Cutting FR4 boards - Page 1
Forum section: electronics / general

author: OndraSter
author_rank: Contributor
timestamp: July 30, 2012, 07:48:20 pm
content: HelloI am making really small and cheap (almost Chinese-like priced!) gadget. The board itself is 23x34mm big. The cheapest option is (how else than) iTeadStudio with their $15 5x5cm colour boards.I can fit two of these designs onto one board and save actually a lot of money (parts are less than $2.5 and I'd like the board to be sub-$1). I am wondering what is the easiest and most convenient way to cut the board in half (since they do not allow you to make v-grooving)? I tried exacto knife with not much of a success.My idea is that one could use glass cutter since it is FR4?Basically "V-groove" it manually and then just snap it.Thanks for any hintsPS: PCBCart asks much more $$, just as any local PCB fab house.

author: Short Circuit
author_rank: Frequent Contributor
timestamp: July 30, 2012, 07:54:48 pm
content: Ordinary hacksaw will do fine.

author: Chet T16
author_rank: Frequent Contributor
timestamp: July 30, 2012, 07:55:12 pm
content: I think I seen someone mention here that they had used a tile cutter. Dust would be nasty though!

author: mazza85
author_rank: Newbie
timestamp: July 30, 2012, 07:57:16 pm
content: Usually I score the board several times with a piece of hacksaw blade sharpened at the end, then I bend the board until it snaps in two.Sent from my phone with Tapatalk

author: hlavac
author_rank: Frequent Contributor
timestamp: July 30, 2012, 08:07:59 pm
content: Idea 1: Use a small PCB mill. In my case, I just mount a small mill bit into my pcb drill/mill stand and lower it all the way down.Attach a some bar exactly the width of your pcb away from the mill tip.Slide your double pcb along the bar, cutting right in the middle between the two pcbs.Idea 2: Make the V grove yourself, using some sharp v shaped tool and a steel ruler. Score and snap off.Idea 3: I had some success cutting pcbs with massive scissors used for cutting sheet metal. You need the type that allows cuts longer than the blade. I took a piece of pcb to hardware store and tried all the scissors they had, walked out with acceptable ones. Probably not ideal for your situation as one of the two sides gets bent. Good for cutting excess rims. Great for cutting perfboard.

author: OndraSter
author_rank: Contributor
timestamp: July 30, 2012, 08:19:38 pm
content: Thanks for all the tips guysI tried searching actually on the forums and on the internet of course, but there were 1000 opinions and every odd one said "the even one is wrong!"Hacksaw seems quite thick for my use (since I will go for 1mm thick silkscreen line marking).@hlavac: that's why I asked about glass cutter - it is glass epoxy laminate. V-score from the top and bottom and just snap them.

author: Short Circuit
author_rank: Frequent Contributor
timestamp: July 30, 2012, 09:13:24 pm
content: A glasscutter only creates a scratch in the surface of the glass doesn't it? Then it will not work because you need to score fairlydeep to snap the boards nicely. I guess the cuts need to be about 25% of PCB thickness, and on both sides.Big difference with normal glass is that the layers of woven glass are isolated by the epoxy filler material, somewhat likemultilayered safety glass. And a glasscutter does not work very well on such safety glass either, I think...Also, be carefull when snapping the boards regardless of the scoring method, especially after they have been assembled.Too much warping can easily result in fractures inside components, or in SMT solderjoints.

author: dbinokc
author_rank: Contributor
timestamp: July 30, 2012, 09:25:54 pm
content: Quote from: Chet T16 on July 30, 2012, 07:55:12 pmIf you use a wet tile saw, there will be no dust. This is my preferred way to cut blank PCBs.However I am have not done this with populated boards. before. The kerf for a tile sawis rather wide, so be sure there is enough clearance.

author: Christopher
author_rank: Frequent Contributor
timestamp: July 30, 2012, 09:41:41 pm
content: Hacksaw is too messy, takes ages to cut and nasty dust...Best is a pair of tin snips or I've found an old pair of LARGE kitchen scissors work good, even if the FR4 makes them blunt.

