Plastic Extrusion Research Articles

Influence of Cr-Content on the thermoelectric and mechanical properties of NiCr thin film thermocouples synthesized on thermally sprayed Al2O3

Ni/Ni-Cr thin film thermocouples were deposited by means of DC magnetron sputtering for the application in plastic extrusion dies. In order to ensure the application of the thermocouples on complex surfaces, a thermally sprayed Al2O3 layer was used between the substrate and the thin films for thermal insulation and electrical isolation. The study includes the deposition, characterization, calibration, and validation of thin film thermocouples. The influence of the composition (10 at.-%, 20 at.-% and 30 at.-% Cr) was analyzed concerning mechanical and electrical properties. It was found out that the electrical resistance increases with the temperature and the Cr-content due to a decreasing crystallite size. By means of a scratch-tester and nanoindentation, a higher scratch load and hardness were observed for larger Cr-contents on the thermally sprayed Al2O3 coating. Despite the composition, the influence of the size as well as the thickness of the thermocouples were analyzed regarding the Seebeck coefficient. Independent from the size and Cr-content, all thermocouples feature a comparable Seebeck coefficient of about 40 μV/K. This high coefficient is similar to that of wire thermocouples, showing a low number of defects in the thin films. The ceramic coating features a thermal insulation of about 20 °C at 200 °C, allowing a more accurate measurement of the ambient medium.

RepRapable Recyclebot: Open source 3-D printable extruder for converting plastic to 3-D printing filament

Abstract In order to assist researchers explore the full potential of distributed recycling of post-consumer polymer waste, this article describes a recyclebot, which is a waste plastic extruder capable of making commercial quality 3-D printing filament. The device design takes advantage of both the open source hardware methodology and the paradigm developed by the open source self-replicating rapid prototyper (RepRap) 3-D printer community. Specifically, this paper describes the design, fabrication and operation of a RepRapable Recyclebot, which refers to the Recyclebot’s ability to provide the filament needed to largely replicate the parts for the Recyclebot on any type of RepRap 3-D printer. The device costs less than $700 in mate rials and can be fabricated in about 24 h. Filament is produced at 0.4 kg/h using 0.24 kWh/kg with a diameter ±4.6%. Thus, filament can be manufactured from commercial pellets for

Design and Development of Plastic Filament Extruder for 3D Printing

<p>3D printing is a form of additive manufacturing technology where a three dimensional object is created by laying down successive layers of material. It is mechanized method whereby 3D objects are quickly made on a reasonably sized machine connected to a computer containing blueprints for the object. As 3D printing is growing fast and giving a boost to product development, the factories doing 3D printing need to continuously meet the printing requirements and maintain an adequate amount of inventory of the filament. As the manufactures have to buy these filaments from various vendors, the cost of 3D printing increases. To overcome the problem faced by the manufacturers, small workshop owners, the need of 3D filament making machine arises. This project focuses on designing and fabricating a portable fused deposition 3D printer filament making machine with cheap and easily available components to draw 1.75 mm diameter ABS filament.</p>

Indentation and flattening of rough surfaces spherical asperities

The paper indicates that the application of roughness models and the theories of contacting rough surfaces developed by Greenwood-Williamson and N.B. Demkin for solving the problems of hermetology leads to significant errors. This is explained by much greater contact pressures than for the tribology problems, by describing only the initial part of the reference surface curve, the lack of allowance for the plastic extrusion of the material. A brief review of methods for describing the introduction of a sphere into an elastoplastic reinforced half-space is given. The properties of the elastoplastic reinforced material are described by the power law of Hollomon. To describe the indentation and flattening of single spherical asperity, the results of finite element modeling are used. The cases of contacting a rigid rough surface with an elastoplastic half-space and a rigid smooth surface with a rough surface are considered. To determine the relative contact area, the discrete roughness model is used in the form of a set of spherical segments distributed along the height in accordance with the curve of the reference surface.

