Technologies
PDF


WARF: P06358US

Injection Molding Quality Control System


INVENTORS -

Lih-Sheng Turng, Zhongbao Chen

The Wisconsin Alumni Research Foundation (WARF) is seeking commercial partners interested in developing an online, adaptive injection molding quality control system.
OVERVIEWInjection molding is a widely used manufacturing process for mass production of plastic parts, constituting a multi-billion dollar industry. Despite the popularity of injection-molded parts, however, their quality has remained difficult to predict and control without frequent intervention by machine operators.
THE INVENTIONBy making use of the unique signal of mold separation (MS), UW-Madison researchers have created an online and adaptive injection molding quality control system that outperforms conventional cavity or hydraulic pressure-based systems. MS is the momentary separation of a mold’s core and cavity plates that occurs at the end of filling step in the injection molding process. The maximum value of this separation is highly correlated with part weight, a key index of part consistency and quality.

To continuously monitor the small MS signal (in the micron range) the researchers mounted a non-intrusive, precision linear displacement transducer on the outside of the mold plates. The MS profile measured by the transducer is fed into adaptive control algorithms, which manipulate hydraulic pressure and the switchover point to maintain part consistency from cycle to cycle. Within a single cycle, the system also adjusts hydraulic pressure during the packing step to control the MS profile.
APPLICATIONS
  • Injection molding
KEY BENEFITS
  • Provides 100 percent quality inspection and automatic tuning of the molding process
  • Unlike cavity pressure sensors, which are located inside the mold where they can adversely affect part quality, the transducer of this invention is easily mounted outside the mold cavity.
  • Applicable to any mold and resin where MS occurs during the process without causing “flash,” or ejection of polymer from the mold
STAGE OF DEVELOPMENTExperiments with different plastic resins and mold geometries found that this technique significantly reduces both long- and short-term variability in part weight as compared to conventional hydraulic pressure control.
ADDITIONAL INFORMATION
For More Information About the Inventors
Publications
  • Chen Z., Turng L.-S. and Wang K.-K. 2006. Adaptive Online Quality Control for Injection-Molding by Monitoring and Controlling Mold Separation. Polymer Eng. Sci. 46, 569-580.
Contact Information
For current licensing status, please contact Emily Bauer at emily@warf.org or 608-960-9842.
The WARF Advantage

Since its founding in 1925 as the patenting and licensing organization for the University of Wisconsin-Madison, WARF has been working with business and industry to transform university research into products that benefit society. WARF intellectual property managers and licensing staff members are leaders in the field of university-based technology transfer. They are familiar with the intricacies of patenting, have worked with researchers in relevant disciplines, understand industries and markets, and have negotiated innovative licensing strategies to meet the individual needs of business clients.