author: OndraSter
author_rank: Contributor
timestamp: July 30, 2012, 10:48:12 pm
content: The boards are not necessarily assembled before cutting them apart!Okay, glass cutter is off the list then.The thing is - there is about 2 or so mm thick "line" which I have to make perfect cut (or nasty cut and then sandpaper it).I will try talking to iTead if they could make new offer... something like $17 for 20x 25x50 boards.

author: digsys
author_rank: Unknown
timestamp: July 30, 2012, 11:01:17 pm
content: I've cut up literally 1000's of PCBs using a band-saw. The cut is about 40thou using a thin metal blade,which will last 100M of cut or so.

author: OndraSter
author_rank: Contributor
timestamp: July 30, 2012, 11:10:18 pm
content: I shall buy one then. The one I found in the basement does fairly thick line and is... rusty!Thanks a lot!

author: elCap
author_rank: Regular Contributor
timestamp: July 30, 2012, 11:49:18 pm
content: If you plan to do many, a pcb guillotine is a good tool to have. It's quick and precise.

author: krenzo
author_rank: Regular Contributor
timestamp: July 31, 2012, 12:52:03 am
content: I use a dremel. It takes about 5-10 seconds depending on length.

author: Short Circuit
author_rank: Frequent Contributor
timestamp: July 31, 2012, 01:13:35 am
content: Quote from: digsys on July 30, 2012, 11:01:17 pmThis probably depends a lot on the material of the blade.I have one of these Proxxon bench saws, and tried to use it for cutting a piece of prototyping FR4.The stock blade was completely blunted after ~3cm of cuttinghttp://www.proxxon.com/eng/html/27006.php

author: nanofrog
author_rank: Super Contributor
timestamp: July 31, 2012, 01:22:50 am
content: Quote from: elCap on July 30, 2012, 11:49:18 pm+1They can be expensive though (seen them near $1000 USD, though it was rather large; ~400 x 600mm or so, and rated for 1.6mm board thickness).A small sheet metal shear would be an acceptable alternative for the PCB size the OP listed, and found at a much lower cost.

author: OndraSter
author_rank: Contributor
timestamp: July 31, 2012, 01:25:58 am
content: Quote from: elCap on July 30, 2012, 11:49:18 pmWe have (had) guillotine at school but it was creating really messy edges for more than those few milimetres. Not sure if some other (newer) guillotine works better now. Also those were USSR guillotines and PCBs. They remember even Stalin! That could be part of the cause.I am not planning (yet) to do a lot of them - probably start with 10 or 20 boards (aka 20 or 40 pieces), will see what will be the demand for it.

author: Barryg41
author_rank: Contributor
timestamp: July 31, 2012, 03:52:46 am
content: My wife has a glass cutting bandsaw, she does stained glass art. It has a diamond coated blade that does quite well. It is a hobby version, don't really know the price off hand.

author: notsob
author_rank: Frequent Contributor
timestamp: July 31, 2012, 04:40:03 am
content: Options for at home1. Proxxon mini bench unit - with a diamond blade for tiny cuts2. A mini shearhttp://www.carbatec.com.au/three-in-one-press-brake-bender44-guillotine-roller_c20955http://www.carbatec.com.au/miniature-bending-cutting-shear_c20103

author: digsys
author_rank: Unknown
timestamp: July 31, 2012, 05:17:37 am
content: Quote from: Short Circuit on July 31, 2012, 01:13:35 amI'm talking about this type of band saw -www.diylife.com/2010/07/13/in-the-workshop-bandsaws/(not this one, just a sample pic). Even a cheap metal blade does several dozen PCBs for me.Now days I have the metal blades made up (prefer 8mm depth).The unit I use at home for the last 25 yrs cost app $220 and has done a few 1000 PCB cuts.The metal blades are NOT technically suited for FR4, but hey, they're damn cheap (~$20-25)and they work FINE ! Beautiful cut, a quick linish after and viola. I can save a couple 100$ PERprototype PCB by making an array of smaller PCBs, then cutting them up.

