Achieving genuinely uniform radial pressure from twelve independent hydraulic cylinders requires careful control system design — simultaneous command issuance alone isn't sufficient when cylinder response characteristics vary slightly across the array.
Multi-Cylinder Synchronisation Architecture
A practical way to manage this is a radial press controller that tracks the state of all twelve cylinders together rather than driving each one open-loop. The controller is initialised with the cylinder count (twelve), a target pressing force of 50 kN, and a synchronisation tolerance of 2 percent, and it keeps running arrays of each cylinder's current position and current force.
At the heart of the controller is a closed-loop synchronisation routine. On every control cycle, it reads the current position and force of all cylinders, then calculates the group's mean position. Any cylinder lagging behind that mean gets a boost to its flow command, while any cylinder running ahead is held back slightly, through a proportional correction scaled by a tunable gain factor. Layered on top of that is a simple proportional controller driving every cylinder toward the 50 kN target force based on its own force error. The two corrections are summed into a single velocity command per cylinder, so each one is simultaneously being pushed toward the target force and pulled back into alignment with its neighbours. This prevents the asymmetric band deformation that a naive simultaneous-command approach would allow.
A companion synchronisation check compares every cylinder's position against the group mean and expresses the worst-case deviation as a percentage. If that deviation stays within the 2 percent tolerance, the system is considered synchronised; if not, the cycle is flagged for quality review.
A full press cycle ties these pieces together: position and force sensors are read on a tight loop, every reading is logged, the synchronisation check runs each iteration, and the velocity commands are sent out to the valve controllers. The cycle ends either when the average cylinder position reaches the 15 mm target or when a ten-second timeout is hit, whichever comes first. At the end, the routine reports the total cycle time, the final positions and forces of every cylinder, the percentage of the cycle during which synchronisation was maintained, the spread between the most- and least-advanced cylinders, and an overall pass/fail flag based on whether synchronisation held for more than 95 percent of the cycle.
Traceability Record Generation
Every pressed shell needs a permanent quality record, so each completed cycle feeds into a traceability record generator. Given the shell's serial number, its caliber specification, the cycle result produced above, and the operator's ID, the generator stamps the record with a UTC timestamp and pulls together the cycle time, the final cylinder positions, the position spread, and the synchronisation quality percentage from that cycle. It then resolves a single overall result field — PASS if the cycle met the quality threshold, or REVIEW REQUIRED if it didn't — giving quality teams a single authoritative record per unit rather than raw sensor logs to interpret by hand.
The Neometrix Copper Band Press implements synchronised radial cylinder control with this class of architecture to maintain consistent band seating quality across high-volume ordnance production runs.
More detail here: https://neometrixgroup.com/products/copper-band-press-for-ammuniton-shell
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