In this article featured in MoldMaking Technology Magazine, 8/1/2008, contributor Laura Carrabine describes the critical role that mold flow analysis has played in PM Mold's approach for Cessna Aircraft Company
CAE Services Corporation is a silver-certified Moldflow consulting firm that has been providing Moldflow consulting services for more than 20 years via an in-depth analytical solution-based approach to mold flow analysis. The company recently assisted PM Mold as it approached a complex molding program for its customer, Cessna Aircraft Company.
PM Mold (Schaumburg, IL) offers injection molding and mold building services from design conception through production in injection, 2-shot and in-mold decorating (IMD) in the automotive, appliance, aerospace, electrical and houseware markets. It operates 20 presses with tonnage ranging from 28 to 500 tons.
Larry Hauck, PM Mold’s general manager, oversees both operations. When Cessna contracted with PM Mold to produce interior plastic injection components for the Cessna Mustang aircraft, Hauck contacted CAE Services to perform the mold flow analysis of the parts. “We asked CAE Services to conduct all the mold fill, pack and cooling analysis on all of the parts related to the program,” says Hauck.
Due to the stringent quality demands that Cessna required for the plastic parts that Hauck and his team were charged with, Hauck and Cessna agreed to the Moldflow analysis. “All the components had to meet size, shape and other detail requirements. We thought that Moldflow analysis would provide the best advantage to obtain proper gating and cooling locations. All the components were visual, Class-A surface parts. Aesthetics were very important on this job. That’s why we contacted CAE Services,” adds Hauck.
From the onset of the project, Hauck admits that he wasn’t sure that analysis would be 100 percent accurate. “I was expecting that we would obtain approximately 50 percent accuracy, and re-working gates and trial and error testing would be necessary. I was pleasantly surprised that my initial expectations were not the case at all. We experienced no problems whatsoever using the analysis,” Hauck says. The simulation results correlated nearly 100 percent with real world results.
Cessna was receptive to investing in Moldflow analysis for this project. When Hauck and his team relayed their concerns about meeting Cessna’s quality and aesthetics requirements, Tim Lankisch, CAE Services’ engineering manager, made it clear that Moldflow analysis would help them achieve Cessna’s needs. Hence, the customer agreed to the additional costs.
For this project, PM Mold contracted CAE Services to conduct filling, packing and cooling analyses. CAE Services exclusively uses Moldflow’s Plastics Insight (MPI) software for in-depth part and mold design simulation. With proper education, training and a thorough understanding of the molding process, as well as mold design and application know-how, MPI can accurately simulate plastics flow, packing, mold cooling, part shrinkage, and warpage for thermoplastic injection molding, gas-assisted injection molding, co-injection molding, and injection-compression molding processes.
With regard to these projects, Lankisch says, “Some of the main outputs that the customer was looking for was filling pattern—making sure within the constraints of the tool that there was balanced filling. We wanted to determine number and location of gates, as well as if knit lines needed to be changed to less visible areas.”
Hauck says the cost of analysis is justifiable. “Using Moldflow simulations for the Cessna project eliminated secondary re-work, secondary charges to the customer and any disappointments on the customer’s part that components didn’t work after molding,” notes Hauck. He also says that the analyses were necessary because of the customer-imposed tight production timeline. There was no time allotted for reworking any component.
He adds, “The cost of the analysis was less than if we had to use the traditional trial-and-error methodology. That strategy would have extended the production timeline and possibly caused us to lose that customer.” Instead, the Cessna project progressed on target without any problems or production slow-downs. “We made the customer extremely happy and we continue our relationship with them today,” notes Hauck.
PM Mold’s work with CAE Services took about six weeks as CAE Moldflow experts analyzed approximately 12 Cessna parts. Hauck says, “Our relationship with CAE Services was very pleasant. CAE’s experts are very helpful, knowledgeable and professional.”
PM Mold does not currently own a seat of Moldflow, however, Hauck says that the company may decide to purchase the software based on customer part requirements. For now, Hauck will decide when to outsource Moldflow analysis based on past experiences. “If the part is something new that we haven’t come across before or if aesthetic requirements are important, we usually opt for Moldflow. We also would highly consider using it if we need to produce high-volume, aesthetic tooling.”
Making the Analysis Investment
For those customers who refuse to pay for Moldflow analysis, PM Mold engineers and its customers mutually agree upon gate locations. Hauck says that if the gate location is not accurate, PM Mold more often than not absorbs the costs to rework the gating. “That situation alone makes me more of a Moldflow advocate,” Hauck says. Expenses associated with changing gate locations after a mold is built can range from $1,000 to $4,000 depending on the part and gate type. Other bigger considerations associated with this scenario are time tacked onto the production schedule and labor and machine over-time costs. For these reasons, increasingly more PM Mold customers are willing to make the analysis investment—depending on the project.
“Early customer involvement is key to the success of any given MPI project. We don’t do Moldflow analysis in a vacuum. Everyone has their own agenda as to how a mold should be built. However, when you work collaboratively, you’re able to solve problems much faster.” Besides face-to-face meetings, Lankisch and his team conduct on-line sessions to ensure everyone involved in any given project are all on the same page at any given moment. “We conduct thousands of simulations,” Lankisch notes. “We consider ourselves the leader in Moldflow consulting for good reason. We can conduct accurate analyses quickly and we are able to anticipate the needs of our customers. PM Mold was no exception.”
From a consultant’s perspective, Lankisch considers the criteria required to ensure optimum results for any given analysis. He says, “Much of that criteria boils down to management of expectations. Many times, new customers such as PM Mold tell us they need a Moldflow analysis, but they do not know what to expect from the results. Usually, their customers mandate the work even though they do not have guidelines as to what the analysis data will provide. Hence, it’s incumbent upon us to interview our clients and understand in detail what they expect from the analyses.”
Mark Solberg, CAE services’ vice-president of sales, says, “Our goal is to ‘get it right the first time.’ This approach ultimately translates cost savings to our clients. Eliminating trial and error methods is our primary objective. Reducing our customers’ costs translates to value. Providing value to our customer is our ultimate goal.”
In a fiercely competitive global marketplace, many U.S.-based manufacturers are losing business to the Far East. PM Mold is taking steps to maintain its customer base. Hauck says that the company is offering more value-added services such as program management, Moldflow analysis, and technical support for their products. Hauck ends by saying, “The bottom line is PM Mold offers quality and value in all of the products and services we offer.”