Abstract:
Diffusion bonding cycle times can be a large cost factor in the production of metal
microchannel devices. The challenge is to significantly minimize this cost by reducing
the bonding cycle time through rapid and uniform heating and cooling within the bonding
process. Heating rates in diffusion bonding processes are typically limited by the need to
minimize internal thermal gradients during bonding. A novel method is described which
takes advantage of the internal flow passages within microchannel devices for convective
heat transfer during the bonding process. The internal convective heating (ICH) technique
makes use of heated inert gas to provide the microchannel assembly with rapid and
uniform heat input. The first paper in this thesis manuscript investigates the feasibility of
the ICH method by studying leakage rates and thermal requirements within the process.
The second paper provides results and a statistical analysis demonstrating that the ICH
technique is feasible and capable of shorter bonding cycle times than traditional vacuum
hot press methods. Results suggest that this may be due to smaller thermal gradients
within microchannel devices during the ICH bonding cycle. Appendices are provided at
the end of this manuscript providing the raw data to support these findings.
