Punching, sawing, milling, laser cutting. At first glance, there are numerous ways to separate printed circuit boards. But a closer look reveals that only a few methods are suitable for separating PCBs with complex contours and/or sensitive components: Sawing and punching are already ruled out here due to inflexible layouts during depaneling.
Anyone who manufactures small assemblies with a flexible design (Fig. 1) therefore only has two options: Laser or milling. Both systems approach depaneling in the same way. The material is removed layer by layer, so that engravings can also be realized. Flexible cutting contours are also no problem. The biggest obvious difference is that the mechanical process uses a milling head and the laser process - obviously - uses a laser beam. So is it better to use a laser or a milling machine?
If you look more closely, the laser differs considerably from the milling machine: With the laser, the separation is completely contactless, no mechanical stress is transferred to the material. Damage to sensitive components is therefore impossible. Changing tools is also a thing of the past with the laser, since the cutting tool wears out very slowly. In this way follow-up costs in terms of material and retooling are reduced. Another difference: unlike milling, laser cutting does not produce dust that can settle on the circuit board. The material is vaporized and sucked off.
However, when separating by laser, the panel is heated up considerably and sensitive components are damaged. This sentence sounds logical, but has nothing to do with the reality of depaneling. The laser technology has been greatly developed in recent years. For example, the temperatures during the cutting process are only about half as high as in the previous reflow process. Instead of burning and forming soot, the material melts. With the CleanCut technology developed by LPKF (Fig. 2), 100 % technically clean and carbonization-free cut edges are achieved. In addition, the low temperature development and the minimal laser diameter mean that neither tabs nor heat-affected zones need to be taken into account in the PCB design. Significantly more printed circuit boards can be placed on a panel (Fig. 3).
Printed circuit boards - better milled or lasered? Even though every cutting process has its own area of application, in industries with high quality requirements the motto is: "better lasered”. Not only is the separation process improved in terms of mechanical stress and the generation of dust, but also the product life, the PCB design and the allocation of the total benefit can be optimized with SmartRep and LPKF's laser depaneling technology.
"Depanelization should therefore not be underestimated - the right depanelizator enables numerous optimizations in terms of product quality and depanelization design that can create long-term benefits".
06 November 2020
- Circuit board