How to design spare parts for stereolithography to replace injection moulded parts

Abstract

The goal of this thesis was to provide designers guidance in designing their yet-to-be designed products that contain injection moulded parts in a way that allows for interchangeable, functionally equivalent spare parts produced with additive manufacturing in the future. The project was scoped to stereolithography as the additive manufacturing technology, focusing on geometrical and mechanical aspects of product design. The result of the thesis is a newly developed guide, referred to as the ‘form factor optimisation guide’. This guide was developed by analysing literature and conducting various case studies.

Two newly developed approaches are part of the form factor optimisation guide, referred to as the ‘geometry-based part coupling approach' and the ‘form factor definition approach’. A designer can compose a product architecture map using the geometry-based part coupling approach to map the relationships of coupled parts. Parts are considered coupled when they influence each other’s geometry. The product architecture map, along with the list of requirements, is used to define the ‘form factor’ of a part. This form factor is the design space and non-design space for the part's geometry. Using the form factor, the designer can optimise the part for production with injection moulding and stereolithography. It may occur that the form factor does not allow the designer to cope with the limitations of each manufacturing technology. In this case, ‘reciprocity’ is applied. Reciprocity is the term that is used to describe the process of going back and forth between the designs of coupled parts and their requirements. Reciprocity is applied until the form factor allows for interchangeable, functionally equivalent parts produced with injection moulding and stereolithography.