PCB Panel Formatting
Assembly Panel Tips
Below is our guide to panel formatted fabrication and how to ready the job for assembly.
Aside from the standard, individually routed, single profile, printed circuit board. Fabricated circuit boards can also come supplied in a grid formatted panel configuration. This method of fabricating circuit boards in a panel format is commonly used for assembly line steps and SMT. This can improve the processes and handling.
After the boards are through final assembly they are typically removed from the panel, or de-panelized, and individually bagged in ESD-safe packaging ready for QA and shipping.
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Rout and Retain Panel Types
- Preferred method to use for odd shaped and round boards.
- Common with thin core and flexible circuits.
- Use a 0.100″ typ. gap surrounding each circuit board.
- Place 0.100″ typ. break-away perforated tabs evenly around board edge with .020-0.022 holes on 0.040″ centers.
- The breakaway tabs are often called mouse bites.
V-Groove Panel Types
- Preferred method to use for rectangle shaped boards.
- Boards are placed next to each other with no gaps in between.
- 30-degree angled score lines are machined between each board and continue across the entire pallet both top and bottom side.
- A webbing of 0.015″ panel material remains where the top and bottom score lines meet to keep boards intact.
Pallet Rails, Tooling Holes, and Fiducial Marks
- Assembly panels require pallet rails surrounding the panelized board array to create a framed border. Or a minimum 2 rails on opposing sides of the pallet. Thickness can be 0.300″-.500″ typ.
- Side rails must be free of any board design data unless special instructions are called-out.
- All assembly pallets require tooling holes.
- Use a 0.126″ or 0.156″ non-plated drilled tooling holes at pallet corners.
- Place tooling holes on 0.250″ centers from the corner edge of the panel.
- Use a 0.039″ exposed surface circular pad free of soldermask at each corner of the panel. A minimum of 3 pads is required.
- Pull back soldermask around fiducial mark using a square or circle shape of 0.100″.
Why do we panelize boards?
The purpose of supplying boards on a pallet is typically for two reasons:
- Customer is requesting to combine more than one circuit board design on a panel to save on costs; and
- in order to prepare the circuit board for component assembly. 99% of the time panelization is for the latter, component assembly.
In this section we are going to talk about panelizing circuit boards on a pallet for the purpose of assembly only.
Panelized boards are a configuration where the circuit board is reproduced in successive images stepped-up in a repeat grid pattern. This is necessary for assembly SMT operation so the assembly pick and place machine can populate more than one board during the automatic assembly process. This is typically a must when the order requires more than a handful of boards, and almost a necessity when looking at production runs.
The circuit boards are de-panelized after assembly leaving each populated PC Board individually bagged and ready for testing.
We follow a series of different panelization methods and rules depending on the circuit board features. The panelization begins during pre-manufacturing CAM steps and is completed at the end of bare board manufacturing during final fabrication.
There are two standard types of assembly pallets:
- Rout and Retain. Boards are separated by a gap between each board with connecting perforated tabs.
- V-groove Scoring. Boards are separated by machined score lines that run vertical and horizontal between the boards.
Common features of the assembly pallet:
- Pallet Rails. A border of panel material surrounding the circuit board grid used for clamping onto the line during assembly.
- Fiducial Marks. Round copper pads are placed at each corner of the assembly rails for SMT automatic Pick and Place machine.
- Tooling holes. 0.126″ or 0.156″ non-plated holes are added to the pallet rail corners for additional support during assembly processing.