Cutting a PCB

[perts]

I have a machine that comes in 2 flavors (single, and dual machine). I want to have one PCB for both types of machine. Is it possible to create a PCB that I can cut when I am building a single machine. I would put the circuitry to control the second machine on side of the pcb that we can cut if we want to just build a single machine. I can not put the whole board into the single machine cuz there is not enough room?

Has anyone design something like this before? Is there special layout tricks that I can use for this? Is there an issue with cutting the PCB (eg like exposing traces, etc).

 

[MikeHalloran]

Been done many times.

Easy way; define a band across the board. Keep circuits out of that band, except traces that go from half1 to half2.

In production, you can use a router to separate the boards if you want to be fancy, or use the faster method:

Drill a row of closely spaced holes down the middle of the band at the same time you are drilling all the other holes in the board. When you need a split board, just snap the halves apart along that weak line defined by the row of holes.

The holes don't have to be real close together in a cotton/phenolic board. They have to be pretty close in a glass/epoxy board.



Mike Halloran
Pembroke Pines, FL, USA

 

[cranky108]

Once upon a time we just used a hake saw to remove the part of the PCB we did not want.

 

[Skogsgurra]

The router also makes very nice slots. Use that instead of holes. Looks neater - in a way.

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[itsmoked]

I bought a power jig saw specifically to do that. It was a disaster. It just tried to burn its way thru the boards. Un-saw-able as far as my experience went.

Have the board designed as Mike sez then have the board scribed so you can snap it. Or route it and leave a few rat bites for the tie points.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[MikeHalloran]

If you want to try a jigsaw on FRP, a Remington Grit-Edge blade will probably work.

( I've used Grit-Edge hacksaw blades to section potted electronic assemblies, including FRP circuit boards and glass lenses. )



Mike Halloran
Pembroke Pines, FL, USA

 

[MacGyverS2000]

I use a diamond-edge blade (very thin)... little dust (though there is some, so you have to take preventative measures for it), and the cut is clean.

Dan - Owner

http://www.Hi-TecDesigns.com

 

[mcgyvr]

We just use a regular metal shear to cut boards when needed. There are also pcb specific scoring machines that you can pick up cheaply on ebay,etc...

 

[DRWeig]

We often have multi-boards made with a notch routed between sections at the board house. At production time, they just snap apart.

If you use the notch method, be sure and support at the notch if using double-board without breaking apart...

Good on ya,

Goober Dave

 

[btrueblood]

Metal shear works well. Even a standard paper cutter (like your kindergarten teacher would never let you use) will slice thinner (single layer) boards fairly well. Don't tell the secretary it was you that did it, though - just show her how to order replacement or resharpened blades.

 

[zappedagain]

If you snap the boards apart be careful with surface mount components. Some components mounted perpendicular to the shear line can't handle the stress and will break, particularly capacitors. They sometimes don't fail until months after the get cracked and can become a major field support issue.

John D

 

[itsmoked]

Excellent point to remember zap!

Keith Cress
kcress -

http://www.flaminsystems.com