Mouse Bite PCB Perforation Design

[ngkl99]

Hi, may I know if mouse bite design is applicable for 1) FR-4 PCB material
and 2) automatic cutter instead of hand separation process?

Thanks!

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attached is the mouse bite design

 

[FvM]

"Mouse bite" perforation is standard for FR4 panels.
Automatic cutters are used with V-scored panels. I'm not sure if they are suitable for mouse bite perforation.

 

[ngkl99]

Hi FvM, it means in this case, use hand separation right?
But is hand separation OK even when SMD parts are on the board?

 

[ftsolutions]

It can be, provided that you have followed some standards for placement/location of parts near the edges of the PCB.
If seen/worked with layouts that had both, depending upon clients needs.

 

[FvM]

Bending forces with mouse bite perforation are low. You should nevertheless avoid MLCC near and oriented towards the cutting line.

 

[marce]

Slide 29 of the attached, have a look at the rat bite pattern, the one you show has to much PCB material at either side, this will tear or have to be cut with side cutters.
https://www.palsrvs.com/files/IPC_DC_Mtg Aug_Rev_B.pdf

 

[ftsolutions]

Many of the bite patterns used by numerous layout people often result is rough edges of extra remaining material sticking out the side. IF one doesn't need a smooth edge for mechanical fitment, this is not of major concern. But if a smooth edge is needed, then using a V-scored edge for mechanical separation or even milling the edges of the PCB may be necessary. Rat Bites can be economical for hand separating, especially if one uses a pattern that will tend to undercut the edge and not leave estra material protruding outward, provided that you've kept enough pullback and placement keepouts so the "dent" in the edge of the PCB doesn't compromise the integrity of the assembly. I've also found that Rat Bites work better on thinner PCBs - when one has thicker (>.093") PCBs they tend to require alot more holes for easy break, but then the assemblies also tend to become more expensive and candidate for mechanical separation with V-score.

 

[marce]

V score is one of the most stressful way of de-panelising PCBs, routing out is the best option for minimum stress. Though with the use of side cutters and an experienced operator rat bits are very good and get used on a lot of jobs.