Production process development of adhesive dispensing with focus on cost and quality.
Abstract: In our society, digital cameras are used for a countless number of different purposes. There are many components going in to making such a complex product but one could argue that the camera sensor and lens make out the heart of a digital camera. Axis Communications AB, founded in 1984, is a Swedish company which pioneered and specialize in digital network cameras. In 1996 Axis delivered the first network camera to the market and has remained a leading actor in the field ever since. The thesis focus on one of the fixed focus cameras in Axis assortment called Hedwig. In Hedwig, the lens and sensor are bonded using adhesive were the dispensing of the adhesive both drive costs and quality due to high variations in precision and quantity. The thesis focuses on the adhesive dispensing process and assembly of the optical module in Hedwig. The focus areas are; minimizing the use of adhesive, controlling the bonding process for repeatable result, investigating if a new adhesive can be introduced and to analyze effects on cost and quality. To be able to analyze this, Axis acquired a high precision automated dispensing system. The system, if fully implemented on all production sites is considered a big investment and hence a deep production cost analysis was done to see how the production cost is affected by the automated system. To start, the current production has been mapped and data and information gathered. The authors visited the production and analyzed the current production. The current production generates variable quality and through six sigma analysis it was gathered that the sigma levels were in general at level 2, except in one process step. The module cost was uncertain due to lack of existing economic data and production statistics relevant for the optical module. Analysis of current production shows that adhesive amount varies a lot between modules and excessive use to compensate for inaccuracy in the manual dispensing process. All parts are weighed to assure adhesive amount is within allowed interval. Push-out tests are used to validate that the curing is done correctly. It makes out 6,8% of the calculated module cost. A series of test were performed using the new automated system to see what results could be achieved. The dispenser tolerance was high enough to allow the adhesive weighing to completely be removed. Test results conclude that the quantity of adhesive used have small effect on the quality. On the other hand, the position and curing has great impact on the quality of the bond. From the tests, the sigma levels were all increased to 4, resulting in a theoretical yield greater than 99,7%. It has been shown that an automated dispenser could efficiently be introduced into the current production. Production cost can be lowered by as much as 13% if the all the proposed cost savers were implemented. The cost reduction is due to the removal of unnecessary production steps, decreasing the use of adhesive and removing the push out testing.
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