EEVblog Electronics Community Forum
Electronics => Manufacturing & Assembly => Topic started by: OndraSter on July 30, 2012, 07:48:20 pm
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Hello :)
I 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 hints :)
PS: PCBCart asks much more $$, just as any local PCB fab house.
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Ordinary hacksaw will do fine.
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I think I seen someone mention here that they had used a tile cutter. Dust would be nasty though!
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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
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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.
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Thanks for all the tips guys :)
I 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!" :D
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.
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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 fairly
deep 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 like
multilayered 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.
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I think I seen someone mention here that they had used a tile cutter. Dust would be nasty though!
If 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 saw
is rather wide, so be sure there is enough clearance.
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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.
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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 :).
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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.
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I shall buy one then. The one I found in the basement does fairly thick line and is... rusty!
Thanks a lot! :)
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If you plan to do many, a pcb guillotine is a good tool to have. It's quick and precise.
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I use a dremel. It takes about 5-10 seconds depending on length.
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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.
This 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 cutting >:(
http://www.proxxon.com/eng/html/27006.php (http://www.proxxon.com/eng/html/27006.php)
(http://www.proxxon.com/eng/images/produkte/lightbox/27006.jpg)
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If you plan to do many, a pcb guillotine is a good tool to have. It's quick and precise.
+1
They 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.
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If you plan to do many, a pcb guillotine is a good tool to have. It's quick and precise.
We 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 :).
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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.
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Options for at home
1. Proxxon mini bench unit - with a diamond blade for tiny cuts
2. A mini shear http://www.carbatec.com.au/three-in-one-press-brake-bender44-guillotine-roller_c20955 (http://www.carbatec.com.au/three-in-one-press-brake-bender44-guillotine-roller_c20955)
http://www.carbatec.com.au/miniature-bending-cutting-shear_c20103 (http://www.carbatec.com.au/miniature-bending-cutting-shear_c20103)
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This 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 cutting >:(
I'm talking about this type of band saw - www.diylife.com/2010/07/13/in-the-workshop-bandsaws/ (http://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 (~$20-25)
and they work FINE ! Beautiful cut, a quick linish after and viola. I can save a couple 100$ PER
prototype PCB by making an array of smaller PCBs, then cutting them up.
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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.
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Have you emailed itead with the gerbers for a specific quote? They have done odd sizes for cheap in the past for me.
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I have only sent them email asking whether they could offer 25x50 and 25x100 boards (another project). Without reply though :(.
That was without gerbers.
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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.
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(http://www.worldoftools.nl/popup_image.php?pID=4710)
No dust, nice clean edges, can cut a mm of a board without a problem. Use one for years
Link wont work,
http://www.worldoftools.nl/product_info.php?manufacturers_id=26&products_id=4710 (http://www.worldoftools.nl/product_info.php?manufacturers_id=26&products_id=4710) maybe like so
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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.
I feel sorry for your chisels.
People, don't do this with chisels worth using on wood.
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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.
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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.
I'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. ;)
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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 (http://www.machineryhouse.com.au/S650)
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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_1141 (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_1141)
What about just having a line of drill holes, and snapping?
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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=item1c29a5e9fa (http://www.ebay.com/itm/SET-OF-TWO-Adel-Tool-Co-Soft-Material-Nibbler-18-GA-047-steel-/120957823482?pt=LH_DefaultDomain_0&hash=item1c29a5e9fa)
The 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=item4169ad3ccd (http://www.ebay.com/itm/FIRSTINFO-Power-Drill-Nibbler-Metal-Sheet-Cutter-for-brass-Aluminum-Stainless-/280945835213?pt=Drills&hash=item4169ad3ccd)
Richard.
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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.html (http://www.harborfreight.com/12-inch-power-snips-98091.html)
The blades are removable, but unfortunately harbor freight doesn't sell a set of replacement blades.
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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.html (http://www.harborfreight.com/12-inch-power-snips-98091.html)
The blades are removable, but unfortunately harbor freight doesn't sell a set of replacement blades.
I 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. :)
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I've had a Kepro 12" PCB shear for years. Still sharp and accurate. It was a very good investment.
Not my pic.
(http://technology.niagarac.on.ca/courses/elnc1236/images/pcbFab/keproSear.jpg)
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/T10051 (http://www.grizzly.com/products/12-Bench-Shear/T10051)
Harbor Freight has one that is mentioned on Adafruit.
http://www.harborfreight.com/8-inch-bench-top-shear-brake-90757.html (http://www.harborfreight.com/8-inch-bench-top-shear-brake-90757.html)
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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.
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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 (http://www.machineryhouse.com.au/S648)
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along with replacing all the sub par metric fasteners.
You may want to reword that, as I can't see what them being sane has to do with anything. ;)
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along with replacing all the sub par metric fasteners.
You may want to reword that, as I can't see what them being sane has to do with anything. ;)
I 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"
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along with replacing all the sub par metric fasteners.
You may want to reword that, as I can't see what them being sane has to do with anything. ;)
I 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"
I figured, it's just the way it's worded.
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along with replacing all the sub par metric fasteners.
You may want to reword that, as I can't see what them being sane has to do with anything. ;)
I 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"
I figured, it's just the way it's worded.
It'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?
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It'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?
No, 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..
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It'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?
No, 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..
OK 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.
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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.
I'm aware of this. Others may not be, which is why I simply suggested changing the ambiguous wording.
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I have one of these,
http://www.harborfreight.com/8-inch-bench-top-shear-brake-90757.html (http://www.harborfreight.com/8-inch-bench-top-shear-brake-90757.html)
Mine 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.
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I would say Monkeh made a good call considering the volatility of threads that debate the "imperial vs metric" topics ;D
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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.
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Have a look at W2AEW's suggestions.
How to cut circuit board PCB material - a couple of favorite methods I use... (https://www.youtube.com/watch?v=uBkPX_QhRI0#ws)
Incidentally if your board is double sided note that you have to score both sides.
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Have a look at W2AEW's suggestions.
I 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. ;)
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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.
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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.
This 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 cutting >:(
http://www.proxxon.com/eng/html/27006.php (http://www.proxxon.com/eng/html/27006.php)
(http://www.proxxon.com/eng/images/produkte/lightbox/27006.jpg)
I 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=item1c33ca8f36 (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=item1c33ca8f36)
They 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.
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I use a PROXXON FET
(http://static1.comercialpazos.com/media/catalog/product/cache/1/image/17f82f742ffe127f42dca9de82fb58b1/p/r/prx27070_1_1.jpg)
with the carbide tipped blade
(http://ecx.images-amazon.com/images/I/81htx2I0NLL._SL1500_.jpg)
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If you are not doing many just get some 'Tin Snips'
I use something like ->
http://www.toolman.co.uk/acatalog/tinsnips.html (http://www.toolman.co.uk/acatalog/tinsnips.html)
The only time this is a problem is on large sheets (cutting more than say 10cm in one go)
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could not use v-cut?