The SPE Library contains thousands of papers, presentations, journal briefs and recorded webinars from the best minds in the Plastics Industry. Spanning almost two decades, this collection of published research and development work in polymer science and plastics technology is a wealth of knowledge and information for anyone involved in plastics.
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Progressive Forming of Thermoplastic Laminates
Thermoplastic composite laminates can be post-manufactured by progressively thermoforming them to generate contoured parts from prior flat panels. This process is attractive for expanding the potential usage of composite materials in next generation transportation infrastructure marine and military sectors for part replacement and structural applications. Thermoforming has proven to be an efficient means for creating parts of complex geometries. Accurately predicting material properties and temperatures prior to forming is of utmost importance to minimize waste and reduce cost for mass-production applications. This paper presents a finiteelement modeling approach to establish the manufacturing parameters for locally formed thermoplastic composite plates.
Thin Wall and Superior Surface Quality Processing Method of Fiber Reinforced Thermoplastic for Cosmetic Applications
The induction heating capabilities allow high-heat molding of the tool to obtain a resin-rich surface of the final part and avoid forming issues or surface defects while also keeping cycle time and energy consumption at acceptable levels. This presentation will discuss some design rules describing key points such as: steel selection inductive integration thermal expansion H&C performance and energy consumption. Finally examples of tool design and associated cycle time will be shared along with trends for large parts in order to propose an out-of-autoclave process
Process Material & Part Characterization of the Innovative Direct SMC Process
For manufacturing of compression moulded parts with long fibre reinforcement and thermoset matrix the Direct Sheet Moulding Compound Process (D-SMC) has been developed. In this process the compound is being inline manufactured and subsequently directly moulded. In that way a consistent compounding process with constant material treatment is achieved with very short processing times of minimum 15 minutes from mixing to molding. A prototype manufacturing D-SMC line has been set up in full industrial scale in conjunction with a 3600 tons press. The process control is fully integrated from raw material dosing over compound manufacturing until compression moulding of parts. In this paper the characteristics of this new and innovative process have been investigated with respect to the achievable material and part properties.
New Molding Process Offers Unique Levels of Design Complexity Mechanical Strength Cost Reduction for Long-Fiber Thermoplastic Composites
A new technology has emerged that offers significant advantages vs. traditional molding processes through rapid cycles excellent surface finish and 3D design possibilities in a closed molding process similar to injection molding while producing parts with material properties similar to compression molding by keeping post-mold fibers longer – typically 10 mm / 0.4 in. in very-complex designs and up to 50 mm / 2 in. in simpler structures. This paper summarizes the research and results of a comprehensive 10-year study on the effects and benefits demonstrated by this new molding process through an analysis of its design flexibility material formulation cycle-time reduction strength improvement aesthetic enhancement and weight-saving capabilities.
Aerospace Process Control for Automotive Composites: Defect Prevention Data Collection and Documentation
As the automotive industry makes the transition from metal parts to high-performance composite materials in critical structures it will encounter many of the problems that the aerospace industry has already grappled with and resolved. The systems used in aerospace composites to verify and document acceptable fiber orientation absence of FOD (Foreign Objects or Debris) accurate vacuum and debulk out time and material batch are described. Current development efforts to extend capabilities to automatically address wrinkles and other forms of fiber distortion are also discussed.
Production of a Class 8 Truck Trailer Bed Using c-PBT Thermoplastic Prepreg and Vacuum Bag Processing
An ambitious multi-year program was recently undertaken in Europe to improve the sustainability of composites used in transportation – particularly with respect to the ability to develop thick parts with large surface areas economically. The program worked with a novel highly reinforced thermoplastic composite based on cyclic oligomers of polybutylene terephthalate (cPBT) which were used to produce thermoplastic prepregs that were then evaluated in vacuum bag processes while liquid cPBT / fiberglass systems were assessed in vacuum infusion and vacuum-assisted resin-transfer molding – all forming processes traditionally used for composites with thermoset (not thermoplastic) matrices. Once the best material / process combination for the program was determined and small-scale testing confirmed the finished composite provided sufficient mechanical performance the prepreg / vacuum bag process was selected to mold one of the largest thermoplastic parts ever produced: a 3-piece structural floor for a flat-bed trailer for a Class 8 truck which is the focus of this paper.
Dielectric Sensing Technology: Key to Productivity & Product Consistency
Breakthroughs in dielectric sensor design have resulted in the development of durable in-mold sensors that can operate on the production floor and in the laboratory. Thermoset molders can now “see” changes in flow and cure inside their production tools and in spiral flow tools allowing automatic “real-time” adjustments for process variation and enabling significant gains in productivity and quality. Dielectric cure monitoring has been used in thermoset laboratories for decades to characterize materials. Historically attempts to take the technology to the production floor where the benefits can be maximized in production tools have failed due to shortcomings in sensor durability and system re-liability. Signature Control Engineering has made significant advances in sensor design cabling and hardware to provide molders with a robust system capable of operating in the harsh production envi-ronment. Additionally advances in spiral flow tool design coupled with the SmartTrac technology have opened a window of opportunity to optimize thermoset compound processes. Production and laboratory dielectric cure control uses in-mold sensors to measure the electrical impedance across the mold cavity during curing of the thermoset materials. The dielectric properties of thermosets vary dramatically during cure due to the changing ability of dipolar molecules to oscillate in the applied electrical field. An impedance “signature” is created for the material during the cure which is correlated to adequate cure state by a computer control system. Benefits to compression and injection olders include:5-20% reductions in cycle time due to the elimination of safety factors built into the process to accommodate for process variation Improvements in quality because you are curing to a fixed cure state rather than a fixed cure time. Fixed cure states mean consistent finished part properties and the elimination of cure related scrap better understanding of flow and cure rates inside the mold.
