# Cutting disks from copper clad FR4



## datiLED (Apr 15, 2011)

Does anyone have a method of cutting, or punching 0.59" (15mm) diameter disks from blank FR4 PCB material (0.060" and 0.015" thick)? I have tried a punch and hammer, but it won't go through the 0.060" material. The results with the 0.015" material are OK, but not as clean as I would like. 

I need about 100 disks cut, and cutting and filing them by hand is brutal. If anybody can help me with this task, please send me a PM to discuss price and logistics.

Thanks in advance.


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## Slickseth (Apr 15, 2011)

For small quantities. I usually score the board with a utility knife the snap them using the edge of the countertop. Then I use a pair of old scissors to cut them to a slightly larger rough edged disc. Then use a file to get them perfect. 

This takes about five to ten minutes per disc. So probably not an ideal method. I'm also curious to find a more efficient method.


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## datiLED (Apr 15, 2011)

Slickseth said:


> For small quantities. I usually score the board with a utility knife the snap them using the edge of the countertop. Then I use a pair of old scissors to cut them to a slightly larger rough edged disc. Then use a file to get them perfect.
> 
> This takes about five to ten minutes per disc. So probably not an ideal method. I'm also curious to find a more efficient method.


 
I use metal snips to cut the 0.60" board, and then file it to size. I think that it does take about 5 minutes each. 

The thinner boards can be cut with a pair of scissors, but still need to be filed to get the board round. I have to do this for each of the PCB's that I etch, so I am looking to speed up the process for the bare copper boards.


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## calipsoii (Apr 15, 2011)

If you find a better way, let me know as well datiLED. The A2 rings I make get etched 20 to a board, then I score between them with a box knife, snap them apart, score/snap the square corners off and file them into circles. Easily the longest part of the production process.


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## Sway (Apr 15, 2011)

Look for a local machine shop with a punch press or you could try and make a bottle jack punch press if you have the dies.....just a thought never tried it myself 

Later
Kelly


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## beley (Apr 15, 2011)

What about a hole saw without the centering drill bit?


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## MikeAusC (Apr 15, 2011)

You can get drill bits for ceramic tiles that are a hollow tube with Tungsten carbide chips on the end - I have seen ones around the size you want.


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## alpg88 (Apr 15, 2011)

beley said:


> What about a hole saw without the centering drill bit?



regular toothed holesaw gives you very rough cut, unless you do it with holesaw that glass shops use, with diamond edge and no teeth.


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## 65535 (Apr 15, 2011)

alpg88 said:


> regular toothed holesaw gives you very rough cut, unless you do it with holesaw that glass shops use, with diamond edge and no teeth.


 
The carbide grit hole saws are that kind, if you go with a glass cutting hole saw, make sure you rig up a guide for it, or use a drill press to keep the saw from walking and messing up your pcbs. Normally they are cut on a waterjet, mill, or laser cutter.

There are a few waterjet companies that could probably do it for you, fairly cheap if you supply the CAD drawing for the toolpaths.


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## precisionworks (Apr 15, 2011)

> You can get drill bits for ceramic tiles that are a hollow tube with Tungsten carbide chips on the end


An annular cutter is exactly that type of hole saw. Edges are smooth as glass, requiring almost no secondary finishing. Hougen & Jancy are the two largest makers, and eBay always has a few (523 listings right now).

http://www.hougen.com/cutters/cutters_index.html

http://www.jancy.com/index.cfm?fuseaction=products.showProducts&cat=27

They are sized by the OD of the hole being cut, so you may need to phone or email the manufacturer regarding the ID of the "slug" (which is the part you need).


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## 350xfire (Apr 16, 2011)

Water jet?


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## datiLED (Apr 17, 2011)

precisionworks said:


> An annular cutter is exactly that type of hole saw. Edges are smooth as glass, requiring almost no secondary finishing. Hougen & Jancy are the two largest makers, and eBay always has a few (523 listings right now).
> 
> http://www.hougen.com/cutters/cutters_index.html
> 
> ...



Thanks precisionworks,

This avenue looks very promising. I am going to check this out. I can borrow a drill press for a while, and should be able to knock out 100 disks in short order.

I appreciate all of the other comments too, guys.


