An investigation of the grinding wheel wear with the use of root-mean-square value of acoustic emission
This paper presents the results of an investigation of the grinding wheel wear in a peripheral surface grinding process. During this investigation varying geometrical parameters of an active grinding wheel surface have been measured and the components of the grinding force and acoustic emission signal have been recorded. On the basis of these output quantities an analysis has been conducted of an acoustic emission descriptor's practicability, i.e. a root-mean-square (RMS) value, to characterize the cutting abilities of a grinding wheel in the time progress of its work. This article also presents a new energy coefficient, which determines the rate of grinding wheel wear in the form of a RMS value of acoustic emission signal falling on a contact surface of a grinding wheel. Moreover, the article presents some examples of a correlation between the root-mean-square value of acoustic emission signal and the surface roughness of a workpiece, which shows that the parameters of acoustic emission signal can be a useful tool to monitor the surface roughness during the grinding process.
Acoustic emission in dressing of grinding wheels: AE intensity, dressing energy, and quantification of dressing sharpness and increase in diamond wear-flat size
Abstract Although significant work has been done on the application of acoustic emission (AE) to grinding and to dressing of grinding wheels, several fundamental AE relationships between have not been established. These are: 1) the relationship between dressing energy and the measured AE signal; 2) how different diamond/grit contact modes (fracture, plastic deformation, rubbing, etc.) affect AE energy; and 3) how this can be used to quantify dressing efficiency, wheel sharpness and wear-induced changes in diamond shape. This paper describes an investigation into these fundamental concepts, with quantification of the relationship between AE intensity and dressing energy and the influence of different diamond/grit contact modes. A new parameter is introduced, the specific acoustic-emission dressing energy, which can be used to quantify dressing efficiency and wheel sharpness. Finally, the use of the AE intensity in evaluating diamond wear is explored, allowing the operator to know the size of the wear flat and when changes are necessary to avoid workpiece burn. Experimental work validates these concepts and practical recommendations are given on its application in industry.
Composite monolayer fabrication by an arc-spray process
A single layer (monotape) technique for fabricating complex high-temperature tungsten-fiber-reinforced superalloy composites is proposed. The fabrication of sheets of arc-sprayed monotape 38 cm wide and 122 cm long has been demonstrated. Composites fabricated using the method are shown to have equal tensile strength and a cleaner matrix than composites fabricated from powder metal cloth monotapes, and the present technique is less expensive than the powder metal fabrication techniques.