Inconsistent Fill Volumes During Start-Stop-Start Operation

In addition to continuous operation, Pacific filling machines maintain excellent accuracy during stop-start operation.

In our last issue, we discussed how to address under fills. In this months issue, we address over fills during stop-start operation.

If this is something you experience, use the following list of potential causes and solutions to troubleshoot and easily adjust the filling machine back to its original operating condition:

  • The time-delay for the turret start rotation is too long. This allows the fill nozzles to drip/drain before the filling turret starts to rotate.
    Solution: Decrease the time in seconds on the relay-timer (non-PLC fillers) or the HMI Configuration Screen (PLC fillers) to ensure the turret starts to rotate right after all the fill nozzles are fully open.
  • The time-delay for the nozzle close on a machine stop is too long. This allows the nozzles to drain after the turret comes to a complete stop.
    Solution: Decrease the time in seconds on the zero speed timer (non-PLC fillers) or the HMI Configuration Screen (PLC fillers) to ensure that the filling nozzles close as soon as the filling turret comes to a complete stop.
  • The turret ramp up and ramp down speed is too gradual.
    Solution: Set the turret drive acceleration and deceleration time to 2 seconds or less. Note that the turret acceleration and deceleration times should also be set to the same value.
  • For an individual station (or stations) that are always high, the filling nozzle or plunger is not operating properly.
    Solution: Re-gauge the plunger stroke. If this does not solve the problem, replace the plunger and/or filling nozzle. If the problem still persists, rebuild the air cylinder.
  • One or more filling nozzles within the fill zone do not open before the machine starts to rotate or close after the machine stops.
    Solution: Ensure that the fill valve air regulator is set to at least 30 PSI. Also confirm that the air manifold, air cylinder lines, and air cylinder seals are not leaking excessively. Finally, confirm that the 4-way valve and solenoid are in good working order.
  • There is excessive pressure at the inlet of the filling turret.
    Solution: Ensure that the drive system is in good operating condition and that the pump does not continue to run once the filling turret stops and the valves close.
  • The product tank level is too high (Only applies to low viscosity products).
    Solution: Install a tank level sensor and configure to maintain a tank level of +/- 6″ or better.
  • Erratic rotation of the filling turret.
    Solution: Verify the main spindle bearings are in good condition. Inspect the filling turret drive system for worn parts.
  • Erratic rotation of the pump.
    Solution: Verify that the pump and the pump drive system are good working condition.

Also note that many of the above items can be added to your semi-annual preventative maintenance check lists in order to ensure that your filling machine does not produce over fills on stop/start operation.

For additional information or answers to other filling machine questions, contact Tommy Rawson at