Cutting populated PCB's into new shapes - Page 1
Forum section: electronics / projects

author: Auzeras
author_rank: Newbie
timestamp: September 30, 2014, 05:30:42 am
content: Bit on an interesting question I suppose, I'm working on a project where I'll be cutting up old PCB's into shapes which will then be inlaid in wood and cased in resin. As far as I know no one has done this before. It's for a university furniture design project in which I have chosen to incorporate dead electronics, hence the old PCBs.There are plenty of ways to cut PCB which we're all familiar with such as CNC, guillotines etc but I am using already populated boards so whatever is used to cut will have to cut through the board & whatever is on the board. Mostly surface mount stuff as well as the occasional through hole (although I'm trying to minimise through hole for aesthetic reasons. I have been told the university's CNC router for cutting PCB's won't go through components and they seem a tad reluctant to "give it a shot"I was thinking of using a water jet cutter but ours is current out of action, I think it would cut through everything well though. We have a few laser cutters but I have my doubts as to how well they'll go through the boards, especially the components. No idea on power but they do 6-9mm MDF. My only other solution is to get a hacksaw and cut them to size but I feel that would leave a really rough finish.As far as specs go I've yet to finalise the design as the final will rely on my actual ability to make it. So far most pieces are around 1cm wide although I have designs which use pieces down to a few mm. Keeping them all geometric shapes so they're going to be simple to form, mostly triangles/rectangles.So, what's the best way to do this? I've got no clue really since I've never tried to cut through the middle of a populated board. I'm hoping some of the logical brains on here will show me up with a reasonable solution within seconds! If anyone wants to see the designs I can put them up if it will help visualise what's going on.Thanks!

author: Smokey
author_rank: Super Contributor
timestamp: September 30, 2014, 06:24:48 am
content: I vote water jet.... I have no idea if it will work, but it sounds like a cool project. Take lots of pictures

author: Richard Crowley
author_rank: Super Contributor
timestamp: September 30, 2014, 06:43:49 am
content: I have successfully done that with a diamond saw blade on a precision table saw.

author: lowimpedance
author_rank: Super Contributor
timestamp: September 30, 2014, 06:47:08 am
content: And if no diamond saw, perhaps a band saw!. You will still have to clean up the edge though.

author: tggzzz
author_rank: Super Contributor
timestamp: September 30, 2014, 07:01:08 am
content: Be aware some components contain some nasty chemicals internally, which will be hazardous to the person cutting them.Beryllium in power transistors is a well-known example, andit would be wise to presume there are others. Airborne beryllium isA Bad Thing, seehttps://www.osha.gov/SLTC/beryllium/be_and_chronic_be_disease.htmlor any other reputable source.Lead in solder is another obvious hazard.Completely encasing cut components in resin before inserting them into the furniture would probably prevent them leaching out thereafter. Even so, I would be reluctant to eat off them, but that's possibly an overreaction.

author: poorchava
author_rank: Super Contributor
timestamp: September 30, 2014, 07:50:39 am
content: Remove hazardous stuff (like batteries, electrolytics) and really tough stuff (eg. heavy duty screw terminals etc) and throw in a router with a serrated edge tungsten carbide endmill, preferably 1/4" or thereabouts, 1/8" is a lot cheaper but you'll need to be conservative about feedrates. Then press go and observe as the carbide shreds through all the stuff on the board.

author: Auzeras
author_rank: Newbie
timestamp: September 30, 2014, 08:04:08 am
content: Thanks for all the suggestions guys, keep 'em coming if you can think of more. I really hope to use the jet cutter since I feel that's going to be the best option at the moment. Good advice on the hazardous materials. I'd forgotten about the likes of Beryllium but more importantly is the lead dust. We can't use treated timber in the workshop so I'll have to be very careful with the dust. That and resin dust is pretty nasty anyway.As far as bandsaws go I've heard PCB dulls them pretty bad, but that was a guy using a wood blade, he'd chop his boards before changing the blade because it was too dull for wood. He said afterwards it was near useless. We have some pretty tough ones at the shop for cutting through big steel chunks and whatnot though which are much finer toothed and will stand up to the abrasion better. Will look into that.I'll try out the router idea too if I have time, the uni might have a bit I can use which would save me buying one for the sole purpose of trial and error.I don't have a precision table saw but that sounds like a good idea too.Thanks for the suggestions so far! I'll definately keep everyone updated on the progress. Final product is a "coffee table" but optimised for a digital world where you're more likely to have phone, not coffee or magazines on your desk. Kitted out with wireless charger and eventually an Rpi or similar to stream media from. Should be cool!

