Development of tabletop dual-spindle ultra precision CNC machine tool and research of mould fabrication for microscopic examination of cells

• Main Authors: Chih-Hsien Chang, 張智賢
• Other Authors: Shun-Tong Chen
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/39327423833467043661

碩士 === 國立臺灣師範大學 === 機電科技研究所 === 99 === The primary purpose of the thesis is to develop a tabletop dual-spindle ultra precision CNC machine tool and using the finished machine tool to fabricate crisscross microgrooves on ductile material as NAK80 steel and on brittle material as optical glass. This developed technology can be applied to the fabrication of biomedical chip mould for the microscopy examination chip of cells of urinary sediments. The tabletop CNC machine tool is designed with gantry framework to possess high system stiffness for precisely machining the microgrooves on the mould steel. A dual-spindle design which two tools are mutually perpendicularly mounted on the developed machine tool is proposed and four technologies including micro EDM, grinding, polishing and measurement are constructed respectively on the machine tool to in-situ fabricate the micro chip mould. The on-line WEDG method verifies that the boron-doped PCD can be thinned down to 5-µm in edge-thickness on the developed machine. The thinned wheel-tool is then directly positioned on the mould steel to generate multiple microgrooves on-line. A technique called High Speed and Fast-Shallow Grinding (HSFSG), which utilizes a very high machining speed, a fast feed rate, and shallow depth grinding, is employed to effectively generate precise microgrooves of high integrity. Experimental results show that the width of the grooves in the array is 8 um and a surface finish of Ra equal to 10 nm is simultaneously achieved on the mould steel. The wheel-tool fabrication and microgroove generation are carried out on the same machine, decreasing vibration occurring and guaranteeing machining accuracy. In addition, the sharpness of grinding edge of boron-doped PCD can be kept for a long time. Due to a very shallow grinding depth used results in cold machining. This can prompt diamond grain working at SP3 bond structure, reduce the affinity between iron and carbon atoms and then retard the tool wear as a result of cold processing although the grinding object is carbon steel. The surface of the chip mould is then directly polished to remove the burrs at the microgrooves after switching to the vertical polishing tool. The finished chip mould has been successfully employed to fabricate the biochip by micro injection and then it is used to the clinical trial stage. This study demonstrates that the tabletop dual-spindle ultra precision CNC machine tool has been successfully developed and the micro technologies can be really utilized to the fabrication of biomedical chip mould. It is expected that the technique will contribute significantly to the bio-medical field.