Note: This is the second of a three-part series covering plastics manufacturing automation (1) trends, (2) material/process advances and (3) applications.

Plastics processing information exchange in the internet age has spawned interesting evolutionary development in plastics manufacturing oriented automation networks.

The integration of plastics processing equipment — both auxiliary equipment as well as primary processing machines into a company-operated intranet and/or internet offers a number of possibilities. Automation improves monitoring and control of manufacturing processes in a plastics processing plant, as well as provides for the universal exchange of data and other information.

Continuous advances in industrial network components, based on mature and open technology have made such developments possible. The industrial use the TCP/IP protocol has seen a boom in the process control of primary processing machines during recent years, and such advances are now also taking place in auxiliary equipment and robotics.

Process parameters such as temperature set points for temperature controllers or dryers, and even teach programs for robots can be centrally administered. Important information regarding the operating status of various pieces of connected equipment, as well as possible error conditions, diagnostic or maintenance information can be routed to a central server. From there the server can supply the information to various clients or it can be set up to transmit error messages or important changes in operating status to e-mail enabled devices such as personal digital assistants or cell phones.

Starting off in the area of open network capable auxiliary and primary equipment, various plastics industry primary and auxiliary equipment suppliers have developed and provided network communications capabilities. The vision of auxiliary equipment and robotics supplier Wittmann Kunststoffgeräte GmbH is to connect all peripheral equipment on the factory floor together via WittLink, the firm's network communication program.

WittLink is an open network designed to allow processors to connect all auxiliary equipment including those of competitors to a central computer and to view operations via a standard web browser. Web cameras in the production place also integrate into WittLink, to allow the user to view via webcams production processes from any location in the world.

WittLink is really a collection of products and product options at the center of which is web server software that communicates with equipment using two interfaces, Euromap/SPI 63 Protocol for CNC6 6.2 robots and embedded web servers for other products. Wittlink has appealed to most injection molders; particularly the small to medium molder aiming at a 'lights out' low cost factory environment.

Wittman Battenfeld
WitLink open network.

Husky Injection Molding Systems, a provider of injection molding equipment and services to the plastics industry has evolved and built "Husky Host," a flexible network with OPC-based standards to provide turn-key solutions for plant and equipment monitoring. The network integrates new Husky equipment controllers with customers' existing control and monitoring applications.

Husky Host uses Matrikon's MatrikonOPC server to provide connectivity. OPC is a standards-based software communications protocol that provides a common data exchange method between industrial devices and applications.

The MatrikonOPC server allows Husky Host to reliably connect legacy equipment together, while avoiding DCOM setup and security issues, and have the data available to SmartLink Husky's web-enabled, plant monitoring system. SmartLink provides plant management and engineers with key real-time performance data for the entire factory, in including information on all injection molding machines, auxiliaries and building services.

Husky Injection Molding Systems
Equipment network connections without and with Husky Host.

Other plastics industry equipment suppliers have also been developing network systems. Motan USA's ControlNet, referred to by some as the network of networks, ties together Motan's LuxorNet, GraviNet and MetroNet for drying, blending and conveying. It also can be used for outside connections. Using EtherNet, TCP/IP, HTTP and e-mail standard protocols it can communicate via the internet and also links easily with other reporting and monitoring systems including ERP and other factory automation programs.

Concluding in the field of blow-molded materials system technology, Krones AG originated as a small manufacturer of labelers, but has evolved into much more than just a machinery supplier. A world leader in the design and manufacture of high-speed equipment for the packaging industry, the company has adopted a holistic approach, becoming an "all-around problem-solver" for its clients as well as a systems engineering vendor.

The Krones Group designs, develops, manufactures and installs machines with complete filling and packaging lines mainly to breweries and beverage producers. The company emphasizes technical excellence, and maintains a high level of research and development, which underpins its high-precision manufacturing to stringent standards of quality and more than 1,500 patents.

As the quality of polyethylene terephthalate (PET) bottles produced in stretch blow-molding machines such as the Krones Contiform depends on the quality of the preforms used, Krones has developed the Improved Resolution Inspection System (IRIS), a camera inspection unit to check the exact screw thread roundness of the PET preforms directly after the unscrambler.

Up to 55,000 preforms per hour can be checked for ovality or deviation from the nominal diameter as well as preform neck finish for chips or unevenness. Preforms detected as faulty are automatically removed and do not enter the stretch blow-molding machine.

Krones' PET-View vision inspection checks the quality of the newly-blown PET bottles in the Contiform stretch blow-molding process. The inspection system is based on IRIS technology and the calculated values can also be used to readjust the parameters within the blow-molding machine. Inspection parameters can include base contamination, turbidity and size/position of the gate; neck finish and ovality; side wall contamination, turbidity, wrinkling and container shape.

Krones AG
IRIS vision inspection of preforms (top), PET-View bottle inspection (bottom).

To reduce costs incurred in beverage bottle production, Krones has developed the Air Wizard a package of hardware and software that significantly reduces compressed air use and operating costs in stretch blow molding. In producing returnable PET bottles with a blow molding machine, the high pressure air used is the single largest consumer of energy consuming, more than half the total energy required in the blow molding process.

The Air Wizard system, which can be retrofitted to all Krones Contifirm S machines, focuses on three areas to reduce the volume of dead space, reduce the blow molding pressure and recycle the blow molding air. Krones estimates that the total Air Wizard package can potentially realize total savings of more than $150,000 per year on a Contiform S16 stretch blow molding machine.

Two other systems are also designed to reduce processing costs. Temperature Wizard using an infrared camera measures the temperature profile of each preform at the linear oven exit and reduces bottle wall thickness fluctuation, while Wall Wizard monitors what the Temperature Wizard regulates. Wall Wizard detects wall thickness at up to four points on the container wall, and enables automatic regulation of thickness distribution by changing the temperature profile during preform heating.