Low-cost process controls for injection, extrusion, blow molding.

Three developments will acquaint a wider range of processors with low-cost, digital process controls from Northwest Technical Integrators (NTI) of Crystal Lake, Ill. One is a new update of the firm's injection molding controller series. Second, NTI is now branching out into extrusion and blow molding controls. Third, NTI's products will become more widely available due to a sales and service pact with SunSource Inc., a hydraulics engineering firm that has more than 50 offices across the U.S., Canada, and Mexico. The deal covers NTI's entire line, which runs on Allen-Bradley SLC-500 small logic controllers.

INJECTION UPGRADE

For injection molders, NTI's updated Mold-Rite series covers a range of sophistication. The most basic product, Mold-Rite Jr., provides only open-loop control and is intended mainly for presses under 100 tons. Mold-Rite 2100 adds real-time closed-loop control of both injection and clamp functions. All PID loops can be tuned while you view the process screens. "That way, you can see the effect of the tuning on the process," says president Donald King. The screen can show up to seven shot profiles simultaneously. Price is about $30,000.

The newest addition is the top-of-the-line Mold-Rite Dominator, which adds extensive SPC features and maintenance reporting capabilities to the standard Mold-Rite package. It also replaces the Allen-Bradley PanelView interface of the other controllers with an industrial PC. Dominator recently emerged from a year of beta testing at GE Plastics' Polymer Process Development Center in Pittsfield, Mass. "It's a good package," says processing engineer Greg Tremblay. "It presents whatever process data you want in a clear manner."

Dominator offers up to 25 real-time and 25 historical SPC charts of a range of user-defined parameters. "For example, you can monitor injection pressure in real time while logging that data for future use," explains King. "With the historical charts, you can trace critical quality information down to the second it was generated," he adds. In addition, a set-point-change log stores information on the time, date, setpoint change, and the person who made it.

Dominator also provides up to 1000 monthly reports on tool and machine maintenance - such as hours run since maintenance work was completed. "It gives you a maintenance history for a given machine right at that machine," says King.

Dominator stores all this information on board for a year. Data stretching farther back would have to be archived on disk.

The Dominator package, which includes a hydraulics upgrade for the injection unit and installation of a digital position sensor, costs around $35,000. Networking the Mold-Rite 2100 or Dominator costs about $200/machine.

EXTRUSION & BLOW MOLDING

NTI has just come out with another Dominator for extrusion. Though tailored to extrusion process parameters such as barrel temperatures and drive speeds, it offers essentially the same SPC and maintenance-reporting capabilities as the molding version.

NTI's first extrusion application was a control upgrade in 1993 for a compounding plant owned by Morton International. That project ran on the pricier Allen-Bradley PLC 5 platform. The new extrusion controller, however, is based on an SLC 500 with a PanelView 550 user interface. King expects the complete price with installation to be around $23,000 for a Dominator version and about $15,000 for a standard version without the reporting capabilities.

A Dominator control for blow-molding is slated for next year.