title: Laser bonded microjoints between titanium and polyimide for applications in medical implants.
abstract: Bioencapsulation of medical implant devices, and neural implant devices in particular, requires development of reliable hermetic joints between packaging materials that are often dissimilar. Titanium-polyimide is one of the biocompatible material systems, which are of interest to our research groups at Wayne State University and Fraunhofer USA. We have found processing conditions for successful joining of titanium with polyimide using near-infrared diode lasers or fiber lasers along transmission bonding lines with widths ranging from 200 to 300 microm. Laser powers of 2.2 and 3.8 W were used to create these joints. Laser-joined samples were tested in a microtester under tensile loading to determine joint strengths. In addition, finite element analysis (FEA) was conducted to understand the stress distribution within the bond area under tensile loading. The FEA model provides a full-field stress distribution in and around the joint that cause eventual failure. Results from the investigation provide an initial approach to characterize laser-fabricated microjoints between dissimilar materials that can be potentially used in optimization of bio-encapsulation design.
authors.affiliation: Department of Mechanical Engineering, Wayne State University, Detroit, Michigan, USA.
authors.forename: A
authors.initials: A
authors.lastname: Mian
authors.forename: G
authors.initials: G
authors.lastname: Newaz
authors.forename: L
authors.initials: L
authors.lastname: Vendra
authors.forename: N
authors.initials: N
authors.lastname: Rahman
authors.forename: D G
authors.initials: DG
authors.lastname: Georgiev
authors.forename: G
authors.initials: G
authors.lastname: Auner
authors.forename: R
authors.initials: R
authors.lastname: Witte
authors.forename: H
authors.initials: H
authors.lastname: Herfurth
mesh_terms: D019544:Equipment Failure Analysis; D020342:Finite Element Analysis; D007094:Imides / Q000737:chemistry*; D007259:Infrared Rays; D007595:Joint Prosthesis; D007834:Lasers; D008422:Materials Testing / Q000379:methods; D008853:Microscopy; D011108:Polymers / Q000737:chemistry*; D019736:Prostheses and Implants; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength; D014025:Titanium / Q000737:chemistry*; D014965:X-Rays
chemical_list: D007094:Imides; D011108:Polymers; D014025:Titanium
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