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 30, 2014, 08:50:07 am
content: Bandsaw is not a good idea as fibreglass dust is very abrasive and can damage bearings.carbide chip-breaker router bit is probably the best bet.

author: tggzzz
author_rank: Super Contributor
timestamp: September 30, 2014, 09:14:08 am
content: Have you consideredavoiding cuttingaltogether, either by finding a suitable size of PCB or by changing the size of the furniture to match the available PCBs?That would simplify your task not only w.r.t. obeying local health and safety regulations, but also w.r.t. getting permission to use cutting equipment.

author: zapta
author_rank: Super Contributor
timestamp: September 30, 2014, 02:39:59 pm
content: Quote from: tggzzz on September 30, 2014, 09:14:08 amOr embedding pictures of boards.OP, do you need to cut arbitrary shapes our just straight lines?

author: Kjelt
author_rank: Super Contributor
timestamp: September 30, 2014, 02:48:34 pm
content: I used a lot of different tools but the one that worked best was a "slijptol" (no idea what the english term is (grinder?) so placed picture below) but it is not a fine cut but it is very rough but goes through pcb's as a hot knive through butter. You can always use a belt sander to get the sides nice.Use good dust extraction though it dusts as hell and it is not good for your lungsEdit: it can have two discs, one is thick and is for grinding, the one you need is thin and is for cutting metal or pcbs

author: mikerj
author_rank: Super Contributor
timestamp: September 30, 2014, 03:42:47 pm
content: Quote from: Kjelt on September 30, 2014, 02:48:34 pmIt's called an "Angle grinder" in English. Perfect for removing skin, fingers, eyes etc.

author: jolshefsky
author_rank: Regular Contributor
timestamp: September 30, 2014, 04:04:59 pm
content: I don't think you'll have success with the water-jet cutter. I work with a water jet house and asked about circuit boards (very small ones) and they said it just blows all over because it's laminated. The high pressure gets between the layers and forces out horizontally, ripping the material apart.You could try it, though. That's what they said about their own experience ... maybe a finer nozzle would cut fast enough to work.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: September 30, 2014, 04:07:06 pm
content: There are PCBs embedded in the rocks on the pedestrian path near me.

author: KJDS
author_rank: Super Contributor
timestamp: September 30, 2014, 04:24:34 pm
content: Use an axe

author: tggzzz
author_rank: Super Contributor
timestamp: September 30, 2014, 05:09:40 pm
content: Quote from: mikerj on September 30, 2014, 03:42:47 pm... and for filling nearby lungs with dust.

author: Kjelt
author_rank: Super Contributor
timestamp: September 30, 2014, 08:40:13 pm
content: Quote from: mikerj on September 30, 2014, 03:42:47 pmThat is not where i use it forand i use it often, just be carefull and wear protective gear.All tools can be dangerous, for instance a solder iron could cause first degree burns.

author: zapta
author_rank: Super Contributor
timestamp: September 30, 2014, 08:52:26 pm
content: Quote from: Alex Eisenhut on September 30, 2014, 04:07:06 pmPictures?

author: robrenz
author_rank: Super Contributor
timestamp: September 30, 2014, 08:58:38 pm
content: Why is everyone avoiding the obvious?Use a light saber!On a serious note I have had lots of 3/4" thick G11 epoxy glass cut with abrasive water jet with excellent results. That would be the ideal method since none of the material on a board will stop the abrasive water jet. A ceramic package would require a much slower feed rate than bare board so the operator needs to be on his toes. It must be abrasive water jet not a water only system.Edit: I also agree the wet tile saw will work well if you only need straight cuts.

