Tools for cutting plastic

[bitbyteword3]

I am creating a project that requires a square-shaped cut on the enclosure. I feel stupid but what can I use?

 

[Ian Rogers]

What plastic? If its soft enough drill four holes, corner to corner, use a sharp craft knife, finish with a file.. If its hard! loads of holes and the join them up, finish with a file..

 

[KeepItSimpleStupid]

You didn't mention the size of the hole, but the nibbling tool is customarily used. https://en.wikipedia.org/wiki/Nibbler Given a general geographic location we might be able to find a source.

Jewlers files, x-acto knife, hot knives, coping saw, jewlers saw, hack saw and Dremel tool to name a few. Cut a round hole using a pilot pit and file.

For huge holes, use a jig saw.

And for a complex way. An x-y table on a drill press or mill with a router bit.

Give me an idea of the size and shape of the hole, the accuracy required and the plastic thickness and I may be able to help more.

 

[HommerSimpson]

I use table saw with blade turned around backwards...works pretty good for plexiglass

 

[Ian Rogers]

I use table saw with blade turned around backwards...works pretty good for plexiglass

I take it you mean the teeth move backwards as opposed to the dull side of the blade..

 

[KeepItSimpleStupid]

The backwards saw blade (reverse direction) is typical, especially for cutting laminate. Carbide works great for cutting plexiglass although it would depend on thickness. A carbide tipped blade goes through 1/4" plexiglass or polycarbonate like butter.

 

[Sceadwian]

A standard freehand jigsaw works great as well, as long as the scale is appropriate. Size really does matter as to what tools you use.

 

[HommerSimpson]

I take it you mean the teeth move backwards as opposed to the dull side of the blade..

as in when the blade turns the back side of the tooth hits first..as in... putting saw blade on wrong way as to the right way :} lol

 

[cr0sh]

When using a jigsaw (or if you need more precision - a scroll saw) - make sure that after you use a blade on plastic, you mark it for "plastic cutting only". You'll also need to keep the speed of the saw and the feed rate at a certain level; too slow, and you may crack things, too fast, and the plastic will melt...

 

[Sceadwian]

Most of the plastics I've cut are fine for even rip cutting, not Acrylic or anything overly brittle or thick.

 

[KeepItSimpleStupid]

Today, I just cut a 4" piece of PVC pipe that was burried in a catch basin. Couldn't use my normal way. Mark and use a jigsaw and cut around. I used a right angle drive and a 2" saw blade on the Dremel tool. It's cutting plastic, right? Accuracy wasn't as good either.

 

[tvtech]

I am at a loss here. I have designed an Electronic product that is good to go. Constant testing for around a year now. Electronics are good. No problems ever......

The casing however is a nightmare...

Polycarbonate is a ***** to work with....hard as nails on a cold day...cuts cleanly.
Warm day, it's like butter. And all changes. The polycarbonate sheet makes grooves in my Dremel table while I am cutting it....too hot.

Please any advise here??

My solution should be simple with the knowledgeable polycarbonate experts out there

 

[ronsimpson]

I use a small mill.
I have used a soldering iron with a knife blade attached.

 

[Sceadwian]

If it's melting the plastic the blade is going too fast, you may be using the wrong type of blade as well you want course teeth. Any particular reason you chose polycarbonate? Thin sheet metal is pretty easy to work with, and provides RF/EMI isolation as well. It takes a little more time to work with metal as it cuts slower, but you can also bend it much more controllably than most plastics by simply scoring the bending point to create a week point and using proper leverage with wood blocks and a pry bar.

 

[jpanhalt]

Here are a few hints about cutting plastics:

1) Generally, plastics tend to "hog" in. Use a negative rake tool (https://en.wikipedia.org/wiki/File:Metal_Cut_diag.jpg). That gives you more of a scrapping action than a cutting action. The previous post about using a saw blade installed backward simply is another way to get negative rake.

2) If drilling, "dub" off the cutting lip. In other words, grind the cutting edge so its contact angle with the plastic is perpendicular or a little past. That also gives negative rake.

3) I use the Harbor Freight version of the mill shown in #13. Don't trust the downfeed dial. Put a cheap dial indicator on the spindle housing and use that to gauge your depth of cut.

4) Use water cooling, if possible. Some people add a little detergent to enhance wetting.

John

 

[KeepItSimpleStupid]

Thats exactly what i use. Water and dishwashing liquid. I had to regrind the bit ends to drill 5/8 holes. I made them look like a pilot or brad point bit.