 Automated shell manufacturing system for custom hearing aids
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 Rion Co., Ltd (President Kiyotsune Inoue, Headquarters in Kokubunji, Tokyo) has developed an innovative CAD/CAM technique for manufacturing custom hearing aid shells. The shell is a major part of a custom hearing aid, and the new system which will go into production from this spring is expected to significantly streamline the manufacturing process. An outline of the new system is presented below.Rionet is an early adopter of 3-D CAD/CAM, and Rionet hearing aids have always been at the forefront of manufacturing technology. In 1989, the company began its switch to 3-D processing for the design of hearing aids, which was a first for a Japanese manufacturer. In 1995, 3-D CAM was adopted, so that the entire process from product design to mold production for general hearing aids was now 3-D CAD/CAM based. In the 1990s, the demand for custom hearing aids increased tremendously, and now such hearing aids have become the mainstay of our output. By their very mature, custom hearing aids require a number of manual manufacturing steps, which made automatization difficult. Yet, in the interest of manufacturing efficiency and quality control, the development of a computer assisted automated manufacturing system was highly desirable. Therefore a company-internal research project was begun in 1999 with the aim of automating shell production. The project received a major boost in 2000, when the Techno-Aid Foundation provided a 2-year grant from its fostering program for welfare related products. Four patents owned by Rion Co., Ltd formed the basis of the research efforts. The newly developed system is called "Rioted Yumeji Koubou" and covers three major processing steps. 1. Based on a laser scan of the customer's ear mold, the system automatically generates 3-D data. This was made possible by the development of the Rion Complete High Fidelity Scanning Algorithm which allows a faithful, high-speed rendering of the entire ear mold without the need to cut it. 2. Using the war mold data and hearing aid unit data, the system performs layout design and shell shape definition, to arrive at a design that is optimized to match the outer ear canal shape of the customer. For this step, another algorithm was developed which takes the special characteristics of the Japanese anatomy into account. The algorithm is called Rion Japanese Optimized Shell Trimming Algorithm. 3. The shape data for the optimized shell are used to automatically manufacture the shell in a laser-based prototyping system. Compared to conventional production techniques, "Rionet Ymeji Koubou" offers a number of important advantages. High-precision 3-D measurement allows faithful recreation of the outer ear canal in a stable and controlled process. Dependable results can be obtained every time, and matching to the individual ear is improved. During the 3-D CAD layout process, the shape can be efficiently optimized and size can be kept to minimum. The earmold impression shape data and other information are then stored in an electronic database. This eliminates the need for making a new ear impression when the customer requires another hearing aid, for example as a spare or when the original one was lost. As will be apparent from the above outline, "Rionet Yumefi Koubou" is a highly sophisticated system implementing 3-D measurement techniques for parts of the human anatomy and using CAD/CAM-based rapid prototyping to manufacture a precision order-made product. Following monitoring tests to be conducted until the end of 2003, "Rionet Yumeji Koubou" is scheduled to move into full production from 2004 spring. Daily manufacturing capability is 150 units, with a gradual further increase being planned. |
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