A Study of Influence of Electrolyte Composition on ECH of Bevel Gears using Mixture D-Optimal Design
This paper discusses the experimental investigation to find out the optimal electrolyte composition in improving the surface quality of the gear teeth profile during surfacing finishing of bevel gears by the electrochemical honing process. In this study, AISI 1040 was used as the workpiece material, mixtures of sodium chloride and sodium nitrate in different ratios were used as the input parameter, and the percentage improvement in the surface roughness and material removal rate of the process were used as measures of process performance. The experimental runs were designed according to the Mixture DOptimal design. The analysis of the experimental outcome was carried out and 80% NaCl + 20% NaNO3 was found to be theoptimal electrolyte composition to conduct the confirmation experiments. The finding of the study establishes the process for precision finishing of bevel gears.
A Precision Machining of Gears (Slow-Scanning Field Controlled Electrochemical Honing)
This paper presents a new working method of controllable Electro-Chemical Honing (ECH) of gears as follows. A gear shaped cathode which is meshing with a workpiece gear during machining is exposed as cathode pole only on a strip on the tooth dank. By varying the center distance between the cathode and the gear slowly, the electrolysis zone sweeps over the tooth flank from root to tip (slow scanning as we call it). Since the center distance is varied by a step motor, so the time of dwelling of the pole, and hence the amount of metal removal on different spots of the profile can be controlled by programming. An on-line profile error measuring device is provided. The computer calculates the required discharging time which has a relationship with dwelling time, and sends out the programming to control the metal. removing rate so as to cancel the error or to produce profile correction needed by silent transmission. A mathematical model is built for calculating the required discharging time. Several ground gears with typical profile errors are subjected to trial machining on this working principle. It cancels the profile errors very efficiently. The experiment demonstrates that the machining method can step up the profile accuracy to very high order on the basis of the general accuracy guaranteed by the proceeding operationgear grinding.
Finite element analysis of the tooth root bending stress of an unsymmetric gear with double pressure angles
This paper deduced the involute gear total tooth profile equations of unsymmetric teeth with double pressure angles, proposed the calculation formulas of coordinates and load angle at the upper and lower points of single and double teeth mesh areas, and programmed the relevant parametric programs. Compared with a standard involute gear, the unsymmetric involute gear could efficiently improve the tooth root bending strength by finite element analysis. Considering the time-variant mesh stiffness, the calculated results demonstrated the change of tooth root bending stress in one engagement period.