Adaptive Control System for Optimizing the ECG Process under the Overcut Constraint
One of the main limitations 1n Peripheral Electro Chemical Grinding (ECG) is the overcut phenomenon. The dominant parameters which govern the dimensions of the geometrical overcut are the voltage and the feedrate. This paper deals with the development of an empirical model which describes the overcut as a function of the dominant parameters. Pased on this model an adpative control system was built and experiments in Profile Peripheral ECG were carried out. A comparison of the results obtained with and without the adaptive control system is presented as well as the relationship between the side and bottom overcuts. According to the above an adaptive strategy to control the geometrical overcut in Profile ECG is suggested.
An Experimental Investigation of the Electrolytic Grinding Process
Data are presented covering the effect of several variables on grinding rate for the electrolytic grinding process. The relative amount of material removal due to electrolysis and due to conventional grinding action was investigated. The Faraday current efficiency of the electrolytic part of the process was found to be near 100 per cent to the extremely high current density of 700 amps per sq in. This is thought to result from the scraping action of the wheel abrasive which prevents passivation of the work anode. Several phenomena of the process are explained on the basis of hydrogen gas pressure in the work-wheel interface. A formula is presented for calculating the hydrogen gas pressure. Equations are proposed for the basic chemical reactions of the process.
Experiments in the piercing of soft metals
Abstract Experiments on annealed and work-hardened tellurium lead, and cast tin using flat headed and conical tipped punches with and without lands are described. Principally the results presented show: (i) How the parameter, p / Y varies with reduction for a given shape punch; p is the steady state punch pressure and Y the saturation compressive yield stress of the material; these experimental values are compared with theoretical values. (ii) The variation with reduction of certain critical depths and thicknesses at which the steady state and the post-steady state commence. (iii) Photographs of both the metal deformation ahead of the punch, and of cavitation.