author: metalphreak
author_rank: Frequent Contributor
timestamp: August 06, 2012, 09:01:48 am
content: If you are just doing straight cuts, a wet tile cutter isn't a bad choice. The water flow also helps stop that nasty fibreglass dust getting everywhere in the air.

author: jeremy
author_rank: Super Contributor
timestamp: August 06, 2012, 09:42:16 am
content: Have you emailed itead with the gerbers for a specific quote? They have done odd sizes for cheap in the past for me.

author: OndraSter
author_rank: Contributor
timestamp: August 06, 2012, 02:19:49 pm
content: I have only sent them email asking whether they could offer 25x50 and 25x100 boards (another project). Without reply though.That was without gerbers.

author: ampdoctor
author_rank: Frequent Contributor
timestamp: August 27, 2012, 11:59:50 pm
content: I may be a bit late on this thread but reading though it, I can't believe all the flaming hoops people are going through to cut FR4. Here's how I do it. Take a straight edge and secure it along the cut line. Then take your garden variety chisel and run one of the corners along the straight edge. First pass go lightly to just get a bit of a groove dug in for the tool to follow so it wont jump out on subsequent passes. Next pass or two press HARD, and dig in for a deep groove. Now just snap the board material off. If you want a really finished look on the edge make a pass or two along it with a fine file to knock the fuzz off. This whole process takes less than a minute, creates virtually no mess, and uses hand tools that most people have laying around the house.

author: PA4TIM
author_rank: Super Contributor
timestamp: August 28, 2012, 12:10:27 am
content: No dust, nice clean edges, can cut a mm of a board without a problem. Use one for yearsLink wont work,http://www.worldoftools.nl/product_info.php?manufacturers_id=26&products_id=4710maybe like so

author: Monkeh
author_rank: Super Contributor
timestamp: August 28, 2012, 12:12:31 am
content: Quote from: ampdoctor on August 27, 2012, 11:59:50 pmI feel sorry for your chisels.People, don't do this with chisels worth using on wood.

author: ampdoctor
author_rank: Frequent Contributor
timestamp: August 28, 2012, 12:16:08 am
content: Oh hell no! A few passes and you'll need to sharpen the chisel if you're going to use it on wood. But the point is that an el cheapo chisel or even an old rusty junker you never use that's laying around in the garage is more than adequate for the job.

author: Monkeh
author_rank: Super Contributor
timestamp: August 28, 2012, 12:19:04 am
content: Quote from: ampdoctor on August 28, 2012, 12:16:08 amI'm sensible. I have a set of shitty, awful, nasty chisels so crap I had to glue the handles back on, which I use for bad things. Like prying mouldings off. Then I have a set of nice chisels I check the edge on before and after using them.

author: GK
author_rank: Super Contributor
timestamp: August 28, 2012, 12:26:37 am
content: A bit hard not to damage/scratch the photo resist if you're using presensitised board. I bought one of these:http://www.machineryhouse.com.au/S650

author: poptones
author_rank: Frequent Contributor
timestamp: August 28, 2012, 12:35:26 am
content: Seems like one of these would work for the size boards he mentioned, and far cheaper.http://www.ebay.com/itm/Antique-Milton-Bradley-Dandy-Wooden-Guillotine-Paper-Cutter-9-x-9-/330781703942?pt=LH_DefaultDomain_0&hash=item4d04203f06#ht_568wt_1141What about just having a line of drill holes, and snapping?

author: amspire
author_rank: Super Contributor
timestamp: August 28, 2012, 01:48:55 am
content: A good hand nibbler is great. I have one of these exact nibbler models and they are brilliant - over 40 years old and still works great:http://www.ebay.com/itm/SET-OF-TWO-Adel-Tool-Co-Soft-Material-Nibbler-18-GA-047-steel-/120957823482?pt=LH_DefaultDomain_0&hash=item1c29a5e9faThe drill mounted nibblers are not bad, but a bit more cumbersome to use. Here is an example:http://www.ebay.com/itm/FIRSTINFO-Power-Drill-Nibbler-Metal-Sheet-Cutter-for-brass-Aluminum-Stainless-/280945835213?pt=Drills&hash=item4169ad3ccdRichard.

