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High precision glass moulding


Goal: "Develop a manufacturing method for optical components, e.i. high precision biaspherical lenses from optical glass materials, at high accuracy and low cost" Projected application areas: 1. Optoelectronics (optical signal processing) - CD (audio, video, ROM), Fibre optical/communication, Barcode readers, Optical Measurement systems. 2. Optics for image forming - Cameras, Spectacles, Telescopes, Microscopes, etc. Industrial objective: Owing to the development of CAE in optical engineering, very sophisticated optical designs can be made. In many cases, the aim is to reduce size and cost of optical systems. For realisation, the optical engineer has to deal with biaspherical lenses. Several methods are available to manufacture biaspherical lenses, such as: 1. grinding and polishing 2. replication technology 3. injection moulding (plastic lenses) 4. pressing technology. As usual there are advantages and disadvantages connected to these processes, such as: a. accurate but expensive b. very difficult for biaspheres and also too expensive c. optical quality limited and low cost demanding large series d. relative overall high costs. The objective as described under "GOAL" requires a new technical approach. Technical objectives To develop a non-isothemm closed form precision pressing technology to cope with quality, cycle time and cost requirements. This will need development in the following three (3) technology areas: 1. the heating process 2. the forming process 3. the cooling process Ad 1 The heating process has two stages. 1.1 a conventional pre-heating process and 1.2 a dedicated microwave heating process for the material needed to get in a controlled manner the conditions for the closed non-isotherm form pressing technology. Ad 2 The forming process needs development in two areas: 2.1 the mould and the pressing equipment respectively to obtain the required lifetime of the moulds and the surface quality during the lifetime and 2.2 the press design related to the sub-micron product tolerances on the dimensions. Ad 3 The cooling process in order to secure the lenses are tension free. Additional relevant remarks: 1. The pre-heating of the material (glass) mass must care of a specified surface quality. The dielectric loss-factor of glass is direct proportional to the temperature of the mass. 2. During the pressing process the pressing tool temperature must, within close tolerances, be the transformation temperature (Tg) of the glass material or at equivalent level for the thermoplastics.


6026 AA Maarheeze

Participants (1)

Hauzer Coating Centrum BV
5916 PB Venlo