bluuebunny/crossref_metadata_2025_split huggingface dataset:
Computer integrated manufacturing for plastic parts
Authors: Singh Kamar J. 
Published: April 2003

AbstractProductivity gains from a CAD/CAM system through integration with other factory automation systems have shown tremendous benefits for the plastics industry. For successful utilization of CAD/CAM systems, companies have to maximize the use of electronic data base and communication with other systems. General Electric, through its Calma operation, is aggressively addressing these integration opportunities in the plastics industry. The importance of the Computer Integrated Manufacturing system along with design and engineering tools available for increased productivity, are described in this paper.
Experimental techniques for analyzing distributive laminar mixing in continuous flows
Authors: Strasser Rolland A. , Erwin Lewis 
Published: April 2003

AbstractThis paper addresses experimental techniques for evaluating distributive laminar mixing in continuous flows. Analysis of mixing performance for arbitrary mixers and fluids is too complex to be solved from first principles for all but the simplest systems. Procedures for the acquisition and interpretation of mixing data from modelled mixers under laboratory analysis are reviewed, and guidelines for future mixing experimentation are presented.
Microcomputers in small injection molding machines—operation and design
Authors: Klein H. , Morell H.‐J. 
Published: April 2003

AbstractModern, trend‐setting small injection molding machines should be designed so that they open up new applications to the plastics processor through utilization of microelectronics. In the sector of control, it would be equivalent to stagnation if only the familiar functions were realized with modern control circuits of a higher integration level and if the possibilities of these modules were not utilized to simplify operation, to expand the technological possibilities, and to illustrate the sequences of processes. The mechanical and hydraulic designs should be adjusted to these requirements.The design and extent of the electronic control system should be such as to ensure an economically reasonable relation between extra price and additional benefit—a basic requirement for offering standard supplies.
Basis for the design of single‐screw devolatilizing extruders
Authors: Potente H. 
Published: April 2003

AbstractThe mathematical treatment of single‐screw devolatilizing extruders has been based up until now on the Newtonian law of flow. Only very recently have mathematical models been developed that take into account the intrinsically viscous behavior of plastic melts. Here, however, solutions are possible only by using numerical procedures.In this paper, a different approach is taken. On the basis of known numerical solutions and experimental investigations, approximation equations are presented that enable devolatilizing extruders to be designed by relatively simple means. There is good agreement between the numerical and experimental results.
The DISKPACK plastics compounder
Authors: Valsamis Lefteris N. , Donoian Gary S. 
Published: April 2003

AbstractThe design and operation of a 150mm multistage co‐rotating disk polymer compounder (DISKPACKTrademark of Farrel Company
) are presented and discussed. The processor consists of five parallel fed melting chambers followed in series by four mixing, one venting, and one pumping chamber. The experimental operational characteristics, specifically melting, mixing, degassing, and pumping of the processor for a variety of polymer compounds are presented and discussed. Examples of extensive and intensive mixing are presented.
Expandable polystyrene beads: Preexpansion processing
Authors: Tock Richard Wm. , Fuller Robert , Barron Jerry 
Published: April 2003

AbstractBecause the expansion of expandable polystyrene beads (EPS) results in a reduction in bulk density of more than one‐thirtieth, the beads require a pre‐expansion step prior to the final molding operation. Hence, the pre‐expansion process has become an important unit operation for foamed bead molders. This article presents some of the design concepts used for EPS pre‐expansion processing. Included are the characteristics of startup, temperature control and agitation during operation, and shutdown procedures. By following the suggestions outlined, the pre‐expansion process should deliver a uniform product, regardless of the raw bead supplier, and thereby help eliminate waste due to poor foam structure.
The effect of compounding on the conductive properties of EMI shielding compounds
Authors: Bigg D. M. 
Published: April 2003

AbstractConductive fillers are currently being evaluated for their ability to produce conductive plastic parts which shield electromagnetic interference (EMI). These fillers all have a geometrical characteristic to them which makes them susceptible to damage during compounding and processing. In this paper the effects of compounding and processing on the electrical properties of compounds produced from a variety of conductive fillers are presented. These fillers include carbon black, carbon fibers, aluminum‐coated glass fibers, stainless steel fibers, and aluminum flakes. Thermoplastic polymers were used as matrices in the preparation of the conductive compounds. This study shows that a balance must be reached between dispersive mixing requirements and minimizing damage to the filler particles.
PET beverage bottles: Carbonation losses in perspective
Authors: Tock Richard Wm. , Woo Christy , Watson Jim , Schwarz Richard 
Published: April 2003

