The Rapid Template Fabrication Process for Producing a LIGA Heat Exchanger Bonded to a Mechanical Seal

• Main Author: Tuma, Jason Patrick
• Other Authors: Kevin Kelly
• Format: Others
• Language: en
• Published: LSU 2003
• Subjects: Mechanical Engineering
• Online Access: http://etd.lsu.edu/docs/available/etd-0708103-111405/

Mechanical seals are widely used in the chemical processing, aerospace, and automotive, industries. When a mechanical seal fails, considerable cost is typically involved in replacing the seal. Most seal failures are a result of high temperatures generated by frictional heating. Effectively removing the heat generated would significantly increase the mechanical seals work life and lead to significant monetary savings. One method of removing the heat generated is bonding an effective LIGA micro heat exchanger to the mechanical seal and forcing coolant through the heat exchanger. Previous work on this subject revealed promising results, especially for micro heat exchangers with microstructures taller than 500 mm. This previous work relied on PMMA templates that were lithographically patterned at CAMD by a synchrotron radiation source. These templates were 500 mm thick and patterned with an electron energy of 1.4 GeV. In this effort, 1000 mm tall templates were desired and had to be produced at CAMDs current electron energy of 1.3 GeV. The combination of thicker templates and lower electron energy made numerous lithographically patterned PMMA templates impractical. Therefore, a new template fabrication process was developed that only required one lithographically pattern template. Another issue of the previous work was that the adhesion strength of the micro heat exchanger was relatively weak and needed to be improved. The purpose of this thesis is to present how a fabrication process consisting of silicone casting, machine wax casting, and electroforming can result in producing a LIGA heat exchanger bonded to a mechanical seal with the single use of CAMDs synchrotron radiation source. This thesis will also state how the adhesion between the micro heat exchanger and seal was strengthened through surface treatments and electroplating conditions. The surface treatments included the use of sandblasting, activation, and Woods strike procedure. The electroplating conditions included setting the electroforming surface at an inclined orientation and applying a relatively low current density of 5 mA/cm2 to the electroforming surface.