MIM Case Study – Contact
• Application: Medical Electronics
• Functional Requirements:
Structurally intact; low thermal
expansion
• Competing Technology: Stamped
flat base, welded wire for posts
• Overall Size:
– Base 0.25 mm thick, 1.25 mm
square
– Posts 0.5 mm diameter x 1.2
mm tall
• Part Weight: 0.007 grams
• Material: MIM-Alloy 42,
subsequent Ni & Au plating
MIM Case Study – Contact
-
Small Part!
MIM to replace existing
process:
- Base stamped out of goldplated sheet
- Posts made from wire
form welded to base
• - MIM seen as a cost savings
with better consistency
Key Characteristics- Contact
One of two posts intact
No cracks
Minimal flash
Posts strong enough to
not deflect when wire is
welded to posts; center
support section added
Parts needs to be solderable to the circuit
board; bumps molded in to allow flow of
solder under part
MIM Case Study – Contact
• Why MIM?
– More consistent position of posts
– Connection of the posts to the base is more reliable in a onepiece MIM part than the welded wire to the stamped base.
– MIM Alloy 42 consistent with expected material properties
– Economics of MIM regarding CAPEX, part price significantly
better than stamp & weld
– MIM a more repeatable for high-volume technology for this
application
MIM Case Study – Contact