I have a PCB finished in invidividual size for customer but they gave me comment that it can't be used by their assembly vendor and ask me make the new batch for them, When we make the board in 2 up only adding 2 rails with 5 mm per side and ask for the approval from customer ,they refused again and need the array in 4 up with routing and v-scoring , That will add the production cost much . Can somebody let me know why the assembly house need a extra up in one panel and prefer Routing than V-scoring ?
This is a square PCB with size of 100*120 mm ,when we make 2 up in the panel to get the size of 210*120 mm,then we can make the production panel size within 400*300 to get the best usage of the material.
Best Answer
The need for a larger number of boards per panel may simply be a requirement of the pick and place machine, which requires a particular panel size, and two PCB's may be wasteful of space.
As Lior mentioned in a comment, V-scoring can be problematic depending on the board thickness. It is also not particularly recommended for boards with surface mount components, as the bending of the board to break it off at the scoring line can put stress on the components. It is possible to get around this by sawing along the scoring line, but this takes a lot more time.
Instead, we have separated the boards from the rest of the panel, and the boards from themselves, by having a router mill out a space between them; and the boards and panels are then connected together by "mouse bites", which are much easier to separate than a scored line running down the entire length of the board.
A second requirement for most pick and place machines is to have a set of fiducial markers located on each board. Usually they are placed in three corners of the board, like this:
By using thee, rather than four, it is easy to tell if the board is oriented upside down, and three are all that are necessary to fix the location of the board in both X and Y directions.
As shown in the photo, each fiducial is usually just a circle of bare copper, inside a slightly larger circle of overlapping solder mask. A camera on the pick and place machine accurately locates each fiducial and uses this information to accurately place all of the components.