Recording the Fastener Sequence for a Power Module Baseplate

A final torque value does not describe how a multi-fastener power module was seated. Screw order, intermediate stages and assembly support can be part of the product’s mounting requirements. Capture the complete approved sequence so the finished result can be traced to the method that produced it.

Use the specific module instructions

Infineon’s HybridPACK Drive G2 mounting instructions distinguish screw types and define order and clamping considerations for that module. This illustrates why a generic tighten-all-screws instruction is incomplete; its particular sequence and values should not be transferred to unrelated modules.

Identify the module, cooler material, fasteners and any seal or interface material. Record the current supplier instructions that govern this combination before selecting a tool program.

Give every fastening position an identity

Use a map that remains unambiguous when the assembly is rotated at the workstation. An operator-side label can become confusing if the fixture orientation changes.

Verify the real tool path

Confirm that the driver can reach each fastener without loading nearby components or losing its intended alignment. Include the populated PCB and production fixture in this review. An empty mechanical mockup may leave access problems undiscovered.

For example, a driver may reach the required torque after its socket contacts a neighboring feature. That event deserves investigation even when the tool displays a pass because the physical operation may differ from the qualified one.

Keep screw-type changes visible. A different thread-forming or prethreaded arrangement can require a different interpretation of tool data and a different permitted assembly sequence.

Handle interruptions explicitly

Define the response to a missed position, tool fault or interrupted cycle. Do not restart a completed sequence indiscriminately or add an extra tightening pass unless the supplier-approved process allows it.

Retain enough information to identify which positions were completed before the interruption. This supports a controlled disposition instead of relying on paint marks or memory as the only record.

After mounting, verify the product’s required seating, leak and functional conditions. A completed tool program is process evidence; it does not replace every final assembly check.

The cooler inspection guide covers the interface before closure, while heat-stake review addresses another fastening operation that may follow in an approved assembly route.