Benny Schacht

Interaction between workpiece and CMM during geometrical quality control in non-standard thermal conditions

Industrial quality demands have resulted in increasing attention towards the thermal behavior of coordinate measuring machines. The influence of the workpiece on the measurement accuracy is hereby often disregarded. This can lead to significant measurement errors. The described research examines the interaction between the measurement device and the measured object. Four distinct measurement error types that result from non-standard temperatures are listed. Temperature variations during the measurement lead to the most challenging situation. The key to measurement accuracy lies in linking the measurement time to the accompanying temperature variation. The possibilities of this methodology are indicated by an experiment on a reference object.

An erosion index for wire electrode materials in EDM

In this paper, the authors propose an erosion index for wire materials or wire coatings. In sinking EDM research and practice, an erosion index is commonly available. In wire EDM few efforts have been made to identify possible electrode materials from the point of view of cutting speed. The index is based on physical understanding of the process and uses thermal properties of the electrode material, as is the case for the sinking EDM erosion index. The most important materials used as a coating for wire electrodes, like Zn, Cu, W and Mo, are analyzed and the proposed index is in good correlation with experimental cutting data, both from literature reports and own experiments. The theory can also be applied to alloys, such as brass (Cu-Zn) with different amounts of zinc.Copyright