Manufacturing AUTOMATION

Features Factory
Forming the future: Packaging machines boost high-speed performance with automation updates


July 21, 2010
By Mary Del


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G.N. Plastics is a leader in the design, development and manufacture of thermoforming machines and tools. After moving to Chester, N.S., from Austria in 1968, the company now produces plastic products and packaging for the foodstuffs industry (which is 95 percent of its customer base). Between 70 and 80 of its systems are sold yearly. Today, customers in more than 60 countries trust in G.N. Plastics’ solutions.

The Maritimes-based machine manufacturer offers common development and production of prototypes as well as application-specific support. "Although G.N. is involved in a niche industry, competition in the global marketplace is strong with the largest competitors based in Germany, Italy and the U.S.," G.N. general director Georg Nemeskeri explains.

INCREASED EFFICIENCY

Thermoforming machines are normally used to process plastic sheets that are first heated and formed and then cut and stacked. From wrapping for fine foods to sweets, all types of packaging can be produced. "In the past, we often used several different solutions for our machines, which increased the time required for programming and commissioning," Nemeskeri says.

High-quality plastic packaging is the result of a multi-layered production process. High forming speeds and precise positioning of the plastic are important factors when processing various foil materials. In cooperation with B&R Automation, G.N. Plastics was able to combine progressive machine design and maximum performance in a very short time.

In 2005, G.N. Plastics began collaborating with B&R. Using its Automation Studio software, the company greatly simplified management and control of the automation system. It was then possible to considerably reduce the programming time required for the various components – and annoying interfaces became a thing of the past.

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G.N. Plastics and B&R’s first joint project was the fundamental reconstruction of a robotic stacking unit. This was followed by the development of a new automation system based on a B&R Power Panel and ACOPOs servo drives and servomotors. Advantages of the new concept include its "extraordinary user friendliness and reliability."

A MULTI-LAYERED PRODUCTION PROCESS
"In particular, the use of Automation Studio allows simple integration of a control solution that can be ideally adapted to all of the requirements of our thermoforming machines," Nemeskeri explains.

Additionally, Christian Kastinger, an applications manager with B&R in Mississauga, Ont., says the new 15-inch, colour HMI provides an enhanced graphical representation of process parameter and diagnostic information, and the B&R System Diagnostic Manager provides web-based access to diagnostic information. Additionally, G.N. "reduced cabinet space and wiring effort due to the power panel technology" with the combined HMI and PLC and by using compact X20 slice I/Os.

The main steps for plastic processing include:
• Heating the plastic material: The plastic is unwound from a roll and fed into the forming area. Here it is trapped in place by a double toggle mechanism that closes the forming press. Compressed air is injected through the mold ensuring complete contact of the plastic material with the heating plates.
Adds Kastinger: "Besides a higher throughput (parts/min.), the new B&R software-based temperature controller provides outstanding stability of the temperature zones [that] is crucial for the product quality."
• Forming: As the plastic material reaches the optimum forming temperature, air is exhausted from the mold. Air pressure is then applied through thousands of tiny holes in the heating plate assembly. This forming pressure forces the plastic into the mold cavity.
• Cutting the formed plastic: As the forming air is vented, a second toggle movement forces the knife blade of the cutting die through the plastic sheet.
• Ejecting the completed part: After cutting, the press opens and the formed parts are ejected using pressurized air.
• Material transport: The formed parts, which are still connected to the material web, are transported to the stacking station.
• Stacking: The stacking units can easily be attached to any thermoforming machine in order to accurately count, stack and deliver the formed parts.

The integration of B&R technology ensures consistency. In addition, the components’ modularity makes it possible to quickly adjust machine solutions to specific requirements.

As for challenges, the biggest came to testing the control program. "All possible operator inputs at any step of the process had to be tested in order to ensure highest possible reliability and repeatability of the thermoforming process," Kastinger says.

The first updated machine was shipped to a European customer familiar with G.N.’s machines and with high expectations. "The machine has been working well since Day 1 and satisfied the customer’s expectations," he adds. It was even possible for G.N. technicians to monitor production parameters of a machine operating across the Atlantic Ocean and to even implement and download minor program advancements.

"Because of the success of our partnership during the projects, we decided to use B&R components for all of our machines’ needs in the future," Nemeskeri says, a process that is well underway.

"Based on modularity and the excellent availability of all the B&R components, we are now able to make powerful systems available right on time," he adds.