Suppression of Surface Waviness Error of Fresnel Micro-Structured Mold by Using Non-Integer Rotation Speed Ratio in Parallel Grinding Process

Fresnel micro-structured lenses are widely used in the field of modern optoelectronic technology. High-precision Fresnel micro-structured mold is the key technology to achieve its large-scale replication production. Focusing on the surface waviness error of Fresnel micro-structured mold machined by parallel grinding process, this paper conducted theoretical modeling and experiment research. Based on the grinding kinematics theory, the simulation models of the surface waviness topography and the circular waviness profiles of the ground Fresnel micro-structured mold were developed, considering the combined influence of the non-integer rotation speed ratio and other grinding parameters. A series of grinding experiments were carried out to verify the proposed simulation models. The influence of a non-integer rotation speed ratio and a wave-shift value upon the surface waviness error of the ground Fresnel micro-structured molds were analyzed. Both the simulation and experimental results proved that choosing the non-integer rotation speed ratio and a proper wave-shift value could greatly reduce the surface waviness error and improve the surface quality and uniformity.

Modeling and Simulation of the Surface Topography Generation With Ordinary Grinding Wheel

In order to simulate the surface grinding process of the common grinding wheel and evaluate the surface topography of the workpiece, the mathematical model of the common grinding wheel is established by using the abrasive vibration method to realize the parameterization of the simulated grinding wheel. The grinding wheel body with random arrangement of abrasive grains is generated, and the simulation of common grinding wheel morphology is completed. Then, according to the grinding kinematics model, elastic deformation model and plastic accumulation model, the simulation of the process is realized, and the workpiece surface morphology matrix is generated. Finally, the influence of grinding parameters and grinding wheel parameters on the workpiece surface morphology and surface roughness is studied by calculating the surface roughness value.

Präzisionsschleifen mit groben Diamantkörnern*/Precision grinding with coarse diamond grains - Application characteristics of coarse-grained diamond grinding wheels

Der Fachbeitrag beschreibt die Weiterentwicklung von galvanisch einschichtig belegten grobkörnigen Diamantschleifscheiben – auch Engineered Grinding Wheels genannt. Verschiedene sprödharte Werkstoffe wurden anhand von Quer-Umfangs-Planschleifversuchen mit angestellter Probenoberfläche bearbeitet. Anhand der Oberflächenqualität und der Bauteilrandzone wurde anschließend der Einfluss einer variierten Zustellung sowie der Prozesskinematik auf einen duktilen Schleifprozess untersucht.   This study describes the application of coarse-grained diamond grinding wheels with electroplated abrasive single-layers (engineered grinding wheels) for ductile mode grinding of different brittle materials. Grinding experiments were performed in cross grinding kinematics while the workpiece is tilted in order to achieve different depths of cut over the workpiece’s surface. Influence of kinematics and depth of cut are investigated by measuring surface roughness and subsurface damage.

The method of assessment of the grinding wheel cutting ability in the plunge grinding

This article presents the method of comparative assessment of the grinding wheel cutting ability in the plunge grinding kinematics. A new method has been developed to facilitate multicriterial assessment of the working conditions of the abrasive grains and the bond bridges, as well as the wear mechanisms of the GWAS, which occur during the grinding process, with simultaneous limitation of the workshop tests range. The work hereby describes the methodology of assessment of the grinding wheel cutting ability in a short grinding test that lasts for 3 seconds, for example, with a specially shaped grinding wheel, in plunge grinding. The grinding wheel macrogeometry modification applied in the developed method consists in forming a cone or a few zones of various diameters on its surface in the dressing cut. It presents an exemplary application of two variants of the method in the internal cylindrical plunge grinding, in 100Cr6 steel. Grinding wheels with microcrystalline corundum grains and ceramic bond underwent assessment. Analysis of the registered machining results showed greater efficacy of the method of cutting using a grinding wheel with zones of various diameters. The method allows for comparative tests upon different grinding wheels, with various grinding parameters and different machined materials.