An 8-station automated assembly line for safety-critical munitions requires a quality gate architecture where each station must positively confirm its operation before the line indexes to the next position.
The fundamental design principle: the line does not advance until every active station confirms its operation complete and within tolerance. This is implemented as a distributed confirmation architecture — each station has its own local controller (or direct PLC I/O block) that executes the station function and returns one of three signals to the main sequence controller: DONE (completed within tolerance, advance permitted), REJECT (completed but out of tolerance, divert this unit and advance), or FAULT (station cannot complete — halt line for operator intervention).
The main sequence controller — Mitsubishi FX5U PLC in the Neometrix design — manages line indexing, tracks each shell position across all 8 stations, maintains the rejection map (knowing which position currently holds a rejected unit), and ensures rejected units are actively diverted at the appropriate divert point rather than advancing to completion.
For the gravimetric fill station specifically, the local fill controller executes a dispense-and-weigh loop: dispense a small increment of composition, measure accumulated weight, compare against target curve, continue or stop dispensing based on the comparison. This real-time feedback compensates for powder flow rate variation within a single fill cycle — not just between batches.
The torque station uses servo drive feedback to control both torque and angle: the closure is run to a specified torque value, with the rotation angle from first contact to final torque logged as a secondary quality indicator. An unusually large or small angle at final torque indicates a thread or dimensional anomaly that may not show up in the torque value alone.
The batch traceability database record is built up incrementally as each shell progresses through the line — fill weight added at station 3, igniter confirmations at station 5, torque at station 7, QR code at station 8 — with the reject flag updated immediately if any station triggers a rejection. The complete record exists in the database before the shell reaches the output end of the line.
Product page: neometrixgroup.com/products/stun-shell-composition-filling-&-assembling-machine
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