AbstractPlastic bottles for carbonated beverages have many advantages over glass and metal containers. However, plastic bottles are also known to be imperfect barriers for gaseous fluids; i.e., they are semipermeable. This characteristic results in serious carbon dioxide transmission losses, particularly on the ½‐L or smaller single‐service bottles which have high area‐to‐volume ratios. Shelf life of these smaller beverage containers is therefore reduced. This article combines literature data and a simple diffusion model to predict shelf life for PET beverage bottles. As anticipated, the model shows that the smaller bottles have an unacceptable shelf life based on industrial standards. Moreover, while refrigerated temperatures increase shelf life to acceptable levels, temperatures for storage above 100°F can also reduce the 2‐L bottle to less than acceptable levels. The shelf life predictions developed with the model are close to those observed in practice. Further manipulation with the model shows that a hypothetical multilayered barrier wall could be constructed which would give an acceptable shelf life at any reasonable temperature.
On the methods of measurement of the flow properties of polyethylenes and their blends
Authors: Utracki L. A. 
Published: April 2003

AbstractSamples of commercial LDPE, HDPE, LLDPE, and their blends were tested in the steady state (rotational and capillary), dynamic, and extensional modes. The steady state data at low rates of deformation followed the dynamic viscosity, η = η′, and at higher rates the complex viscosity η ≃ η*. In elongational tests strain hardening was observed for LDPE and some for HDPE. There was no strain hardening in flow of a standard LLDPE, and the equilibrium extensional viscosity η ≃ 3η′ in full range of deformation rates. In blends with ultrahigh molecular weight PE and with LLDPE strain hardening and an increase of the maximum strain at break, εb, were found. Some newer types of LLDPEs and their homologous blends show the strain hardening behavior. A brief review of the methods of measurement of the flow properties of polyethylene (PE) melt is provided. The text is divided into three parts: (1) types of melt flow; (2) comparative rheology of polyethylenes; and (3) linear low density polyethylene (LLDPE) blends. In the first part, the methods of measurement and correlation between the measured values are discussed. The steady state shearing, dynamic deformation, and uniaxial extensions are considered. In the second part rheological behavior of the three principal types of PEs, low density PE (LDPE), high density PE (HDPE), and LLDPE are presented. In part 3, the flow of four different types of LLDPE blends is reported on.
In line compounding and extrusion of PP with talc and chalk
Authors: Cormont J. M. 
Published: April 2003

AbstractClose cooperation between DSM, Werner & Pfleiderer, and Reifenhäuser has resulted in the development of a continuous process in which a filled copolymer polypropylene (40% talc and 40% chalk) is compounded and extruded to sheets which, whether or not bonded to carpet (semifinished product), are ready for subsequent deep drawing. Addition of recycled material (up to 100%) is possible: the stability of the material is sufficient when some fresh stabilizer is added to the PP copolymer and when a suitable talc is chosen. Mixing and degassing are guaranteed and temperature level, temperature distribution, constancy of throughput, and pressure buildup capacity of the ZSK are sufficient for a continuous, direct process, yielding a uniform quality. Flexibility and economy are the result.
Experimental analysis of plastic sheet extrusion
Authors: Marinelli J. M. , Lee L. James 
Published: April 2003

AbstractAnalysis of a plastic sheet extrusion line was carried out using a 2.5‐in. extruder in conjunction with a three‐roll stack system for processing of both poly(methyl methacrylate) (PMMA) and high‐impact polystyrene (HIPS). Tests conducted include dynamic responses, sheet cooling behavior, velocity and thickness profiles, and frozen‐in strain measurements. Experiments with PMMA were also performed on an extrusion‐air cooling line to provide a basis for comparison with the extrusion‐roll stack system. The results showed that the size and stability of the bank in the extrusion‐roll stack system affected the thickness variations and the frozen‐in strains. Operating the roll stack system was found to allow for fairly rapid rearrangements from parabolic to plug velocity profiles. Line comparisons between the roll stack and air cooling showed that the roll stack minimized thickness variations, frozen‐in strains, and surface flaws.
Practical techniques for the use of pet—glass fiber reinforcements in composites
Authors: Cordova D. S. , Coffin D. R. , Rowan H. H. 
Published: April 2003

AbstractThe need for composite materials with improved properties tailored to the requirements of specific end uses has led to the development of hybrids reinforcement systems in which two or more reinforcing fibers are combined in a thermosetting matrix. Polyester fibers (PET) are currently being used in combination with other fibers, particularly fiberglass, for impact strength and surface quality improvement. The use of polyester fiber in combination with glass fiber as a reinforcement for composite materials has resulted in the development of novel types of hybrid composites. This study discusses our work to achieve an optimum balance of composite properties through changes in matrix formulation, composite compounding, and processing steps. A number of these parameters are shown to have a significant effect on the performance of the composite. This work includes an analysis of thermoset polyester and epoxy resin formulations, in addition to the effect of other additives for typical BMC, SMC, and injection‐molding operations. The fiber loading, PET–glass fiber ratio, and fiber length are briefly discussed, as these are factors in determining the composite properties. These characteristics are discussed in combination with the compounding techniques. The combination of both factors were observed to have a major effect on the mechanical and surface appearance of the composite. The coherency and dispersibility of the specific PET fiber used had additional effects on resin compounding and final composite characteristics.
From the layout to the scientifically engineered molded part—the computer opens up new horizons
Authors: Schmitz J. , Haack W. , Lutterbeck K. , Rest H. , Schmachtenberg E. , Wölfel U. 
Published: April 2003

