Burr formation and effects when drilling metallic/composite stack assemblies

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Abdelhafeez Hassan, Ali Mohamed (2017). Burr formation and effects when drilling metallic/composite stack assemblies. University of Birmingham. Ph.D.

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Abstract

Burr formation and poor hole quality can be detrimental to fatigue life as well as hinder the assembly and functionality of drilled components, particularly those made from metallic-composite stacks. Following a detailed literature review, four phases of experimental work were carried out to evaluate the effects of varying cutting parameters, tool geometries/coatings, workpiece configuration and machining strategies on hole quality/integrity, burr formation and subsequent workpiece fatigue performance, following drilling of several 2-layer stack configurations (CFRP/AA2024, AA2024/AA7010 and CFRP/Ti-6A1-4V). This was complemented by the development of numerical models to predict burr formation when drilling metallic alloys. Key contributions of the research were: (i) improved understanding with regard to the influence of cutting speed and feed rate on burr formation and hole quality when drilling individual Ti-6A1-4V, AA2024 and AA7010 alloys together with various stack assemblies; (ii) identification of appropriate tool type and cutting conditions in addition to possible alternative burr suppression methods; (iii) understanding of the significance of burr formation on fatigue life of individual metallic materials and; (iv) derivation of an
analytical model for entrance and interlayer burrs as well as formulation of an FE model for enhanced burr formation (entrance and exit) predictions when drilling individual metallic materials.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):