When reject rates on a choc-ice packaging line began to climb, the company needed an engineering solution. The resulting scheme, featuring Control Techniques Drives, has cut rejects by 90%.

Decreasing accuracy and a drift on the synchronisation between conveyor speeds and the actions on the ice cream wrapping machine resulted in increasing reject rates. The waste was a mixture of ice cream and packaging, which had to be sent to land-fill, creating an additional cost on top of the lost production.

Rewinds & J. Windsor, a Control Techniques drives reseller, analysed the problem and designed a solution based on six servo drives. The key was precise synchronisation between the drives themselves and the choc-ice production line. Six Control Techniques ‘Maxi Maestro’ high performance DC servo amplifiers were chosen to control the lane/crimping drives, another for the wrapper feeder and a 7.5 kW Unidrive SP for the jaw drive. The on-board SM application module provided complete programming for the wrapping machine through SyPT programming software.

“The key to this project is the functionality of the Unidrive SP,” explained Rewinds & J. Windsor’s Project Manager, Mark Swayne. “We used the SM applications module as the programming platform, using Control Techniques’ SyPT programming software. This gave us the performance of a level 3 PLC, which greatly simplified the project, eliminated the need for a PLC and made the solution highly cost-effective. Now, any length of product can be accommodated by simple parameter adjustments and the whole system is digitally locked into precise synchronism.” Since the ice cream wrapping machine has been refurbished, rejects due to synchronism faults have been totally eliminated, with the reject rate on the line as a whole down by a massive 90%.

This has boosted line production as waste has been cut drastically and, taking into account savings in production, plus the reduced costs in sending waste to landfill, payback on this project was even sooner than anticipated.