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Solvay : Moldflow

Founded in 1863, Solvay (Brussels, Belgium) is an international chemical and pharmaceutical company that operates more than 400 companies in 50 countries. It employs more than 32,000 people and serves 160,000 customers worldwide. The company is organized into four sectors: Chemicals, Plastics, Processing and Pharmaceuticals. The Plastics and Plastics Processing groups represent approximately 45% of the company's earnings. They offer polyvinyl chloride (PVC), high-density polyethylene (HD-PE) and various specialty polymers and technical compounds for which Solvay is among the top manufacturers in the world.

The Plastics Processing group focuses on a range of advanced materials and plastics specialties for the automotive, medical, piping, engineering, and construction markets. Solvay is the first world producer of plastic fuel systems for the automotive industry (through joint venture Inergy), foils for the medical community, and is among the largest manufacturers of plastic pipes (joint venture Pipelife).

Dr. Vito Leo has been with Solvay for nearly 20 years and currently is a Senior Scientist at the company's 1,000-person corporate R&D laboratory – the largest Solvay research lab in the world. His work focuses on rheology and injection molding. Rheology is the study of strain and flow of plastics including elasticity, viscosity, and plasticity. Leo says, "Rheology is mostly relevant to the melted state of plastics. There are other scientists here who concentrate on the solid state, mechanical behavior of plastics. I am mostly involved in all the scientific aspects of the molten state of plastics from basic rheological material characterization to processing issues. That includes both testing polymers' rheology to understand their molecular structure or to better assess their flow behavior during processing or part manufacturing. We also study rheology to understand how the molten plastic will flow into molds once we start making actual parts with injection molding or other technologies. Injection molding is one processing method that involves large temperature and pressure variations both in terms of gradients and rates. The behavior of molten plastics that we study through rheology is critical to injection molding and moldability of plastics."

Leo started using Moldflow software from Moldflow Corporation (Wayland, MA) when he began working at Solvay. Back then, the results were purely alpha-numerical - no colorful graphics. Approximately 50 percent of Leo's team work is corporate research (new processing methods, improved polymer grades or novel testing developments for instance) and the other 50% is selling services internally. "We sell our Moldflow analyses to our colleagues here at Solvay who in turn support external customers. This activity allows us to have very close contact with our external customers. I probably spend one week per month visiting external customers to show them Moldflow results and discuss material, design or processing issues," says Leo.

Discussing Moldflow results is a very good opportunity to present in detail the specific behavior or particular strength of our polymers.

Solvay customers
Solvay owns a large part of the polymer commodity window including polypropylene, PVC, and polyethylene. In addition, over the last several years, the market for specialty polymers has been growing. In this area, Solvay is one of three major producers in the world of fluorinated polymers such as PVDF. "We have a wide range of specialized polymers," adds Leo. "And we use Moldflow extensively to support this business. This is particularly true for our range of IXEF materials - the commercial name of semi-aromatic nylons (chemical class PAA poly-aryl-amides). These are sold as glass fiber filled compounds only. They show exceptional stiffness, low viscosity characteristics, good surface aspect and are processed only by injection molding."

Leo manages a 10-person Advanced Polymer Support Team (APST) that solves customers' problems by implementing a "big picture" approach. Leo adds, "Rather than just making measurements and performing computer analyses, we try to be on the front line with a customer as they design a part. As a result of us working closely with customers, manufacturers such as Nokia and Ericsson, leading mobile phone makers, we are helping them design very thin, intricate parts that are very critical in terms of dimensional tolerances, stiffness and impact behavior. We provide a lot of support early in the critical design phase to assure that the customer will be able to produce the parts they need. Moldflow software plays an integral role in this process."

He says that Solvay is also similarly involved with companies such as Schneider, a leader in EE equipment, Philips, the consumer electronics giant, and Braun, a major consumer goods producer. "All these companies use our materials and expertise to design and manufacture many critical plastic parts," explains Leo.