author: Jebnor
author_rank: Regular Contributor
timestamp: September 30, 2014, 09:12:46 pm
content: I have successfully used a wet tile saw to cut them. It has a diamond saw and the wet keeps the dust to nothing. I use it on new boards as well.Like this one.http://www.canadiantire.ca/en/pdp/qep-wet-tile-saw-4-in-0556707p.html#.VCsctmSwLYM

author: AmmoJammo
author_rank: Frequent Contributor
timestamp: September 30, 2014, 09:49:07 pm
content: I've hacksawed boards before, that I wanted to use part of in a circuit still....That would be my suggestion, then clean up the edges with a file/bench sander/grinder...

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: September 30, 2014, 11:07:52 pm
content: Quote from: zapta on September 30, 2014, 08:52:26 pmNo, not pictures, actual PCBs.OK OK I know what you meant, I guess I opened my big yap I gotta prove it now eh?Sun sets mighty early this time of year, I'll have to go over there soon before it gets dark at 3 PM...

author: lowimpedance
author_rank: Super Contributor
timestamp: October 01, 2014, 12:54:30 am
content: Yes the fibres are abrasive, but how many pcbs are being cut up ?., and what access does the OP have to suitable tools apart from the water jet?.In the end the hacksaw may well be the easiest and most controllable for the waste produced.Quote from: mikeselectricstufflink=topic=37109.msg522000#msg522000 date=1412067007

author: Auzeras
author_rank: Newbie
timestamp: October 01, 2014, 06:16:06 am
content: As far as tools go I've got a pretty well kitted out workshop and fabrication workshop at my disposal. I talked to the lady who runs the fab lab and she's refusing to allow me to use their CNC routers to cut PCB, the PCB they cut is epoxy and cloth instead of fibre based like most commercial stuff. Also she's adverse to me even trying to cut through a populated boardRight now my best best I think is to cut with the jet cutter but I don't want to rely on it as the pump is out at the moment (burst a bunch of seals) and the project is due in in two weeks from today. I will however be casing each part in resin before cutting, partly to make it easier to cast each one with a very smooth finish but it will also help reduce tearout on the board and in the case of the jet cutter will support the boards layers.So far my current options I'm considering are:Bandsaw with carbide bladeHacksawJet cutterPossible angle grinder with a thin cutting disk on it - danger of fine dust management. At least the jet cutter and bandswaw have pretty decent vacuums/disposal systems to minimise harmful particulate matter.Someone mentioned photos - that could be a valid option if I print high quality pics out, my major is in photography (I just happen to mess around with everything haha) so I have easy access to high quality printers. I might try a test strip and see how they come out. It could also mitigate the problem of trying to stop bubbles forming around everything.I've attached some of the designs I'm thinking of using, to whomever asked about the shapes, I've kept them to simple geometric lines. Partly for ease of cutting but also to match the somewhat "electronic" aesthetic. Hard sharp lines etc. Big Niantic logo in there for the Ingressers amongst usAnd before anyone asks I'm Enlightened! Also note the scale varies! So don't expect to get any relevant dimensions. On the big ones on a rectangular white background are to scale though, table is 1000x500. Small square ones are on a 150x150 canvas. I drew the square ones in illustrator for vector output for CNC/Jet cutter.Thank you so much for all your feedback and suggestions! Very helpful, even if I don't end up using any of them and dying in a cloud of dust hahaha!

author: Kjelt
author_rank: Super Contributor
timestamp: October 01, 2014, 07:35:07 am
content: I also used a hacksaw, works but takes a lot of time and energy.I had the job of sawing 30 small pcbs through the microcontroller in half on an evening and the first pcb with the hacksaw took 5 minutes, the second 7 minutes, the third 9 minutes and I realized the blade became dull and my muscles start to hurt. That's when I went to the angle grinder and was finished 8 minutes later. I took the job outside and used a nozzle with a vacuum to collect as much dust as possible.I clamped both parts of the pcb that I was cutting to make sure they were not "launched" after the cut went through. Advise use some of the small clamps on numerous places to fix the pcb, or drill some holes and screw all parts of the pcb to a wooden underground to mechanically fix them.You have some pretty designs there I can not see the size of them but if these are as small as wooden inlay I am afraid you will have big problems with pcb's. At least with rough tools as the grinder and hacksaw.Good luck and show us some pictures if you have some.

