Panelization is the process of arranging multiple individual PCBs into a larger array (panel) for manufacturing efficiency. If your boards are going through automated SMT assembly, panelization is not optional — pick-and-place machines, reflow ovens, and conveyors are designed for panels, not individual small boards.
Why Panelize?
- SMT machine efficiency: Panels feed through pick-and-place machines and reflow ovens smoothly. Individual small boards may be too small for the conveyor.
- Assembly speed: Loading one panel of 20 boards is faster than loading 20 individual boards.
- Cost reduction: Panel-level processing reduces setup time and handling per board.
- Consistency: All boards in a panel go through identical processing conditions.
Panelization Methods
V-Cut (V-Scoring)
A V-shaped groove is cut from both sides of the board, leaving a thin web of material in the center. Boards are separated after assembly by snapping along the score line. V-cut is the most common and economical panelization method.
- Best for: Rectangular boards with straight edges
- Board thickness: Minimum 0.6mm, recommended 1.0mm+
- V-cut depth: Typically 1/3 from each side, leaving 1/3 material
- Keep components 3mm away from V-cut lines
Tab Routing (Mouse Bites)
Individual boards are routed out with small tabs connecting them to the panel frame. The tabs are perforated with small drill holes (mouse bites) for clean separation. This method supports irregular board shapes.
- Best for: Non-rectangular boards, boards with overhanging components
- Tab width: 3–5mm typically
- Mouse bite holes: 0.5mm non-plated holes, 3–5 per tab
- Keep components 2mm from tab locations
Solid Tab (Breakaway)
Similar to tab routing but without perforations. Boards are separated by cutting the tabs with a tool. Simple and strong, but requires manual depaneling.
Panel Design Guidelines
- Panel size: Target 100 × 100mm to 250 × 250mm. Common SMT panel sizes are 150 × 150mm, 200 × 150mm, and 250 × 188mm.
- Process rails: Add 5–10mm rails on panel edges for conveyor handling. Include fiducial marks on rails.
- Fiducials: Place 2–3 global fiducials on the panel frame and 2 local fiducials per board for fine-pitch components.
- Tooling holes: 2–4 holes (3–4mm diameter) in the panel frame for fixture alignment.
- Orientation: All boards in a panel should face the same direction for efficient pick-and-place programming.
- Spacing: Minimum 0mm for V-cut, 2–3mm for tab routing between boards.
Cost Optimization
Maximize the number of boards per panel to reduce per-board assembly cost. Standard panel sizes fit common SMT equipment widths. Avoid oversized panels that require special handling. If your board is very small (under 25 × 25mm), consider panelizing with 10–50 pieces per panel. Your manufacturer can recommend the optimal panel layout for their specific equipment.
Common Mistakes
- Placing components too close to V-cut lines — they get damaged during depaneling
- Forgetting fiducial marks on the panel frame
- Using V-cut for non-straight board outlines
- Making panels too large or too small for standard SMT equipment
- Not accounting for panel rails in the overall panel dimensions
If you are unsure about panelization, most PCB manufacturers (including JCPCB) offer panelization design as a free service. Send your single-board design and specify your assembly requirements, and the engineering team will create an optimal panel layout.
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