Gerrie Booysen

Using RP to promote collaborative design of customised medical implants

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 ma...

Rapid manufacturing of patient‐specific shielding masks, using RP in parallel with metal spraying

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, ...

Anaesthetic mouthpiece development through QFD and customer interaction with functional prototypes

– The paper reflects on the development of a medical product using rapid prototyping technologies and customer interaction through a quality function deployment (QFD) approach to speed up the process, and to result in customer satisfaction. The purpose of the specific medical product was to develop a device for fixing an Endo‐tracheal (ET) tube in a patient during anaesthesia, as it is common for an ET tube to move and/or become dislodged due to various extraneous reasons. If the tube deviates from the correct position it can cause one or both lungs to collapse, which can be fatal. The paper reviews how the anaesthetists idea, which was to develop a product that could hold an ET tube in place in a more secure manner than is possible with current technologies, was brought to fruition through customer interaction., – Using an action‐research approach, the design evolved through series of design concepts, which through customer interaction contributed to a total optimized design. Virtual and physical prototypes, together with silicone mouldings were used as part of the customer interaction., – As with any new product, some functional parts were needed to conduct tests, which in turn would help to prove the product, and hence, the design. Traditionally this meant the manufacturing of a hard tool and proving of the design through trial and error. Hard tooling allows for some small changes to be made, but if the changes are radical a new tool will have to be designed and manufactured., – Following a developmental approach through the application of various types/stages of prototyping (such as virtual prototypes), revolutionised this process by simplifying and accelerating the development iteration process – it also developed a new version/paradigm of QFD., – Opposed to traditional forms of QFD where customer inputs are gathered through questionnaires, this case study proved that functional models provide an efficient client‐feedback, through constant involvement in the development process, as well as evaluation of the systematic progress., – The case study shows that experts in other disciplines can become involved in the product development process through the availability of functional prototypes, and builds on previous work to introduce a concept of customer interaction with functional prototypes.

Three-dimensional model of an ancient Egyptian falcon mummy skeleton

– The purpose of this paper is to present the first detailed three-dimensional (3D) print from micro-computed tomography data of the skeleton of an ancient Egyptian falcon mummy. , – Radiographic analysis of an ancient Egyptian falcon mummy housed at Iziko Museums of South Africa was performed using non-destructive x-ray micro-computed tomography. A 1:1 physical replica of its skeleton was printed in a polymer material (polyamide) using 3D printing technology. , – The combination of high-resolution computed tomography scanning and rapid prototyping allowed us to create an accurate 1:1 model of a biological object hidden by wrappings. This model can be used to study skeletal features and morphology and also enhance exhibitions hosted within the museum. , – This is the first replica of its kind made of an ancient Egyptian falcon mummy skeleton. The combination of computed tomography scanning and 3D printing has the potential to facilitate scientific research and stimulate public interest in Egyptology.

Microfocus X-ray computed tomography (CT) analysis of laser sintered parts

Microfocus X-ray computed tomography (CT) scanning is a three-dimensional (3D) nondestructive technique that is useful in many research and technology fields. Similar to twodimensional (2D) X-ray inspections, this 3D technology allows the investigation of almost any material down to 1 micron spatial resolution and higher. In this paper we present a characterisation and demonstration of the use of CT to analyse the 3D volume of laser sintered parts including analyses of porosity, dimensional measurement of cracks and other features, and a demonstration of quality testing methods which can be used to quickly identify problems in production. OPSOMMING

Rapid tooling in support of accelerated new product development

Purpose – The paper examines whether additive manufacturing can deliver durable injection‐moulding tools – fast, reliable, accurate and economic. Researchers from the Central University of Technology, Free State (CUT), South Africa, are involved in rapid prototyping (RP) applications‐based research, simultaneously using results to support small‐ and medium‐sized enterprises (SMEs) on a national basis – both with contract research and technology transfer[1]. SMEs in South Africa involved in product development, are often hampered by economies of scale. Many new products simply disappear in the product development valley of death, partly due to manufacturing costs and limited product development budgets. RP has been used extensively by Technimark, one of the CUTs industrial partners, to evaluate and verify designs in various design stages. To remain competitive in the global market, Technimark and the CUT often have to apply RP directly as the manufacturing method. The paper discusses the use of RP to supp...