author: nctnico
author_rank: Super Contributor
timestamp: October 01, 2014, 07:51:28 am
content: Quote from: poorchava on September 30, 2014, 07:50:39 amI agree. I have actually used that method in the past to cut interesting bits from old motherboards like the ISA slots and the oscillator circuit.

author: Auzeras
author_rank: Newbie
timestamp: October 01, 2014, 08:04:41 am
content: I plan to refine the designs a lot more once I know what I can deal with and the time frame, no point in churning out heaps if I can't possibly make them! Also no point in working on something impossibly small and detailed if it's possibly to cut but incredibly difficult/time consuming.Photos are pretty average phone snaps from my Nexus for including in the workbook. Table is 500x1000x450 and made from 4lm of 50mm Kwila ($207 worth.. poor student tears!) The design is meant to resemble a DIP package somewhat. The legs are made from 22.5mm mild steel tube machined down to ~22mm to fit in the holes (they don't make 22.5mm forstner bits, and the .5mm shoulder gives a nice finish to the hole)The table is 3x planks of 200x50 Kwila wide, glued and biscuit jointed with Tightbond II, I plan to finish it with teak oil and buff to a shine. I have danish oil but I feel that the glossier teak finish will go better with the inlaid epoxy.Photos in order:Gluing & Clamping table topMachined steel (mild steel is ugly to machine)Testing fit in legsHow it will look once table holes drilledTable being drilledRealising a few holes are a mm or so out and the compound error has screwed you (not shown, manic crying at prospect of ruining $200 in timber)Working out a solution to aformentioned errorsTimber cut to size (this pic should be first but order got messed)

author: nctnico
author_rank: Super Contributor
timestamp: October 01, 2014, 08:31:01 am
content: Can't you use unpopulated PCBs as an alternative? You can have these made by Itead, Seeedstudio, etc.

author: tggzzz
author_rank: Super Contributor
timestamp: October 01, 2014, 08:37:31 am
content: Quote from: Auzeras on October 01, 2014, 06:16:06 amI wonder why!More seriously, it might be worth you knowing why. Equipment safety/damage is one thing, but people's safety/injury is another.QuoteDon't forget it isn't necessarily solely dust that will damage people. Fumes can be pretty nasty too, and they wouldn't be caught by a dust filter, of course.I'm sure you don't want your project to endanger other people in the vicinity.

author: Auzeras
author_rank: Newbie
timestamp: October 01, 2014, 08:50:10 am
content: [quote author=tggzzz link=topic=37109.msg522602#msg522602 date=1412152651I wonder why!More seriously, it might be worth you knowing why. Equipment safety/damage is one thing, but people's safety/injury is another.Don't forget it isn't necessarily solely dust that will damage people. Fumes can be pretty nasty too, and they wouldn't be caught by a dust filter, of course.I'm sure you don't want your project to endanger other people in the vicinity.I know why was just letting other people know that any CNC routing was out of business, even with a good carbide bit. They don't want to deal with the dust & mess as well as they fab lab crew are a tad less into trying things out, preferring instead the more engineered proven approaches.Fumes are a good point, although I should think they'll be at a minimum and any caused by friction will swiftly drawn out by the dust extractors, there's pretty solid airflow. Dust is the main concern.If I suspect it could be a little dicey the n I'll just grab a grinder and go outside (assuming I go the grinding route) if not I can arrange to come into the shop early and seal off the area to work so no one else has to deal with my dust & fumes.Even without the extractors I think that the fumes produced would be pretty mild in terms of ppm. I'm more worried about the dustAll valid points though, and taken into consideration.

