High Reliability Pb-Free Printed Circuit Board Assembly

2010 ◽  
Vol 450 ◽  
pp. 9-12
Author(s):  
S.D.T. Weller ◽  
I.P. Jones ◽  
Ian M. Fox ◽  
Terry Hirst
Keyword(s):  
Process Parameters ◽  
Printed Circuit Board ◽  
High Reliability ◽  
Electroless Nickel ◽  
Cycling Performance ◽  
Circuit Board ◽  
Optimum Process ◽  
Printed Circuit Board Assembly ◽  
Circuit Board Assembly ◽  
Lead Free Solders

The solderability and reliability of SnAgCu and SnAgCuSbBiNi lead-free solders were assessed against SnPbAg solder on a range of PCB finishes. A novel solderability test has been developed to assess the solder system’s ability to realign when a deliberately inaccurate solder stencil printing process was applied. This has shown to be an excellent way to compare PCB finishes and solders, as well as define process parameters. Electroless Nickel Immersion Gold (ENIG) finish proved to give the best solderability and the optimum process parameters were also found. SnPbAg solder has shown superior thermal cycling performance compared to SnAgCu.

Kinetics of Cavity Growth In Solder Joints During Thermal Cycle

1984 ◽  
Vol 40 ◽  
Author(s):  
Donald S. Stone ◽  
Thomas R. Homa ◽  
Che-Yu Li
Keyword(s):  
Printed Circuit Board ◽  
Solder Joints ◽  
Cavity Growth ◽  
Circuit Board ◽  
Printed Circuit Board Assembly ◽  
State Variable ◽  
Circuit Board Assembly ◽  
Variable Equation ◽  
Chip Carrier ◽  
Kinetics Of

AbstractGrain boundary cavity growth in solder joints during thermal fatigue is analyzed. The stress cycle profile is estimated based on a geometrically simplified model of a ceramic chip carrier - printed circuit board assembly and a state variable equation for plastic flow in the solder.

A Robot Learning from Demonstration Framework for Skillful Small Parts Assembly

2021 ◽  
Author(s):  
Haopeng Hu ◽  
Xiansheng Yang ◽  
Yunjiang Lou
Keyword(s):  
Printed Circuit Board ◽  
Impedance Control ◽  
Circuit Board ◽  
Batch Size ◽  
Learning From Demonstration ◽  
Printed Circuit Board Assembly ◽  
Motion Error ◽  
Circuit Board Assembly ◽  
Position Data ◽  
Small Parts

Abstract Increasing demand for higher production flexibility and smaller production batch size pushes the development of manufacturing expertise towards robotic solutions with fast setup and reprogram capability. Aiming to facilitate assembly lines with robots, the learning from demonstration (LfD) paradigm has attracted attention. A robot LfD framework designed for skillful small parts assembly applications is developed, which takes position, orientation and wrench demonstration data into consideration while utilizes impedance control to deal with the motion error. In view of constraints in industrial assembly applications, we propose a robot LfD framework where policy learning is carried out with separated assembly demonstration data to avoid potential under-fitting problem. With the proposed assembly policies, reference orientation and wrench trajectories are generated as well as coupled with the position data to boost their generalization and robust performance. Effectiveness of the proposed LfD framework is validated by a printed circuit board assembly experiment with a 7-DOF torque-controlled robot.

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