Preparing a PCB panel for assembly? Review panel dimensions, support rails, fiducials, tooling features and the depanelization method with the assembler before releasing fabrication files. A panel that suits fabrication still needs to support placement, soldering, inspection and safe separation.

Confirm before production: The dimensions below describe this guide’s existing reference requirements. They are not universal design rules. Send your panel drawing, component clearances and board revision for project-specific approval; do not manufacture a panel solely from a general online checklist.

PCB panel refers to multiple small PCB boards spliced together to form a large PCB panel. After the panel production, the PCB panel will be cut into diverse small single boards.
For smaller PCBs and PCBs of various shapes, you can use panelization to improve the production efficiency of printed circuit boards. We recommend using panelization technology for PCBs smaller than 50mm*50mm.

PCB assembly panel refers to mounting electronic components on a blank PCB panel board through SMT mounting equipment.

Assembly panel type

Assembly panels and there are two main types in the SMT mounting process:

• Single-sided PCB panel

Single-sided PCB panels can only be placed on a single-designed printed circuit board. This type of PCB panel is suitable for use on a single larger printed circuit board and small-batch PCB panel board assembly processes.

• Multi-connected PCB panels

Multi-connected PCB panels can lay two or more PCB boards of the same design. The number of PCB boards installed depends on the size of the PCB boards.

Advantages of PCB panels

• Increase productivity

PCB panel boards reduce the number of board changes during the production process, thereby improving production efficiency. PCB panels can also achieve batch-automated production.

• Cut costs

Using PCB panels can reduce board waste and thus reduce production costs.

• Easy to assemble and test

Automated equipment assembly and test PCB panels can reduce assembly and testing difficulty and workload.

• Diversify the design

PCB designers can design different PCB circuit diagrams through PCB panelization technology at the same time. In designing PCB prototypes, we used area division to arrange printed circuit boards to manufacture multiple PCB prototype circuit boards.

• Ensure product safety

PCB panel technology can protect printed circuit boards from mechanical stress, vibration, shock, and other factors during the panel board assembly.

• PCB panel requirement of Assembly

1. The minimum size of a PCB board is generally not less than 50mm*50mm, and the maximum size is not more than 310mm*410mm.
2. When designing the PCB frame, the frame tries to form a closed loop to prevent the PCB panel from deforming during SMT assembly.
3. There should be a space of more than 0.5mm between the electronic components and the edge of the PCB board.
4. Positioning holes should be added at the four corners of the panel edge, and the hole diameter can be 4mm±0.01mm.
5. Wiring or welding is banned within 1mm of the edge positioning hole.
6. When PCB panels are assembled, we should add the reference mark, usually located at the diagonal edge of the panel.
7. when adopting gapless paneling, the distance between the boards is 0. In addition, it is necessary to add process edges on both sides of the assembled board to fix the circuit board during SMT assembly and welding.

Our company’s requirement for process edges is a minimum width of 3mm, and we generally use 5mm.
8. If there are gaps between the boards, the distance between the boards must be greater than or equal to 1.6mm.

9. If you adopt stamp holes for connection, you need to place 5 to 8 holes on the edge of the circuit board and place them in double rows. The hole diameter is required to be 0.6 mm. The distance between holes should be 0.25 to 0.35 mm. The stamp holes can be placed in the middle of the board frame line or extend to 1/3 of the board.

When to Use PCB Panel Assembly

• Small circuit board size

Since many factories now have fully automated production, automated equipment has restrictions on the size of printed circuit boards. Cutting tools cannot be used when assembling small-sized circuit boards. In this case, it is necessary to create a large panel to facilitate circuit board assembly.

• Mass production

When you need to produce PCB boards in large quantities, splicing multiple boards into a large panel and, at the same time, assembling many boards can improve assembly efficiency and save time and labor costs.

• Electronic components close to the edge of the board

If the electronic components are too close to the edge of the circuit board, many problems will occur during the PCB assembly process. For example, uneven solder paste printing, SMT assembly out of range, etc. So, PCB panel board assembly is a safer processing method than single PCB assembly.

Send your panel drawing for an assembly review before ordering bare boards. Include any edge-mounted connectors, overhanging components, sensitive packages and handling restrictions.

PCB panel manufacturing and assembly process

After the PCB panel design is completed, you can find a manufacturer to assemble the PCB panel. The PCB panel assembly process has the following steps:

• PCB panel manufacturing

PCB panel manufacturing uses photolithography. The photoresist is applied to the PCB panel and exposed to ultraviolet light through a photomask. Photoresist contains a chemical that hardens when exposed to ultraviolet light, then etches away unwanted copper to create the desired circuit pattern.

• Solder Paste Printing

Place the PCB panel on a stainless steel plate, and evenly apply solder paste to the pads on the circuit board surface. Then, the SPI machine detects the printing quality of the solder paste and whether there is any tin leakage or insufficient tin.

• SMT Assembly

The automatic placement machine places the surface mount components on the prepared PCB panel and then solders the BGA, IC, resistors, capacitors, and others to the PCB surface through the machine equipment.

• Reflow

The PCB panel is put into a reflow oven for heating, and the solder paste undergoes a process of melting at high temperature and cooling, fixing the electronic components on the board.

• PCB panel testing

After reflow soldering, the PCB panel will undergo testing, such as automatic optical inspection (AOI), X-ray inspection, in-circuit testing (ICT), etc, to detect whether the PCB circuit board capability and quality meet requirements.

Depanelization

Confirm the proposed separation method, such as V-scoring or routing, against the board outline, component placement and mechanical stress limits. Keep sensitive components and connectors clear of the separation area according to the approved manufacturing plan.

• Final inspection and packaging

The separated PCBs undergo a final visual inspection to ensure PCBs meet quality standards. They are packaged and shipped to customers.

Prepare your panel drawing for assembly review

Include overall panel dimensions, board count and orientation, support rails, fiducials, tooling holes, board-to-board spacing and the intended depanelization method. Specify component overhang, test access, special handling and quantity per revision.

For a first build, see prototype PCB assembly. For multiple designs, explore low-volume, high-mix PCB assembly; for larger repeated builds, see high-volume PCB assembly. Use our RFQ checklist to provide matching files.

Panelization is a critical step in PCB assembly. It can improve efficiency, reduce costs, and ensure consistent quality in mass production. It is necessary to cooperate with an experienced PCB manufacturer throughout the process.

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