PCB Assembly (PCBA) Depaneling | Seperating
Printed Circuit Boards (PCBs) are typically manufactured in large panels containing multiple boards at a time, while also can be produced as single units if need be. When PCBA panels are finished assembly and necessary checks, it’s time to go to Depaneling process. Your contract manufacturer’s depaneling methods impact your PCB assembly costs and quality, especially if you are trying to create smaller electronic products.
Printed boards smaller than about 100mm (39.37mil) are typical in PCB array fabrication. After they PCB arrays go through the assembly process, the individual boards are separated or “depaneled”. The methods your printed board assembly manufacturer uses for this seemingly simple step will affect costs and quality. By understanding the different methods available and talking with your contact manufacturer before finalizing a PCB design, you and your designers can avoid expensive problems later.
Depaneling methods can impact various factors, including:
Material Cost -By fitting as many boards as possible into a standard PCB panel, you can reduce waste and minimize material costs.
Labor Cost and Throughput -Cutters and punches are manual operations, but faster than laser cutting. If you require edge sanding, that adds cost and time.
Tooling Costs -Punches may require custom tooling to fit the board design. Laser cutting systems are programmable with low setup time. Cutters may or may not require tooling. But for your attention, flex circuit manufacturing requires both punching and laser cutting in mass production.
Tolerances -If your tolerances on board dimensions are tight, or you need to place components very close to the edge of the board, you should look for a printed board manufacturer with laser cutting capabilities.
PCB designers can create both the layout and the array drawing to meet the constrains of the process to be used. It is especially critical to keep surface mount device (SMD) assembly a safe distance from the edge of the board to avoid damage from the depanling tool. If engineers don’t know what tool will be used, they need to err on the side of safety -perhaps making the printed board bigger than it needs to be.
PCBA Depaneling Methods
Cutter -For rectangular printed boards, PCB panels are usually fabricated with a v-score between boards. After components are placed and soldered, we use specialized tools to separate the boards along the score with minimal bending stress. A guillotine type cutter is suitable for thin boards, and a wheel cutter (commonly called a “pizza cutter”) is used for thicker boards.
Hook Tool & Sand off -For printed boards with curves and other shapes, the bare PCB panels will usually come pre-routed with tabs or drilled perforations to hold the panel together during PCB assembly. We separate the pre-routed boards at the tabs using a hook tool. The tool will leave a rough edge, called “mouse bites”, at the tab locations. If the boards have a tight fit or needs to have smooth edges when installed in your product, these may need to be sanded off -an extra step and expense.
Router with Dust-Proof -Some PCB assembly manufacturers use a mechanical router to depanel curves and other shapes. The router creates less bending stress, but more vibration stress. It also produces a lot of dust, a dust-proof router equipped PCB assembly manufacturer will be fit for your board assembly and depaneling. MADPCB has such system to control the dust and keep it off your printed board assemblies.
Laser Cutting -Laser cutting is a newer depaneling method that eliminates bending stresses altogether. The laser makes extremely narrow, very previse cuts in many shapes of flex PCB assembly. It allows components to be placed much closer to edge of the board, helping your maximize the use of board space in very small PCB assemblies.
All of these methods reduce but do not eliminate bending stresses on the board during depaneling. Ceramic capacitors are particularly susceptible to cracking from bending stress, as are end caps on resistors. Observing the safe distance from the edge of the printed board helps prevent this damage. Talking with MADPCB about depaneling options can help you get the right combination of reliability, material cost, and manufacturing cost, precision and throughout in all of your PCB assembly projects, including rigid board, flex circuit and rigid-flex PCB.