Looking for a fab house that can cut plexiglass (small quantity)  - Page 1
Forum section: electronics / projects

author: tkamiya
author_rank: Super Contributor
timestamp: August 31, 2020, 05:04:28 pm
content: I usually don't farm out portions of my projects, but for this particular use, I want my final product to look somewhat nice. I need someone to cut plexiglass for me. I need a clear plexi cover and black plexi bezel, so that I can clean up how LCD looks on front panel. There are few on Tindie and other places for usual 20x4 but what I have is much larger.I have this LCD panel:https://www.aliexpress.com/item/1704861756.html?spm=a2g0s.9042311.0.0.5e3d4c4dvEQ0BbI had someone who showed interest in doing a custom job (he sells standard size bezels on Tindie) but he hasn't responded to my email, so I'd imagine he is not interested.Can anyone recommend someone who will do a small quantity job? I'm looking for no more than five. I am in Orlando, Florida but the vendor can be anywhere.By the way, this panel is NICE. I bought blue and green version. Large, crisp, and bright. If you look carefully, data sheet shows 16 pin but the real panel has 18 positions. There is a trace connected to pin 17 and 18 is N/C. Some documentations show 17 is -5V out, but on mine, it is not. It appears to be N/C. Rest is just a standard configuration. Be forewarned, standard shipping took over a months.

author: Renate
author_rank: Super Contributor
timestamp: August 31, 2020, 05:09:09 pm
content: Pololu does laser cutting:https://www.pololu.com/product/749

author: Ian.M
author_rank: Super Contributor
timestamp: August 31, 2020, 05:43:11 pm
content: Thin acrylic sheet laser cuts very nicely. Some assembly by gluing would be required as laser cutters can only do well controlled 2D cuts. Also, its worth checking if there are any reasonably local hackerspaces with a laser cutter, and trying to get friendly with a local plastic sign shop (bring coffee and donuts), who may well be able to cut your bezel from an offcut for little more than their time.

author: Benta
author_rank: Super Contributor
timestamp: August 31, 2020, 05:47:42 pm
content: I wouldn't recommend laser cutting for plexiglass. Melting (which laser cutting is) usually looks a mess. I'd recommend either CNC milling or water jet cutting followed by edge polishing.For very thin acrylic it works, but then you could just do it yourself with a carpet cutter.For the bezel, consider 3D printing.

author: wizard69
author_rank: Super Contributor
timestamp: August 31, 2020, 06:23:03 pm
content: Lexan might be preferred over plexiglass as it machines better. I've gotten good results on wood working machines cutting Lexan to size. So cutting out a rectangle for the window isn't a big deal. A local wood worker or even a metal worker can help with that.Cutting a bezel is a different matter though. First off bezels by their nature are thin items that are not very stiff under machining pressure so you need to carefully consider how the bezel will be created. Then you need to consider how to make that bezel look good. To be perfectly honest I can't see anybody doing this for free due to the set up time and the likely need to create jigs and fixtures. In fact it is things like this that make small CNC machines like routers, mills and even 3D printers so useful. You could do the parts on a manual mill too if you keep complexity low. You also need too realize that just about any method used to cut these out will leave noticeable machining marks that will need to be cleaned up.So the window should be easy to get. You might be able to find a local plastics supply shop to cut them out for you. The bezels are an entirely different matter in my mind and it really depends upon what you want out of that bezel.One DIY approach for the bezel, would be to use a wood working router. You would need to make a series of jigs and fixtures to guide the router. The problem here is that just making the fixtures will require a table saw at a minimal. Also a bunch of hand tools that you may or may not have.

author: Benta
author_rank: Super Contributor
timestamp: August 31, 2020, 06:30:14 pm
content: Lexan (polycarbonate) is a really good idea. It's not prone to cracking like Plexiglass. It's a little bit duller, though.

author: floobydust
author_rank: Super Contributor
timestamp: August 31, 2020, 08:51:10 pm
content: Quote from: Renate on August 31, 2020, 05:09:09 pmYes Pololu is very good and you also don't have to buy a large sheet- unless you need a custom thickness/colour etc.Their laser cut acrylic is quite smooth and no melting or burning seen. They don't do lexan but you could ask about it.

