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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Long fiber thermoplastic (LFT) composite design
studies often emphasize fiber content but are sketchy on
fiber-orientation, fiber-matrix interface and mold design.
In this paper we detail a comprehensive approach to
designing with LFT materials. Specific examples are
given. Carbon-fiber compounds were successfully
substituted for die-cast magnesium parts by redesigning
the metal part for injection molding. Tailored fiber
architectures were achieved through strategic gate
locations, as advised by Finite Element Analysis (FEA)
and Mold Flow Analysis (MFA). Mechanical properties
were enhanced through modified molding processes.
Walter Michaeli | Christian Hopmann | Silke Allert, November 2011
The use of pulsed cold water instead of tempered
coolant is suggested to be a versatile and cost-efficient
technique for the cooling of injection moulds. However,
the advantages and limitations of such discontinuous
cooling strategies are still a controversial issue. In this
paper the behaviour of a discontinuous temperature
control system is analysed with a particular focus on the
reproducibility of the process and the realisable
dimensional stability of the parts and compared to that of
a continuous cooling. For the investigations both a
conventional and a conformal cooling channel geometry
are considered. It turns out that at high mould
temperatures the warpage of the parts can be reduced by
use of discontinuous cooling, but at the same time the
reproducibility of the process is affected adversely. The
regulation of the discontinuous cooling proved to be
challenging especially in combination with conformal
cooling.
E.h. W. Michaeli | Ch. Hopmann | Klaus Küsters, November 2011
Weld lines are formed during injection molding, when
two flow fronts meet. They are often not avoidable in
complex technical parts. Their presence reduces
mechanical strength, especially in high performance short
fiber reinforced materials. Evaluating the load of highly
stressed parts requires accurate knowledge of the
interrelationship between the type of weld line, its
morphological structure and the resulting mechanical
properties. This paper aims at the development of a
simulation method which enables the mechanical
properties of weld lines to be considered precisely in part
design.
Mariangel Berroterán | María Virginia Candal | Nelson Colls | Magda Castillo | Luis Marín, November 2011
The plastic parts for a float-valve system were designed. In the design was considered the use of PET bottles as floating device instead of the regular spheres, in order to promote the reuse of this plastic container and to decrease plastics residues. Additionally, the part thickness was reduced to use less plastic on the parts, and to decrease cycle times. All molds are two-plate and two cavities. The refrigerating system proposed uses U-shape channel, and the expulsion system is composed by ejector pins. Threaded connector´s mold is more complex due to require two-step opening.
Scott W. Steele | Sumit Mukherjee | Mark Rule, November 2011
The use of performance modeling is becoming
more and more critical to the packaging industry.
This trend is driven both by lightweighting efforts
and the need to shorten package development
times. The primary driver for reducing the amount
of material used in packaging is cost reduction,
with environmental positioning an ancillary
benefit. However, it is critical to not compromise
the shelf life or creep performance of the package,
particularly in regions of the world with
temperature extremes.
This paper will explain key elements necessary
for precise modeling of package shelf-life
performance. The mathematical models
considered are M-RULE® Container Performance
Model and Virtual Prototyping™ Software. Some
examples of how computer modeling has been
applied to optimize package performance will be
discussed.
E.h. W. Michaeli | Ch. Hopmann | A. Rebmann, November 2011
The conventional control of the injection moulding
process is based on machine variables, which cannot
sufficiently characterise the course of the process.
Hence, a system that controls the injection moulding
process based on process variables has been developed
at the Institute of Plastics Processing at RWTH Aachen
University during the last years.
The concept of the self-optimising injection moulding
process is based on this research. This paper describes
the concept of the self-optimising injection moulding
process during the holding pressure phase and the idea
of an extension by an incremental cooling system using
small-sized cooling areas.
Christian Hopmann | E.h. Walter Michaeli | Thomas Baranowski | Barbara Heesel, November 2011
The general aim of the Cluster of Excellence
“Integrative Production Technology for High-Wage
Countries” is to overcome the actual contradictions
between value- and planning-orientation as well as
between scale and scope in production technology. One
important aspect of this approach is the development of
virtual production systems to increase simulation
accuracy and thereby to reduce development times and
costs as well as to optimise the utilisation of material. In
this paper new developments in the field of the
calculation of molecular orientation are described and a
validation with different experimental measurements is
presented.
