Author Topic: Cutting acrylic plastic for case? Would a dremel or drill+milling table work?  (Read 1468 times)

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Offline cdev

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I have some clear and also some UV fluorescent colored acrylic plastic material I would like to use for electronics cases if it's possible to do it neatly.

What do people use for something like this, besides a laser? All the pieces of plastic I have appear to be between 1 and 2 mm thick.

I have a dremel, also Ive thought about using my drill press horizontally. I could likely do straight cuts with that- Because its pretty plastic, however, I would like to get a nice smooth cut. Maybe its possible to do that with some kind of abrasive lubricant?
« Last Edit: November 09, 2018, 02:56:59 am by cdev »
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Offline JackJones

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I just use a hacksaw. You do need to clean the cut with sandpaper but I've never really had any problems.
 
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Offline cdev

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How do you get straight cuts? I have never been so good with a hand hacksaw as far as it looking good cosmetically. On wood, etc, my cuts always wander a bit.
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Offline JackJones

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I guess it's just a matter of experience. Once you get some practice in you should be able to get a pretty nice cut.
 

Online Fred27

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Acrylic cuts really nicely on a CNC mill/router without any lubricant. I'd have thought using your pillar drill would be OK if you used an endmill in it. Not ideal to have lateral loads on the bearings but it should work.
 
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Online Benta

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Dremel: No. It runs much too fast and will melt the material.
A mill/drill with a fine toothed slitting saw is perfect for this job and will make straight and fine edges that you only need to touch up with a fine file and very fine sand paper.
Make certain the mill head is trammed correctly, otherwise you risk cracks.
 
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Offline cdev

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Thank you. I dont think the lateral force in the drilling plastic scenario is likely to be that strong compared to metals.

I may still have some kind of lateral cutting bit, I bought at one time a long time ago for some other material (and my hand drill)

So, no kind of fluid etc, is needed-

 
« Last Edit: November 09, 2018, 04:26:38 am by cdev »
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Offline Richard Crowley

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I use a mini table saw for cutting acrylic (and aluminum) ...

https://www.amazon.com/gp/product/B005FI3MKC



This one is rather more fancy (and expensive) than the one I got a few years ago.  Feature/price creep.
 
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Offline cdev

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Cute.. that looks like it would be ideal..

is that a rotary saw or jigsaw or small band saw?
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Offline Richard Crowley

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It is a scaled-down table-saw with a circular blade, etc.
You can get many different blades including diamond and carbide-tip.
 

Offline cdev

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Proxonn is insanely expensive and some of their tools bear a superficial resemblance I think, perhaps to Liyang, a Chinese brand. They make little saws like that.

They appear to be a huge company - at least from the variety of stuff they make they seem to be so.
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Online KL27x

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Quote
How do you get straight cuts? I have never been so good with a hand hacksaw as far as it looking good cosmetically. On wood, etc, my cuts always wander a bit.

Can be done with a hacksaw, no doubt. If you don't have a garage full of tools, you might want to take a look at a small dozuki type of hand saw. This is kinda like a western style miter saw, but cutting on the pull instead of the push.
1. thin, thin kerf, because it cuts on the pull stroke it doesn't need a thick blade to keep the blade straight. This kerf means less work.
2. it is a back saw. Meaning it has a rigid spine. Perfect for straight cuts through thin material. You can cut unlimited stock size, since there's no frame to limit the cut depth/length. Keep the angle of the cut shallow so it is self-guiding through the cut. The saw much closer to parallel to the sheet than perpendicular.
3. Fine sharp crosscut teeth leave a great finish in plastic. A hack saw or a western miter saw has set on over other tooth or whatnot. The teeth are the same shape, though, 90 degrees to the sides. The dozuki has every other tooth sharpened the other way at an angle, and is just crazy sharp and efficient.

Many hobby and craft stores sell tiny versions of this saw. I didn't know the origin or proper name until years later. On Amazon US you can search "mini dozuki" and get Amazon's choice for 15 dollars.

A tablesaw is the most efficient way to cut this size of stock (which I imagine) down, but you can't buy a good table saw, cheaply. If you want the best edge possible, it won't come off a table saw, anyway. A 2 flute endmill is the stuff of dreams. In the US, you can buy a craftsmen router and table combo for $150.00. It's not the best way to cut acrylic sheets down, but no matter how else you do it (say score and snap), you could quickly dimension and finish the edges on the router table. For larger pieces, hand router and straight edge. And you can do shaping, inside openings, slots and rails, for starters.
« Last Edit: November 09, 2018, 07:05:56 am by KL27x »
 
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Offline 6PTsocket

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I don't saw or mill it at all. They sell plastic scoring knives for a few bucks. Any craft or big box store should have one. I think mine is Olfa, a good Japanese company. Just take a straight edge and make severeral deep scores and it will snap off clean as a whistle; at least as clean or cleaner than a saw blade. No melting, no plastic dust, no waste. If the edge is going to show, you can sand and polish it but you have to do that no matter how you cut it. When you snap it, do it over a square edge, right under the score line. I cut acrylic for framed pictures with no problem

