Research On Automatic Sharpening System For PCB Micro Drill Bit

PCB micro drill bit is the main consumption tool for making PCBs, and sharpening andinspecting PCB drill mainly rely on manual work. In view of the characteristics of PCB microdrill bit such as the mini-dimensions, the special spatial structure of the blade, the highinspecting precision requirements, lots of dust produced in the grinding process, artificialgrinding can’t meet the requirement of production of the micro drill bit, so it is meaningful toresearch and develop an automatic grinding system for resolving urgent need in PCB drill bitindustry. According to the property of the automatic grinding and testing system, the systemprogram, tool presetting algorithm and system implementation are investigated in this paper.Firstly, system program is investigated. The shell structure, wear principle and commondefects of the PCB drill bit are researched. On the basis of studying micro-grinding process,the two-terminal grinding program is put forward. The key mechanical structure, motioncontrol subsystem and the vision detection subsystem are designed in the paper.Image preprocessing plays an important part in vision detection. A series of imagepreprocessing methods for removing interference information is presented in the paper, whichis consisted by filter process, adaptive threshold segmentation, edge of the neighborhoodsearch algorithm.This paper presents one kind of tool presetting angle calculation algorithm bases onmicro-drill blade. Firstly, the principle of the micro drill bit blade presetting and the microdrill bit blades contour about blob analysis are studied. Then based on micro drill bit bladescontour feature, a connected component labeling algorithm based on region growing contouris put forward. Finally the angle calculation achieve in detail based on the blade surface isstudied in detail.Micro drill bit automatic sharpening system movement logic is very complex, whichrequires high-precision control. In this paper, the implementation method of Soft-PLC basedon DSP/BIOS real-time system kernel is discussed in detail. The whole closed-loop servocontrol system for the feed shafts is built and the simulation is carried on withMatlab/Simulink. Finally, according to the PCB micro drill bit automatic sharpening systemrequirements, system software architecture and module division are designed, and systemsoftware code is written in Visual C++platform. The experiment indicates that the systemdesign of automatic sharpening and testing PCB mini-drilling is feasible, which plays an important part in improving the quality and the efficiency of PCB micro drill bit sharpeningand testing.