AbstractPlastic components can only be competitive if they make use of the material and thereby emerge technically and economically superior to conventional materials. This places, high requirements on designers and presupposes extensive experience. A situation where the optimal version can only be established in expensive prototype molds is unacceptable. Above all, though, the time that this takes is preventing substitution by plastic parts from gaining an increasing market in the industrial component sector. The tasks which companies have to tackle today include increasing performance and making freely available experience that is currently confined to individuals. The establishment of specified work sequences helps to avoid errors. The chief tasks involved in design are compilation of specifications, material selection, and shaping and dimensioning. The designer's work can be broken down into acquisition of information, calculation, decision making, and drawing. The use of computers can help towards rationalization in the design field as well. This rationalization ought not only to give shorter transit times but improved components as well. The following program packages are available: a data bank program for managing design data, a search program with corresponding data file for material selection, a 3D graphic system for compiling drawings, a FE program for dimensioning, and an expert program to aid the designer in decision making. Apart from the conventional free design it is also possible to define individual functional elements or assemblies, such as snap fastenings or ribs, by way of design macros. These macros are designed and calculated in principle and then simply aligned auttomatically when incorporated in a specific part. Computersided dimensioning makes it possible to establish all the factors influencing quality in a specific application and to recognize weak points in simulated tests right at the design stage. The conventional concept of dimensioning (applying a sum of reducing coefficients to make allowance for loading) has thus been dispensed with, and a route is shown which permits precise allowance to be made for all the influences in a particular loading case. This therefore ensures optimum material utilization.
Microscopy techniques used in polymer research
Authors: Bartosiewicz L. , Kelly C. J. 
Published: April 2003

AbstractMicrostructural analyses with optical and scanning electron microscopy can identify processing variables that lead to less than optimum mechanical properties of molded and friction welded polymer components. Delineation of the major phase arrangements in blends of polycarbonate (PC) and poly(butylene terephthalate) (PBT) was key to identifying stress concentrations and internal defects. Phase separations, crystalline arrangement, structure refinements, and shear stresses introduced during molding or friction welding were evident and help to explain the unpredictable impact fracture mode and strength. The techniques help identify when the brittle ribbonlike PC phase extends to the surface without being encapsulated or surrounded by the PBT phase.
Intensification of the calendering process with the help of wedge‐shaped parts
Authors: Kohlert C. , Reher E. O. , Bothmer D. 
Published: April 2003

AbstractIncreased quality demands on products of the elastomer processing industry induced special investigations on additional intensifying components in processing machines. Thus, in collaboration with Soviet colleagues, a special wedge to be fitted into calenders for cord coating has been developed and tested. Elongation of the deformation zone results in improved homogenization, in higher degassing effect, in improved thread guidance and hence in an improvement in the quality of the coated cord. This paper presents the modelling of the flow between the wedge and the roll, up to the level of a parameter study of the dependence of the integral process parameters on geometrical, technological, and rheological factors. The construction of the wedge is explained, and the results obtained in the experimental investigation of the effect of the wedge technology on qualitative and quantitative parameters of the cord are discussed. The utilization of such wedgeshaped components as a continuously operating process viscometer, particularly for rolling and calendering processes, is presented, and further potential applications of the wedge technology in the production of high‐grade finished products are discussed.
Nylon 66 fundamentals and its processes
Authors: Ku Ping L. 
Published: April 2003

AbstractThe objective of this paper is to search for and critically examine the pertinent details of the current bulk continuous nylon 66 processes (described in the patents), which are practiced or followed by most nylon producing industries. The two monomers for making nylon 66 and their homologues including dibasic and monobasic acids, diamines, and primary amines show very interesting melting point behavior. On the other hand, compounds containing even numbers of carbon atoms show consistently higher melting points than the neighboring odd number compounds of higher molecular weights. However, the boiling points of all four series follow the usual rule: The higher the molecular weight, the higher the boiling point. It has been proven that the quality of nylon 66 has been greatly improved by lowering the residence time during the polymerization. For instance, the spinning rate employed was at a level of 7000 m/min, and the tensile strength of the spun yarn was much improved, which was attributed to the overall quality of the polymer.
Orientation development and crystallization in melt spinning of fibers
Authors: White James L. , Cakmak Mukerrem 
Published: April 2003