Reconstruction of an extensive midfacial defect using additive manufacturing techniques

Malignant peripheral nerve sheath tumors are extremely rare tumors arising in peripheral nerves. Only 17 cases involving the trigeminal nerve have ever been reported. These tumors have a very poor prognosis and very high rates of recurrence and metastases. Their recommended treatment involves complete tumor resection followed by radiation. This can be problematic in the head and neck region. We present a clinical case involving a 33-year-old female patient presenting with a slow-growing, exophytic mass of the anterior maxilla. Incisional biopsy and subsequent histological examination revealed a diagnosis of a malignant peripheral nerve sheath tumor. Surgical resection involved a complete maxillectomy, rhinectomy, and resection of the upper lip and aspects of the left and right cheeks. Reconstruction of the subsequent defect incorporated the placement of four zygomatic oncology implants to aid in retention of a facial prosthesis. These implants, however, were subsequently lost; and an anatomical model of the hard tissues was manufactured via 3D printing. This model was used to design and manufacture a titanium frame (customized implant) for the patient. The frame was then fixated and secured intraoperatively with 21 cortical screws. A maxillary denture and silicone facial prosthesis were also made to fit onto this frame. This is the first known case where additive manufacturing, via the use of rapid prototyping and 3D printing, was employed to manufacture a facial prosthesis.

Notice of Retraction Application of laser sintering technology in heat exchanger design and manufacture

Laser sintering technology is being widely applied in different industries. There is, however, a resistance to the application of this technology and the applications are limited due to the nature of the process. For example, the surface roughness of the final laser sintered product is often a major technical issue. The disadvantages in one area can probably displayed as the advantages in another area. The use of laser sintering technology in the design and manufacture of heat exchangers is such an example. In the areas of thermodynamics, heat transfer, and fluid mechanics, the enhancement of heat transfer is the key research topic. Heat exchangers are commonly used in engineering applications from power generation to computer processors. Some types of heat exchangers, such as finned-tube heat exchangers, helical internal or external tube heat exchangers and double tube heat exchangers, are recommended in many areas. In mass and volume critical applications such as aerospace, aeronautic, marine, biomedical, and computer engineering, the need for weight and volume efficient designs is paramount. Unfortunately these heat exchangers are difficult to be manufactured in the traditional ways, and the heat transfer is restricted by the existing contact thermal resistance between different assembles and the required rough surface is always beyond the control. The use of laser sintering technology in the design and manufacture of some kinds of heat exchangers is presented in this paper. The results show that the laser sintering technology is the feasible way to manufacture some high quality heat exchangers to reach high surface area to volume ratios through the use of unique geometries and some specific heat exchangers can be successfully manufactured, meanwhile the challenges facing the laser sintering are also identified for further investigation.

Direct metal laser sintering, using conformal cooling, for high volume production tooling

Existing techniques to manufacture conventional tool steel inserts for the plastic injection moulding process are expensive and time-consuming. Complex mould inserts, difficult to manufacture with conventional processes, can be produced using Direct Metal Laser Sintering (DMLS) with Maraging tool steel (MS1). MS1 is an additive manufacturing (AM) material made available by Electro Optical Systems (EOS) GmbH. Contrary to material removal processes, DMLS can produce MS1 tool steel inserts directly from Computer-Aided Design (CAD) files suitable for high volume plastic injection moulding. Through DMLS it is possible to create conformal cooling channels inside the MS1 inserts that have advantages in reducing heat rapidly and evenly. This can result in a reduction of cycle times, cost per product as well as improving part quality by eliminating defects such as warpage and heat sinks. This paper will present a comparison between Finite Element Analysis (FEA) simulations of the injection mould inserts with actual mould trails of AM and conventional manufactured inserts. It also includes the design and manufacturing of conventional and DMLS inserts and compares the manufacturing costs and lead times. Using FEA simulations, the design of conformal cooling channels is optimised by comparing the mould temperature of different cooling channel layouts.

3D digital geometry designs for Poland’s syndrome using Magics and Geomagic® Freeform®

Purpose Poland’s syndrome patients often seek medical interventions to improve their aesthetic appearances. Design and manufacturing technologies make it possible to produce custom-made implants for such medical conditions. The purpose of this study was to compare the 3D digital geometries that were designed using Magics and Geomagic® Freeform® for two anonymous case studies of Poland’s syndrome patients. Design/methodology/approach Computed tomography data were acquired and processed in Mimics® to isolate the pectoralis muscles in STL file format. STL files were imported into Magics and Geomagic® Freeform® to design 3D digital geometries. Thereafter, comparative analyses were performed of the respective 3D digital geometries. Findings The angle between the vertical and oblique planes for both sides of the thorax was 6.5° for the female and 14° for the male. The surface areas and volumes of the geometries for the female were smaller than the male. Deviation analyses between the healthy side and reconstructed side of a thorax showed that 73 per cent of the test points for Magics and 78 per cent for Geomagic® Freeform® fell in the nominated tolerance region of >−5 and <+5 mm for the female. For the male, it was 83 per cent for Magics and 88 per cent for Geomagic® Freeform®. Practical implications Geomagic® Freeform® provides a more versatile design environment; however, the STL editor Magics may be an option to design 3D geometries for less intricate and less contoured implants. Originality/value This was a first attempt to compare the 3D geometries for Poland’s syndrome designed with an STL editor to those designed with a computer-aided design program.