Salt Lake City, Utah
June 20, 2004
June 20, 2004
June 23, 2004
9.533.1 - 9.533.13
Energy Savings in Injection-Molded Plastic Manufacturing
Stephen Williams, Glenn Wrate, Thomas Wanke, Michael Scheuerell Milwaukee School of Engineering Milwaukee, WI 53202
The results of a joint project between the Wisconsin Focus on Energy program, the Milwaukee School of Engineering (MSOE), and Plastic Molded Concepts, Incorporated to improve the injection-molded plastic manufacturing process are described.
Medium range (10 - 100 HP) motors are used to pump hydraulic fluid in injection-molded plastic processes. Hydraulic power required during one cycle of manufacturing a single part varies greatly. With a single speed motor driving a fixed displacement hydraulic pump, the electric power consumed over one cycle is constant and equal to at least the maximum required hydraulic power plus losses.
Energy savings are realized by reducing the speed of the motor via a variable frequency drive (VFD) during those times of the part cycle when less than maximum hydraulic power is required. Another energy saving alternative is to replace the fixed displacement hydraulic pump with a pressure compensated variable volume hydraulic pump.
Variable frequency drives are installed on a number of presses at Plastic Molded Concepts (PMC) in Eagle, Wisconsin. One of these presses is used as a test bed for this study. The test bed system at PMC is used to compare several different process technologies. A multidisciplinary team of students and faculty (ME and EE) conducted baseline energy studies and redesigned the process to include variable displacement hydraulic pumps or VFD technology.
Verified energy savings of the redesigned system with VFD technology are presented. Projected energy savings of the redesigned system with a variable displacement hydraulic pump are also presented. This paper includes a description of the manufacturing process, information on the instrumentation used for the energy studies, and a description of the redesign. Feedback from the student team involved in the baseline studies, redesign, and verification are offered.
Student Design Involvement
The Wisconsin Focus on Energy is a program funded by Wisconsin electric rate-payers to encourage energy efficiency and the use of renewable energy, enhance the environment, and ensure the future supply of energy for Wisconsin. University involvement in the program is a deliberate decision intended to expose engineering students to energy conservation concepts and techniques.
As a result of this decision, students at Milwaukee School of Engineering (MSOE) are participating in a number of Focus on Energy projects. The faculty at MSOE view the projects as
Wanke, T., & Williams, S., & Scheuerell, M., & Wrate, G. (2004, June), Energy Savings In Injection Molded Plastic Manufacturing Paper presented at 2004 Annual Conference, Salt Lake City, Utah. https://peer.asee.org/13933
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