A Three-Dimensional Model for the Surface Texture in Surface Grinding, Part 2: Grinding Wheel Surface Texture Model
In order to produce ground parts that have desirable surface properties, it is necessary to understand the evolution of these characteristics through the surface generation mechanisms involved in the grinding process. Since the geometry of the wheel surface, in part, determines the final workpiece geometry, the influence of the 3-D structure of a wheel surface on the final workpiece geometry is studied. In this work, a wheel surface model is developed that can be integrated with a surface grinding process model for simulating workpiece surface texture. The simulations utilizing the integrated model are used to study the workpiece surface roughness as a function of the frequency characteristics of the wheel surface. The 2-D Fourier forward and inverse transforms are employed to study and model the 3-D surface structure. In particular, the effect of specific frequency components in the wheel surface on the ground surface are analyzed. It is shown that workpiece surfaces resulting from wheel surfaces with dominant low frequency components have higher roughness, and that the low frequency components indicate a clustering of abrasive grains on the wheel surface. @DOI: 10.1115/1.1391428#
Influence of wheel speed on surface finish and chip geometry in precision contour grinding
Abstract A geometric computer model of a precision grinding operation was developed to calculate the surface features generated during contour grinding with a radiused wheel. This simulation includes the influence of the wheel (rotational speed, diameter, and nose radius), the workpiece (radius at cutting point, rotational speed), and the feedrate of the grinding wheel over the part. The model indicates that small changes in the wheel speed relative to the workpiece can have a dramatic effect on the surface finish over a specific area. Analysis of ground surfaces reveals uniform surface profiles and easily distinguished features that could only be produced by a constant wheel speed. This occurs for an air-bearing, air-turbude grinding spindle that has limited torque and is driven under open-loop control. The effects of the relative speeds are analyzed and an energy-based “phase locking” mechanism is proposed that can provide feedback to the grinding spindle from the material removal operation. By monitoring the spindle speeds during the grinding process and evaluating the resulting surface features, the phase effect has been experimentally verified.
Review Of Precision Surface Generating Processes And Their Potential Application To The Fabrication Of Large Optical Components
Over the last decade a wide variety of processes applicable to ultraprecision contouring and polishing have evolved. Examples of these processes include float polishing, elastic emission machining, erosive jet, ion milling, plasma assisted chemical etching, and precision ductile grinding. These processes are reviewed with the intent of comparing their removal rates, resultant surface roughness, demonstrated contour accuracy, and applicability to the manufacture of large optical components. The incentive for this study is the evolution of a deterministic manufacturing process able to lower the cost of fabricating large precision optical components by an order of magnitude.