Cutting PCBs

[ljcox]

In the past, I've always cut PCBs with a hacksaw.

I'm wondering if there is a better way.

For example, score the PCB on both sides with a sharp knife and then either break it (carefuly) along that line or keep scoring until the blade goes through.

Any advice will be appreciated

 

[Bob Scott]

I have found that using a table-top paper cutter (the type with the long sword-like blade) is ideal for cutting small boards to size. This method has the advantage of not producing any glass-epoxy saw dust. Just hold the board TIGHTLY to get a straight cut. You don't have to worry about breathing in the dust either.

 

[RadioRon]

I've been using some tin snips with good success but you need the longer ones to get good leverage. Something like this only with longer handles:

 

[Oznog]

I have some carbon grit bandsaw blade stock. Actually I don't use my bandsaw for this, but broke a short bit off the roll and put it in my scroll saw. Some PCBs need other than straight cuts. Unfortunately most blades will dull very fast on PCB, carbide grit never will.

 

[justDIY]

not exactly safe, but no more dangerous than an other sort of motorized saw with an upward facing blade

**broken link removed**

the blade is turned around in the saw, so the teeth are facing toward the foot, which acts as a cutting table. I use sheet metal blades, they do dull quick, but a local discount store sells them cheap enough it's not a worry.

 

[Speakerguy]

Find a way that avoids dust. That's the biggest hassle by far.

I'm anxious to try the paper cutter method.

 

[TekNoir]

I typically use either 1/48" or 1/64" thick FR4 board or I use 1/32" thick paper phenolic board, any of which can be easily cut by a guillotine cutter, made for cutting multiple sheets of heavy paper or card-stock.

 

[philba]

I use a brake/shear combo machine to cut my PCBs. Something like this:
**broken link removed**
not super cheap but fast, clean and very precise if done right. The above one is from harbor freight and is $130. I have a larger grizzley model. What is nice is these units can be used to bend metal for various projects.

I've used all manner of aproaches before getting my brake/shear. paper cutters work but really wear out fast on FR4. Hand shears are really hard to be accurate at all and any kind of saw makes a mess. Note that FR4 is is *very* *very* abrasive. If you don't have carbide cutters, your tool will wear out very fast.

I dress up the edges on a cheap disk sander for a fairly professional looking finish.

 

[jpanhalt]

I use a brake/shear combo machine to cut my PCBs. Something like this:
**broken link removed**

Hi Philba,
Do you know anyone who has actually used the HF unit? I have thought of getting one many times and questioned how well it would hold up. Unfortunately, my local HF store doesn't carry the small shear in stock, so I can't go look at it. Even the best shear blades don't hold up particularly well, so I wanted a dedicated shear for PCBs rather than sacrifice my trusty PEXTO.

Also, as longer carbide blades are becoming more common (as for wood planers and so forth), I was wondering whether one could be adapted to the HF shear?

I tried a paper cutter, and I guess my experience was similar to yours. I got just a very few cuts done before the blade was ruined. It was a Boston #2612, which is not the cheapest, but is not a heavy-duty commercial unit. It has a steel blade on a plastic backing. An older unit with the solid steel/cast blade might hold up better.

Right now, I use a metal-cutting blade in my scroll saw with a very slow speed.

John

 

[Dean Huster]

That HF unit looks a little like the model Kepro sells and is about a fourth the cost. Looks like an attractive deal to me, although you need to be careful of the offerings of Harbor Freight -- may be cheap, but some of the stuff you get from there falls a part shortly after purchase.

"JustDIY", I'm not against using the tool in a vise like that -- most of us have. But why not drill and tap some holes in that jigsaw base and install a table for a larger and safer work surface?

Dean

 

[Bob Scott]

I'm not against using the tool in a vise like that -- most of us have. But why not drill and tap some holes in that jigsaw base and install a table for a larger and safer work surface?

Dean

I have used a small router table with a scroll/jig saw installed upside down for cutting holes in aluminum front panels. Mounting in a vise should work almost as well if you have a steady hand.

After using a paper cutter to separate approximately 300 2"X3" glass/epoxy boards I found no noticeable wear on the cutter. Of course, the cutter belonged to someone else for multiple purposes and nobody I know ever tried actually cutting paper with it.

"The best kind of car to use in a demolition derby is a rented car."

Bob

 

[ljcox]

Thanks for the replies.

The PCB I have to cut is 300 x 300 mm which (after finding an imperial ruler) is about 11 3/4 inches.

So I suspect that it would be very difficult with tin snips.