Adhesive Technology for Automotive Multi-Material Substrate Bonding
The global trend towards improved fuel efficiency and reduced environmental impact is driving the use of new and dissimilar substrates for lightweight vehicle construction. Modern lightweight designs require new joining technologies to support the use of new materials as well as an increased use of mixed material substrates. Adhesive bonding is an enabler for lightweight and mixed substrate construction — allowing joining where traditional methods are not feasible — and takes advantage of structural bonding benefits such as improved load bearing capability enhanced NVH performance ride and handling and safety. This presentation will focus on the available adhesive-bonding solutions and will give an outlook into future adhesive-development directions.
Precision Waterjet Cutting in the Composites Industry Utilizing Robots for High Quality Accurate Machining
5 Axis Gantry robots and 6 axis Articulated arm robots have been used with plain waterjets for many applications especially in the automotive industry. This paper is on extending the use of these robots to abrasive waterjets and for a much wider range of applications primarily in the composites market. This paper discusses the cutting process of the ultra high pressure waterjet and its technical advantages over conventional mechanical cutting tools. The integration of the abrasive waterjet process on robotic arms has been successfully developed to address the end effector supply of high pressure water and abrasives to the cutting head and operational safety. Off line programming calibration and inspection are discussed. Advanced software packages typically used in the aerospace industry have been successfully adapted. A few case studies are presented in this paper addressing composite trimming for wing skins used in aircraft and wind turbines small airframe composite parts glass trimming for high efficiency solar panels and three dimensional machining of relatively small parts used in jet engines.
Heatpipe / Thermosyphon Augmented Mandrels to Improve Cure Quality and to Reduce Cure Time in the Thermoset Pipe and Tube Filament Winding Process
Filament winding as a composite process for fabricating highstrength reinforced thermoset hollow structures is well documented. Traditionally cure was accomplished in a convection oven and this cure sequence was the most time consuming portion of the overall process as well as the least predictably controlled. This paper will define and detail a new method for curing filament-wound composites. Here a closed-loop controlled heatpipe thermally enhanced mandrel heated by induction heating replaces a cure oven allowing for very-rapid cure and permitting the escape of volatiles and water vapour that normally are trapped interstitially.
Continuous Fiber Reinforced Thermoplastic (CFRT®) Inserts for Injection Over-Molding in Structural Applications
A primary goal in automotive structures is reduction of weight while maintaining or improving other desirable attributes. Composite materials offer solutions to weight reduction in comparison to metal structures and thermoplastic composite materials offer the added benefits of improved cycle times high impact resistance cost-effective solutions and a path for sustainability. Developments in the area of injection over-molding of structural inserts produced from continuous-fiber-reinforced thermoplastics (CFRT ®) are an example of this and combine the advantages of injection molding with CFRT properties. Typical applications are in seat structures airbag housings front-end modules and crash beams that take advantage of the excellent strength and impact characteristics of the materials. A seat back application produced with injection over-molding of CFRT inserts is used as a demonstration case study.
High Pressure Resin Transfer Molding—Process Advancements
The resin transfer moulding (RTM) process is well established for low-volume manufacturing and has recently gained interest for manufacturing higher volumes particularly in automotive to produce lightweight composite structures. However the process is currently limited by the low-volume production capacity of the preforming processes long impregnation times and lack of robust processing equipment all of which limit RTM’s use for continuous manufacturing of components. This presentation addresses recent developments in the RTM process and RandD strategies of a trilateral collaboration working to address these issues.
Robotic Trimming Cutting & Sanding of Carbon Fiber Body Structures
Stamped steel body structures set a benchmark for construction and aesthetics that any alternative including carbon fiber body structures must meet. The challenge to carbon fiber body structure manufacturers is to achieve the traditional body structure standards while maintaining the most competitive possible per part manufacturing costs. Fortunately for these manufacturers there is a great deal of accumulated experience in composite manufacturing including the finishing and trimming processes that can be among the most challenging to automate. This paper will discuss some of the robotic technologies that have been adopted from other composite finishing and trimming processes to meet the needs of carbon fiber body structure manufacturers. Specific examples will be discussed including robotic sanding of Class A surfaces and abrasive waterjet cutting of holes and features on various carbon fiber body structures both of which are or will soon be in full production. For abrasive waterjet cutting this paper will elaborate on a unique approach that was developed using robots to manipulate parts while secondary robots manipulate the abrasive waterjet media.The paper will also discuss the advantages of these robotic solutions vs. other approaches including lower running costs and the flexibility to quickly adapt to product or model changes.