T. Ottnad | S. Gepp | F. Irlinger | T. C. Lüth, November 2011
Miniaturization and individualization are some of
the current and in future ongoing trends in producing
business in general and they also are influencing the
plastics processing industry. To meet the upcoming
challenges a lot of research is being done in the field of
micro-extrusion. This work investigates a method to
identify the phenomenon of extrudate swelling of micro
extruded polypropylene using an optical analyzing
method. Experimental data varying the pressure is
presented and an optical analysis is explained. The results
show the suitability of the method but reveal that some
more experiments have to be done in order to formulate
clear statements.
The role of slip additives as a crucial contributing agent in
product failures due to it’s migration to the surface of
plastic films is explored in the context of 5 case studies
highlighting different aspects of the complex interrelationships
that exist between the base resins, the slip
additive present in the base resins, slip agent added by the
film processor in the form of masterbatches, the color
pigments , processing condition / storage conditions and
the products which are subsequently packed inside the
flexible pouch or flexible laminates.
E. h. Walter Michaeli | Christian Hopmann | Sebastian Grammel, November 2011
This paper presents a 3D numerical model to analyze
the melting process in a single-screw extruder. The
fundamental equations of fluid dynamics are solved using
the Finite Volume Method. The software Fluent
distributed by ANSYS, Inc. was used for the numerical
calculations. The computing domain is a helical-shaped
screw channel. The solid bed is modeled as a fluid with a
very high viscosity by adjusting the formulation of the
Carreau model for temperatures below the melting
temperature. The model predicts the melting length,
pressure build-up and the velocity and temperature
distribution within the channel.
A. B. Coffey | P.R. Walsh | C. Stanley | N.E. Murphy, November 2011
There has been much research in the biomodeling of human blood vessels. Models of human blood vessels can be used for aids in future research of new medical devices that can be preliminarily tested in an in vitro setting and that could potentially lead to breakthroughs in the medical device industry. There is also the possibility to use such models for the training of surgeons, especially for complex operations, analysis of arterial diseases, and to provide the basis for hemodynamic studies. Within the last two decades accurate models have been fabricated using corrosion casts obtained from cadavers and the lost wax process.
Recently, there has been a trend towards replicating the properties of blood vessels more accurately. The use of hydrogels has the potential to achieve this, as it is possible to represent properties such as viscoelasticity, anisotropy, and lubriciousness, all of which have been shown to be present in human blood vessels. The goal of this study is to apply casting methods to a core, which represents similar tortuosity and dimensions to a section of blood vessel, and achieve a low cost model that will represent the dimensional accuracy as well as representing physical properties of blood vessels as accurately as possible. In order to achieve this, poly(vinyl alcohol) (PVOH)/poly (acrylic acid) (PAA) hydrogels were chosen as a material that has the potential to match the properties of blood vessels. The PVOH/PAA hydrogels were prepared using a freeze/thaw processing technique.
W. Michaeli | Ch. Hopmann | P. Awakowicz | K. Bahroun | S. Steves | H. Behm | F. von Fragstein, November 2011
In the presented project a new coating plant for large area microwave (2.45 GHz) excited low pressure plasma coating with substrate bias has been designed, which allows the coating of foils up to a size of 300 * 300 mm². The objective of the research work is to characterize the effects of the process parameters on the properties of plasma-polymerised coatings, particularly regarding their behaviour under strain. Investigations are carried out using a microwave plasma source and polyethylene terephthalate (PET) as substrate material. As layer forming monomers for plasma polymer barrier coating of the substrates are used.
Jiying Fan | Elias Nassiopoulos | James Brighton | Alain De Larminat | James Njuguna, November 2011
Recently advances in research and manufacturing techniques of biocomposites have allowed the car manufactures to use bio-composite in various applications. Biocomposites are fast emerging as viable alternative to traditional materials due to their low cost, lightweight, good mechanical performance and biodegradable properties. ECOSHELL project (Development of new light high-performance environmentally benign composites made of bio-materials and bio-resins for electric car application) proposes to achieve a full bio-composite made of high performance natural resins matrices, resulting in the use of totally natural, environment friendly composites, with enhanced strength and bio-degradability characteristics designed for the electric car.