author: cellularmitosis
author_rank: Unknown
timestamp: February 04, 2014, 12:09:29 am
content: I've been using this $10 set of shears to cut up copper clad recently (for doing manhattan-style prototyping).http://www.harborfreight.com/12-inch-power-snips-98091.htmlThe blades are removable, but unfortunately harbor freight doesn't sell a set of replacement blades.

author: nanofrog
author_rank: Super Contributor
timestamp: February 04, 2014, 01:11:45 am
content: Quote from: cellularmitosis on February 04, 2014, 12:09:29 amI have a similar pair, but haven't ever tried them for cutting PCB. Will have to give it a try sometime. Thanks for the idea.

author: Rory
author_rank: Frequent Contributor
timestamp: February 04, 2014, 01:30:02 am
content: I've had a Kepro 12" PCB shear for years. Still sharp and accurate. It was a very good investment.Not my pic.If you were in the USA, I'd recommend looking at these:Grizzly has a suitable one:http://www.grizzly.com/products/12-Bench-Shear/T10051Harbor Freight has one that is mentioned on Adafruit.http://www.harborfreight.com/8-inch-bench-top-shear-brake-90757.html

author: robrenz
author_rank: Super Contributor
timestamp: February 04, 2014, 02:32:56 am
content: I have the Grizzly shear. I bought it thinking it would be the typical Chinese quality. Meaning as long as you consider it as a kit that will need a lot of work you will be ok. It is pretty sad as purchased but it will probably do an ok job on circuit board as purchased. I spent a whole day in my machine shop adding stiffening bracing material and re machining just about every piece of it along with replacing all the sub par metric fasteners. it works great now.

author: notsob
author_rank: Frequent Contributor
timestamp: February 04, 2014, 08:30:41 am
content: I have something similar to this, it cuts and bends and rolls. Got it years ago and cannot remember where I got it from.http://www.machineryhouse.com.au/S648

author: Monkeh
author_rank: Super Contributor
timestamp: February 04, 2014, 01:07:28 pm
content: Quote from: robrenz on February 04, 2014, 02:32:56 amYou may want to reword that, as I can't see what them being sane has to do with anything.

author: robrenz
author_rank: Super Contributor
timestamp: February 04, 2014, 01:13:23 pm
content: Quote from: Monkeh on February 04, 2014, 01:07:28 pmI was using "sub par" as a general term for very poor quality. From the free dictionary "Not measuring up to traditional standards of performance, value, or production."I also was NOT implying that metric fasteners as a class of fasteners are "sub par"

author: Monkeh
author_rank: Super Contributor
timestamp: February 04, 2014, 01:14:14 pm
content: Quote from: robrenz on February 04, 2014, 01:13:23 pmI figured, it's just the way it's worded.

author: Rory
author_rank: Frequent Contributor
timestamp: February 04, 2014, 07:38:51 pm
content: Quote from: Monkeh on February 04, 2014, 01:14:14 pmIt's the way us Yanks talk our gibberish... I read it as he meant, he replaced the poor quality metric hardware. "Sub par" in UK means crazy, nuts, coo-coo?

author: Monkeh
author_rank: Super Contributor
timestamp: February 04, 2014, 07:46:45 pm
content: Quote from: Rory on February 04, 2014, 07:38:51 pmNo, it means exactly the same thing. Wording it that way, however, implies that being metric has some part of it. One must remember there is no body language, tone, or inflection in text..