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## 350xfire (Apr 17, 2011)

You may need to use a milling machine as drill press may "walk" a bit. If you don't need super precision the drill press may be OK though.


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## PEU (Apr 17, 2011)

I can do these with my CNC router, but shipping time may kill the deal for you, or maybe not 


Pablo


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## precisionworks (Apr 17, 2011)

There's a special type of annular cutter called a "sheet metal cutter":

http://www.hougen.com/cutters/sheetmetal/Rotacut.html

http://www.jancy.com/index.cfm?fuseaction=products.showProduct&productid=87

Either of these should do a great job in a drill press (according to the website info). You may want to phone or email first & talk with tech support, as they are the experts on these products.


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## archer6817j (Apr 19, 2011)

I think the abrasive hole saws are worth taking another look at. 

I've never tried to cut FR4 with an annular cutter but I have a hard time thinking it will come out clean. My only experience is with carbon fiber and automotive fiberglass. I see three things working against you: an annular cutter uses a "lifting" action which will tend to de-laminate the sheet, the cutting edge is quite wide meaning a lot more cutting force is being generated, most fiber based laminates only cut cleanly when the tool is razor sharp...otherwise it tends to tear. I suppose you might get 100 holes, but an annular cutter is also going to run you around $50-$100 bucks for that size. A carbide grit hole saw is about $10. 

In any case, let us know how it works out. It would be good knowledge for all of us and I always prefer applied science over my personal conjecture  good luck.


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## precisionworks (Apr 19, 2011)

Tim at Hougen tech support said their sheet metal cutter will give a smooth edge  

Two choices will get close (but not exactly) the diameter you need:

Their 3/4" cutter has an ID of .570", or the 20mm cutter has an ID of .607". Either one needs to run around 700 rpm. These are designed to be used in a hand held drill & should work very well in a drill press. Cost on either one is under $20.


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## datiLED (Apr 19, 2011)

precisionworks said:


> Tim at Hougen tech support said their sheet metal cutter will give a smooth edge
> 
> Two choices will get close (but not exactly) the diameter you need:
> 
> Their 3/4" cutter has an ID of .570", or the 20mm cutter has an ID of .607". Either one needs to run around 700 rpm. These are designed to be used in a hand held drill & should work very well in a drill press. Cost on either one is under $20.


 
Awesome! Thank you for that information! That is exactly what I needed to know. 
I had been on the company website looking for a contact, and was going to call today. You made my work that much easier. :twothumbs

I think that the 20mm will be perfect for what I need. If I use a wood clamp to steady the board while I drill, it should yield some smooth blanks without a lot of waste. I will just need to watch out for the fiberglass dust. Maybe I'll need to rig up a vacuum to clean the work area as I work.

Thanks again, precisionworks!!!


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## precisionworks (Apr 19, 2011)

Glad to help a fellow machinist  I'm surprised about the low cost of the sheet metal cutter, but at least it doesn't cost a fortune. Tim at Hougen also said that the "regular" annular cutter would do a terrible job as it is much too aggressive.

One of the parts we make at the tool & die shop is a jig plate that has two fairly large through holes, with each hole just over 1.5" diameter. We use an annular cutter to quickly get rid of the waste & finish the job with a boring head. Before the annular, we would drill a starter hole at .500", enlarge that to 1.000", enlarge that to 1.500", and bore to size. The annular significantly reduced the time needed to make each hole


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## choffman (Apr 21, 2011)

Just gonna throw this out there FWIW. For going on the cheap, what about a modified forstner or spade bit? Modifying the bit with a die grinder (or whatever) wouldn't take that long. You could mill out a little block of wood the size and depth of the FR4 for a "vise".

Just a thought. good luck


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## bbawkon (May 20, 2011)

datiLED said:


> Does anyone have a method of cutting, or punching 0.59" (15mm) diameter disks from blank FR4 PCB material (0.060" and 0.015" thick)? I have tried a punch and hammer, but it won't go through the 0.060" material. The results with the 0.015" material are OK, but not as clean as I would like.
> 
> I need about 100 disks cut, and cutting and filing them by hand is brutal. If anybody can help me with this task, please send me a PM to discuss price and logistics.
> 
> Thanks in advance.


 
If you still need these, PM me a snail-mail address and I'll drop a gift in the mail.

Ben


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