AbstractA critical review is presented of the development of orientation and crystallization in melt spinning. Methods of characterizing fiber structure are described. The development of molecular orientation in flow and approaches to the representation of crystallization in melt spinning processes are considered. Detailed critiques of the literature are given for the melt spinning of polystyrene, polyethylene, polypropylene, poly(vinylidene fluoride), poly(ethylene terephthalate), nylon‐6, and nylon‐66. Emphasis is given to the problems of spinline crystallization, polymorphism, orientation development, and crystalline morphology. The important role of spinline stress in determining structure development is emphasized. The influence of high speeds on melt spun fiber structure is described.
Process optimization in stretch blow molding
Authors: Menges G. , Esser K. , Hüsgen U. , Kunze B. 
Published: April 2003

AbstractIn stretch below molding the stretching temperature has the most significant influence on the article performance besides the stretching ratio. Therefore, a very sophisticated control system was developed for a laboratory stretch below molding plant on which PP bottles are produced. The processing window for the stretching of the used polypropylene homopolymer is within a temperature range of 145–153°C. For that reason a very precisely operating temperature control system had to be developed and integrated into the microprocessor, which runs the complete process beginning with the heating of the preform and ending with demolding the finished bottle. For the heating infrared heaters are used, which are able to heat up the preform (6 mm wall thickness) in times of about 60 s. During the so‐called transient time shortly before the preform is moved into the mold, its surface temperature is read at four different spots simultaneously. That is done by a device developed especially for this task, which consists mainly of four pyrometers. The temperature signals are fed into the microprocessor which then in the case of deviation from the set points adjusts the power of the IR heaters. The closed‐loop temperature control is done by a special algorithm, which takes into account that the controlled system is a coupled multivariable system, which is modeled by a system of linear equations. Tests have proved that the control system is able to react fast and precisely to set point changes and to keep the preform temperature and its distribution constant throughout the production within a range of approximately 2°C.
Rheological observation of gelation and fusion process of poly(vinyl chloride) plastisol
Authors: Nakajima N. , Harrell E. R. 
Published: April 2003

AbstractThis paper begins with a brief description of the history of development of PVC plastisol. It, then, presents technical background on the nature of PVC plastisol, covering subjects of particle size distribution and nature of agglomerates, viscosity aging and deagglomeration, rheology of suspension, gelation and fusion, and thermodynamic interaction between polymer and plasticizer. The main part of the paper concerns rheological observation of the gelation and fusion process of PVC plastisol, as the title of the paper indicates. This is a summary of recent work by the authors plus their new work on the effect of plasticizer type. The first half is the investigation of gelation and fusion mechanisms with use of a model plastisol system. Viscoelastic measurements, thermal analyses on the behavior of glass transition, and the scanning electron microscopic examination of the particulate structure were used to support the investigation. The last half considers the effect of the material variables on the gelation and fusion behavior; molecular weight, extractable additives (emulsifiers), agglomerates and fine particles, size of primary particles and plasticizer type are covered. Among these material variables, the plasticizer type has by far the largest influence on the gelation behavior. The observed solvent power is not necessarily in agreement with the thermodynamic interaction parameters found in the literature. It is indicated that a further systematic investigation is necessary to elucidate the nature of the plasticizer–polymer interaction.
Fluid flow and heat transfer in wire coating: A review
Authors: Mitsoulis Evan 
Published: April 2003

AbstractProgress in the analysis of the wire‐coating process is reviewed. In particular, the melt flow analysis inside high‐speed, pressure‐type, wire‐coating dies is presented. Early analytical efforts have been based on the lubrication approximation theory under isothermal conditions. Recent advances include full nonisothermal flow analysis using numerical finite element methods. Wire‐coating coextrusion is also reviewed. A need for more experimental data and inclusion of viscoelastic effects in the constitutive models used in the analysis are of primary importance for future work.
Phase separation effects in processing of glass‐bead‐ and glass‐fiber‐filled thermoplastics by injection molding
Authors: Hegler Ralph P. , Mennig Günter , Schmauch Claus 
Published: April 2003

AbstractDumbbell specimens, tubular specimens, spirals, and rectangular boxes were used to study phase separation effects occurring in injection molding of glass‐bead‐ and glass‐fiber‐filled thermoplastics. The weight specific separation effects were more pronounced with beads than with fibers, and they increase with increasing bead diameter. The weight distribution is further influenced by mold geometry, filler concentration, matrix material, and processing conditions. If the use of fillers, which promote inhomogeneity, is unavoidable, it is possible to improve the distribution of the rigid phase by a favorable choice of injection speed and melt temperature. Analysis which was made with dumbbell specimens and spirals showed no significant measurable size specific separation effects. With the theories available at present a qualitative interpretation of the origin of the observed separation phenomena is feasible.