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Offline Teledog

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Ideally, a band saw is what I use.
As 6PTsocket stated, I have scored the plastic, both sides with a carbide blade, takes a while..use a taped/secured straight edge, works OK.. esp. thinner stuff.
Use a sharp edge for the final break- while clamped.
A variable speed jigsaw MAY work, if it's well clamped -close to the cut.
After that..for a straight edge, a belt sander is ideal, other than that..good old sandpaper, then finer "wet & dry" sandpaper on a glass/flat surface.
For a fine finished edge, use the wet & dry sandpaper - wetted, 120 & work to ~200-400-ish grit, then for a very nice edge finish, use plastic polish (I use Novus, good stuff - fine version works well- also works very well for your dull plastic car headlights).
To glue it, use methylene chloride, hold the edges together & apply dropwise with a ~18-20 Ga needle syringe to the very edge (careful not to slop, as it will dull any parts you don't want it on) & hold it for ~30 seconds.
Methylene chloride is available at plastics shops..and also some neon sign shops..don't need much at all- 100ml should be more than enough for a few small projects!
And keep it well sealed..it evaporates like nobody's business!

G'Luck! :-+
 
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Offline 6PTsocket

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Ideally, a band saw is what I use.
As 6PTsocket stated, I have scored the plastic, both sides with a carbide blade, takes a while..use a taped/secured straight edge, works OK.. esp. thinner stuff.
Use a sharp edge for the final break- while clamped.
A variable speed jigsaw MAY work, if it's well clamped -close to the cut.
After that..for a straight edge, a belt sander is ideal, other than that..good old sandpaper, then finer "wet & dry" sandpaper on a glass/flat surface.
For a fine finished edge, use the wet & dry sandpaper - wetted, 120 & work to ~200-400-ish grit, then for a very nice edge finish, use plastic polish (I use Novus, good stuff - fine version works well- also works very well for your dull plastic car headlights).
To glue it, use methylene chloride, hold the edges together & apply dropwise with a ~18-20 Ga needle syringe to the very edge (careful not to slop, as it will dull any parts you don't want it on) & hold it for ~30 seconds.
Methylene chloride is available at plastics shops..and also some neon sign shops..don't need much at all- 100ml should be more than enough for a few small projects!
And keep it well sealed..it evaporates like nobody's business!

G'Luck! :-+
Methylene Chloride is the active ingredient in many paint strippers. The EPA is pushing to get it banned for non commercial sale. Lowes took strippers containing methelene chloride off the shelf. I would imagine a few drops are not nearly as risky as slathering it all over a piece of furniture. They say there are a few confirmed deaths from it but who knows. I never knew what the solvent was for plastic cement. Mention of certain substances like benzine and methelene chloride always catch my eye.

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Online KL27x

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Honestly, I just cut a piece of 1/8" acrylic in my garage with my dozuki, just to make sure I'm not full of it. I now have a garage full of power tools. So it's been awhile since I hand-cut acrylic. These days, I use a bandsaw and router table.

Beau T ful cut, right on the line. Engineering square straight. It takes time to do, but very little skill or effort. So if you can stand in one spot for a few minutes, you can make beautiful cuts with a dozuki. (Reminds me of when I cut a dead 4" thick tree with the big boy pull saw.... It took five minutes, but I did it with one hand while smoking a cigarette with the other and not breaking a sweat, lol).

The cutting angle I used for the sheet is so flat, I just held the sheet over the edge of a cutting board to keep from sawing into my bench. You could do this anywhere, in case you don't have a good bench corner/edge for your handed-ness.


 
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Offline CatalinaWOW

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I would definitely score and snap it.  Fast.  Easy.  Clean edge.  No fumes.  No fouled up tools if you go to fast and melt the plastic.  2mm is getting towards the thicknesses where I have difficulty with the scoring and snapping technique, but is on the right side of that border.  Some folks are successful up to 6 mm or more.
 
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Offline Fludo

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How do you get straight cuts? I have never been so good with a hand hacksaw as far as it looking good cosmetically. On wood, etc, my cuts always wander a bit.

A hacksaw is thin and fine toothed for cutting hard metals like bolts and steel.  For a straighter cut you will need a wider blade and less teeth per inch.  Try one of the all purpose back saws/panel saws from the hardware store.
 

Offline 6PTsocket

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I would definitely score and snap it.  Fast.  Easy.  Clean edge.  No fumes.  No fouled up tools if you go to fast and melt the plastic.  2mm is getting towards the thicknesses where I have difficulty with the scoring and snapping technique, but is on the right side of that border.  Some folks are successful up to 6 mm or more.
2 mm is about the .08" thickness of the lucite/plexiglass/acrylic sheets that I regularly cut up for picture frame "glass". No trouble with a scoring knife at all. You can also flip clear plastic over and score both sides and it will almost complete the cut.