Matthew Gande | Ryan Fenton | Urs Stadler | Sungyeun Choi, November 2011
Silver is a known antimicrobial agent, and has found use in
protecting a range of products against bacterial growth.
The inherently large surface area of silver nanoparticles
allow for a high release rate of silver ions to the
environment, where they can be active against a wide
range of microbes. Herein, we report a new method of
producing silver nanoparticles using a plasma furnace. This
process easily allows for the support of the nano-silver
material on micron-sized inorganic particles. Silver formed
in this manner is more easily dispersed in polymer systems,
while maintaining antimicrobial activity against gram
positive and negative bacteria.
The European injection moulding market is filled with
numerous injection moulding resins that claim resistance
to ultraviolet light from outdoor exposure. However, few,
if any, have actual comparable data that allows a buyer to
distinguish the performance of one resin to another.
Likewise, if artificial weathering results are given, how
does this relate to actual outdoor performance? Can a
relation to outdoor performance be translated to
geographic variances in weather?
This paper gives a summary of several published
artificial ultraviolet exposure studies, some known
standards with industry acceptance and how the tests
relate to outdoor exposure with a concise experiment
between two UV test methods. Finally, a proposal is
given of standardized ultraviolet resistant testing for the
injection moulding world of polyethylene. This includes
estimating outdoor performance with the variances of
solar radiation based on geography.
Molding and extrusion lines rely on the auxiliary equipment that works with them. This equipment supplies the regrind, resin and additives, cools the process, maintains critical temperatures and even monitors the entire operation. Inadequate process cooling, material handling or size reduction equipment can cause many problems, including the following:; Inadequate process cooling can reduce product output; Poor temperature control can cause product quality issues; Material can be contaminated if not handled and stored properly; The output of the line can be reduced, and even interrupted, if the material is not conveyed to the extruder at the required rate; Product quality will suffer if the material is not blended and metered into the extruder throat at the correct ratios; Excess dust caused by poor size reduction equipment can create processing problems. The following auxiliary equipment is crucial to any molding or extrusion process, and needs to be taken into consideration:; Cooling tower system; Chilled water system; Temperature control units; Bulk storage of the raw material; Material conveying system; Blending and feeding equipment; Crystallizing and drying systems; Size reduction systems. This paper will focus on material handling and blending systems – the other areas will be discussed at a later time.
D.J.M. (Linda) Havermans – van Beek | Rudy Deblieck, November 2011
Resistance to slow crack growth is an important material property of polyethylene which determines the application lifetime, especially for utility pipe applications. Usually, the slow crack growth resistance of materials is accessed by time consuming testing methods such as NPT, FNCT, PENT, etc. These methods require often the use of notched samples, the use of specific fluids (e.g. detergents) and elevated temperatures. Here we present the outline and validation of an elegant method to predict slow crack growth resistance in materials in a simple, accurate and fast way. The resistance to slow crack growth is predicted from a simple tensile measurement at 80 C. It will be shown that the slope of the stress-strain curve above the natural draw ratio (i.e. the strain hardening regime) correlates very well with the results obtained by the full notch creep test (FNCT), Notch Pipe Test (NPT) and the stress intensity ranking of the cyclic loaded Cracked Round Bar test (CRB) of the same materials. This strain hardening method is elegant in that it does not require notched specimen and/or detergents. Besides the advantage that the method is easy to implement in laboratories, its main advantage is the dramatic decrease of measurement times from thousands of hours to only a few. This method is very suitable in the development of new grades, but also very valuable as a batch release test for both resin suppliers and pipe converters.
Hans-Peter Heim | Martin Rohleder | Andrzej K. Bledzki, November 2011
This investigation analyses the notched impact strength of microcellular polycarbonate which was produced by injection molding using physical blowing agents. By varying different processing parameters, such as blowing agent concentration or the injection velocity, injection moulded plates were produced and characterized with regard to morphology and the Charpy notched impact strength. A temperature-dependent analysis concerning the correlation between the foam morphology and the notched impact strength was carried out. Additionally investigations were performed to find out if the failure mechanisms, which occur at low temperatures, also function the same when exposed to temperatures higher than 80°C.
Any article that is cited in another manuscript or other work is required to use the correct reference style. Below is an example of the reference style for SPE articles:
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
Available: www.4spe.org.
Note: if there are more than three authors you may use the first author's name and et al. EG Brown, H. L. et al.
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