author: Kjelt
author_rank: Super Contributor
timestamp: October 01, 2014, 10:57:33 am
content: Another reason is that an industry cnc mill can reach speeds of 50000 rpm (even double that) and if a small smd component shoots loose with those speeds it is a small projectile, that is why industry routers are almost all completely encased.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: October 01, 2014, 02:20:27 pm
content: Here we go...

author: Auzeras
author_rank: Newbie
timestamp: October 01, 2014, 11:14:36 pm
content: Well that's cool! Mind if I use that photo for my workbook? Although I searched I never managed to find any examples of PCB's being set or encased in anything other than their intended machinery

author: Richard Crowley
author_rank: Super Contributor
timestamp: October 01, 2014, 11:33:06 pm
content: Quote from: Auzeras on October 01, 2014, 11:14:36 pmhttps://www.google.com/search?q=circuit+board+art&source=lnms&tbm=isch

author: ozwolf
author_rank: Regular Contributor
timestamp: October 01, 2014, 11:44:20 pm
content: I've attached a picture of a desktop computer motherboard that I'm using to mount three analogue meters as a clock. This will be a piece of "tech art" for my office.The board had a lot of surface mount components removed (hot air gun) as I wanted the trace artwork to show. I hot glued the pcb to an aluminium frame which will be used to mount to the office wall. This picture is early stages of developing the Arduino board/software and RTC workings. I'm now working on my on PCB to drive the meters.I used a hole saw to cut three 50mm holes, messy but manageable. I understand people issuing you cautions about dust, but I believe normal personal protection and normal safe working practices will suffice for hobby type projects (one off quantities). I'd take a different approach if this was production and much larger quantities.

author: Auzeras
author_rank: Newbie
timestamp: October 02, 2014, 04:03:42 am
content: Very Cool ozwolf! I agree with your sentiments on the low impact of a small batch but since this is a university workshop the trick will be keeping within the OSH regulations for the department. That being said the workshop staff aren't worried about dust, it's only the people in the fabrication building (and the ones with the CNC router) who don't want me within a 10 mile radius with my FR4 boardsI will be routing out the recesses for the PCBs with the CNC though.Will get back with updates when the time comes, thanks for your cautions, suggestions and comments so far!

author: Seekonk
author_rank: Super Contributor
timestamp: October 02, 2014, 07:06:30 pm
content: I cut up old circuit boards all the time. I have great access to parts except when I go to my camp in the summer. My entire colar/fridge UNO controller is from parts cut out old UPS and other boards. Need a FET or regulator, cut out a square inch and hot melt glue it to a board. I just use an angle grinder and a thin cutoff wheel then a hand file to clean the edged.WARNING!!!!!!!!STAY AWAY FROM PRE 90'S COMPUTER BOARDS. SOME COMPUTER CHIP HOUSINGS WERE MADE OF BERILIUM ( however you spell it) GRIND ONE OF THEM AND THE DUST IS POISONOUS.

author: Auzeras
author_rank: Newbie
timestamp: October 14, 2014, 05:53:13 am
content: UPDATE TIME! With pictures!I was advised the best way to do this would be to to cast the resin, cut it out and stick it in. WRONG! If anyone does this in the future don't waste $50 in kleer kast like me and destroy the only large PCB you have lying around the day before you need to finish the pieceI recommend cutting out the PCB on a bandsaw with a blade designed for cutting metals then casting over the top & sanding a finish instead of casting face down on glass & cutting into shape later.Basically I f'ed up the cuts and it's nearly impossible to get them to fit well. I got one simple shape in after about an hour of sanding.So yeah the CNC routing came up beautiful but unfortunately the PCB inlay looks a bit shite. I'll do my best and hope to re cast it some day when I have more money, student lifeThe resin came up beautifully clear. It's a shame I couldn't cut accurately enough to get the shapes rightPics in order:Test cast with PCB - Although it looks like there are bubbles in it it's just dust. It come up gorgeously clear & bubble free. No vacuum chamber used. Just lucky!Test shapesMore Test shapesCasting motherboard (after removing headers & most through hole components)CNC routing designAwww yiss, looking greatAww no I f'ed upWell...