Finishing of Micro-Aspheric Tungsten Carbide Mold Using Small Viscoelastic Tool

Tungsten carbide is widely used as the material of replication mold to produce small aspheric optics, and the polishing process determines the precision of the mold. However, for micro-aspheric tungsten carbide mold, the existing polishing methods are difficult to realize the from error modification during the polishing because the polishing tool is always larger than small mold. Therefore, a polishing tool which using polyester fiber cloth to wrap small-size rigid ball is used in this paper. In order to predict the tool influence function (TIF) of this polishing tool, a series of theoretical analysis and experimental verification are carried out in this paper. Firstly, by analyzing the structural and viscoelastic characteristics of the fiber cloth, the pressure distribution in the polishing contact area is determined. And the polishing speed distribution is obtained by analyzing the kinematic movement of the polishing tool; Then, combined with Preston equation, the tool influence function is derived; Afterward, through a series of single point polishing experiments, it is verified that the volume error between the theoretical removal model and the experimental removal is less than 10.8%; Finally, the tool influence function is applied to the form error corrective polishing of small size symmetric aspheric tungsten carbide mold. After one form error corrective polishing, the PV value (Peak to Valley) of form error is decreased from 0.405um to 0.068um, which verifies the effectiveness of the polishing method of small size tungsten carbide mold in form error correction.

Study on the Electrorheological Ultra-Precision Polishing Process with an Annular Integrated Electrode

Electrorheological (ER) polishing, as a new ultra-precision super-effect polishing method, provides little damage to the workpiece surface and is suitable for polishing all kinds of small and complex curved surface workpieces. In this paper, an ER polishing tool with an annular integrated electrode is developed. The orthogonal experiments are carried out on the six influencing factors of ER polishing which include the applied voltage, the abrasive particle size, the abrasive concentration, the polishing gap, the polishing time and the tool spindle speed. The influence order of these six factors on the ER polishing is obtained. On this basis, the effect of a single process parameter of ER polishing on surface roughness is studied experimentally.

Modeling and simulation of reconfigurable systems with applications to the polishing process

This thesis presents a newly developed system for simulation and control of reconfigurable machines and applications in the polishing process. A software package is developed that consists of the Varying Topology Simulation and Control System (VT-Sim) as well as the Polishing CAM (P-CAM) software system. VT-Sim can simulate and control reconfigurable machines of serial or tree structures. It is developed based on mechatronic modules, each of which has a graphic user interface that can be connected to a physical module. The selected modules are linked through a graph-based topology design platform to generate an assembled system together with the equations for simulation and control. P-CAM can simulate and generate CNC codes for the polishing process. The roughness of the polished parts is simulated for selected polishing parameters. Once satisfied, polishing tool paths can be generated and visualized.

Modeling and simulation of reconfigurable systems with applications to the polishing process

This thesis presents a newly developed system for simulation and control of reconfigurable machines and applications in the polishing process. A software package is developed that consists of the Varying Topology Simulation and Control System (VT-Sim) as well as the Polishing CAM (P-CAM) software system. VT-Sim can simulate and control reconfigurable machines of serial or tree structures. It is developed based on mechatronic modules, each of which has a graphic user interface that can be connected to a physical module. The selected modules are linked through a graph-based topology design platform to generate an assembled system together with the equations for simulation and control. P-CAM can simulate and generate CNC codes for the polishing process. The roughness of the polished parts is simulated for selected polishing parameters. Once satisfied, polishing tool paths can be generated and visualized.

Coverage Based Tool-Path Planning For Automated Polishing Using Contact Mechanics Theory

Presented in this thesis is a method for tool-path planning for automated polishing. This work is an intergral part of the research program on automated polishing/deburring being carried out at Ryerson University. Whereas tool-path planning for machining is treated as a geometry problem, it ks shown here that tool-path planning for polishing should be treated as a contact mechanics problem because of the contact action between the polishing tool and the part surface. To develop this algorithm, contact mechanics is applied for contact area modeling and analysis, Once the contact area is determined, for multiple contact points along the given polishing path, a map of the contact area is generated and utilized to show the coverage area during polishing. This map is then used to plan a polishing path that ensures complete coverage for polishing, Simulation has been carried out to show the effetiveness of this new polishing path algorithm.

Coverage Based Tool-Path Planning For Automated Polishing Using Contact Mechanics Theory

Presented in this thesis is a method for tool-path planning for automated polishing. This work is an intergral part of the research program on automated polishing/deburring being carried out at Ryerson University. Whereas tool-path planning for machining is treated as a geometry problem, it ks shown here that tool-path planning for polishing should be treated as a contact mechanics problem because of the contact action between the polishing tool and the part surface. To develop this algorithm, contact mechanics is applied for contact area modeling and analysis, Once the contact area is determined, for multiple contact points along the given polishing path, a map of the contact area is generated and utilized to show the coverage area during polishing. This map is then used to plan a polishing path that ensures complete coverage for polishing, Simulation has been carried out to show the effetiveness of this new polishing path algorithm.