) I lose a $5K camera.

Billy

Billy ,
here are a couple of links that may help,,,,,

http://www.cityplastics.com.au/acrylic.html
http://www.acrylic-designs.com/plastic_FAQ's.htm

kev.