CMK Corporation

Stress Easing PWB Technology series

Solder crack control PWB / For Automotive

Product & Technology Product & Technology


  • Control the spread of solder crack from thermal shock and improve the connectivity of mounted parts in severe circumstances.


  • Reliability
    Improved solder joint reliability. (Temperature cycle test)
  • Design
    Covers conventional plated through hole PWB.
  • Environment
    Includes Pb free soldering applications.


  • Automotive: Direct engine mounting and actuator unit mounting.
  • Substitute for ceramic PWBs. (lighter weight/lower cost due to organic materials)


Conventional FR-4:Strain occurs between SMT and PCB because of difference of CTE (after Temperature cycle test) -> SEPT Series:The special structure developed by CMK can decline the strain between parts and materials. Suppress the solder crack.

Performance comparison

SEPT(Solder crack resistance:high, Cost:middle), Ceramics(Solder crack resistance:high, Cost:high), FR-4(Solder crack resistance:low, Cost:low), High Tg FR-4(Solder crack resistance:middle, Cost:middle)

What's SEPT

Cost performance:It succeed in balancing solder crack resistance and cost in high level
Substitute for ceramics:It realizes maximum solder crack resistance as an organic PWB