Numerical study of mixed convection in a horizontal no parallel-plates channel with an unheated moving plate

PurposeThe purpose of this paper is to analyze the thermal and fluid dynamic behaviors of mixed convection in air because of the interaction between a buoyancy flow and a moving plate induced flow in a horizontal no parallel-plates channel to investigate the effects of the minimum channel spacing, wall heat flux, moving plate velocity and converging angle.Design/methodology/approachThe horizontal channel is made up of an upper inclined plate heated at uniform wall heat flux and a lower adiabatic moving surface (belt). The belt moves from the minimum channel spacing section to the maximum channel spacing section at a constant velocity so that its effect interferes with the buoyancy effect. The numerical analysis is accomplished by means of the finite volume method, using the commercial code Fluent.FindingsResults in terms of heated upper plate and moving lower plate temperatures and stream function fields are presented. The paper underlines the thermal and fluid dynamic differences when natural convection or mixed convection takes place, varying minimum channel spacing, wall heat flux, moving plate velocity and converging angle.Research limitations/implicationsThe hypotheses on which the present analysis is based are two-dimensional, laminar and steady state flow and constant thermo physical properties with the Boussinesq approximation. The minimum distance between the upper heated plate of the channel and its lower adiabatic moving plate is 10 and 20 mm. The moving plate velocity varies in the range 0-1 m/s; the belt moves from the right reservoir to the left one. Three values of the uniform wall heat flux are considered, 30, 60 and 120 W/m2, whereas the inclination angle of the upper plate θ is 2° and 10°.Practical implicationsMixed convection because of moving surfaces in channels is present in many industrial applications; examples of processes include continuous casting, extrusion of plastics and other polymeric materials, bonding, annealing and tempering, cooling and/or drying of paper and textiles, chemical catalytic reactors, nuclear waste repositories, petroleum reservoirs, composite materials manufacturing and many others. The investigated configuration is used in applications such as re-heating of billets in furnaces for hot rolling process, continuous extrusion of materials and chemical vapor deposition, and it could also be used in thermal control of electronic systems.Originality/valueThis paper evaluates the thermal and velocity fields to detect the maximum temperature location and the presence of fluid recirculation. The paper is useful to thermal designers.

Jon M. Huntsman is dead at 80

Jon M. Huntsman Sr., the Huntsman Corp. founder, packaging innovator, and philanthropist, died on Feb. 2. He was 80 years old. To the chemical industry, Huntsman is best known for the company that bears his name. In 2016, Huntsman Corp. was the sixth-largest U.S. chemical company, with $9.6 billion in sales. Huntsman came to the chemical industry in the early 1960s as an egg salesperson in Southern California. Using a plastic extruder and an improvised thermoforming machine, he developed the first polystyrene foam egg cartons. This invention led to a packaging joint venture with Styrofoam giant Dow Chemical and the founding of Huntsman Container Corp. in 1970. That company would continue to innovate, inventing the polystyrene foam clamshell container used for the Big Mac and other takeout food. Huntsman founded Huntsman Corp. in 1983 with the purchase of a Shell polystyrene plant in Belpre, Ohio. He would grow to be

Experimental Study on Gear Extrusion Machining Process of Gearbox Synchronizer Gear Hub

This study treats the synchronizer gear hub gear extrusion machining process for J6L medium truck. The CA6140 lathe has been reformed into a gear extrusion machine and the experimental research about the gear extrusion plastic forming processing has been did. The tooth surface roughness and hardness after the gear extruding process under the given process parameters had also been analyzed. The experimental results showed that the surface roughness had been improved after the gear extruding processing, and the tooth surface hardness was became higher compare with the original tooth surface. It is obviously that the gear extrusion machining process can improve the tooth surface quality of the gear hub and get a better process result.

