Issue link: https://iconnect007.uberflip.com/i/1129312
76 PCB007 MAGAZINE I JUNE 2019 For micro-machining, a proper process setup is spindle stability and drilling from drill bit selection to RPM, so there's one more item in setup to discuss, route planning. So far in this article, all of our examples use 0.5-mm slots. Making smaller slots with smaller bits is not a problem. Router bits with ball tips of 0.02 mm are used in the metal industry and have been for many years. The strength in these small bits is that you do not put pressure on the side of the bit but only on the tip in line with the direction of the shaft. The bit is much stronger when a con- stant pressure/load is applied on the tip (axial) compared to applying only a radial load. Con- tact your tool bit supplier for help selecting the correct bit and setting the right parameters. Measurement and Inspection In addition to micro-machining, it is impor- tant to check the dimensions of the structure. Figures 10–12 were generated using a laser profiler. The data from the laser profiler is pro- cessed, and sections from different planes can be made for analysis. This is not only faster Figure 8: Typical drill bit; slot wandered on this particular drill hole. Figure 9: Alternative bit created straight slot a medium to high depths (2.8 mm). Figure 10: Laser profiling is highly accurate; even with the scoring lines, the bit created at the bottom of the slot is visible.