Cutting PCBs with a Dremel....

[diracshore]

Hi all,

Trying to cut a multi layer pcb. Want a straight cut, thinking I will use a Dremel. Last time I used a Dremel to cut it was difficult to prevent the jitter from interfering, although that was metal.

So has anyone had experience trying this ? Is there a better way ?

Which Dremel unit is the best for this type of work ?
What Dremel head works best on PCBs ?
Does high speed give a more precise cut or is low speed preferable ?
Is there some type of extension for the Dremel that insures straight cuts ?
And also what is the best size g-clamp to hold the pcb down ?

Thanks !

[Psi]

High speed will burn the pcb edge leaving a black mark. It will also create whiskers of fiberglass on the edge.
But you can tidy it up with a file afterwards.

[electrode]

I've used a dremel with PCBs before, and it's really not a great way of doing things. I just used one of the emery cutoff wheels.

If you really want a straight, nicely cut edge, either:
a) Score and snap, then use a file.
b) Hacksaw along it (ie. long, but shallow cut), then use a file.
c) Go to the trouble of making some sort of mini-table saw arrangement (using a dremel or otherwise) with a rip fence.

A rotary tool doesn't lend itself well to a straight edge unless it's configured as a table saw, table router or milling machine.

I bought a mini table saw years ago and it works wonders for PCBs, but I can't stress enough how much better the lowly hacksaw is than a handheld dremel.

[TerminalJack505]

I've got a Dremel but I've never tried cutting PCB with it.  I use either sheet metal cutters or a tiny little table saw (which isn't good for much else.)

I'm sure a Dremel tool will work fine.  Cutting a straight edge will be a trick, however.  I saw a video on You Tube where a guy turned his Dremel into a table saw using something like a step stool (if I remember correctly.)  He basically cut a slit in the surface and then mounted the Dremel underneath.

[diracshore]

I did see that video but can't find a suitable table. Not really into the idea, too many things can go wrong. Hacksaw won't fit. Not confident scoring, its tricky the board has components installed.

Considering a wet tile saw..... $50, but its going to take up space, so might end up throwing it after just one use.

http://electronics.stackexchange.com/questions/1151/how-do-you-cut-pcb

[electrode]

Did you see this video?

[diracshore]

Thats very cool, but too much work to build for a one time job. Its a shame they don't sell a kit.

[electrode]

One other idea is to go to 2:48 in that video I posted, and see if you can get that attachment for your dremel. Then simply clamp a piece of aluminium bar or even wood onto your PCB as a fence, and use the dremel vertically with a suitable dremel router bit.

[mobbarley]

if you only have to do small cuts - like to remove tabs - then a nibbling tool is quick and really clean. If you have to do long cuts it can still be done but you have to take care to get a straight edge.

[george graves]

I hate to be the nervouse-nelly.  But, I really wonder about the health risks of breathing in such fine particles of fiberglass.  I once hard someone say that the fibers used in fiberglass in insulation are big enough for your lungs to expel them, but that fine glass particles will stay in your lungs to a greater degree and cause trouble.  Anyone have some solid info of the risks of breathing in fiberglass dust?

[electrode]

There are plenty of studies if you google "fibre glass health". Supposedly it hooks into your lungs ala asbestos. A vacuum cleaner is a good friend.

[ejeffrey]

A woodworking dust mask is sufficient to protect your lungs from fiberglass dust while cutting.  Then use a small vacuum to clean up.

[metalphreak]

I've use a tile cutter before and it works quite well for straight edges. Just beware that the blade eats up about 2mm wide of your board.

Make sure you use some water in the tile cutter as well. There is very little if any fibreglass dust thrown into the air when there's a constant stream of water over where its cutting

If you have small boards though, like <5cm edges, it gets a bit difficult as it needs to clear the blade guard for you to hold onto it. You can get nice straight cuts if you use the included slide/guides.

[Balaur]

Just my two cents on this:

I've tried most of the methods to cut PCBs short of a PCB guillotine. I would guess that the guillotine is the better solution, but the tool is not exactly cheap.

While Dremel stuff has his usages, cutting the PCB is not one of them. I've tried the following:

• Cutoff wheels - works, but it's difficult to keep a straight edge and makes a lot of fine dust. Also, kinda affects the photoresist
• Milling bits - useful I guess, for intricate detail, but a huge amount of dust
• Mini-Saw accessory - Not bad, but goes through wheels like crazy

My recommendation? Forget all this. Go old school and buy one of this:



and one of this:



and you'will be set for life.

The full (i.e. not junior) hacksaw goes through PCBs like butter with minimal dust and the blades are very affordable. The huge (10-12 inches) flat file will bring the edges to a very nice finishing.

Cheers,
Dan

[george graves]

Personally I use 1/64" boards 1 oz copper from ebay, and cut score them with a utility blade.  You can snap them with your hands.  Done and done.

[mikeselectricstuff]

Personally I use 1/64" boards 1 oz copper from ebay, and cut score them with a utility blade.  You can snap them with your hands.  Done and done.

0.8mm and below can be cut with a decent pair of scissors.
I'd agree that the hacksaw method is the way to go if you don't have a guillotine - clamp the board to the bench edge with a sheet of wood & it's easy to get a straight cut - keep the blade at a shallow angle.
Noting beats a guillotine though.
 

[george graves]

Tin snips work great too.  Sears sells a great set. 

[AnonymousGuy]

I have access to a guillotine style (aka "massive scissors") pcb cutting tool.  But I'm worried that it's going to short the ground and power planes together in my 4 layer pcb?

[david77]

I either use the good old hacksaw + file or if I can't be bothered score the PCB along a metal ruler with one of those cheap cutter knifes with the snap-off blades from both sides. Then clamp the PCB along the cut into a vice or on a table edge and just snap it off and file the edges down.
The Dremel stays in it's box for simple straight cuts, far too messy and noisy.

[andersendr]

If you have any access to a milling machine, you could use that.  I have had great success when putting multiple designs on one board, then cutting them out on my end.  I use a 1.5mm end mill at the fastest the mill will go.