The technique most commonly used to produce cylindrical gears, both external and internal, is gear shaping with a pinion-type cutter which generates gear flanks with rotating motion and removes chips by reciprocating action. Though the gear shaping cutter of a specific module can be used to cut gears with a wide range of teeth of the same module, in practice the inherent errors limit the number of teeth that can be cut on the gear. This paper analyses such inherent errors for both external and internal gears, taking into account the effect of a tip-relief angle and considering both "corrected" and "uncorrected" gear forms. © 1983.

Shunmugam M S

Department of Mechanical Engineering

Narayanan S. Srinivasan

GEAR CUTTING

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Limiting conditions in gear shaping for corrected involute gears

International Journal of Machine Tool Design and Research

In gear generation processes, the involute profile of the gear is obtained as an envelope of the successive cuts made by the flank of the generating tool. The irregularities of the profile thus generated limit the quality of the gear. This paper reports the minimum achievable quality based on the maximum theoretical height of the irregularity for the involute spur gears. © 1988, All rights reserved.

International Journal of Machine Tools and Manufacture

Minimum achievable quality of involute gears in generation processes

Gear shaping cutters are provided with top-relief and rake angles. As a result of this, the profile representing the cutting edge is modified. This paper deals with the method of obtaining the effective profile on the rack-type and pinion-type cutters for spur gears. Analysis of the effective profile shows that the effective profile of the rack-type cutter is actually a straight-sided tooth form with different pressure angle and tooth thickness at the reference (pitch) line. In the case of the pinion-type cutter, tooth thinning takes place and the effective profile could not be identified with any involute form. This paper also deals with the methods of correcting the cutter profile form so that profile close to the theoretical form can be obtained on grinding the rake face. This approach would be quite useful to the designers and manufacturers of the shaping cutters. © 1983, Institution of Mechanical Engineers. All rights reserved.

Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science

Effect of top-relief and rake angles on the gear shaping cutter profile

When a scale of metal cutting process reduces to micrometer range, mechanics of material removal are affected by various factors such as workpiece material, cutting tool geometry and cutting conditions. A suitable model of constitutive behaviour of the material is needed to represent properties of the work material at the conditions existing during chip formation. In this paper, a material model based on theory of strain gradient plasticity is proposed for material strengthening in micro cutting, taking into account size effect in micro cutting with a tool having an edge radius. The proposed model effectively combines strain gradient plasticity and basic mechanics of orthogonal cutting. The material model thus developed is validated using results obtained from micro-orthogonal cutting experiments on mild steel (AISI 1019). Micro-orthogonal experiments with varying uncut chip thickness are also carried out to fine-tune the material model and investigate the mechanics of micro cutting considering the minimum uncut chip thickness effect. The results are encouraging and shear strength is predicted with an average absolute error of 11.8%. FE simulations carried out with flow stress obtained from Johnson-Cook relation yield cutting forces that follow the trend in the experimentally obtained force signals, but they are unable to capture the strain gradient and ploughing effects. Copyright © 2013 Inderscience Enterprises Ltd.

Journal	International Journal of Machine Tool Design and Research
ISSN	00207357
Open Access	No