Fluid Elasticity in Plastic Pipe Extrusion: Loads on Die Barrel

Abstract In large thick plastic pipe extrusion, the residence time in the cooling chamber is long, and the melt inside the pipe sags under its own weight, causing the product to thicken on the bottom (and to thin on the top). To compensate for sag, engineers normally shift the die centerpiece downward. This paper focuses on how this decentering triggers unintended consequences for elastic polymer melts. We employ eccentric cylindrical coordinates, to capture exactly the geometry of our problem, the flow between eccentric cylinders. Specifically, we arrive at an exact analytical expression for the axial and lateral forces on the die barrel using the polymer process partitioning approach, designed for elastic liquids. We choose the Oldroyd 8-constant framework due to its rich diversity of constitutive special cases. Since our main results are in a form of simple algebraic expression along with two sets of curves, they can thus be used not only by engineers, but any practitioner. We close our paper with detailed dimensional worked examples to help practitioners with their pipe die designs.

Tightening the loop on the circular economy: Coupled distributed recycling and manufacturing with recyclebot and RepRap 3-D printing

A promising method of enhancing the circular economy is distributed plastic recycling. In this study plastic waste is upcycled into 3-D printing filament with a recyclebot, which is an open source waste plastic extruder. The recyclebot is combined with an open source self-replicating rapid prototyper (RepRap) 3-D printer, to enable post-consumer ABS plastic filament from computer waste to be further upcycled into valuable consumer products pre-designed in the digital commons. The total electrical energy consumption for the combined process is monitored and an economic evaluation is completed. The coupled distributed recycling and manufacturing method for complex products reduces embodied energy by half, while reducing the cost of consumer products to pennies. This economic benefit provides an incentive for consumers to both home recycle and home manufacture, which tightens the loop on the circular economy by eliminating waste associated from transportation and retail. It is clear from the results that waste plastic can be significantly upcycled at the individual level using this commons-based approach. This tightening of the loop of the circular economy benefits the environment and sustainability as well as the economic stability of consumers/prosumers.

Optimal Performance of Plastic Extrusion Process Using Fuzzy Goal Programming

Optimal Performance of Plastic Extrusion Process Using Fuzzy Goal Programming

Knuckle formation from melt elasticity in plastic pipe extrusion

When plastic pipe is solidified, it proceeds through a long cooling chamber. Inside the chamber, inside the extrudate, the plastic is molten, and this inner surface solidifies last. Sag then happens inside this cooling chamber, and sometimes, thickened regions (called knuckles) arise in the lower quadrants of the pipe, and specifically in large diameter thick-walled pipes. To compensate for sag, we normally shift the die centerpiece downward. Here, we investigate this die eccentricity, and its remarkable interaction with fluid elasticity in knuckle formation in annular flow of polymeric liquids.We develop a map to help plastics engineers predict the extrudate shape, including extrudate knuckles, and then from the mass balance over the postdie region, to predict the extrudate shape entering the cooling chamber. We find that Newtonian extrudates, or extrudates for small pipe, never knuckle. Both of these findings agree with industrial experience. We also include a worked example to help plastics engineers suppress extrudate knuckling.

Open-Source-Based 3D Printing of Thin Silica Gel Layers in Planar Chromatography.

On the basis of open-source packages, 3D printing of thin silica gel layers is demonstrated as proof-of-principle for use in planar chromatography. A slurry doser was designed to replace the plastic extruder of an open-source Prusa i3 printer. The optimal parameters for 3D printing of layers were studied, and the planar chromatographic separations on these printed layers were successfully demonstrated with a mixture of dyes. The layer printing process was fast. For printing a 0.2 mm layer on a 10 cm × 10 cm format, it took less than 5 min. It was affordable, i.e., the running costs for producing such a plate were less than 0.25 Euro and the investment costs for the modified hardware were 630 Euro. This approach demonstrated not only the potential of the 3D printing environment in planar chromatography but also opened new avenues and new perspectives for tailor-made plates, not only with regard to layer materials and their combinations (gradient plates) but also with regard to different layer shapes and patterns. As such an example, separations on a printed plane layer were compared with those obtained from a printed channeled layer. For the latter, 40 channels were printed in parallel on a 10 cm × 10 cm format for the separation of 40 samples. For producing such a channeled plate, the running costs were below 0.04 Euro and the printing process took only 2 min. All modifications of the device and software were released open-source to encourage reuse and improvements and to stimulate the users to contribute to this technology. By this proof-of-principle, another asset was demonstrated to be integrated into the Office Chromatography concept, in which all relevant steps for online miniaturized planar chromatography are performed by a single device.

