Clean Way to Cut FR4 PCB - Page 1
Forum section: electronics / general

author: bruce0126
author_rank: Newbie
timestamp: January 24, 2016, 09:23:49 am
content: Hi,Can anyone share their experience on cutting FR4 PCBs? Trying to see if there's a good way to have a clean cut (smooth PCB edges as well as minimal dust).Thanks,Bruce

author: Psi
author_rank: Super Contributor
timestamp: January 24, 2016, 09:43:29 am
content: try a good pair of tin snips

author: sleemanj
author_rank: Super Contributor
timestamp: January 24, 2016, 09:59:47 am
content: I use one of these:http://www.bunnings.co.nz/trojan-laminate-cutter-195mm_p00242200Along with a couple of steel rulers mounted to a piece of wood as a cutting jig. The laminate cutter has a carbide tip on each end, a couple drags of that on each side and snap the board.

author: matseng
author_rank: Frequent Contributor
timestamp: January 24, 2016, 10:05:14 am
content: Use 0.8mm instead of the regular 1.6mm. Two scores with a box cutter on each side and it snaps effortlessly apart.

author: IanJ
author_rank: Unknown
timestamp: January 24, 2016, 11:32:58 am
content: Back in the day we used to cut with a small bench top guillotine and edge sand afterwards.Ian.Quote from: bruce0126 on January 24, 2016, 09:23:49 am

author: tautech
author_rank: Super Contributor
timestamp: January 24, 2016, 11:35:34 am
content: Quote from: bruce0126 on January 24, 2016, 09:23:49 amWelcome to the forum.Serious hobbyists might use a PCB guillotine like these:http://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_20160124032323&SearchText=pcb+guillotineYou might try a sturdy paper guillotine for infrequent use.I have used a wood plane to tidy up a ragged hacksaw cut in the past.Or any of the above replies.

author: poorchava
author_rank: Super Contributor
timestamp: January 24, 2016, 11:43:22 am
content: High RPM (30k) rotary tool with serrated edge 6-flute carbide milling cutter. Dremel will do, but carbide bits don't like vibrations. CNC or some other rigid setup is preferred.Sent from my HTC One M8s using Tapatalk.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: January 24, 2016, 02:28:30 pm
content: Tin snips. I have a pair from Harbor Freight which are amazingly serviceable (cast aluminum handles, hardened steel blades). Quick and relatively dirty: the cut is something of a mess (the laminate is frayed in the process), and the material is bent and has to be straightened out.Hacksaw. Use a blade with enough teeth so that > 2 teeth are in the cut at any time. For common 1.6mm board, a blade of 32 TPI (8 TPcm?) will do. You can always cut at an angle so the cut is longer, which helps for thinner stock.The saw leaves saw marks (depending on how stable you are with a hacksaw), which take a while to sand down, but the edge is relatively undisturbed, and the stock is not bent up.In both cases, a smooth, clean edge is had by sanding with SiC (wet-or-dry) sandpaper.Sawing is good for boards that have components on them, or where you want to inspect the contents -- I recently sectioned a multilayer board in this way, which was interesting (it appears to be a build-up type assembly, which is interesting because the 'core' is as thin as any prepreg layers on top).Tim

author: MrSlack
author_rank: Frequent Contributor
timestamp: January 24, 2016, 03:29:41 pm
content: Score both sides with a stanley knife and safety edged metal ruler. Bend, snap. Use wet and dry paper on a flat surface and move the board rather than the paper. Comes out nice clean edges and not much dust. Make sure you wet the paper.

author: KL27x
author_rank: Super Contributor
timestamp: January 25, 2016, 08:24:12 pm
content: I have used a lot of those methods. I'll add a few more.1. Tile cutting saw. The low end saws cost less than $100.00.pro's: cheap, fast, easy, no heating/fumes/airborne dust, smooth edges. Tile cutting diamond blade lasts forever; they do not dull or slow down over time; they wear down and reveal new teeth, constantly, and the original crappy blade on the lowest end saw can cut a metric ton of FR4; you will not need a replacement in your lifetime. Did I mention fast? They are made to cut ceramic tiles. You can cut a stack of 10 boards on a tile saw and you will hardly feel resistance.cons: filling/emptying the water, noise/vibration, water spray. Large kerf. Fence on some saws not great for thin pcb's. Straight lines only or "removal" grinding of notches/corners. It's a little nerve racking with the spinning blade, even though a diamond saw can't really cut your fingers off without a lot of pain killers and motivation/intent. The blade is basically smooth/toothless to anything that is not hard/rigid.2. What I use anymore is a Proxxon rotary tool in a custom DIY mini router table. The angle of the tool/cutter can be adjusted. I use a carbide end mill tilted to 45 degrees to score a 90 degree V either partway to score, or even all the way through the board in one go. Afterwards, you can square and shape edges with the cutter set to 90 degrees, easily (but usually just a few quick rubs on sandpaper is sufficient for straight edges). But making that first plunge into FR4, the 45 degree tilt makes it effortless to advance the board against a fence with bare hands, smooth like butter, straight as an arrow, and fast fast fast. And Proxxon rotary tools are super quiet.