However, I have a Triton jig saw table that I can mount my jig saw (similar to the photo inserted by justDYI) and it has an adjustable guide so there will be no problem in making the cut straight. (I'll take a photo later and post it)

I have a mask to protect the lungs.

 

[k7elp60]

I used to use my 10 inch table saw with a fine carbide tipped blade. Just had to allow for the width of the the blade, 1/8".
I have a shear very similar to the one posted by Phiba. I purchased if from Northern Tool about 2 years ago. I use it all the time and it works very well for me.

 

[ljcox]

I used to use my 10 inch table saw with a fine carbide tipped blade. Just had to allow for the width of the the blade, 1/8".
I have a shear very similar to the one posted by Phiba. I purchased if from Northern Tool about 2 years ago. I use it all the time and it works very well for me.

That sounds like a good idea. I could then cut it on the Triton.

Do you mean that you used a carbide tipped wood saw blade? Or some other type of blade?

I took a photo of the Triton in the Jigsaw/Router mode but without the Jigsaw or router mounted.

For anyone that is interested & has not seen a Triton, I also took photos of it in some of its other modes.

Photo 2 shows the bench saw mode.

Photo 3 shows the cross cut saw mode, but I oriented the saw incorrectly. It should have been turned 180 degrees.

Photo 4 shows the planer mode.

It has adjustable mounting plates for a variety of comercially available power tools.

There is also an extension table that can be set up for sawing large sheets of chipboard, plywood, etc. but I need the car out of the garage to set it up.

It only takes 2 ~ 3 minutes to change modes.

There is also a vacuum dust extractor available - it uses a standard vacuum cleaner.

EDIT. I've had problems attaching the photos - I'll try again later.

 

[bryan1]

Hiya len,
Eh mate i'd be very dubious about using a carbide wood blade for cutting pcb material. Here's a thought which shouldn't be expensive. you can get 4" diamond blades to fit a 4" angle grinder for under $10, put one in a grinder jig (a cheap one from bunnings) and set it up inverted where you can make a cutting table. I reckon you should be able to picture what I mean here and I reckon it wouldn't cost more then $60 including the grinder.

Be a much safer way to cut if your sick of using the hacksaw.

Hope this helps

Cheers Bryan

 

[ljcox]

Hiya len,
Eh mate i'd be very dubious about using a carbide wood blade for cutting pcb material. Here's a thought which shouldn't be expensive. you can get 4" diamond blades to fit a 4" angle grinder for under $10, put one in a grinder jig (a cheap one from bunnings) and set it up inverted where you can make a cutting table. I reckon you should be able to picture what I mean here and I reckon it wouldn't cost more then $60 including the grinder.

Be a much safer way to cut if your sick of using the hacksaw.

Hope this helps

Cheers Bryan

Thanks Bryan,
I have both an angle grinder and a diamond blade. I'll have a look in Bunnings for the grinder jig.

It's not that I'm sick of using the hacksaw, the PCB is too big to cut with a hacksaw.

By the way, we may be coming over your way in a few weeks, I'll let you know.

 

[ljcox]

Here are the photos I tried to post before. See the descriptions above.

 

[philba]

man, you guys sure seem to like creating FR4 dust. Hope you use a mask or better.

Using a power tool to cut a 300mmX300mm board would probably be safe but for a 40mmX40mm board, well, that just sounds plain dangerous to me. A shear is 10X faster, cleaner and safer.

By the way, I've cut a lot of FR4 on my Grizzly shear and it seems sharp as ever.

 

[jpanhalt]

By the way, I've cut a lot of FR4 on my Grizzly shear and it seems sharp as ever.

Let me clarify my comment regarding the shear. The shear probably stays in fine shape for cutting FR4. However, I worked in a shop once where there was shear for cutting thin sheet aluminum and other metals. It was a strict rule not to cut FR4 on that shear. Another shear had to be used for that purpose.

The reason given to me was that the FR4 dulled the blades enough so one got burrs on the aluminum (mostly 2024T3, copper, and brass). I never challenged the boss. For less demanding uses, it is probably not an issue. Sharpening a set of blades for a PEXTO costs more than the HF shear, so for me, it is not worth finding out. John

 

[ljcox]

man, you guys sure seem to like creating FR4 dust. Hope you use a mask or better.

Using a power tool to cut a 300mmX300mm board would probably be safe but for a 40mmX40mm board, well, that just sounds plain dangerous to me. A shear is 10X faster, cleaner and safer.

By the way, I've cut a lot of FR4 on my Grizzly shear and it seems sharp as ever.

I would certainly prefer to use a guillotine if I had one. But I don't know if I can justify the cost just to cut a few PCBs. However, I'll find out how much they cost before making a final decision.

Thanks for the comments.