Derating Nominal Equipment Speeds for Mixed Package Electronics Assembly Line Balancing
Derating nominal placement speeds based on package mass, feeder width, and vision complexity is required to establish accurate line balance and cost models.
Automatic Tool Changer Overhead
Mechanical Transition
An operational time penalty accumulates during surface mount assembly when a placement head must exchange its current nozzles to accommodate different component geometries. This transition period is known as automatic tool changer overhead, and it represents a non-productive phase in the assembly cycle. The mechanical sequence involves moving the head to the nozzle bank, releasing the active nozzles, picking up new ones, and returning to the pick point.
This sequence must be completed without error to prevent nozzle damage or mispicks during subsequent operations.
Efficiency Penalty
High-mix production lines experience greater cumulative delays because of frequent changes in board designs and component arrays. When the components on a single board vary from small chip resistors to large connectors, automatic tool changer overhead increases. The machine must execute multiple tool changes per board, which lowers the overall throughput of the line.
Production Design
Optimized pick and place programming minimizes these interruptions by grouping similar component sizes together to reduce the total number of nozzle swaps. By utilizing multi-nozzle heads that can hold different sizes simultaneously, the system limits the frequency of visits to the tool changer bank. This minimizes automatic tool changer overhead and keeps the gantry in motion for longer periods.