Robots help Power Plastics increase output

At Power Plastics in Sydney, Australia, hand-packing 3000 polyethylene condiment bottles an hour was taking a high toll in labour costs and operator health and safety — in a highly competitive market.

Six months after giving the job to an ABB robot, two-thirds of the line’s staff had other jobs, efficiency was on target and weekend output from the line was up 30 to 40%.
“We began in 1997 with four old blow moulding machines and six employees,” said Power Plastics’ managing director Russell Barber. “We’re not about being the biggest operator out there. We just want to be the best.”

Skyrocketing raw materials prices influenced the decision to go for a robotic solution for the company’s squeezable condiment bottle operation, but the operational and human costs of hand-packing 60,000 bottles a day, in 250 and 500 mL sizes and five different colours, were the key drivers. “The final crunch was we had a bad year with workers compensation claims from RSI (repetitive strain injury). The best way to make sure we didn’t have any RSI was to get a robot,” he said.

Sydney-based systems integrator Apex Automation and Robotics had already built a non-robotic automation solution for Power Plastics. When Apex’s general manager Dany Seif first looked at the condiment bottle line, he found two operators on each shift filling plastic-lined cardboard boxes with the bottles, sealing them and then placing them on pallets.

“Power Plastics required a high degree of flexibility and ability to handle product diversity. Our challenge was to generate a concept using the most suitable technology for the application,” Seif said.

“ABB has a wide range of robots, user-friendly software and we keep our finger on the pulse of their latest developments. They also provide a high level of training and technical support to our customers, after the project is completed.”

The robotic cell built for Power Plastics is based around one 6-axis IRB 4400L robot, with a 2.43 metre reach and 30 kilogram payload. Bottles are fed from two extrusion blow moulding machines (EBMs), along accumulation conveyors, from which the robot picks them — 8, 9 or 10 at a time, depending on bottle size — using an Apex designed and built gripper.

The gripper uses vacuum cups to pick up a row of bottles, space them and place them upright on a stainless steel platen. In the next cycle, the gripper rotates 180°, then spaces and places the bottles up-side down between each bottle in the first row.

When the platen is full, the cell signals the operator, who inspects the bottles, slips a plastic bag over them, seals it and takes it to a pallet.

The robot sits between two in-feed conveyors, which supply two identical packing zones 180<0x00B0> apart. When the operator is bagging one platen of bottles, the robot works in the opposite zone.

“Apex said they could automate the whole line,” said Barber, “but I was concerned about going from essentially 100% inspection to zero inspection. “I think we got it just right. We have the right amount of operator intervention where we can guarantee quality.

“After six months of moulding millions of bottles, our quality has not been diminished one bit. “The line started with six employees over three shifts. Now we’re down to one per shift, but that person also works on something else, while running both EBMs.”

The line runs 24 hours a day, so measuring any improvement in output was difficult, said Barber. “But, on weekends — when we always operated with a skeleton crew — output is up between 30 and 40%,” he said.

“We provided the whole turnkey robotic cell from scratch,” said Apex’s project manager Angelo Di Lorenzo. “We designed and programmed all the elements, including the gripper, marshalling equipment, PLC, the HMI and the safety integration, in accordance with the relevant Australian standards.”

ABB Australia Pty Ltd
www.au.abb.com