Any ideas to secure this pcb to a fixture?

[Binow]

I am looking for any ideas to secure a PCB panel to a fixture plate. I generally use tooling holes on each board to depanel them from an array. I have in the past had boards that had no tooling holes at all available so I made and aluminum cover that clamped down over the panel while I cut the individual boards. I am faced with this problem again, but hope to find a better method this time.

The board is about .75"x.55". It has a tab on all four sides which raises the problem of using a top plate. I'd have to have two covers and cut half of the board and then switch and cut the rest. The panel has 16 boards (4x4).

I have nothing in the way of vacuum fixturing, and even if I did I don’t think it would work with this application.

Any good ideas on how to hold these in place while I cut around them?

I didn't see a forum for this type of questions so if this is the wrong place mods feel free to move it to the correct location. Thanks in advance.

[CNCadmin]

I have used carpet tape, that will hold that down real well.

[Binow]

Hrmm...was hoping for a more permanent solution. How do you index the board using tape? It has to be placed in the same location every time. The tolerance on these are +/- .05" for the OD measurement. The only thing I'm coming up with is sort of boxing in the corners, but I don't know if that is going to work either.

[CNCadmin]

I place stops to locate the board, the tape works very well, otherwise maybe a vacuum system maybe the ticket?

[Binow]

I have no means of a vacuum plate. I wouldn’t even know how to incorporate one that would work with our machine. I might look into the tape. Only thing I can think about that wouldn't be good is the residue the tape leaves. It is going to have to be some serious tape to hold the board completely still which leads me to believe the residue is going to be a problem. What's your experience with this?

[CNCadmin]

The stuff that I have used does not leave a residue, and if it does lacquer or acetone will take it off.

[Binow]

Yeah that is for sure a no go. No kind of tape or anything is going to work for these as they will have conformal coat applied to them before they get depaneled. I am probably just going to have to use some of the plated holes on the board where components go. They will just have to hand place those few parts as this is really the only solution I can see working. Thanks for the ideas though, I might be able to use them on something in the future.

[Graham S]

You are depaneling so I assume the central section of the PCB is free. If so use:

A steel plate and some chunky neodynium magnets. Add thin rubber under the board for grip.

See ebay for suitable magnets or Mr George at: http://www.engconcepts.net

These magnets are VERY strong.

Graham