Rigid flex board and flexible PCB board with single-sided is not allowed to cut single-sided sheet directly. They must be etched into single-sided sheets from 2 layer flex PCB to ensure the bonding force between layers and avoid delamination.
Inner Layer Circuit
Check that FlexPCB is flat without discounts, wrinkles, and no glue stains on the board surface, etc.
All flex board PCBs must be attached to the pallet for development and etching, and one pallet is attached to one flex PCB to prevent the flex PCB from being folded and wrinkled due to etching transmission problems.
All boards must pass through AOI, and the flex-printed circuit does not allow supplementary lines.
Rigid Flex PCB Lamination
Rigid flex PCB board lamination must use a special program. The lamination program can not be mixed with other boards.
When the flex PCB is browned, it must be attached with a pallet. After browning, the flexible circuit board with wrinkles will be discarded. Before riveting, the flexible PCB board must be browned OK.
After riveting FR-4, flex PCB, and No-Flow PP, first check whether there is less or more PP, then use an X-ray to check whether there is layer deviation.
Rigid Flex PCB drilling is a process of PCB manufacturing, and it is also a very important step.
The inspection process focuses on checking whether there are any residual glue burrs on the flexible circuit board at the T position of the rigid and flex PCB joint. If there is any abnormality, notify the process in time for follow-up processing.
Plating Through Hole
The program for besmearing the rigid flex board is special. Please pay attention to the switching of the besmearing program before copper plating.
After removing the slag, the rigid, flexible printed circuit board is copper-precipitated according to the 2-layer PCB procedure after the PI is adjusted. The PI potion is prepared according to the volume concentration of 40%. The working temperature of the potion is 40°C, and the adjustment time is 4~8MIN.
Rigid Flex PCB Board Opening Technology
The rigid flex board is not an ordinary circuit board, but is composed of a rigid circuit board and a flex circuit board. The flexible area of the rigid-flex PCB board is formed by removing the rigid layer in the area, leaving only the flexible layer and removing the rigid layer. The whole process is called opening technology.
There are three ways to open the rigid, flexible board: laser opening, gong machine-controlled deep opening, and V-CUT opening.
Rigid Flex PCB Circuit Open-Short Circut Test
The electrical performance of the rigid flex PCB is usually achieved through the PCB open-short circuit test. There are two test methods of PCB open-short circuit test. One is a fixture test, and the other is a flying probe test.
Fixture testing is based on the test points on the circuit board to make a fixture with a bed of needles and many thin needles on it. Each needle corresponds to a test point and is pressed to make contact. Then, conduct a continuity test or a functional test.
A flying probe test is a rapid movement of several probes at these test points, contact with these test points, and then the instrument measures the results.
Inspection of Rigid-Flex PCB Board
Dimension measurement: measure whether the actual dimension of the PCB matches the customer’s original rigid-flex circuit design file.
Holes: Check for missing holes, multiple holes, blocked holes, and hole sizes if they match the rigid-flex PCB design file.
Circuit: No short circuit, open circuit, exposed copper in the conductor, floating copper foil, repair wire, etc.
Silkscreen Printing: The silk screen printing of characters and symbols on the surface of the rigid flex PCB must be clear, and obvious, and the color must meet the requirements, without repeated printing, missing printing, multiple printing, position deviation, and misprinting.
Rigid flex PCB warp and twist inspection: According to the IPC-6012 standard, the warp and twist of the rigid-flex circuits should be within 0.75%.
Solderability Test: Take part of the rigid-flex PCB for actual soldering to check whether the parts can be easily soldered.
Packaging: colorless air bag vacuum packaging, with a desiccant inside, tightly packed.