Cutting Plexiglass (Perspex)

Have a look at laser cutting. Bonus: you can cut complex shapes as easily as simple shapes. Caution: not all materials can be cut like that.

Look for a local Hackspace or Makerspace, if you want to learn how to use laser cutters yourself.

Alternatively there are many commercial companies available. Usually you just send them the CAD file and they return the items by post, but obviously you could pick them up from a local company.

I have used a local company with a laser cutter for making prototype front panels. It really does work very nicely.

John

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It works but you'll get a fair failure rate without proper clamping. I woul dn't recommend it.

Standard twist drills are geometrically all wrong for acrylic. Abrasive wor ks well. Fixing to holes has a habit of putting a lot of stress on a little plastic, often resulting in cracks later. Fine for small loads, but to han g it on hinges like this is not recommended.

NT

Does it have to be perspex? 1/8" polycarbonate (Lexan) cuts with tinsnips, no cracks, nice enough edge if you are covering it with any frame; otherwise pass them a few times over a big file held in the vise.

use a drop saw instead.

send these guys 1:1 scale SVG with your outlines, they'll cut them into a sheet.

they seem to have a "first order free" deal going at the moment.

As others have said, use a CO2 laser. About 40 watts or higher should do the job. They cost from about $4000 upwards, and are so useful that many hobbyists and clubs have them. It leaves a nice smooth edge on acrylic. Acrylic is one of the materials that it can cut well and safely. (e.g. Don't ask them to cut PVC, it makes acidic fumes that attack the mechanism of the machine and poison the bystanders.)

A triple chip for plastic would be your best bet.

On Aug 31, 2017, snipped-for-privacy@tubes.com wrote (in article):

When drilling plastics like plexiglass, one does it flooded with tap water, to prevent overheating amd melting into a gooey mess. Do not use oil - this will crack most plastics.

Joe Gwinn

This looks promising. I'll look into it and see what the costs are (future projects). It's a great concept, sorta like sending Gerber files to a PCB house, and they make the board to my specs.

OK, thanks for all the suggestions. I just got a response from an Ebay seller, saying that if I buy a suitable panel of his Plexiglas, he will cut into pieces of my specifications at no charge!! Can't beat a deal like that. BTW, the seller's Ebay name is seefinestore, based in New York. Don't know if he gave me a one-time deal, or if he will do this for any order, but it solves my immediate problem.

Thanks for the pointer to ponoko, I'll keep it for reference for future projects. Dave M

Real Plexiglas normally cannot be sheared. it can be scored with a special knife and snapped off like glass cutting. It can also be machined with a router or mill. Just be sure the cutter is super sharp and keep the tool moving fast. Cutting slowly leads to heat build up and melting.

I do NOT think you can hot wire-cut acrylic. It will make a LOT of fumes and cut very slow. Acrylic has a pretty high melting point.

Just rectangles? Why would clamping be tricky? If making a lot, you clamp a sheet by the edges, and rout out the pieces, leaving a little space between parts.

My scheme, if really setting up to make a bunch, would be to set up a fence on the table saw and cut a bunch of strips the length of the Plexi sheets to match one of your dimensions. Then, stacking a bunch of these strips, cut the other dimension. That would make a lot of parts quickly.

If you need highly accurate dimensions, then the mill is the way to go.

Jon

Ah, OK, then rough cut with whatever you have available. Use a custom-made holder on the table saw. You can make this with some pieces of wood with grooves in them, to grab the edge of the plexi.

Then, mill to final size. Put the 3 pieces on end in the mill vise, and face off the top edge. Flip over, and you can mill the opposite edge to correct dimension and it will be parallel. Then, stack 3 pieces flat in the vise, and cut the ends with the side of the end mill. (Maybe use a carbide router bit.)

Jon

Around here, we'd walk over to Tap Plastics and let them do it for us. They can do bends, too.

They have a cool scrap bin, too. Great cutting boards.

I worked in a high-end cabinet making workshop and have used a free-hand spindle moulder before for cutting acrylic for kitchen drawer fronts etc. Just fix it to a (thick wooden) template (for the bearing to run on) with double sided tape and Bob's your uncle.

A small spindle moulder can be made using a decent router.

You can cut 3mm acrylic with a fine (eg. 80 tooth on a 10") carbide blade on a table saw. No problem- just don't push it through too fat.

Or use a CO2 laser in the 40W range with air assist.

Or use a small CNC engraver with 4-flute mill.

--sp

It melt-cuts just fine, and no risk of cracking as there is with sawing. Fumes are approx zero. I prefer to melt-drill than cut-drill it.

NT

I've done hot-wire *bends* of Plexiglas... works very nicely. Made up a Bakelite "cutting board" with a slot in it... spring-loaded (so it doesn't droop) NiCr wire in the slot for the heater.

But I've never tried hot-wire cutting. ...Jim Thompson

A hot wire cutter will create a lip on the cut surface.

I guess it could then be sanded off?

I think the sawing approach is easier, but mind your fingers.

The last time I cut a more substantial piece of acrylic I used a mitre type of saw.

The problem is keeping the wire from bending.