Polishing tool for KDP crystals

• Main Author: Lim, Eugene Chen Yew.
• Other Authors: Georg Lothar Thimm
• Format: Final Year Project
• Language: English
• Published: 2009
• Subjects: DRNTU::Engineering::Mechanical engineering::Machine design and construction
• Online Access: http://hdl.handle.net/10356/16955
• Institution: Nanyang Technological University

Polishing machines are used in laboratories to polish various materials ranging from soft crystals to metals. In this project, the specimens to be polished are the KDP crystals which are soft and brittle. Most of the polishing machines in the market have high torque and high rotational velocity which can cause the KDP crystal to chip, crack or experience uneven polishing. Therefore, there is a need to develop an automated polishing device which is simple yet effective to polish the crystals in eccentric motion without damaging them. The conceptual idea used to develop the prototype for the automated polishing device utilizes a set of gear train that translates the one directional rotational motion from a D.C. motor to a multidirectional rotational motion. The back and forth circular motion coupled with a roller and rail mechanism enables the crystal to rotate about an axis a distance away and also about its own axis. This will ensure that the polishing over the crystals surface is done uniformly and the forces and distributed evenly. After the fabrication and assembly, the prototype was subjected to testing to observe whether the mechanism can work as intended and achieve the objective of a surface fineness of 10µm. The device was able to work as intended but did achieve the target of 10µm. Finally, the flaws of the machine were evaluated for the testing. The shortcomings of the machine were due to factors such as manufacturing defects and limitations of certain parts of the mechanism. Future improvements and development were suggested to solve the problem faced and to improve the prototype.