author: tkamiya
author_rank: Super Contributor
timestamp: August 31, 2020, 08:56:22 pm
content: Thanks everybody! Although tempting, I'm thinking I'd rather not buy yet another box. Lab is already full of test equipmentLaser cutter will also do engraving front panel wouldn't it.....

author: wraper
author_rank: Unknown
timestamp: August 31, 2020, 09:03:41 pm
content: Quote from: Benta on August 31, 2020, 05:47:42 pmI guess you never seen laser cut acrylic done half-decently to make such a bold claim. Also it's not melting but evaporating.Quote

author: notsob
author_rank: Frequent Contributor
timestamp: August 31, 2020, 09:07:40 pm
content: I have had polycarbonate cut to spec by a waterjet cutting service in Brendale, QLD

author: wraper
author_rank: Unknown
timestamp: August 31, 2020, 09:09:42 pm
content: Quote from: Benta on August 31, 2020, 06:30:14 pmGet cast acrylic instead of extruded and it's won't crack easily. Also as long as you don't do complex shapes with narrow features and simply keep it square, it's not that easy to crack even extruded.

author: Renate
author_rank: Super Contributor
timestamp: August 31, 2020, 11:03:13 pm
content: Actually, I used to cut plexiglas with a wood crosscut saw that I bought for $1.Ok, the edges were a bit rough though.Mmm, it was mostly to cut large sheets down to fit into the laser cutter.

author: Renate
author_rank: Super Contributor
timestamp: August 31, 2020, 11:10:33 pm
content: These were cut by Pololu:

author: Ian.M
author_rank: Super Contributor
timestamp: August 31, 2020, 11:27:32 pm
content: Most shops refuse to laser cut polycarbonate because "polycarbonate sheets (Lexan) produces flames, creates long stringy clouds of soot that float up, ruin the optics and mess up the machine and which is extremely hazardous to the health of people nearby."You'd need a higher than usual power laser, an actively purged light path and an inert atmosphere to even contemplate cutting it.A sandwich construction of thin acrylic sheets solvent glued together is quite practical for the bezel. If you make it three sheets thick, you can trap hex nuts invisibly in hex holes in the middle one to allow the display to be mounted to the back of it with the fixings invisible from the front. Glue the window in place from behind after assembling the layers of the bezel using an adhesive that wont mar the window.

author: Mecanix
author_rank: Frequent Contributor
timestamp: September 01, 2020, 08:38:01 am
content: Plexy or PMMA both will require anti-scratch coating if fitted onto a illuminating device such as lcd, led, or anything bright for that same matter. A costly and extra surface process I understand however worth keeping in mind. If this coating is omitted then consider utilizing a cleaning technique that will not scratch the surface. It only needs 1(one) dirty cloth rub and you end up with a hundred micro-scratches. Guessing you aren't into 'smoky-looking' surface finishes so that's why I'm chiming in...I'm guessing you could get away by applying a commercially available thin anti-scratch film on the surface and have them laser cut to size after. Might leave some nasty burns and burs, or might not... needs experimenting. I do however recommend coating though (dipping process).Depending on the location of the hardware (fixed? portable?) you've considered glass cutting instead? Normally the guys specializing in optics can get this done rather quickly...

author: jfiresto
author_rank: Frequent Contributor
timestamp: September 01, 2020, 11:48:07 am
content: Quote from: notsob on August 31, 2020, 09:07:40 pmPolycarbonate is a great plastic but it is susceptible to Environmental Stress Cracking (ESC), the combination of stress plus the right (wrong?) solvent or oil, for example, as found in some hand creams. If you can avoid the one or the other, you are golden.

author: tkamiya
author_rank: Super Contributor
timestamp: September 01, 2020, 08:10:09 pm
content: Quote from: Renate on August 31, 2020, 11:10:33 pmThat looks more than adequate for my needs. My current one looks similar though I do not know how they were cut. Thanks for the reference.