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Give me four transducers, hold the controller, and add the PC

December 30, 1999

3 Min Read
Give me four transducers, hold the controller, and add the PC

It’s nice, as a molder, to be able to keep up with new technology. But many hesitate at the cost, effort, and time required to install and run new equipment.

Delphi Interior Lighting Systems in Adrian, MI found itself in this position when it decided to start monitoring cavity and hydraulic pressure and injection velocity. The plant runs presses ranging from 1500 to 3300 tons molding interior components, instrument panels, and door trims for GM cars and trucks.

As many molders are starting to do, David Cheney, supervisor of electrical engineering, wanted to use pressure monitoring to control the molding process better and optimize cycles. But he didn’t want to replace the plant’s respected and large collection of machine controls. Each press is equipped with an Allen-Bradley Proset 200 control system that has performed well with strong technical support from Allen-Bradley, but it couldn’t display pressure data.

“What I like about the controls is that the machine control portion seems to do a good job of controlling the press at a lower cost,” Cheney says. “But I wasn’t as happy with the operator interface. It didn’t allow us to display pressure information, and that’s information we really wanted available at the press.”

To solve the problem, Cheney and Delphi teamed up with software manufacturer Festech Software Solutions (Findlay, OH) to write a new interface for the Allen-Bradley control that displays the pressure data Delphi is capturing. “We took the existing Proset 200 control structure and redesigned the software to modify the operator interface,” Cheney says.

Under Pressure
Cheney and Delphi are using transducers at four locations on the press. Two are located in the cavity—one at the gate, the other at end-of-fill. Another measures hydraulic pressure on the ram. The fourth is an injection cylinder position transducer that measures injection velocity.

Data from these four sensors is sent to the SLC 5/04 on board the Allen-Bradley Proset 200 control. Cheney reprogrammed the SLC to massage this data and then store it in a specified file format.

The Festech software, called Injection Profiler, runs on a WindowsNT-based PC that’s interfaced with the Proset 200 via an Allen-Bradley scanner card. It retrieves each data file generated by the control, formats it, and displays it to the operator on a color touch screen in the form of temperature and pressure curves (Figure 1).

The operator can view all data simultaneously, generate curve overlays, or perform discrete analysis of data coming from each transducer. The injection and cooling stages can be optimized, and injection velocity is more precisely measured and monitored. With historical trending, the operator can check for pressure degradation, short shots, pressure spikes, and other process anomalies that might otherwise go unnoticed.

Delphi has realized benefits from the system in improved part quality, faster cycles, and reduced scrap. “In a nutshell,” says Cheney, “it’s higher quality because you can really see if you have variation in your process and machine. You can see if you’ve filled the mold correctly or whether it shorted.”

Although Festech developed the Injection Profiler in conjunction with Delphi, the product has been enhanced and commercialized to the rest of the industry. Priced at $2500, the Injection Profiler runs on WindowsNT, 95, or 98 operating systems and can be customized for specific requirements. Festech reports that software drivers are currently written only to accommodate an Allen-Bradley PLC, but others could be made available for interested molders. All communications drivers are imbedded in the product and can be used immediately.

Contact information
Festech Software Solutions Inc.
Findlay, OH
Steve Ludwig
Phone: (800) 945-8842
Fax: (419) 423-8844
Web: www.festech.com

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