The Challenge
A manufacturer of pneumatic assembly tools had eight assembly stations that occasionally stopped mid-cycle — air-powered tools losing pressure, clamping fixtures releasing, and automated test stations failing mid-sequence. The interruptions lasted 2–8 seconds and occurred several times per shift. The maintenance team had replaced two regulators and inspected the compressors without identifying the cause.
The interruptions were demand spikes — brief, high-volume draws from multiple stations simultaneously that overwhelmed the distribution system's ability to maintain pressure. When three assembly stations entered their clamping cycles at the same moment, air demand spiked to 160% of normal flow for approximately 3 seconds. The distribution network was sized for average demand, not peak simultaneous demand — a common design condition that becomes a problem only at specific coincidence frequencies.
What Changed
High-frequency pressure and flow monitoring at all eight assembly stations. Demand spike detection and correlation with line cycle data to identify simultaneous demand events.
The monitoring captured 47 spike events in the first three days — each lasting 2–6 seconds and correlating with simultaneous clamping cycles at adjacent stations. The solution was demand sequencing: assembly station clamping cycles were staggered by 1.8 seconds through PLC reprogramming, eliminating simultaneous demand events entirely. A 500-litre receiver tank was added as a buffer for residual spikes.
Results
elimination of stoppage downtime
receiver tank only — PLC change was zero cost
“Not all compressed air problems are supply problems. Demand spike analysis reveals cases where the issue is not how much air is being generated but how it is being consumed — specifically, whether multiple high-demand events are coinciding in time. Solving a demand problem with additional supply capacity is expensive and ineffective; solving it with demand sequencing is cheap and immediate.”