Challenge

• Client was launching a new “drive by wire” product, consisting of a sensor module and pedal
• Given the safety-critical nature of the part, a risk-free process was required that was capable of part tracking, documentation and extensive validation
• High risk processes included precision PCB placement, PCB-sensor solder bond, PCB heat stake, and rotor armature defect inspection
• It was impossible to do manual final pedal-sensor calibration repeatably
• Production was on a daily build-to-order basis and required design for flexibility

Solution

• Two lines were designed, one for the PCB load and the second for the armature load, final assembly and functional test
• Machine vision was used extensively to inspect for PCB defect after singulation and for precision PCB alignment (to 20µ)
• Commercial die bonders were integrated, with traffic control functions and accumulation before each to maximize bonder utilization
• Batch countdown feature were implemented to assist build-to-order
• A modular line design was employed to providing maximum flexibility and expandability
• Final test involved verifying output for each assembled product for sensor linearity, hysteresis, and correlation with a reference encoder

Technologies integrated

• Precision machine vision for robotic guidance and solder inspection
• System integration with precision standard die bonders
• System design for serviceability, flexibility and expandability
• Fully documented in-line test and part tracking