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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.

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  • \$\begingroup\$ What is the thickness of the board? V scoring can be problematic with very thin boards. \$\endgroup\$ – Lior Bilia Nov 3 '14 at 7:30
  • \$\begingroup\$ Can you ask to speak to the assembly vendor in order to get this right? \$\endgroup\$ – pjc50 Nov 3 '14 at 9:07
  • \$\begingroup\$ One last question, perhaps the customer has already built a test jig for a 4-up panel in a certain configuration? Changing a bed of nails is much more expansive than changing a setup for the PCB manufacturer. \$\endgroup\$ – Lior Bilia Nov 3 '14 at 12:44
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    \$\begingroup\$ Reaaaaallly great resource for this stuff: eevblog.com/2010/11/15/… \$\endgroup\$ – Scott Seidman Nov 3 '14 at 13:32
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    \$\begingroup\$ @LiorBilia Then the customer should be providing the vendor with detailed drawings of the panelization or Gerber files with the panelization implemented. How's the vendor supposed to know orientation, spacing etc.? \$\endgroup\$ – Spehro Pefhany Nov 3 '14 at 18:29
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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.

enter image description here

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:

enter image description here

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.

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    \$\begingroup\$ You need to be careful that an agressive pick and place doesn't "bounce" a board with a lattice of panels like that. Assembly houses generally use a tool with circular blades to depanelize v grooves without bending \$\endgroup\$ – Scott Seidman Nov 3 '14 at 11:43
  • \$\begingroup\$ @tcrosley, Thanks for your explanation with photo added, it is very clear to me now .We did get feedback from other customers on the V-scoring issues,If It is too deep ,the boards will be easily breaked off before the assembly .if it is too slight, then it is hard for them to break the rest of panel off. We are in the process of discussing and explaining the issue and always have test on sample boards to decide what depth is good for the total production finally. When we change the V-scoring into Routing, May be we can solve this problem but need to afford the extra cost in manufacturing. \$\endgroup\$ – NancyZhang Nov 4 '14 at 8:24
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The requirement for n-up and tooling strips means they don't have to make carriers for the boards, so it reduces their tooling costs. It's rare these days that there are not parts out near the edges that prevent using individual boards directly. Handling is reduced too, because several boards can be handled as one until the final steps.

Routing and V-groove is typically used where there is a requirement to have some sides of the boards smooth (and very accurate) or not straight lines from one side of the panel to the other, and other bits can be the rough V-groove type after depanelizing. The rough edges with prickly glass fibers sticking out are also hard on the hands of the assembly workers, so it's better to minimize them. Combining route plus V-groove gives the best of both worlds, at some expense in PCB manufacturing.

http://rayshobby.net/wordpress/wp-content/uploads/2013/07/IMG_0066.jpg

It sounds like you're the PCB vendor- I don't see why you are getting so involved in this- you can ask the customer to provide the gerbers for a panelized board set (you can advise on economical panel sizes). Or at least provide a drawing of what they want .. guessing, then making samples and shipping them around is a horrific waste of resources. Personally I like to do the panelizing in-house and know exactly what I am getting. The customer should send the gerbers or drawings to you and to the PCBA vendor to get feedback. Maybe they are not very experienced. Beware they may discover they need tooling holes or fiducial marks next..

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  • \$\begingroup\$ Your given board shown in the photo must be made in China .panel in 2 up with 5.0mm x 2 rails added ,3*2mm Tooling hole,3 x 1.27 mm fiducial marks with 2.0 mm clearance around . But we will prefer 4 up than 2 up for this PCB to get best usage of material due to its limited size of each board. and you will get a lower unit price wit h the new panel .You are right,The customer should provide the panelized files to us for production ,we will always give them the economical panel drawing but that won't be the best one for assembly house. \$\endgroup\$ – NancyZhang Nov 4 '14 at 7:44

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