Papers by Keyword: Rapid Tooling (RT)

Abstract: This paper presents an integrated approach for denture (dental prosthesis) manufacturing process by integrating information from patient denture requirement, design flow and manufacturing activities. The aim is to produce a removable complete denture with high degree of precision, good quality of denture and rapid fabrication process. The method includes data acquisition, design process and teeth assembly of the denture that reduces the dependency on experienced craftsmen and reduces the time consumption in denture processing chain. The system also aims to reduce patient visiting times and consequently reduces the expenses. The basic system has been developed at the Faculty of Mechanical and Manufacturing Engineering, UTHM with the cooperation of the School of Dental Sciences, USM and Klinik Pergigian Batu Pahat, Johor. By implementing the integrated system, denture can be produced using centralize manufacturing facilities of several dental clinics and provide denture replacement services which can be delivered in 24hrs. Although the basic system has been tested and found very satisfactory result, there are development works and improvements are still needed in order for the system ready for commercialization.

Abstract: This paper presents the research on manufacturing for full denture components. The aim is to develop a new manufacturing procedure for the removal full denture by integrating the techniques used in the Advanced Manufacturing Technology (AMT). The 3D-ATOS scanning system was used to obtain the surface data of the denture teeth sets, the edentulous models and the rims for patient. The surface quality of the digitized images was further refined by using Geomagic Studio 10 and the complete model of the denture components were prepared using Solid Work CAD application tool. A set of library for teeth was developed in the CAD system which includes the reference lines and points for setup and assembly process. The master models of the full denture were produced using MJM rapid prototyping system. The full denture was fabricated using acrylic resin (Vertex Castavaria) material using vacuum casting technique. The finish denture was then tested on patient and found satisfactory with good fitting accuracy as compared to the conventional denture. The use of vacuum casting procedure also has improved about 30% flexural strength as compared to the conventional technique (compression flask).

Abstract: As a new fabrication technique based on rapid prototyping, vacuum casting process can be especially used in the stage of products development. In this paper, a self-designed and made silicone mould was used to study process of vacuum casting panel part. ProCAST software was adopted to analyze the melt flowing behavior and effects of processing parameters. The key vacuum casting parameters, such as mould temperature, melt temperature, degree of vacuum and coefficient of heat transfer, on the effects of the filling rate of polymer melt were emphasized to be numerical studied. The results indicate that mould temperature and coefficient of heat transfer have the most important influence on quality of the formed panel.

Abstract: We present an approach that combines Computer Tomography (CT), reverse engineering (RE) and rapid prototyping (RP) for individual implant production in maxillofacial surgery. 3D acquisition of the patient’s skull is performed, after acquisition of data; an individual computer-based 3D model of the bony defect is generated. These data are transferred into RE software to create the implant using a computer-aided design (CAD) model, which is directed into the RP machine for the production of the physical model. The implant is then directly used in investment casting such as “Quick Cast” pattern to produce the titanium model. In the clinical reports presented here, reconstructions of one patient with mandible bone defects were performed using this method. The custom prostheses perfectly fit the defects during the operations, and surgery time was reduced.

Abstract: The mixing blades of concrete mixer, is a relatively complex spatial surface, which is difficult to manufacture. The high cost of traditional mold making does not apply to new product development and experimental studies. So, this paper presents a rapid manufacture method of balde mold, which using the UG software for blade parametric design, and then sub-cutting it to calculate the section coordinates. According to the coordinates, the steel plate had been cut and welded into a mold, through which, the blades can be pressed. Because of its convenient and low-cost, the method is particularly applicable to the occasions of experimental research.

Abstract: To improve the maxillofacial surgery outcome, modern manufacturing methods such as rapid prototyping (RP), reverse engineering (RE) and medical imaging data have been utilised to manufacture custom-made prostheses after previous failed reconstructive surgery. After acquisition of data, an individual computer-based 3D model of the bony defect was generated and transferred into RE software to create the prosthesis CAD model. Then the physical model of the prosthesis was fabricated by RP technique. The precise fit of the prosthesis was evaluated using the prosthesis and skull models. The prosthesis was then directly used in investment casting such as “Quick Cast” pattern to produce the titanium model. In the clinical reports presented here, reconstructions of one patient with large mandible bone defects were performed using this method. The custom prostheses perfectly fit the defects during the operations, and surgery time was reduced. These cases showed that the prefabrication of a prosthesis using modern manufacturing technology is an effective method for maxillofacial defect reconstruction.