Development of a Wood Plastic Composite Extruder

Wood plastic composites (WPC) is the recycling of wood flour and plastic into new products like particle boards, floor tiles and other structural building applications. An extruding machine is developed at the workshop of Agricultural and Environmental Engineering Department of The Federal University of Technology, Akure, Ondo State to handle the production of these products. The major components of the machine include the melting/mixing chamber, the extruding chamber, the frame and the discharging chamber. The working principle of the machine is by allowing the recycled shredded plastic to melt at 200°C before adding the wood flour and mixed thoroughly. This is now fed into the extruding chamber at same temperature which further kneads the mixture into slurry before discharging it into a mould of dimension 150 mm × 80 mm × 70 mm. The machine is powered by 10 Hp three phase electric motor. Specimen produced is now hot-pressed at 120°C to a thickness of 13mm and allowed to cool before removal. The machine had a throughput of 0.78 kg/hr and functional efficiency of 86%. The total production cost as at the time of fabrication is Three Hundred and Fifteen Thousand Naira Only (N 315,000). It is recommended for small and medium scale entrepreneurs.

From PSS to CPS Design: A Real Industrial Use Case Toward Industry 4.0

During the last 10 years, manufacturing companies have faced new challenges for improving their value proposition and being more efficient and effective on the market, satisfying the customer needs. According to this trend, several technologies have been developed and applied in different sectors and with different aims, in order to support such the companies in their reconfiguration. For example, the recent advances in Information and Communications Technologies (ICT) could give also to manufacturing industries the competences required to develop novel sustainable products embedded with a dedicated infrastructure able to provide more service functionalities to customer. In this context, the application of Internet of Things (IoT) have allowed developing the so named Product Service Systems (PSSs). Moreover, the cross-fertilization between such the technologies with the development of other ones have fostered the application of these novel ICT technologies inside the manufacturing companies also at process level. This approach has encouraged the study and development of Cyber-Physical Systems (CPSs). The present paper deals with a real industrial use case, where the application of ICT technologies and specifically the adoption of IoT at a plant of plastic extrusion pipes have allowed optimizing the production process in terms of energy efficiency.

Study on Slow Crack Growth Resistance of High-Density Polyethylene Pipes Prepared by Vibration Extrusion

The slow crack growth resistance is one of the key factors to improve the service life of the plastic pipes. The high-density polyethylene (HDPE) pipes were prepared using a self-made electromagnetic dynamic plasticating extruder, which applied a vibration force field to the entire plasticating and extrusion process by the axial vibration of the screw. The slow crack growth resistance of HDPE pipes prepared by static extrusion and vibration extrusion was investigated. The effects of the vibration force field on the slow crack growth resistance of HDPE pipes were studied by DSC and WAXD analysis. The results showed that HDPE pipes prepared by vibration extrusion had higher melting temperature, higher crystallinity, larger crystal sizes, thicker lamellas and more perfect crystals. At the same time, the quasi net structure of the HDPE pipes chains can be obtained. All these are favorable for the improvement of the slow crack growth resistance property HDPE pipes.

Hybrid dcMS/HPPMS PVD nitride and oxynitride hard coatings for adhesion and abrasion reduction in plastics processing

