5. TITANIUM ANEURYSM CLIPS/BRAIN ELECTRODES/TISSUE EXPANDERS

A. Problem/Issue

A Medical Products Company had various products that needed assistance. The aneurysm clips were a new product to them and they were looking for expertise. They had only chosen a material and had competitor samples that they were evaluating. A larger product development company quote the entire project and they had sticker shock! The brain electrodes were also being upgraded to a more dependable design. The competitor had a much more robust process for joining the electrodes to the connecting lead. The tissue expanders were suffering from problems with the HVAC/humidity system. The controls would not keep a consistent humidity to enable the silicone to cure adequately. Some tackiness was evident in their completed product.

B. Analysis

We looked at the aneurysm clip design and found that a significant amount of research had to be done with many iterations of a prototype. The issues identified were work hardening of the titanium, ultimate material selection, processing parameters for spring-back, and surface characteristics. The development company quoted them a project cost that covered them in case of multiple prototypes. The competition brain electrodes were analyzed with a high power stereomicroscope. Cross sections and analysis of the surfaces indicated a heat fusing process using interior mandrels. No adhesives were used in their design. The tissue expander environment was analyzed with a humidity data logger and found to vary significantly beyond established ranges. The problems were traced to the steam humidification system that served two different cleanrooms.

C. Solution/Results

We located a small prototype shop we had used for years that was willing to accept a time and materials blanket PO and work with us over a period of time. This allowed us to modify the design quickly after multiple forming techniques were used. Forming tools were quickly tried in succession and evaluated without CAD design each time. Much time was saved using this technique. The result was that they were able to introduce the new product in 14 weeks with a significant reduction in development costs. The brain electrode design was modified to use fusing rather than adhesive bonding. The new design was more dependable with better appearance. The tissue expander process greatly improved after we tied one steam humidification system to an updated main cleanroom control system. The return air was then used for the other cleanroom that had less demanding HVAC requirements. The silicone cure tested much better after a consistent environment was maintained.