Keeping the heat on

Integrated motion control drives enhance flexibility of thermoforming equipment

by Jim McMahon

The goal of a machine manufacturer is to build machines with bulletproof mechanical, electrical and software that deliver a high ratio of production to downtime. One company that has been successful in achieving this goal is Irwin Research & Development, Inc.

Over the past 40 years, Irwin has engineered one of the most productive lines of thermoforming machines on the market. With an installed base of thousands of machines, the company has established itself as a leader in the OEM thermoforming market worldwide.

The key to Irwin’s success is research and engineering, which it has excelled at since its beginning in 1966. In 1972, Irwin was the first to introduce servo-motor power trains for thermoforming machinery, an improvement over the conventional pneumatic and hydraulic systems used at the time.

Irwin was also the first to develop microprocessor-based controls for use on its thermoforming machines, in 1979. In 1996, the company developed a largely successful software system called Ballerina, that gives its clients the tools to create motion control profiles via a CAD/CAM graphical approach.

Through the years, the company has amassed a portfolio of patented devices for its thermoforming equipment, including a revolutionary 228-inch-long telescoping heat tunnel designed to automatically adjust to exact shot lengths.

The heat control zones relate directly to each shot, insuring that no portion of the shot is subject to overlapped heat. This design solves the long-standing industry problem of non-uniform shot heating in the oven, resulting in more uniform product quality and increased efficiencies in oven heating control.

Controls upgrade
This spirit of innovation led the company to embark upon a complete upgrade of the automation control systems on its line of machines. For years, Irwin had been using its own self-developed microprocessor, which used the processor PC to download the parameters into embedded controllers in the machines.

Irwin’s machines have a large number of functions — many start and stop positions for shot feed, temperature control and trimming. This configuration allowed the machines to maintain the required speed without losing functionality.

“The efficiency of our machine’s function is testimony to the processor’s operability,” says Jere Irwin, President and CEO of Irwin Research & Development, Inc. “However, we listened carefully to our customers’ requests for a machine controls package that was more universally available, can be configured by the customer, and has more maintenance and troubleshooting capability.

“Having utilized Siemens motors on our machines for many years, we asked Siemens to review our thermoforming machine line for a complete overhaul of its control systems,” Irwin continues. “Siemens took a very thorough look at our controls and their functions so they could duplicate those functions with their own system.”

Totally integrated automation
Siemens controls solution was based on a concept called Totally Integrated Automation (TIA). TIA is characterized by its unique continuity, providing maximum transparency at all levels with reduced interfacing requirements. Its influence covers everything from the field level and production control level, up to the corporate management level.

It also provides maximum interoperability, including everything from the controller, HMI, drives, to the process control system. This reduces the complexity of the automation solution in the plant.

The TIA system that Siemens has put into place encompasses products called SIMOTION and SINAMICS, and includes a palate of high-tech control system components which are optimally harmonized with one another.

“We presented SIMOTION, our latest generation of motion controller, and SINAMICS, our latest generation of drives,” says Ian Hall, Service Manager with Siemens. “The motion controller, the drives and the motors encompass the scope of our project. It was a very big step forward for Irwin technologically, in terms of the wiring and drive integration and motion control. We showed them the benefits of taking standard, off-the-shelf Siemens technologies and applying them to a machine solution.”

SIMOTION motion control
Most machines require motion control (positioning, synchronous operation), PLC functionality and technology tasks (pressure control and temperature control). The fusion of these functions into one system — as with SIMOTION — has a number of advantages, such as lower engineering costs, higher machine performance, the elimination of time-critical interfaces between individual components, and simple, uniform and transparent programming and diagnostics for the entire machine. It is a simple and flexible solution for numerous motion control tasks.

SINAMICS drive system
Siemens’ SINAMICS is a modular drive system for high-performance applications in industrial machine building. SINAMICS solves many sophisticated drive tasks for a wide range of industrial applications. It includes high-performance single-motor drives as well as coordinated drives (for multi-axis applications) with vector and servo functionality.

The program’s solutions are structured in the form of modular axis groups instead of individual axes. Instead of connecting each individual axis, all of the components are electronically connected. It provides a high degree of flexibility and combination possibilities, as well as a wide range of products and services.

Pre-assembled cables were used to connect many of the components — including motors and encoders — via the DRIVE-CLiQ electronic interface. This integrated, seamless communicating system simplifies the electrical aspect of Irwin’s machines.

This Siemens system also uses an ASI (Actuator-Sensor-Interface) bus with minimum wiring, having only one cable instead of many. The bus has quick assembly, it is easy to maintain and configuration is easy and fast. It is equipped with safety technology, ASIsafe, enabling direct integration of fail-safe components.

Ballerina HMI
“Irwin has an HMI for its machines, called Ballerina, that they wanted to maintain,” continues Hall. “They wanted to keep the familiar Ballerina screen in place, so that the operators and users would not experience any interface change.”

Ballerina is an Irwin-developed, PC-based software package providing an upgradable, powerful and flexible system to graphically represent the motion profiles of the equipment chain feed and platen drives in terms of time and velocity. This gives the user full control and flexibility of the process. Its features include sorting of product recipes and logs, network capabilities, multiple languages and pass-code protection.

While the screen is still the same Ballerina screen, underneath the interface there is now a state-of-the-art, flexible and efficient Siemens motion control and drive system.

Benefits
The controls upgrade to Irwin’s thermoforming machines is a solution the company can now leverage to bring more value to its customers: Reduced time to assemble the machines, simplified wiring, digital control of the drives, and increased diagnostics from the drives, motors and I/Os combine to bring more machine reliability.

This article appeared in the April/May 2008 issue of MRO Today magazine. Copyright 2008.

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