Tough engineering challenges
The underlying common thread among these Solvay customers is that they use Solvay glass fiber filled aromatic nylons (IXEF) - an excellent alternative to using metal. "Our customers typically face the same issues - they want to produce thin, lightweight parts while maintaining structural integrity," adds Leo. Our glass fiber-filled materials are very good candidates to replace metals. However, when customers use fiber-filled materials, they achieve high stiffness, but can simultaneously inherit a very non-isotropic situation. In other words, shrinkage and warpage issues, as well as non-isotropic mechanical properties become part of the engineering challenge. That's when Moldflow is essential."

In addition, using glass fiber-filled materials causes weak weld lines. Leo and his colleagues use Moldflow to address this problem. He says, "For these materials, the plastic flow will actually have a much stronger influence on the final properties than it might have for unfilled PC/ABS for instance. The combination of crystallinity and fibrous fillers creates challenging problems both in terms of part design and process optimization. That's why we work as a team to concurrently study mechanical and flow related issues.

"When we work on a design issue, we evaluate how to mold the part from the very beginning. We prefer early involvement on all projects and studying the whole problem, not parts or pieces of it. Today, we have interfaces with which we can transport the fiber orientation predicted within Moldflow into codes such as ABAQUS, so that the stress analysis we perform will take into account local properties induced by the molding process."

The Advanced Polymer Support team uses other software besides Moldflow including CAD products such as I-DEAS, Pro/ENGINEER, and CATIA, as well as other analysis tools such as ABAQUS, FLUENT, and POLYFLOW.

Moldflow benefits
Leo says that Solvay's customers benefit from Moldflow because of the expertise that he and his team bring to the customer as a result of using Moldflow themselves. "We measure the value of using Moldflow in terms of the success of our products in many markets all over the world," notes Leo. The Advanced Polymer Support Team is involved in nearly half of the company's current significant global IXEF projects for instance. He says that 20% of the engineering polymer business would not be possible without the use of Moldflow. "We are sure that Solvay's Moldflow application has achieved its return on investment many times over during the past 20 years."

Magura bike project
Magura GmbH makes high-quality bicycle accessories and sophisticated hydraulic bike braking systems. The company uses one of Solvay's engineering polymers that contains 50% glass fibers to make its hydraulic system. Recently, Magura engineers experienced mechanical failures with their plastic parts that comprise the hydraulic braking system for one if its newer model bikes. Leo says, "The part was fairly thick and we decided to test out Moldflow's 3D flow technology to help them determine what was causing the field failures and how to solve it. Using a traditional midplane (2D) approach, we have not been able to correctly predict the flow behavior for this thick cavity. The 3D application was very successful. We were able to predict the short shots very accurately. We were also able to identify areas where shrinkage would be quite high due to the local high thickness of the part. In addition, we found a very good correlation between X-ray observations where we found shrinkage voids inside the parts and areas of very high volumetric shrinkage as predicted by Moldflow 3D. As a result, we were able to work on the gate size and location to eliminate high shrinkage. The effort also helped us eliminate bubbles trapped inside the part, and to obtain optimal mechanical characteristics of the part. Using Moldflow helped make the Magura project a complete success," adds Leo.

Trends in the marketplace
Leo says that over the years, he and his colleagues have seen increasingly more companies relying on Moldflow analyses. They are realizing the benefits to conducting plastic flow analyses prior to committing to costly production measures. "We see a lot of new users coming on the market using this Moldflow technology. The software is widely available, is easy to use, and runs on desktop PCs," says Leo. "However, there remains a tremendous lack of knowledge related to the physics behind the software. Too many people believe that running the software itself will solve their problems. We meet people in very large companies that say that they don't see the need to really understand the physics. Rather, they want the software to be so good that they don't need to understand why things are the way they are. This is very wrong ideology. I would say, the more I work in this technology, the more I am convinced that we are particularly efficient at Solvay because of our experience with the software, deep understanding of the underlying assumptions and significant polymer science culture. I have been working for nearly 20 years in this field, and I still learn something everyday."

For more information about Moldflow, visit Visit for more information about Solvay.

Author: Laura Carrabine

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Page last modified on May 11, 2001
Copyright 2001 by John Stark