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#
Computer synthesis of three-dimensional surfaces
Abstract A new technique for the synthesis of three-dimensional surfaces has been developed. The method is based on the application of the discrete and continuous two-dimensional Fourier transformations associated with the theory of discrete and continuous time series models. This new technique facilitates the synthesis of three-dimensional surfaces with predetermined properties in any number of desired directions.
Submicron polymer structures with X-ray lithography and hot embossing
This article describes the process chain for replication of submicron structures with varying aspect ratios (AR) up to 6 in polymethylmethacrylate (PMMA) by hot embossing to show the capability of the entire LIGA process to fabricate structures with these dimensions. Therefore a 4.7 μm thick layer of MicroChem 950k PMMA A11 resist was spin-coated on a 2.3 μm Ti/TiOx membrane. It was patterned with X-ray lithography at the electron storage ring ANKA (2.5 GeV and λc ≈ 0.4 nm) at a dose of 4 kJ/cm3 using a Si3N4 membrane mask with 2 μm thick gold-absorbers. The samples were developed in GG/BDG and resulted in AR of 6–14. Subsequent nickel plating at 52°C resulted in a 200 μm thick nickel tool of 100 mm diameter, which was used to replicate slit-nozzles and columns in PMMA. Closely packed submicron cavities with AR 6 in the nickel shim were filled to 60% during hot embossing.