No abstract

Purpose -The last decade has seen major advances in rapid prototyping (RP), with it becoming a multi-disciplinary technology, crossing various research fields, and connecting continents. Process and material advancements open up new applications and manufacturing (through RP) is serving non-traditional industries. RP technology is used to support rapid product development (RPD). The purpose of this paper is to describe how the Integrated Product Development research group of the Central University of Technology, Free State, South Africa is applying various CAD/CAM/RP technologies to support a medical team from the Grootte Schuur and Vincent Palotti hospitals in Cape Town, to save limbs -as a last resort at a stage where conventional medical techniques or practices may not apply any longer. Design/methodology/approach -The paper uses action research to justify the proposal of a new method to use CAD/CAM/RP related technologies to substitute lost/damaged bone regions through the use of CT to CAD to.STL manipulation. Findings -A case study where RP related technologies were used to support medical product development for a patient with severe injuries from a road accident is discussed. Originality/value -The paper considers current available technologies, and discusses new advancements in direct metal freeform fabrication, and its potential to revolutionise the medical industry.

Purpose -Not all the inventors and designers have access to computer-aided design (CAD) software to transform their design or invention into a 3D solid model. Therefore, they cannot submit an STL file to a rapid prototyping (RP) service bureau for a quotation but perhaps only a 2D sketch or drawing. This paper proposes an alternative approach to build time estimation that will enable cost quotations to be issued before 3D CAD has been used. Design/methodology/approach -The study presents a method of calculating build time estimations within a target error limit of 10 per cent of the actual build time of a prototype. This is achieved by using basic volumetric shapes, such as cylinders and cones, added together to represent the model in the 2D sketch. By using this information the build time of the product is then calculated with the aid of models created in a mathematical solving software package. Findings -The development of the build time estimator and its application to several build platforms are described together with an analysis of its performance in comparison with the benchmark software. The estimator was found to meet its target 10 per cent error limit in 80 per cent of the stereolithography builds that were analysed. Research limitations/implications -The estimator method was not able to handle multi-component complex parts builds in a timely manner. There is a trade-off between accuracy and processing time. Practical implications -The output from the estimator can be fed directly into cost quotations to be sent to RP bureau customers at a very early stage in the design process. Originality/value -Unlike all the other build estimators that were encountered, this method works directly from a 2D sketch or drawing rather than a 3D CAD file.

Abstract

Purpose -The purpose of the present work is to develop a methodology to manufacture patient-specific models (lead masks) to be used as protective shields during cancer treatment, using 3D photography, rapid prototyping (RP) and metal spraying. It is also intended to reduce the trauma experienced by the patient, by removing any physical contact as with conventional methods, and also to reduce the manufacturing lead time. Design/methodology/approach -Patient-specific data are collected using 3D photography. The data are converted to.STL files, and then prepared for building with an LS 380 in nylon polyamide. Next, the sculpted model is used as the mould in a newly patented metal-spraying device, spraying liquid metal on to the sculpted surface. Findings -Intricate body geometries can be reproduced to effectively create metal shields, to be used in radiography applications. The models created fit the patients more accurately than through conventional methods, reducing the trauma experienced by the patient, and in a reduced time-frame, at similar costs to conventional methods. The new process and its materials management are less of a an environmental risk than conventional methods. Research limitations/implications -Access to 3D photography apparatus will be necessary, as well as to RP or CNC equipment. Using this approach, files can be transferred to a central manufacturing facility, i.e. hospitals or treatment units do not need their own facilities. Added implications are the design of jigs and fixtures, which will ensure accuracy in reuse. Practical implications -Metal shields can be created with ease and great accuracy using RP machines. It takes less time without inflated costs. Models are more accurately and easy to use, with less trauma experienced by the patient during the manufacturing phase. Originality/value -Novel applications, combined with a new process. The research expands the fast-growing field of medical applications of RP technologies. Its practical application will benefit patients on a daily basis.