PCB Cutting

How do you guy's do this, I have bare PCB that is 6x6" and I am building a board of 2x3", what do you use to cut the boards. Before this I used the paper cutter at the office but got caught and don't want to get yelled at by the admin again! I am thinking a trip to Home Depot or ??

Thanks!

I wonder if anyone here has ever tried a scoring knife (essentially a single tooth file that you pull along a guide) as a way to make break lines in PCB material. I think I may have to get one of these and experiment with it. At least it is fairly easy to resharpen.

Reminds me that friend DOES use a small-bladed, carbide-tipped, table saw to cut FR4.

I've also, on rare occasions, used a small hand-held rotary tile saw (Makita) with a diamond blade. Cuts the FR4 cleanly, but tends to "mooosh" the metal edge when you cut across a ground plane.

...Jim Thompson

Jim,

I've used a table top jigsaw with reasonable results. Good points are that the saw kerf is really small so you don't waste a lot of board material. Bad points are that FR4 is a bit tough on the blades (at least they are cheap) and the small blade tends to want to follow the lay of the fiberglass which can make "straight cuts" difficult at times.

While I've never tried it, I always thought the ideal way to cut PCB material would be a band saw with a fine tooth, carbide tipped blade. Using a panel cutting jig so you could clamp the PCB material down and cranking the blade guide down would make cutting even small PCB's pretty safe.

As I have access to them, I also thought about using a table saw or power miter with a fine tooth carbide blade but never did due to the amount of waste in the saw kerf. FR4 is relatively hard and brittle so the chipping might be excessive even with a fine tooth carbide blade designed for cutting wood. Using a non-ferrous metal carbide blade with a negative rake angle might solve this but still removes about 1/8" of material. Table saw safety would dictate using a panel cutting jig with clamps for the PCB. With the power miter you could just clamp the PCB down to the saw table.

I'd be interested if you figure out any better ways to cut PCB material. Good luck and be safe.

by

For small quantities at home with hand tools, use a hack saw then file the edges straight and smooth with a file. I use a sheet metal shear but you probably don't have that available. A band saw also works, use a metal cutting blade. Bob

I've done that too. Works fine for phenolic boards. Glass boards can require DEEP scoring, otherwise the bending force required can be high enough to warp the board. Occasionally I use score-bend on smaller glass boards. Clamping board in a vise along the score while bending the waste results in less warpage.

I used paper cutter many years ago and had the warp problem described above. A metal shear works beautifully ..... but don't let the machinists catch you cutting glass boards on one; I'm told that glass dulls a shear beyond all reason and that re-sharpening is very expensive.

Not having a shear, a paper cutter, nor a bandsaw, I use a nibbling tool to cut boards and a file to clean edges afterward. Yes, it's slow and it wastes mucho board, but it's simple ... and cheap.

I found heavy duty scissors at WalMart for $6.00 that cut right through the stuff. The are made by RubberMaid, go figure. I went shopping with board material in hand and tested alot of different products, this was the least expensive tool I found that worked easily. The ones made for metal did not do good cutting the PCB material.

I like the score and snap idea and will try that next time, I do have one of those scoring type knifes! Thanks for all the input!

by

Try a scroll saw. They're relatively inexpensive and much smaller than even the smallest bandsaw. A bit hard to make a perfectly straight cut unless you clamp an edge guide to its table. OTOH, it's useful to make oddly shaped board and cutouts.

I score it deeply on both sides with a Stanley knife, then snap it. It might need a bit of cleaning up with a file afterwards.

Leon

Excellent! I didn't find one with a carbide tip, but just bought one with a replaceable steel tip.

Now I have to make a cutting board out of a square of plywood with a strip of laminate glued to the near edge as a board stop and a second, narrower strip glued on top of that as a guide for the steel square (set back a bit so that the knife doesn't have to hit it when it reaches the edge of the board) and I will ready to clamp that to the work bench the next time I need to cut a board.

I've always done this. I bought a knife 22 years ago, that was designed for scoring Formica. It has a carbide tip. A take few swipes with that thing along a straight-edge, and snap the board along the score. I score the metal side on single-sided boards. A little sanding smoothes everything right out. Works much better than sawing freehand.

I read in sci.electronics.design that Luhan Monat wrote (in ) about 'PCB Cutting', on Sun, 13 Mar

Drill a very small hole at each end of the score line and score both sides. The holes ensure that the two scores are closely aligned. This allows the inside of the bend to compress and the fibres at the outside are not there to stretch, so the force needed to break along the line is greatly reduced.

I use a "Jeweller's Saw" for smaller projects. A fugitive from my Lapidary days, perfect for cutting, sawing small objects like circut boards .

Yukio YANO

points

excessive

What about a table-mounted router (or roto-zip)? AFAIK, the biggies use such high-speed widgets to cut FR4.

Wrong direction of cut. The bit should "rout", rather than "saw".

Those are scribes. A scoring knife has a slight hook and is sharpened on the handle side of that hook, so it peels a thread of material off when pulled.

I read in sci.electronics.design that James T. White wrote (in ) about 'PCB Cutting', on Sun, 13 Mar 2005:

There was a small PCB maker in UK who used these. The saws were less than 3 mm thick, but I don't know the thickness. Proper guarding is essential because the odd blade can disintegrate suddenly.

Michael Black wrote: (snip)

Aviation offset shears do much better in this regard than normal scissor like tools, since the cut is beside the pivot.

I've always used tin snips that I had around, and once that brief time when I was buying phenolic board that cracked so easily, I've never had problems. The only issue is that they don't work so well on long cuts, since the cutting action is blocked by the material. But I'd think that would apply with any "scissor" type tool.

Michael