Erie, PA – July 5, 2008 – Every new injection molding program comes with challenges to get the mold debugged and running quality parts, ASAP. Add to this pressure by customers to keep costs down while molding zero defects.

A top 100 custom molder in the U.S. (who asked not to be named so that their methods of cost reductions are kept proprietary) found a way to meet all these challenges, and a bit more, with a move toward controlling rheology within the mold. The results of implementing rheological control technologies have been quicker mold commissioning and higher quality parts at a reduced scrap rate, and overall lower costs. The technology, known as MeltFlipper® melt-rotation technologies, comes from Beaumont Technologies, Inc. (BTI) of Erie, PA.

“Getting a mold up and running and parts coming off the machine in hours and days, not weeks, is a constant demand all our customers put on us,” says this custom molder’s purchasing manager. “But when the criteria also includes top quality parts, not just “parts”, while trying to earn a modest molding profit at our end, the challenge becomes a bit more complex.”

Such was the case with a new program earlier this year, when one of this custom molder’s larger customers came to them to produce a new product for convenience store shelving: a special, and patented “free paddle” that pushes the next bottle to the front of the shelf when a customer removes the front one.

Controlling Rheology Provides More than Just a Filling Balance

First, the custom molder had to build a 16-cavity mold to produce enough quantity of the small, 8 oz. polypropylene parts.

Owing to the complexity of the parts, the manufacturing design engineer at this custom molder knew mold imbalance was going to be a problem. Typically they would adjust gates or runner sizes to obtain a filling balance, but they would normally still have dimensional and warp problems even though the filling was balanced.

“I had just purchased a book on troubleshooting molding problems*,” says the company spokesman, “and the section in the book discussing mold imbalances and going to the root cause analysis made a whole lot of sense.”

The root cause of most filling variations is different material properties flowing to each cavity of a mold. No amount of runner or gate tweaking can fix that problem. Injection molding is about plastic flow, and making sure the flow and material properties are the same to and within each cavity is a key component to the success of a mold. Thus the need for rheological control.

“That’s when a colleague and I decided to learn about MeltFlipper® melt rotation technology from BTI,” continues the company purchasing manager. “Frankly, some of our colleagues and management here were skeptical. But the fact that the technology came with a 100% customer satisfaction guarantee and the low cost of the solution made the decision easy.”

Controlling Rheology Adds Consistency to the Part and Process

Initial mold sampling without MeltFlipper showed that the outer parts on the 16-cavity cold runner mold were not packing well and did not meet quality specifications. “The consistency just wasn’t there, even with our years of experience trying to fine tune the process,” note company officials. “In order to get acceptable parts, we would often have to block cavities in order to get production out the door, thus lowering the already minimal profit margin.

“However, after applying MeltFlipper technology to the mold, we began putting out perfect parts in all 16-cavities,” says the manufacturing design engineer. “Plus we now had a much larger process window as we could even change the process parameters and still make perfect parts.”

Both the tool designer and manufacturing design engineer agree, and now so does management that “licensing the MeltFlipper technology was an excellent investment, if not just only in scrap reduction.” The company reports the reduction in scrap alone gives the Beaumont Technology product a three month payback.

“With the goals of dimensional stabilization of the parts as well as a reduction in part distortions, we feel we were quite successful,” the company duo notes. “The reduced scrap rate added to the value of the investment. Because of these successes with the program and as parts production further ramps up, the MeltFlipper technology will not only be applied to two additional molds built for the customer, but also for new programs with other customers,” they conclude.

* Runner and Gating Design Handbook by John P. Beaumont ISBN 1-5 6990-347-6:1-56990-291-7, published by Hanser Gardner.

About Beaumont Technologies, Inc.
Beaumont Technologies, Inc., headquartered in Erie, PA, offers a unique mix of products designed to optimize the efficiencies of the mold, parts, and the injection molding process. These products and services are tools that help the injection molding industry become more competitive and profitable in world markets. The company’s expertise lies within an in-depth understanding of polymer flow and processing technologies which enable molders and moldmakers to decrease lead-times while maintaining a high quality level of process and part control. Products include the patented MeltFlipper® and MeltFlipper® MAX™ melt rotation technologies guaranteed to optimize mold balance and cavity fill patterns in hot and cold runner applications, the 5 Step Process™ mold balance analysis software, CAE by BTI™ flow simulation services, and BTI Training™ Seminars.