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Moldflow : UMass The Plastics Engineering Department at the University of Massachusetts/Lowell (UMass) was founded in 1954 and has been ABET accredited continuously since 1977. The school is the only ABET accredited Plastics Engineering program in the country. The Plastics Engineering Program provides a well-rounded basic level engineering education that prepares graduates for an entry-level position in a lifetime career of plastics engineering. It is designed to graduates for professional engineering careers in the polymers industries of which plastics is the largest. The others include manmade fibers, elastomers, coatings, and adhesives. The curriculum provides a sound foundation in basic science and engineering disciplines plus a detailed study of plastic materials, properties, processing, and design. Moldflow's Dynamic Series including Moldflow Plastics Expert (MPX), Moldflow Parts Adviser (MPA), and Moldflow Plastics Insight (MPI) have been part of the school's curriculum as part of several graduate-level computer aided design classes since the 1980s. In 1997, the Dynamic Series was incorporated into a junior-level experiment called "Process Windows in Injection Molding." For this experiment, simulations replaced actual molding in determining the process window for a machine-mold-material combination. In 1999, molding was added into the experiment. The students perform flow simulations during the first part of the experiment and molding trials during the second part. The simulation results and actual molding are compared using molding area diagrams and in-mold rheology diagrams. In 2000, the process windows experiment was included in the graduate laboratory sequence and used MPI in place of the Dynamic Series. Since MPX became available to the program in 2000, it was incorporated into the processing labs, specifically in the basic injection molding and statistical process control (SPC) experiments. In the basic injection molding experiment, sophomores or graduate students set up and optimize the processing parameters for two injection molding machines. MPX was added to the end of this experiment. Thus, the students compared the set up for the two machines and the parameters for one machine that was set up manually and using MPX. In the SPC experiment, the process parameters were set up and optimized using MPX. Students also attempted to use MPX to monitor and record critical parameters during molding. Dr. Carol Barry, UMass assistant professor of plastics engineering, designs and coordinates the curriculum for the plastics process engineering laboratories for sophomores and juniors, plastics physical properties laboratories for seniors, and the equivalent labs for first year graduate students. She says, "For freshmen students, MPI and MPA provide colorful graphics, an opportunity to examine mold filling, the ability to easily test changes in melt and mold temperature, injection time, materials, and most importantly, the feeling that they are doing something specific to plastics. In this year's group design projects, the students could explain where the air traps should have been and where some ended up, discuss changes in melt temperature and materials used to reduce shear stress during filling, and how meshing changes affected results. In Plastics Process Engineering II, Moldflow is used to elucidate trends and provide the students with a sense of the magnitude of changes that occur when mold geometry and processing conditions are changed." Beth Ann Bergeron is a graduate student in the UMass Plastics Engineering Program. As part of her responsibilities, she instructed other teaching assistants and students in the use of MPX in the school's injection molding laboratories. In the real-world, the technology provides process engineers and plant managers with the tools to take control of the molding process by using shop-floor solutions to the problems associated with injection molding machine set-up, process optimization, and production part quality. Bergeron also did most of the trouble shooting as the MPX software was connected to one of the school's Cincinnati Milacron injection molding machines. She works with both MPX and MPI. MPI is an integrated suite of CAE analysis software that makes it possible for plastics part design, mold design, and machine processing conditions to be optimized during the design stage, saving time and money. She notes, "Although I have used MPI in my computer aided engineering class, I have the most experience with MPX. We have been using MPX in some of the injection molding laboratories. The program correlates to some of the different aspects in injection molding such as setting the process up, process optimization, and statistical process control." In process set-up, students learn the short shot method and how the different steps may affect the parts being produced. At the end of the process, the students obtain a set of molding parameters. Then, the students run the MPX software. Using this methodology, they can correlate the short shot steps to processes taken by the Set Up Expert. The technology opens doors for further discussion regarding any language/concepts used in the Set Up Expert that the student still may not have command of. Also, using the Set up Expert, the students are taught the difference between molding problems caused by the filling and hold stages of set ups. During process optimization, using the Optimization Expert, students run a three-factor, two level optimization. This process helps students understand the general concept of design of experiments before continuing on to other experiments. Using the Production Expert, students run a SPC trial. During this lab, students chart the differences in process variables and part weight. They can visualize the charts while running the software to view the subsequent hydraulic pressure, screw position, and screw velocity curves. These tools are useful for improving the visualization of the molding process. Bergeron adds, "Hopefully we will be able to incorporate the use of MPI as a starting point for the students in the lab so that they can compare their results that were obtained using MPX." Both Bergeron and Barry agree that using tools such as Moldflow prior to entering the workforce have definite advantages. Bergeron says that using Moldflow tools are important teaching aides. "Above and beyond teaching the students upcoming technology, the software lends itself as a discussion generator. Using MPX, for example, the students were able to reinforce their knowledge of process set up and troubleshooting." Barry adds, "Like solid modeling, flow analysis software is a tool that the students should be exposed to while in school. As the software becomes easier to use, its use will be less restricted to specialists and more of our students will be using the software or assessing its results." Author: Laura Carrabine |