Abstract: Thousands of people are affected by the newest achievements of material science and manufacturing technologies each year in the form of biomedical implants. In this field, the aim of developement is to create individual implants to satisfy the geometrical and adapting requirements of the patient. This manufacturing process has been recently improved by shortening the cycle time and using cost effective methods. Biocompatible thermoplastic polymers can be shaped with hot pressing technique. Rapid Tooling was used to create a forming tool for manufacturing process. 3D Printing was used to fabricate the computer generated forming tool. This tool was reinforced by infiltrating it with an epoxy resin. Different epoxy resins were examined to secure the best mechanical properties of this tool. Then the reinforced tool was used for hot pressing of the biocompatible thermoplastic polymer, poly(ε-caprolactone).

Abstract: Nowadays the need for faster development cycle can be found all over in the industry. Rapid prototyping has become a common tool in product development, but available materials in these technologies can not always substitute the materials needed for product. Rapid tooling makes it possible to produce a small series of a product with the same technology and materials as that of the final product. In our work we have used the Polyjet technology (Objet Geometries Ltd.) to produce mold for the injection molding of biodegradable interference screws. Our goal was to produce enough quantity of interference screws for biomechanical measurements, with a technology that is more cost efficient than selective laser sintering (SLS). Two types of mold materials were tested. The first mold was prepared from Fullcure720, an acrylic based, UV curing resin on an Object ALARIS machine. The second mold was prepared with resin casting from AH-12/T-58 (100:40) epoxy resin filled with 25 m% Al2O3 powder. For injection molding Natureworks 3051D polylactide (PLA) was used. After injection molding the weight and the geometry of the screws were measured. The results showed that the molds can withstand 5-10 injection cycles, and the screws manufactured meet the requirements for biomechanical tests on porcine knees.

Abstract: This paper deals with the reduction of residual stress induced during the selective laser melting with a mixture of ferrous based metal powder. To evaluate the residual stresses induced during layered manufacturing processes, a strain gauge is attached on the bottom face of the base plate. The residual stress within the consolidated structure is calculated from the amount of strain change measured by the strain gauge when the consolidated structure is cut with an end mill. The influences of base plate thickness and consolidated structure height on the residual stresses are investigated. In addition, the effect of pre-heating and post heating by a laser beam irradiation are evaluated. The results showed that the deformation of the base plate increased with the increase of the consolidated layer and the decrease of base plate thickness, and the deformation was flattened when the consolidated structure was completely removed with the end mill. The deformation was related to the induced residual stresses. The residual stress distribution within the consolidated structure in the z direction was extremely large at the top layer of the structure and the boundary between the base plate and consolidated structure. The residual stress at the first layer of the structure decreased when the base plate was heated before consolidating the deposited powder. The residual stresses decreased when each of the consolidated layers was repeatedly heated by the laser beam irradiation.

Abstract: The development and manufacturing speed of products have become the focus of competition, at the same time the manufacturing not only has to meet user’s constantly changing needs, but also has to have a relatively strong flexibility of manufacturing technologies. Additive processes can be defined as rapid prototyping, which generate parts (prototyping) in a layered way, is gaining progress by rapid tools (RT) and rapid manufacturing (RM) for production of functional parts in small quantity and even one product without adding the cost becomes more and more critical. The paper describes which mechanism of stereo lithography (SLA) rapid prototyping can be applied to rapid tooling for production complex geometries for long-term consistency. Moreover, the paper demonstrates the application examples of rapid tooling fulfilling the required physical, mechanical and geometrical properties in precision deformation and casting process. The most notable advantage is the integration of production design and digital manufacturing within the product development period.