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Online Buriedcode

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Whilst many recommend hack saws, I would go with a razor saw with 32tpi.  Much thinner, and whilst it has no real advantage for thicker (>3mm) plastic, it makes quick work of thinner stuff - and it leaves very smooth clean cuts.  I clamped the piece down with a metal ruler along the cutting line as a guide - each back stroke cuts about 8mm on 2mm acrylic. 

For stuff that thin you could easily just score both sides and snap.  The edge won't be very nice but a few passes with a decent file and you'll be golden.  The edge finish is fine if you're using acrylic cement, but if you have exposed edges, flame polishing works wonders - plus its quick.
 
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Offline Brumby

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My observations:

 - Straight cuts with hand tools require skill.  Anything longer than 2cm or so and I know I'm not going to be happy with my results.  I just don't do enough to warrant purchase of specialised tools or to get the experience.  I like jigs or mechanised solutions.
 - Anything that grinds or abrades has to have the speed kept right down - otherwise (as others have said) the plastic will melt and you will end up gluing the material to the tool.  That gets very frustrating very quickly.
 - Cutting tools are by far the best - but you need to:
    * have sharp cutting edges
    * support of the material as close to the cutting zone as possible
    * take small bites
 - Score and snap can work well for full length cuts (no good for internal corners) - but practice first so you know how well you need to score for consistent results.  If you don't score properly, you might find yourself with a cut that is fine for part of the cut and then wanders off line.  Murphy's Law will ensure such wanderings will run into the target piece, not into the waste which you could sand off.  Even then, sanding off can leave a different finish to the edge that can sometimes be irritatingly obvious.

I'm looking at building my own laser cutter which could take care of this.  (I know you can buy them - but for the work area I need, they are prohibitively expensive.  Plus I don't require that much engineering.)
 
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Offline not1xor1

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I use a Bosch PKS 16 multi for wood, aluminium, and various kind of polymer sheets.
https://www.bosch-do-it.com/gb/en/diy/tools/pks-16-multi-3165140651240-199896.jsp
You just need an aluminium bar guide for straight cuts.
It does allow you to get straight and reasonably polished edges.
 
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Offline tooki

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Proxonn is insanely expensive and some of their tools bear a superficial resemblance I think, perhaps to Liyang, a Chinese brand. They make little saws like that.

They appear to be a huge company - at least from the variety of stuff they make they seem to be so.
Proxxon is only insanely expensive in North America (or perhaps outside of Europe in general). Within Europe, it's actually eminently affordable, being even cheaper than imported brands like Dremel.

If anyone is copying anyone, then it's the Chinese copying the Germans/Luxembourgers. Proxxon has been around since 1977.
 

Offline Rick Law

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I don't saw or mill it at all. They sell plastic scoring knives for a few bucks. Any craft or big box store should have one. I think mine is Olfa, a good Japanese company. Just take a straight edge and make severeral deep scores and it will snap off clean as a whistle; at least as clean or cleaner than a saw blade. No melting, no plastic dust, no waste. If the edge is going to show, you can sand and polish it but you have to do that no matter how you cut it. When you snap it, do it over a square edge, right under the score line. I cut acrylic for framed pictures with no problem

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At Home Depot, they sell plexi-glass, and they sell plexi-glass acrylic cutting knife similar to the picture 6PTsocket posted above.

Some years back, I had a project using plexi-glass.  I use one of those to cutting quite a number of 1/8" thick plexi-glass sheets.  Worked very well - I cut quite a number of them (making many smaller and smaller sheets out of 4 big ones).  Much better than saw which tends to create cracks.  You just need to make sure your first cut (initial groove) is nice and straight, then you can work it deeper and it snaps nice and clean.

I understand that plexi-glass while in the same family as acrylic but is different.  I think they share enough similarity in property that what works well for plexi-glass should be worth a try.
 
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Offline Old Printer

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I work at an architectural sign company in production. We use a lot of acrylic, plastics of all sorts. I have the luxury of a couple co2 lasers, but a few circular saws as well. The saws are all running fine tooth carbide speciality blades and are the go-to method for straight line cuts because of speed. The type of acrylic is very important, cast being the best for cutting of any method. Extruded being the worst, as it is "gummy" and tends to melt rather than cut. Visually they are tough to identify, being pretty much identical until hit with a blade or beam. Dremel used to make a small, affordable table saw with a 4" diameter blade, and are sometimes seen on places like craigslist. Equipped with a fine tooth carbide blade the cut up to 1/8" think acrylic very well. If you can create a vector file of what you need, a local sign shop with a small laser might be willing to cut it for you at a decent price. Lasers are also popular in awards shops as well, or local maker groups.
 
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