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Abstract

This thesis examines the effects of the frictional conditions at the blank/punch interface on the success of the deep drawing of axi-symmetrical cups.

The programme was conducted in two parts;
(a) establishing the frictional characteristics;
(b) applying an hypothesis to the deep drawing process.

Movement of the material over the punch head was simulated by modified tensile tests enabling material to be pulled around rollers of a given diameter and surface quality. The resulting specimens were then investigated using a scanning electron microscope for the effects of the rollers on the motion of the material, The results were used to predict the behaviour of the materials when subsequently deep drawn.

Axi-symmetrical cups were drawn using plain punches, knurled punches and using a fluid pressure to assist the contact of the blank with the punch. These cups were investigated using a scanning electron microscope for confirmation of the hypothesis from part 1 of the investigation.

It is shown that some improvement in the LDR may be obtained using roughened punches and that some further improvement may be realised by the application of a hydrostatic pressure, Reasoned argument is given to show that this improvement does not depend solely upon the history of the material as given by its n-value which has been suggested by a number of authors. Rather, it is a complex mechanism depending upon the metallurgical and physical properties of the material and the surface characteristics of both the material itself and the punch. The limitations of the present work are discussed in the light of the results obtained and suggestions are made as to how these may be overcome.

During the study a number of interesting areas of investigation presented themselves and these are discussed under "Recommendations for future work." Since the completion of the work the author has been invited to participate in the work of the Sheet Metal Technology Group, the British section of the International Deep Drawing Research Group.

Publication Type:	Thesis (Doctoral)
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) T Technology > TJ Mechanical engineering and machinery
Departments:	School of Science & Technology > Department of Engineering School of Science & Technology > School of Science & Technology Doctoral Theses Doctoral Theses

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