Plastic bottle maker benefits from higher throughput and lower energy use with drive-motor package

2017-08-28 - Drive energy appraisal leads to 60 percent fall in energy costs and 30 percent higher output for plastic container manufacturer.

  • 30 % increase in usable bottles
  • 60 % fall in energy costs on blow molding machine
  • Saved $356,000 cost of upgrading from 600kVA to 800 kVA electrical supply to enable additional all-electric blow molding machine to be installed
  • Saved $44,000 cost of refurbishing pump and drive with same technology
  • Improved working environment as SynRM runs quieter than standard AC motors
PrimePac decided to replace the old hydraulic motor used to run an extruder on a blow molder as it was not operating efficiently and speed holding was erratic. The new solution was ABB SynRM and ACS880 variable frequency drive.PrimePac decided to replace the old hydraulic motor used to run an extruder on a blow molder as it was not operating efficiently and speed holding was erratic. The new solution was ABB SynRM and ACS880 variable frequency drive.


When a 23 year old plastic bottle blow molding machine was failing to deliver its proper output, Northern Ireland’s PrimePac faced a dilemma. The machine uses a hydraulic motor to run an extruder on a blow molder. Because it had spent its life running 24 hours a day, five days a week, its motor was operating inefficiently and suffered poor speed holding properties.

Previously it took 10 seconds to create a bottle. In recent years this had extended to 12 seconds. The extruder was also creating long tails of excess plastic that needed to be trimmed and recycled in a very energy intensive process.

PrimePac was quoted $44,000 to refurbish the machine. This work would have kept it running but with the same technology and still using the same amount of energy. This was a critical factor as the site’s 600 kVA electrical capacity was at its limit. Therefore, plans to introduce an additional all-electric injection molding machine to produce a new type of medicine bottle would require an investment of over $300,000 in upgrading the electrical supply.

Energy appraisal reveals opportunities
To find an alternative, PrimePac asked its energy and automation partner, Advantage Control Limited, an ABB authorized value provider, to carry out an energy appraisal of the existing machine.

Over a week, its energy use was measured against an existing all-electric model. This proved that when making bottles of the same size and weight the old machine consumed significantly more energy. Its power use was also erratic and consumption was high due to the hydraulic pack requiring extra torque on start up.

Furthermore, the old blow molding machine’s speed regulation was causing issues that resulted in a poorly formed bottle.

ACS880-01 drive can be ordered with IP55 enclosure which enables installation close to the process.ACS880-01 drive can be ordered with IP55 enclosure which enables installation close to the process.

It was decided that a package comprising ABB’s synchronous reluctance motor (SynRM) and an ACS880 drive would not only reduce electricity use, improve speed holding and the quality and consistency of the finished product but would also free electrical capacity that could be used to power the new injection molding machine.

Energy saving
Following the installation, logged data revealed a 60 percent energy saving. Even with the modifications that were required to the machine, the $11,000 purchase of the 55 kW, IE4 SynRM package is expected to payback in under 12 months.

The hydraulic pack consumed 68 kW, whereas after installing the SynRM package, power use is constant at 26 kW: a 60 percent energy saving. PrimePac was able to fit a new line without exceeding power restrictions in its electricity supply.The hydraulic pack consumed 68 kW, whereas after installing the SynRM package, power use is constant at 26 kW: a 60 percent energy saving. PrimePac was able to fit a new line without exceeding power restrictions in its electricity supply.


Speed regulation critical to success
The ABB industrial drive features direct torque control (DTC) that has provided a real step forward in terms of the actual speed holding on the drive. It is now much more accurate, leading to a consistent length and weight of plastic through the extruder and into the mold. This means less wastage – no more long tails - as there is no product overspill.

The gained energy savings made it possible to install a new extruder without upgrading the 600 kVA electrical supply.The gained energy savings made it possible to install a new extruder without upgrading the 600 kVA electrical supply.

Improved throughput
Previously, only 63 percent of extrusions actually became bottles. This was due to the erratic and sporadic movement of the machine. Following installation of the SynRM package, 96 percent of extrusions turn into bottles. The missing 4 percent is purely due to when the machine is ramping down.

Because there is less waste, the 18.5 kW granulator used to recycle the waste is used less often. This has saved around 5 percent of the energy on its own.

PrimePac Limited specializes in continuous extrusion blow molding to manufacture a range of plastic bottles, containers and jars together with closures, pumps, sprays and various accessories.PrimePac Limited specializes in continuous extrusion blow molding to manufacture a range of plastic bottles, containers and jars together with closures, pumps, sprays and various accessories.

Other benefits include a significant reduction in noise and vibration, and operators can now hear what their colleagues are saying while standing alongside the motor.

Beating expectations
Clifford Craig, Engineering Manager at PrimePac Ltd, said:

“We couldn’t install a new electric machine because we didn’t have the available power. But with the 60 percent energy saving we achieved on the old blow molder we have been able to install another new all-electric injection molding machine. This is beyond our wildest ambitions. We have managed to massively increase our production, just by installing one SynRM package from ABB.”

The SynRM package offered PrimePac a payback period of less than half a year.The SynRM package offered PrimePac a payback period of less than half a year.




About ABB
ABB (ABBN: SIX Swiss Ex) is a pioneering technology leader in electrification products, robotics and motion, industrial automation and power grids, serving customers in utilities, industry and transport & infrastructure globally. Continuing more than a 125-year history of innovation, ABB today is writing the future of industrial digitalization and driving the Energy and Fourth Industrial Revolutions. ABB operates in more than 100 countries with about 132,000 employees. www.abb.com

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    Clifford Craig, Engineering Manager at PrimePac Ltd, said: “With the 60 percent energy saving we achieved on the old blow molder we have been able to install another new all-electric injection molding machine.”
    Clifford Craig, Engineering Manager at PrimePac Ltd, said: “With the 60 percent energy saving we achieved on the old blow molder we have been able to install another new all-electric injection molding machine.”

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