Engineering Software for Designing Cost Effective Mixed Material Vehicles
This presentation discusses issues that must be addressed by engineering software tools currently used for metal structures and based primarily on geometry so that engineers can efficiently make the tradeoffs required to design mixed-material vehicles. Engineering software must help identify optimal combinations of materials assembly methods and joining technologies by allowing engineers to efficiently conduct tradeoffs. These tradeoffs include assembly complexity vs. part complexity the appropriate mix of material (metals plastics composites) the impact of alternative joining methods and assessment of part manufacturing and assembly alternatives while concurrently conducting an integrated design cost and performance assessment as design features are changed.
Continuing Evolution of Low Density SMC for the Automotive Market
This presentation will showcase some examples of the current market for low-density sheet-molding compound (SMC) and will provide a brief history of weight reduction initiatives and benefits in the automotive industry. One specific development program will be described in detail. This program focused on improving stiffness-to-weight ratio maximizing the benefit of microsphere technologies and creating a paint-ready surface suitable for high-appearance applications. The result was a new low-density SMC with an industry-leading density of 1.18 sp.gr. — 9% lower than the previous industry best. The discussion concludes with a peek at future opportunities for thermoset composites in this specific marketplace.
High-Volume Automotive Structural Composites: Novel Thoughts on Key Enabling Materials and Manufacturing Technologies
Fiberglass-reinforced epoxy (FG/epoxy) and carbon fiber-reinforced epoxy (CF/epoxy) composite components are known to be produced in high volumes using the compression-molding process. This same molding technology can reasonably be expected to produce high volumes of CF/epoxy automotive body structure and chassis components. The author discusses unique epoxy chemistry forming and molding processes possible due to the thermoplastic stage-of-cure referred to as the epoxy “B-stage.” B-staged epoxies are discussed and then compared to what is commonly referred to as a B-staged sheet molding compound (SMC). A progression-molding assembly line concept similar in configuration to existing automotive sheetmetal forming lines is discussed. This conceptual molding operation would be capable of producing complex CF/epoxy structural composite components at a rate of at least 120 / hour.
Decreasing VOC Emissions at the Source with New Additive Technologies for Olefin Composites
New pressures and regulations in the transportation and commercial and residential construction industries intended to improve “interior” air quality are spurring new research in additive technologies to reduce emission of volatile organic compounds (VOCs) odors and fogging for polymeric materials. Much work has already been done to help reduce VOCs odors and fogging by addressing coupling-agent purity. Unfortunately there are many pathways for the release of VOC emissions and in cases where they cannot be eliminated at the source in components of the masterbatch a third strategy is needed. One such approach described in this presentation has studied the use of adsorbents and stripping agents during extrusion compounding of the masterbatch to capture and flashoff (in the case of stripping agents) or permanently bind up (in the case of adsorbents) VOCs and fogging or odor causing emissions.
High-Pressure Resin Injection – Key Technology for Large-Scale Production
The presentation differentiates the high-pressure processes from the standard resin injection molding (RTM) processes and discusses the latest R&D results regarding the development of high-pressure RTM of high-performance fiber compounds. The focal point is set on the innovative production processes suitable for high volume as well as on the industrialization of the so-called RTM process within the high-pressure compression RTM (CRTM) process --from preforming to the final component. The compression process is of special focus. Various process parameters and their influence on part quality are highlighted and a serial process run is demonstrated.
Design and Part Performance Testing for Thermoplastic Automotive Oil Pans—NA Market
Thermoplastic oil pans are an up and coming metal-to-plastic application. With the need for light-weighting vehicles for improved fuel economy and reduced emissions thermoplastic oil pans and oil pan modules that incorporate the windage tray and oil pickup tube are under investigation at a majority of the global OEMs. At present there are 7 serial product thermoplastic oil pans most of which have just launched in the past 18 months. This presentation will provide a brief overview of OEM concerns by global region and outline the component design challenges. The focus will highlight the CAE analysis methodology used on current productions plastic pans and provide a comparison of plastic pan performance relative to aluminum or stamped steel.
Improving DLFT Molding Productivity via Lessons Learned in Non-Automotive Applications
Applying the direct-long-fiber-thermoplastics (DLFT) process to recent composite product launches outside of automotive has given a fresh perspective on how to create more effective products and efficient launches for future DLFT applications. Recent expansions of DLFT into markets such as agricultural construction personal watercraft recreational vehicles and trailers brought unique challenges that fit the flexibility of the DLFT process. Combining common materials such as glass and polypropylene with more unique materials such as wood block and recycled polymers led to a unique over- molding solution for one high-volume molding application with aggressive material cost targets. Other lower volume applications benefited from new predictive-modeling techniques of long-fiber compression molding to ensure the proper tool design of a compression molded part that weighed 40 kg and that had a length of 2.7 m could achieve a 99.9% accuracy in its length from the first shots of the tool.
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