During plastics extrusion, machine components such as extruder screw and extrusion die are exposed to the plastics melt. The resulting tribological loads can lead to excessive wear. In this regard, chromium based nitride and oxy-nitride hard coatings deposited via physical vapor deposition offer great potential in order to protect machine components against wear. In order to produce PVD coatings with increased mechanical properties on complex geometries such as extruder screws the high power pulsed magnetron sputtering/high power impulse magnetron sputtering technology seems to be promising. In this paper Cr-Al-N and Cr-Al-O-N coatings deposited on plasma nitrided steel 34CrAlNi7 10 (1.8550) by a direct current magnetron sputtering hybrid PVD process are investigated. The Cr/Al ratio and the O content of the coatings were varied. Chemical composition, morphology and structure were analyzed by means of scanning electron microscopy, X-ray photo spectroscopy and X-ray diffraction, respectively. High temperature contact angle measurements at the processing temperatures of the plastics were conducted in order to analyze the adhesion behavior of the (coated) surfaces towards industrial relevant types of polyamide, polycarbonate and polypropylene. The tribological behavior of the (coated) surfaces against plastic pins at ambient temperature was investigated in a pin-on-disc tribometer. The contact zones between the (coated) surfaces and the plastics were analyzed by Raman spectroscopy. Furthermore, the wear behavior was investigated. The results reveal a correlation between the chemical composition of the coatings and the adhesion towards the investigated plastics.

Experimental Study on Mechanical Properties of Commercially Pure Copper Processed by Severe Plastic Deformation Technique-Equal Channel Angular Extrusion

Experimental Study on Mechanical Properties of Commercially Pure Copper Processed by Severe Plastic Deformation Technique-Equal Channel Angular Extrusion

COMPUTATIONAL FLUID DYNAMICS SIMULATION OF SINGLE SCREW EXTRUDERS IN CABLE INDUSTRIES

The flow of polymer pellets along the solid conveying screw of a single screw extruder is studied by use of a numerical model based on the Finite Volume Method (FVM). The screw profile of existing Nokia-Malifer plastic extrusion devices (for cable industries) was mesured.Model predictions used is the Power law for Non-Newtonian Fluid, the results are compared with experimental data, showing a good match. The feasiability of using CFD models for designing plastic extrusion devices is analyzed. Basic parameters such as temperature, velocity profiles and pressure show high degree of similarity to practical results.

Slow release fertilizers based on urea/urea–formaldehyde polymer nanocomposites

A novel nanocomposite material based on the exfoliation of montmorillonite into a matrix of urea/urea–formaldehyde polymer was developed to be used as nitrogen-loaded slow release fertilizers. The nanocomposites were produced by cold plastic extrusion, a simple and high-productive method, using a formaldehyde precursor to accomplish polymerization in situ during extrusion processing. Characterizations showed that the extruded fertilizer nanocomposites presented good mechanical resistance, and that the urea release was noticeably controlled by the extent of polymerization. Water immersion experiments demonstrated that the nanocomposite structure was responsible for the effective slow urea release behavior. A dependence of the availability of other nitrogenous compounds (NH4+ and NO3−) on the polymerization degree was also demonstrated by soil incubation tests. The urea/urea–formaldehyde polymer nanocomposites were found to be versatile and smart materials capable of supplying the enormous demand for novel efficient nitrogen fertilizers.

Development of a continuous roll-to-roll processing system for mass production of plastic optical film

This paper reports a highly effective method for the mass production of large-area plastic optical films with a microlens array pattern based on a continuous roll-to-roll film extrusion and roller embossing process. In this study, a thin steel mold with a micro-circular hole array pattern is fabricated by photolithography and a wet chemical etching process. The thin steel mold was then wrapped onto a metal cylinder to form an embossing roller mold. During the roll-to-roll process operation, a thermoplastic raw material (polycarbonate grains) was put into the barrel of the plastic extruder with a flat T-die. Then, the molten polymer film was extruded and immediately pressed against the surface of the embossing roller mold. Under the proper processing conditions, the molten polymer will just partially fill the micro-circular holes of the mold and due to surface tension form a convex lens surface. A continuous plastic optical film with a microlens array pattern was obtained. Experiments are carried out to investigate the effect of plastic microlens formation on the roll-to-roll process. Finally, the geometrical and optical properties of the fabricated plastic optical film were measured and proved satisfactory. This technique shows great potential for the mass production of large-area plastic optical films with a microlens array pattern.