Panelization is usually decided after the layout is finished, by whoever fills the panel, and it is where ten to twenty five percent of board cost is set. The same board can run at 92 percent panel utilization on a V-scored array or at 71 percent on a routed array with generous gaps. Both are correct, and the buyer pays the difference on every unit.
Two questions decide the array: how the boards separate, and what the rails and gaps eat.
V-score against tab routing
| Criterion | V-score | Tab routing |
|---|---|---|
| Separation | Scored lines on both faces, snapped after assembly | Tabs cut with a router, removed with a cutter |
| Board gap needed | None, boards share the web | 2 to 5 mm, the router bit has to pass |
| Panel utilization | Highest | Lower, and the gap grows with board thickness |
| Stress at separation | Bending along the score | Bending at the tabs, but the cut edge is clean |
| Board thickness | 0.6 to 3.2 mm | Any thickness in range |
| Component overhang | Not possible at the scored edge | Handled by tab placement |
| Inside cut-outs | Not possible | Routed, no extra cost beyond program time |
A V-score runs a 30 to 45 degree cut on each face and leaves a web, usually one third of the board thickness. That web is what breaks: too thick and the operator takes a pad with it, too thin and the panel falls apart before assembly.
What the array really costs per board
| Board size | V-scored array | Utilization | Routed array, 3 mm gap | Utilization |
|---|---|---|---|---|
| 100 x 80 mm | 78 boards | 91.9 percent | 65 boards | 76.6 percent |
| 60 x 40 mm | 270 boards | 95.4 percent | 225 boards | 79.5 percent |
| 150 x 100 mm | 40 boards | 88.3 percent | 40 boards | 88.3 percent |
Counts are on a 622 x 1092 mm panel with 5 mm rails on all four sides. The routing gap matters more than people expect: taking it from 3 mm to 5 mm on the 60 x 40 mm board costs 9 boards per panel for no gain in quality. On the 150 x 100 mm board the gap costs nothing, because the panel divides the same way.
So run the array both ways before quoting. When the count is the same, route: the cut edge is clean and the tabs carry the stress away from the components. When routing costs 10 percent or more of the count, check whether the board can take a score.
Rails, fiducials and what the line needs
- Rails. 5 mm per side is the usual minimum for conveyor transport, 8 to 10 mm when the panel is long and thin and tends to sag in the oven.
- Fiducials. Three per panel, two on one edge and one on the opposite edge, 1 mm copper dot with a 2 mm clear area. Panel level fiducials sit on the rail, not on a board, or the array offset cannot be measured.
- Edge clearance. Keep 3 to 5 mm clear of parts near the panel edge for the conveyor fingers and the nozzle of the printer.
- Minimum board. Boards under about 50 x 50 mm will not transport on their own, so they exist only inside a panel. That is a panel decision, not a board decision.
- Rail area is wasted copper. It comes out of the utilization number and appears in the price as material.
Tabs, mouse bites and where they go
A tab is 3 to 5 mm wide and runs from the board edge to the panel frame. Small boards take three tabs, larger boards five, and a tab goes where the board is stiff, not where it is convenient. Mouse bites are 0.5 mm holes drilled in a row across the tab, 0.8 to 1.2 mm apart, leaving enough material to hold the board through assembly and little enough to break cleanly afterward.
Two placement rules save rework: keep tabs away from connectors and from any part that overhangs the edge, because the cutter needs clearance, and keep them off the corner of a thin board, where the bend concentrates.
Inside cut-outs, slots and card edge fingers are where routing earns its cost. A V-score cannot produce an inside cut-out, and a card edge finger needs a routed edge with a chamfer, not a broken web.
Thickness, overhang and the cases that force a decision
Above roughly 3.2 mm a score leaves a web too stiff to break without damage, so thick boards route. Below 0.8 mm the panel needs a carrier, because the array flexes in the printer. Components that overhang the board edge, common on USB connectors and displays, cannot cross a scored line, so those boards route and the overhang sits in the gap.
X-outs are the last cost item. A panel with one failed board is either scrapped whole or shipped with the position marked. Asking for 100 percent good panels pays for that scrap; accepting marked X-outs costs less per good board.
How SUPERB PCB handles panels
SUPERB PCB works to a maximum panel of 622 x 1092 mm, board thickness from 0.1 to 12 mm, minimum line and space of 0.0125 mm, and layer to layer registration of plus or minus 0.025 to 0.06 mm, which is what keeps a scored array aligned after two or three lamination cycles. Panels are cut on an RS-500 visual cutter with optical alignment, so V-scored and routed arrays separate without cracking MLCC parts or lifting pads.
Assembly at SUPERB Assembly runs panels through 3D SPI, pick and place from 0201 to 55 mm BGA, a 10 zone reflow with SAC305 lead free as standard, 3D AOI on every visible joint and 3D X-ray with CT where a BGA or a thermal pad is involved, checked to IPC-7095. Workmanship follows IPC-A-610 Class 2 or Class 3 as the drawing states.
- PCB capability: panel limits, thickness range, registration and copper weights.
- PCBA workshop: printer, placers, reflow and the depaneling cell that handles the array.
- Order PCB online: what the quote form needs before an array can be priced.
Frequently asked questions
Who decides the array, the buyer or the shop?
Either, but one party should own it. If the buyer supplies a panel drawing, the shop builds to it and the utilization is the buyer's number. If the buyer sends single board Gerber data, the shop arrays it and should show the count and the rail width in the quote.
Is a scored panel cheaper than a routed one?
Only when it raises the board count. The score itself saves little; the saving is the gap that routing needs. On a board where both give the same count, routing is the better build because the edge is clean.
Can the same panel be used for a different board revision?
No. A revision that moves a connector or changes the outline invalidates the tooling and the score lines. Ask for the array to be rechecked at every revision change, before the first batch runs.
Next step
Send the board outline, the panel drawing if one exists, the quantity and the assembly side. The reply gives the array count both ways, the utilization figure and the price per board for each.
