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How important is material testing when it comes to quality parts? Just ask Innovative Polymer Compounds Ltd., a specialty compounder of medical grade engineering polymers based in Kilbeggan, County Westmeath, Ireland. IPC is a joint venture company between Associated Plastics of Ireland Ltd., a polymer compounding company, and National Chemical Co. Ltd., a polymer and chemicals distribution company. Both companies have more than 30 years experience in the polymer industry.

PlasticsToday Staff

February 27, 2012

6 Min Read
IPC, Teel Plastics utilize material testing to emphasize quality

Set up in 2008 and certified to ISO 9001, IPC processes polymers from Arkema, Lubrizol, BASF, EMS, DuPont, Evonik and Solvay. IPC compounds these polymers with other polymers, pigments, radioscope fillers such as barium sulphate or bismuth oxychloride and, more recently, antimicrobial additives.

"Our new state-of-the-art compounding facility encompasses all of the features a customer would require of a 100K clean room, with accurate control of air quality, dust extraction and temperature control in each of our material process halls," said Joe Molloy, technical director for IPC.

IPC performs its own color matching using a base range of FDA-approved pigments, which achieves tighter and more consistent color tolerances as well as short lead times for colored compounds to Pantone, Munsell or RAL references. The company also faces unique quality assurance challenges including the careful selection and testing of incoming raw materials. "As our processing and environmental systems are tightly controlled, batch-to-batch variability of our raw materials would cause us the greatest concern in maintaining product quality," Molloy stated. "We have ensured that this variability is kept to a minimum.

To perform these material tests, IPC installed a 5kN-capacity ProLine table top testing machine from Zwick/Roell AG, a global supplier of material and component testing systems headquartered in Ulm, Germany. The ProLine is equipped with a Longstroke extensometer for tensile property testing using a range of injection molded and punched "dumb-bell" samples. Based on previous of the same formulation, decisions on product quality can be determined.

Recently, Zwick/Roell introduced its new Allround-Line, a flexible suite of materials testing systems with two test areas that are well suited to both quality control and research projects, according to Helmut Fahrenholz, Swick industry manager for plastics. "This new generation of Allround-Line testing machines sees Zwick once again setting the standard in static materials testing," said Fahrenholz.

The new Allround-Line has the latest testControl II control electronics, which provides for the greatest accuracy, control and acquisition rate. It also provides high rates of speed in testing and positioning to enable new options in applications which fast data return rates enable short cycle times.  The testControl II electronics also feature integrated adaptive control with automatic setting of all control parameters, sophisticated strain rate control and online compensation for changes in specimen properties.

Fahrenholz adds that a real advantage for raw-materials producers performing repetitive tests is the capabilities of the systems in the Allround-Line to store and retrieve complete toolset data. Automatic positioning and recall of safety-related distances speed changeover from one test setup to another, such as from tensile to flexure.

IPC's Molloy commented on the ProLine system: "Tensile properties are of great benefit to us when processing hygroscopic polymers such as polyurethanes and polyamides as this data can provide information on processing conditions or issues encountered during batch production."

The Zwick/Roell ProLine system has an easy user interface and test reports are clear and easily understood. It uses Zwick's testExpert II software which Molloy said that overall, the ProLine "In day-to-day use is reliable and repeatable."

The new Allround-Line system's mechanical modularity offers addition additional benefits to research facilities that need to test a wide range of specimens under varying applications. The Allround-Line is designed with a flexlble plug and slot system to allow specimen grips and test fixtures to be changed whenever required enabling a single system to address a wide range of tests. "This is extremely useful for testing of long fiber-reinforced composities," Fahrenholz added.

Teel Plastics' add in-house material testing lab to improve quality, performance

While the raw material is just one of many variables in plastics processing, it can often be the source of the most difficult problems to identify and solve. Unless your supplier provides the testing data to you, you might not be getting what you think you're getting. Do you know what your resin is? Teel Plastics decided to find out just exactly whether or not the materials they were using met the standards for the products they were making.

Founded in 1951, Teel Plastics has evolved to become a specialist in custom extruded plastic tubing, cores, profiles, and pultrusion for fiberglass tubes, profiles and handles. Additionally, the company offers custom compounding and extrusion manufacturing through its Teeldas division, which it started in 2010. Today, Teel operates out of four manufacturing facilities, including its newest, a 150,000-sq-ft plant that the company moved into in 2007. In 1999, JLS Investment Group Inc. acquired Teel Plastics, and under the leadership of Chairman Jay Smith, the company has redefined its strategic direction and developed a culture of Lean manufacturing.

Many of the products Teel develops have specific material requirements, such as materials to produce geothermal pipe for industrial uses. "There had been issue with product development in that the material had to have certain properties to meet impact strength under certain burst pressures under ASTM 1599," said Joe Lischefski, Laboratory Supervisor for Teel Plastics. "We struggled to meet that burst pressure requirement.

In the second quarter of 2011, Teel began installing a complete materials testing laboratory to address these issues and to ensure that each and every product that Teel produces meets exacting standards. Primarily, Lischefski uses a differential scanning calorimeter from Mettler-Toledo International Inc.,  that allows him to accurately measure glass transition temperature, melting point, and the crystalinity of the material.

"We use the lab as a tool to get the product where it needs to be with respect to performance," explained Lischefski. "We test raw materials to understand how those properties impact the properties our products require such as the ASTM 1599, a test we perform on a daily basis."

Teel Plastics performs materials testing and characterization process for its top 10 resin suppliers to ensure that the materials that Teel uses have the specific properties the company needs.  Lischefski notes that for the most part the materials Teel tests from these suppliers confirm and verify that the properties are what the supplier claims.  Obviously there is some variability in the materials, said Lischefski.

"They'll provide a specification range of the material but won't tell you where in the range a certain lot of material falls," he said. "While generally we get confirmation that the material properties are where we need them to be, sometimes we get something completely different. We have no way of knowing exactly the properties and materials specs unless we test it ourselves." 

Lischefski said that material testing at the processor level is just one more level of quality assurance. While it's not often that he finds a lot that is off, "every now and then you get that one," he added. "You can go for a long time and everything is great, but if you don't check the materials that one lot will slip through the cracks."

In the long run, the cost of adding a full materials testing laboratory has paid off for Teel Plastics.  "I can't say enough about good quality data to use for process control, troubleshooting support and product development by having the testing performed by properly trained scientists using the correct equipment and validated methods," Lischefski.  "Top quality materials mean top quality parts and fewer rejects."

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