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.
A statistical evaluation was performed to evaluate the effects of design, material and processing conditions on the tensile properties of a filled polypropylene. Coupons were machined from injection molded plaques at different orientations and evaluated using the common tensile test. The results were compared using an analysis of variance (ANOVA). The following effects were found to be of significance in decreasing order: the type of filler, the level of filler and orientation.
A critical first step in analyzing a plastic part failure is the examination of the cracking and the fracture surfaces. Important clues in understanding the failure mechanism are revealed by the recognition of distinctive crack pattern and characteristic fracture surface features. Several actual field failure case histories are described to illustrate the microscopic techniques and how the interaction of mechanical stresses and service environment produce unexpected failures.
Following is the development of a method for the rapid design of bridge or short production tooling for injection molding. Starting with a product definition, part was modeled in a solid modeler. The part model was analyzed by the finite element method for performance under load and by flow analysis software to determine molding characteristics.Once the design was proven, NC code was generated to cut the cavity and runner system. The mold was commissioned and the mold cycle parameters were verified.
Increasingly, companies are looking for leaders and not managers. Inherent in this move is the necessity for skills to motivate and develop employees. One way to cultivate leaders, as opposed to managers, and to drive positive change in an organization is to implement a coaching and mentoring system for employee development and day to day management. The next logical questions is how do you develop coaches and mentors?" This paper will provide some insight into this question and possible solutions that may work for your organization."
This paper describes the development of a system control and data acquisition (SCADA) system for a Killion KTS-100 extruder. At the heart of this computer based system is LabVIEW software that facilitates the various operational requirements. Particular attention is given to the human-machine interface that allows the operator to observe the extruder's operational conditions and permit necessary operational changes to the process.
A new elastomeric homopolymer polypropylene has recently been developed. Its unique properties are caused by the introduction of a controlled level of stereo-errors into the PP chain. This new-to-the-world material has the possibility to replace existing polymers at low cost such as thermoplastic elastomers (TPEs), flexible PVC, rubbers and other high performance polymers with the additional benefit that the polymer is completely recyclable (the only building blocks are propene!).
A new type glass fibers which are coated by thermoplastic resin, PA resin in this paper was used as reinforcements of PP injection molding materials. This fibers and surface the aments created thick interphase and also interdiffusion occurred PA and PP resin. The residual fiber length pellet was longer and interfacial shear strength was larger. Accordingly not only high tensile strength but also high impact strength injection moldings could be achieved by this new type glass fiber.
This research explores the development of thermoplastic olefin compounds through direct sheet extrusion and their thermoforming characteristics. A number of high rubber content formulations were compounded on a twin-screw extruder and formed directly into sheets via a gear pump. Sheets produced by direct sheet extrusion were thermoformed using a several thermoforming techniques, and the effect of material properties on thermoformability was evaluated for high draw applications. A thermoforming process window was developed for each compound and processing method.
In opposite to most screw designs the geometry of some single screw concepts lead to a break-up of the so called solid bed. Therefore the well known Tadmor-Model is not capable to describe this melting behavior. First approaches for such a model were already made by several scientists. Unfortunately these models assuming some simplifications having a strong effect on the accuracy. Thus a new dispersed solids melting model was developed assuming less simplifications. It shows good agreement with experimental results.
The drawing behavior of UHMWPE fibers in supercritical CO2 is compared to that in air at different temperatures. Temperature substantially influences the drawing properties in air, while in scCO2 a constant mechanical response is observed. DSC and WAXS results show that air-drawn samples crystallize during deformation in an internally constrained manner, promoting changes in their thermal behavior. In contrast, scCO2 allows crystals to grow without constraints through a possible crystal-crystal transformation, increasing the processing temperature to 110°C.
There continues to be a need for additional uses of recycled plastics. A significant portion of recycling applications require outdoor exposure including use in aqueous applications. This paper covers the effects of water on the properties of recycled plastics under tensile loads. The paper also covers long term creep effects.
In today's industry, there is a constant debate over the methods used to meet production requirements. Using a single, high cavitation tool is often compared against using multiple low cavitation tools. There are numerous factors that must be considered when deciding on which tooling option to specify and its ultimate effect on part cost. The scope of this paper is to serve as an aid in the tool selection process by providing a step-by-step process that allows a company to make a well-informed decision on tooling layouts while considering the impact of each factor on part cost.
The effect of varying groove geometry on the solids conveying performance of a grooved feed extruder was evaluated. Three groove styles and two resins were evaluated on a single barrier screw design. The results indicate that groove geometry has a strong effect on extruder performance for HDPE but a negligible effect for LLDPE.
A hybrid composite consisting of rubber toughened nylon 6,6, glass fiber and LCP was investigated by varying LCP content. The hybrid system exhibited better processability than the glass fiber reinforced composite. A decrease in the total torque was observed with the LCP content indicating the reduction in the energy consumed during the processing of the hybrid composites. Thermal stability of the glass fiber reinforced composites improved with LCP addition. SEM observation of the tensile fracture surface revealed LCP fibrillation in the toughened matrix.
The effect of absorbed moisture on the rheological behavior of a series of calenderable copolyester resins is studied. Moisture has a profound effect on the viscosity of the resins at calendering temperatures and on the glass transition temperature of the resins. However, moisture does not lead to hydrolysis of the copolyesters at the relatively low temperatures used in calendering.
This paper presents a study on how shear induced melt variations, developed in runners, continue into a cavity and affect the shape of high precision cylindrically molded parts. Melt variations from the runner create asymmetrical conditions within the part forming cavities. These asymmetrical conditions can create side-to-side variations which effect concentricity in high precisions parts such as gears. Effects of process, gating locations and runner designs are presented.
The impact behavior of poly(vinyl chloride) (PVC) siding formulations containing chlorinated polyethylene (CPE) and acrylic core-shell impact modifiers was evaluated using an instrumented impact tester. The samples were tested at room temperature over a range of testing speeds. Differences in strain rate sensitivity were observed for the various formulations. The differences appear to be a result of both the impact modifiers and the overall formulation.
Mechanical spectra of atactic poly(methyl methacrylate) were measured via dynamic mechanical analysis. Measurements were taken on specimens annealed in the temperature range of 23 to 100°C for varying lengths of time. It was found that the effects of thermal treatment are more varied than previously reported, with significant differences found in the breadth and location of the ? and ? relaxation peaks.
The study was made by modifying the simulation mesh model characteristics to mold normalized test specimens. The simulation results were obtained through a filling/cooling simulation program for the injection molding process. The simulated filling time, optimum cycle time and injection pressure, seemed to be influence by the number of elements model. A best agreement between experimental and simulation results were obtained by increasing the number of elements of the mesh model.
The determination of the relaxation modulus using the step imposition of a strain is an important step in the fitting of the parameters of viscoelastic constitutive equation. In the nonlinear region the true shear strain imposed on a polyethylene melt is found to deviate considerably from the targeted strain due to the presence of wall slip which is documented here. The presence of the wall slip reduces the range of strains for which the strain-dependent relaxation modulus can be determined for the linear polyethylene melt investigated.
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Brown, H. L. and Jones, D. H. 2016, May.
"Insert title of paper here in quotes,"
ANTEC 2016 - Indianapolis, Indiana, USA May 23-25, 2016. [On-line].
Society of Plastics Engineers
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