author: Rory
author_rank: Frequent Contributor
timestamp: February 04, 2014, 08:55:14 pm
content: Quote from: Monkeh on February 04, 2014, 07:46:45 pmOK I understand now. Perhaps it has to do with context also, the quality of Harbor Freight and Grizzly equipment is well known. They are very popular here in the USA being readily available and cheap compared to the equipment they are copied from. Grizzly has a fairly decent reputation when it comes to table saws and wood lathes, the company claims to rework the main line products in their own facilities in USA but not all of their equipment goes through the QC process like the high end power tools.Harbor Freight, on the other hand, well, you get what you pay for, and buyers know this is reflected in the price.And if you've been following anything Rob has been putting out, you'd know he is too good a machinist to disparage hardware simply because it is metric.

author: Monkeh
author_rank: Super Contributor
timestamp: February 04, 2014, 08:57:45 pm
content: Quote from: Rory on February 04, 2014, 08:55:14 pmI'm aware of this. Others may not be, which is why I simply suggested changing the ambiguous wording.

author: pickle9000
author_rank: Super Contributor
timestamp: February 04, 2014, 09:08:10 pm
content: I have one of these,http://www.harborfreight.com/8-inch-bench-top-shear-brake-90757.htmlMine is about 10 years old and cost 60 bucks new, Busy Bee Tools (in Canada) doesn't carry them any more. It's a great tool to have and not just for cutting pcbs. It is a brake as well.

author: robrenz
author_rank: Super Contributor
timestamp: February 04, 2014, 09:08:44 pm
content: I would say Monkeh made a good call considering the volatility of threads that debate the "imperial vs metric" topics

author: peter.mitchell
author_rank: Super Contributor
timestamp: February 17, 2014, 07:46:13 am
content: I just get a block of timber, put my boards on it, put some nails in the mounting holes and tap them in. Put the stack in the circular saw and cut. Just gotta make sure there is enough space between boards on the "panel" to account for the kerf. The saw is a pretty decent one, can use many types of blades, has adjustable speed (for tiles/masonry, wood, abrasive steel and cold cut steel), it also came with a mount for a couple of dispensing tubes, for water, air or oil. I use an abrasive wheel with the water dispenser.

author: Dave Turner
author_rank: Frequent Contributor
timestamp: February 17, 2014, 05:46:15 pm
content: Have a look at W2AEW's suggestions.Incidentally if your board is double sided note that you have to score both sides.

author: nanofrog
author_rank: Super Contributor
timestamp: February 17, 2014, 07:11:10 pm
content: Quote from: Dave Turner on February 17, 2014, 05:46:15 pmI like the scroll saw method (he called it a jig saw), as it's quick and easy.Also already had it, which was a nice plus.

author: Dave Turner
author_rank: Frequent Contributor
timestamp: February 17, 2014, 11:51:46 pm
content: If not in the possession of a guillotine for straight cuts I'd prefer the craft knife, straight edge and clamp method. With practice it's less wastage, gives a cleaner break and no dust.

author: Arp
author_rank: Unknown
timestamp: March 21, 2014, 05:56:35 am
content: Quote from: Short Circuit on July 31, 2012, 01:13:35 amI use the Proxxon KS115.Modified these cheap discs with a 10 mm diamond drill bit:http://www.ebay.com/itm/10-pcs-50mm-2-inch-Diamond-coated-rotary-cutting-cut-off-blade-wheels-disc-/121127997238?pt=LH_DefaultDomain_0&hash=item1c33ca8f36They are pretty thin so it doesn't need much work. Have yet to wear one out, and maybe done a 1-2 meters of total cutting.

author: ElektroQuark
author_rank: Unknown
timestamp: March 21, 2014, 07:47:43 am
content: I use a PROXXON FETwith the carbide tipped blade

author: Moshly
author_rank: Regular Contributor
timestamp: July 06, 2015, 07:56:23 am
content: If you are not doing many just get some 'Tin Snips'I use something like ->http://www.toolman.co.uk/acatalog/tinsnips.htmlThe only time this is a problem is on large sheets (cutting more than say 10cm in one go)

author: wxm145
author_rank: Contributor
timestamp: August 03, 2015, 09:40:26 am
content: could not use v-cut?