method to make its acoustic parts. The simulation approach, which took two years to develop, became available for the company’s use this summer.It is cur- rently limited to drape and vacuum forming technologies, but Rieter is work- ing to extend it to compression molding. The ultimate idea is to predict and optimize heating and cooling times, energy cost, material distribution, and COMPOSITES ■ Rieter Automotive Systems, a global producer of automotive trim compo- nents and a leader in acoustic systems, unveiled several new technologies last June at its 17th biennial acoustics con- ference for customers at its headquar- ters in Winterthur, Switzerland. Fore- most among these was novel software for simulating Rieter’s many process and material options for making car- peted acoustic laminates. Other new developments include acoustic lami- nates with full or partial foil heat shields and new technology for using glass or natural fibers in direct com- pounding and molding of long-fiber thermoplastic (DLFT) composites. Simulating laminates Rieter, which has U.S. offices near Detroit, makes acoustic laminates by drape forming, vacuum forming, and matched-metal compression molding, among other methods. The company also has a wide range of acoustic mate- rials to choose from, such as coconut fiber,cotton shoddy (shredded clothing), and small air-filled pouches of PE film glued to the underside of parts.With the help of the Royal Institute of Technol- ogy in Stockholm, Sweden, Rieter devel- oped simulation software to help choose the most efficient manufacturing Close-Up residual stresses during and after form- ing.The software simulates deformation with single- or double-sided tooling, either draping with heat and gravity or thermoforming with heat and vacuum. Rieter’s software combines com- mercial finite-element software mod- ules to model the shear behavior of com- posite textile fabrics (woven, non-woven, and tufted). Rieter also used experi- mental software developed by Dr. J. Bergstrom of Exponent Inc. in Natick, Mass. This models the relative vis- coelastic behavior of mono- and multi- layer polymeric materials, using an approach originally developed for par- ticle-filled elastomers. Rieter tested its new program by simulating relatively simple axial stretching of a multi-layer carpeted material in a “picture-frame” appara- tus. The frame applies shear by pulling a square shape into a rhomboid while measuring the temperature and the New Technologies for Automotive TP Composites & Acoustic Laminates www.ptonline.com Novel software allows Rieter to simulate different process options to find the most efficient way to make carpeted acoustic-shield parts. Rieter deformed multi-layer carpeted samples in a test frame and found they matched the simulated deformations.
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COMPOSITES Close-Up - · PDF file38 December 2005 COMPOSITES Close-Up stress applied in a single plane. Rieter tested a floor underlay panel of nylon-tufted carpet backed
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method to make its acoustic parts.Thesimulation approach, which took twoyears to develop, became available forthe company’s use this summer.It is cur-rently limited to drape and vacuumforming technologies,but Rieter is work-ing to extend it to compression molding.
The ultimate idea is to predict andoptimize heating and cooling times,energy cost, material distribution, and
COMPOSITES
■ Rieter Automotive Systems,a globalproducer of automotive trim compo-nents and a leader in acoustic systems,unveiled several new technologies lastJune at its 17th biennial acoustics con-ference for customers at its headquar-ters in Winterthur, Switzerland. Fore-most among these was novel softwarefor simulating Rieter’s many processand material options for making car-peted acoustic laminates. Other newdevelopments include acoustic lami-nates with full or partial foil heatshields and new technology for usingglass or natural fibers in direct com-pounding and molding of long-fiberthermoplastic (DLFT) composites.
Simulating laminatesRieter, which has U.S. offices near
Detroit, makes acoustic laminates bydrape forming, vacuum forming, andmatched-metal compression molding,among other methods. The companyalso has a wide range of acoustic mate-rials to choose from, such as coconutfiber,cotton shoddy (shredded clothing),and small air-filled pouches of PE filmglued to the underside of parts.With thehelp of the Royal Institute of Technol-ogy in Stockholm,Sweden,Rieter devel-oped simulation software to help choosethe most efficient manufacturing
Close-Up
residual stresses during and after form-ing.The software simulates deformationwith single- or double-sided tooling,either draping with heat and gravity orthermoforming with heat and vacuum.
Rieter’s software combines com-mercial finite-element software mod-ules to model the shear behavior of com-posite textile fabrics (woven,non-woven,and tufted). Rieter also used experi-mental software developed by Dr. J.Bergstrom of Exponent Inc. in Natick,Mass. This models the relative vis-coelastic behavior of mono- and multi-layer polymeric materials, using anapproach originally developed for par-ticle-filled elastomers.
Rieter tested its new program bysimulating relatively simple axialstretching of a multi-layer carpetedmaterial in a “picture-frame” appara-tus.The frame applies shear by pullinga square shape into a rhomboid whilemeasuring the temperature and the
New Technologies for AutomotiveTP Composites & Acoustic Laminates
www.ptonline.com December 2005 37
Novel software allows Rieter to simulate different process options tofind the most efficient way to make carpeted acoustic-shield parts.
Rieterdeformedmulti-layercarpetedsamples in atest frameand foundthey matchedthe simulateddeformations.
December 2005 www.ptonline.com38
COMPOSITES Close-Up
stress applied in a single plane.Rieter tested a floor underlay
panel of nylon-tufted carpet backedwith layers of nonwoven reinforcementfibers, latex adhesive, mixed-feltacoustic substrate,and multi-layer PEfilm.The acoustic substrate was cottonshoddy (40% to 90% cotton) madefrom shredded clothing. Rieter foundgood agreement between the simulated“picture-frame” stretching and actualshear deformation behavior.
ing innovation,called Al-FA (aluminumfoil application), molds a sandwich ofDLFT composite with one or two skins
of aluminum foil as a heat shield.A pro-totype part with one foil skin is beingroad tested.
Rieter says it is far more difficultto apply a partial heat shield than tocover an entire part surface with foil.Until now, parts with partial foil cover-ings were made in two steps: First thepart was formed, and then foil wasapplied with secondary heating. Rieterhas now developed a one-step methodfor partial heat shields.
Natural-fiber compositeRieter’s most celebrated recent
DLFT achievement is its first natural-fiber part, a spare-wheel pan cover forDaimlerChrysler,which is also the first
natural-fiber exter-nal body part for aproduction car. Ituses abaca fibermade by ManilaCordage in thePhilippines. Abacais a relative of thebanana plant that israised for makingmarine rope andtwine. A compoundof polypropyleneand 30% choppedabaca fiber waspatented by Daim-lerChrysler for auto-
motive molding. The part won the topautomotive prize at the JEC show inParis last spring and the Environ-mental category of the SPE Automo-tive Innovation Awards last month.Part of Rieter’s achievement was mov-ing the part from R&D to production inonly 18 months.
Rieter uses a new servo-controlledprofiling die to control the thickness ofthe extruded molten slab.Such a die isalso used for glass-filled DLFT,but it ismore essential for natural-fiber com-pounds because they are much moreviscous. Without profiling they wouldrequire extremely high tonnage topress into thin-wall parts.
Rieter places different profiles ofmolten abaca/PP slab in specific toollocations to optimize the molding cycle.Multiple profiles overlap, so there isno weld-line problem, Rieter says.
A second new Rieter device makesit possible to feed either glass or nat-ural-fiber rovings without changing theproduction set-up. Also, Rieter devel-oped “two-component” compressionmolding, using materials with higherand lower percentages of long-glassfiber at specific locations in a tool.Thisapproach is being tested for an under-floor part. —JanH.Schut