Depaneling an array of assembled circuit boards can be a huge time and money saver for the PCB manufacturing industry. Printed circuit boards can be lumped together en masse in panels and separated after all of the individual boards on the panel have been populated with components. The process of depaneling can be complex because of the massive amount of circuit boards types. With so many things to keep track of, there can be complications, but they can be easily avoided with proper data analysis and preparation.
Printed circuit boards may be manufactured as single units or, more commonly, in large panels containing multiple boards at a time. The process can be semi-automatic, manual, or fully automatic.
The six methods of depaneling are:
- Laser Depaneling
Not all of the above circuit board depaneling methods may be suitable for every board outline. Irregularly shaped boards typically get break-out tabs while square or rectangular designs get scored lines. As you might imagine, straight-sided PCBs can be singulated from a panel of boards with the a shearing, pinching or sawing system that is limited to making strait cuts, but how are PCBs depaneled when they have an irregular shape with a contoured outline? Explore the pros and cons of each of these depaneling methods below to find the most suitable method for you particular application.
Pinching is performed using a two blade method. The panel is passed between a linear blade and a circular rotary blade along the score lines. Specialized blades are used to fit the design of each circuit board. The gap between the blades can be adjusted to fit the thickness of the circuit board. The lower the gap between blades results in a higher level of stress put on the circuit boards. This depaneling method can be done either automatically or manually. Keep in mind that the panel must be repositioned with quarter-turn rotations in order to cut each side of the board.
Shearing can singulate both scored boards and tabbed boards. Although normally done with a press, it can also be manually done with scissors. This method of depanelization is effective, but it is limited to the length of the blade being used and tends to put the most stress on the boards out of all the depaneling methods.
The punching, or die cutting method, is used exclusively for tabbed boards. A tab is put over a support die and below a fixed cutting blade. The blade then comes down on the tab to perform a clean cut. This is often a very brutal process, with significant tooling costs associated with both the custom-designed fixtures and shear blades.
Blades for punching should be thinner than other boards, so they don’t get stuck. Multi-Blade arrangements can be used for punching which will increase throughput, but this can cost extra and take time away from your schedule. Mount punching is another option commonly used for tabbed boards and involves a flat board placed in a custom support die which is mounted on an X-Y-Z table.
The boards can either be automatically or manually loaded. The punch hardly ever needs to be changed, which makes mount punching a great method for environments with a high level of mixing circuit boards.
Routing is an alternative to punching. It involves a routing bit which is mounted on a Cartesian gantry and turns each individual tab into dust. This method is best used for high-mix production and thicker substrates. Ionized air is blown at the routing point to keep static charge down to allow a vacuum to easily remove the dust.
The sawing method of depanelization is best used on the most difficult substrates such as:
- Ceramics and individual packages
- Memory modules
- Ball grid arrays
- Chip-scale packages
The saw contains diamond blades and can cut from either the bottom or the top. Depaneling saws also have a vacuum for dust removal.
The blades used in depaneling can last a long time as they are made out of carbon steel, but they do eventually need to be replaced. It is a good idea to track each blade use to monitor its expected lifespan. The depaneling process is usually done offline, and manufacturers that depanel over a thousand boards per shift should consider using fully automatic equipment to get this done.
There is a cutting method that does not used blades. Laser depaneling uses lasers instead of blades so there is no need to track, monitor, and replace blades. In addition, there are many other benefits which include:
- No mechanical stress
- Versatility – ability to change applications by simply changing settings
- Cuts that are more precise and clean
- Ability to depanel a more diverse set of surfaces
- High quality of cuts due to higher precision and laser control
- Lasers can cut much more complex boards and multidimensional boards
Manufacturers can reduce depaneling time by keeping similar sized tabs together. Occasionally, engineers will finish designing boards before they realize they have to be separated. If designers remember to account for this process, they will greatly reduce the amount of time it takes to depanelize. When done effectively, depaneling can boost profits and increase productivity.