author: Farley
author_rank: Regular Contributor
timestamp: January 25, 2016, 08:48:30 pm
content: W2AEW posted a video a couple of years ago with some suggestions for cutting FR4:

author: KJDS
author_rank: Super Contributor
timestamp: January 25, 2016, 08:49:59 pm
content: Quote from: MrSlack on January 24, 2016, 03:29:41 pmThis is what I've always done. No point in buying another tools, though I do have assorted tinsnips, but I'd rather keep those for metal.

author: KL27x
author_rank: Super Contributor
timestamp: January 25, 2016, 08:54:50 pm
content: A knife works fine, but if you want to manually score, really you guys should check out the double-headed carbide cutter sleemanj posted. It's available at any hardware store, and the angle is made for manually scoring laminate. It will cut long "peels" of FR-4 out of the board, making a perfect V-groove. It's completely rigid (it won't wander back and forth and/or cut your wooden clamps), and it doesn't dull like a knife blade. It will lay flat against a thick guide/clamp, unlike a box cutter that had a big housing next to the tip. Instead of angling the knife blade to get it on the guide, you just lay the entire thing flat/parallel to the guide, and the groove occurs a little away from the clamp/guide. It's probably a lot safer, too, especially considering the ergos and angle.If you clamp things down tight, you can get a deep V score in 2 or 3 passes. If your setup is rigid enough, you could probably cut clean through the board, if you wanted to work at it. A steel knife is only scratching at the tip. A carbide cutter is cutting all the way along either edge in a V.

author: Alexei.Polkhanov
author_rank: Frequent Contributor
timestamp: January 25, 2016, 09:59:04 pm
content: I think you guys make things complicated when it does not have to be. I use this thing and it works perfectly for FR4 and Rogers every time, clean cut. 1.6, 2 mm 2.8 mm anything. Maybe except brittle, cheap plastic laminate, but I never tried.

author: rob77
author_rank: Super Contributor
timestamp: January 25, 2016, 10:24:03 pm
content: proxxon ks230 micro circular saw - works like a charm using regular vacuum cleaner as dust extraction. it's a very compact and silent circular saw.the cuts are extremely clean and smooth - you can't beat it with a guillotine or scoring and snapping the boards.

author: tautech
author_rank: Super Contributor
timestamp: January 25, 2016, 10:55:24 pm
content: Quote from: Alexei.Polkhanov on January 25, 2016, 09:59:04 pmI'd call that a bench shear and it's other uses for sheet metal could make it real handy for the workshop.Here's the best priced ones I could find on Aliexpress:http://www.aliexpress.com/item/Manual-shearing-machine-can-make-plate-thickness-3mm/1756101049.html?spm=2114.01010208.3.206.w5UkVG&ws_ab_test=searchweb201556_10,searchweb201644_1_10001_10002_10005_10006_10003_10004_62,searchweb201560_3,searchweb1451318400_6148,searchweb1451318411_6449&btsid=2cdf77f3-d212-4f16-bc47-72ebd6bde1cfhttp://www.aliexpress.com/item/Manual-guillotine-hand-shears-Zhacao-knife-herbs-guillotine-200mm/32550453345.html?spm=2114.01010208.3.90.cdYUkU&ws_ab_test=searchweb201556_10,searchweb201644_1_10001_10002_10005_10006_10003_10004_62,searchweb201560_3,searchweb1451318400_6148,searchweb1451318411_6449&btsid=6de7bd50-d44d-4b77-b0a8-6c0423108796

author: kwass
author_rank: Frequent Contributor
timestamp: January 25, 2016, 11:04:56 pm
content: Quote from: bruce0126 on January 24, 2016, 09:23:49 amI use a jewler's saw like this one:http://www.amazon.com/SE-Professional-Jewelers-Without-Blades/dp/B00313Q46M/ref=sr_1_2?s=arts-crafts&ie=UTF8&qid=1453762984&sr=1-2&keywords=jewlers+sawwith relatively course (for a jewler) blades from a set like this one:http://www.amazon.com/SE-815JSB-114-Piece-Jewelers-Piercing/dp/B002Q8886CWith a bit of care you can get extremely precise cuts and even if you're sloppy you'll have very little dust.

author: pez.diSpencer
author_rank: Contributor
timestamp: July 17, 2023, 02:47:57 am
content: Adding my 2 cents to an old thread... Wanna give an upvote to the tile cutter suggestion above.For cutting thick fr4 (3mm), I've had great success with a cheap tile cutter from harbor freight. The tabletop cutter is $60 and I use a fine glass/mosaic cutting wheel that cost about $15. Makes short and smooth work of long rip cuts for turret/eyelet boards. Leaves perfect, smooth edges, no sanding required, and no dust. Just gotta dump the water out wipe down the machine after. A pretty good investment if you're gonna be scratch building a few amplifiers.Only con-- if your board extends off the drip table as you're making your cuts, water will spill off of the board. So just cut in an area that can get a little wet, or put a towel down.