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This paper aims to develop an integrated and portable desktop 3D printer using direct extruding technology to expand applied material field. Different from conventional fused deposition modeling (FDM) which uses polymer filaments as feedstock, the developed system can fabricate products directly using polymer pellets. And its printing properties are also investigated.

A conical screw-based extrusion deposition (CSBED) system was developed with a large taper conical screw to plasticize and extrude fed materials. The 3D printer was developed with assistance of precision positioning and controlling system. Biocompatible thermoplastic polyurethane (TPU) pellets were selected as raw materials for experiments. The influences of four processing parameters: nozzle temperature, fill vector orientation, layer thickness and infill density on the product’s internal structure and tensile properties were investigated.

It is concluded that the customized system has a high manufacturing accuracy with a diminutive global size and is suitable for printing soft materials such as TPU. Theoretical calculation shows the developed conical screw is more effective in plasticizing and extruding compared with conventional screw. Printed samples can achieve applicable tensile properties under harmonious parameter cooperation. Deposited materials are found to have voids among adjacent roads under unbefitting parameters.

The developed system efficiently improves material limitations compared to commercial FDM systems and exhibits great potential in medical field because soft materials such as biocompatible TPU pellets can be directly used.

The purpose of this paper is to study the effects of water immersion‐freeze‐thaw treatment on the physical properties, flexural strength (FS) and morphology of wood‐polypropylene composites containing pigments.

Wood‐polypropylene composites containing brown, green and grey pigments were compounded in a conical twin‐screw extruder. A composite manufactured without any pigment addition was used as a reference. The amount of pelletized wood, polypropylene and coupling agent (MAPP) was kept constant. The moisture content, thickness swelling (TS), FS and surface colour of the composites were measured before and after water immersion‐freeze‐thaw cycling. Scanning electron microscopy (SEM) was used to study the morphology of the composites.

FS and dimensional stability were reduced after exposure to water immersion‐freeze‐thaw cycling for all composites. The surface properties (colour and roughness) of the composites also changed after exposure to water immersion‐freeze‐thaw cycling. The degree of change depended on the presence of pigment and the type of polypropylene (neat or recycled), however.

This study is a part of an ongoing study on weathering of wood‐polymer composites (WPC) containing different additives. The results of this study were obtained from accelerated laboratory experiments.

Inorganic pigments are widely used as additives in plastics, because they have an excellent UV absorption, good IR‐reflective properties and heat stability. The research revealed that metal‐containing pigments had an effect on degradation in quality of wood‐polypropylene composites exposed to water immersion‐freeze‐thaw cyclic treatment. The addition of metal‐containing pigments to composite formulation resulted in a higher susceptibility of wood‐polypropylene composites to water absorption, and as a consequence to a higher drop of FS compared to composites made without pigment. The polymer matrix plays an important role in the protection of WPC against weathering.

This paper will help in understanding possible problems in the durability of wood‐polypropylene composites compounded with metal‐based pigments when they are exposed to water immersion‐freeze‐thaw cyclic treatment.

This paper gives a review of the finite element techniques (FE) applied in the analysis and design of machine elements; bolts and screws, belts and chains, springs and dampers, brakes, gears, bearings, gaskets and seals are handled. The range of applications of finite elements on these subjects is extremely wide and cannot be presented in a single paper; therefore the aim of this paper is to give FE researchers/users only an encyclopaedic view of the different possibilities that exist today in the various fields mentioned above. An Appendix included at the end of the paper presents a bibliography on finite element applications in the analysis/design of machine elements for 1977‐1997.

The purpose of the paper is to describe the production of traditional fura and extruded fura blends from 100 per cent pearl millet flour and blends of pearl millet flour with three‐grain legume flour mixtures, i.e. cowpea, soybean, and groundnut at 20 and 30 per cent levels each and to evaluate the influence of extrusion process' on products hydration properties.

Traditional methods of flour preparation were adopted. Extrusion was performed in a single‐screw Brabender Extruder.

The bulk density of traditional fura significantly differed from those of the extrudates (P<0.05). Extrudates exhibited instantization tendency, i.e. ability of easy preparation before eating without the usual rigorous labour involved in the traditional method. Pearl millet: cowpea fura (80:20) had the highest puff ratio of 4.71 while the pearl millet: groundnut (70:30) fura had the least puff ratio, 2.90. Samples with high fat content appear to have lower puff ratio. There were no significant differences in the wettabilities of extruded fura samples (P<0.05) at 28⁰C with the exception of millet: groundnut (70:30) indicating differences (P<0.05) in wettabilities at 50^oC. There were significant differences (P<0.05) in swelling capacities of fura products at each level of water added. The hydration power of extrudates varied significantly (P<0.05) for products both at 28^o and 50^oC; and 100 per cent fura extrudate had the highest hydration power value 63.92 at 28^oC, while traditional fura had the least value, 15.80.

Extrusion cooking revealed good potential opportunities for the manufacture of commercial instant fura and the potential of better storage as a result of low moisture content.

Becker Equipment & Lifts Ltd, of Ealing Rd, Wembley, a Tl Machine Division company, announce what they claim as a major advance in the pre‐packaging of aggressive liquids, by the introduction of a radical new option for their range of Bexuda air‐operated liquid fillers. For the first time highly corrosive liquids, including most acids (even concentrated sulphuric and hydrochloric), organic solvents, bleaches and many alkalis can be filled with maximum safety, on the same filler, with an accuracy of ±0.25% by volume.

Mixing equipment worth some £100,000 is to be supplied to Ciba‐Geigy (UK) Ltd by Machinefabriek Vrieco of Zelham, Holland. The order is the largest for Vrieco mixers yet won by the company's sole distributors in the UK and Eire, Delmec Engineering Ltd of Bacup, Lancs, who specialise in the design and supply of plant for the handling and treatment of powdered and granular materials.

This papers aims to study the influence of water absorption on the mechanical properties of poly lactic acid (PLA) and PLA/Wood composites. Virgin PLA and PLA/Wood double-bone-shaped specimens were prepared by two methods: injection moulding and 3D printing. The results were compared to each other and showed the influence of the production method on the properties of the produced parts.

Morphology studies were done by scanning electron microscopy (SEM) from fracture surfaces of tensile and notched impact specimens of all samples. Tensile properties were analysed by the production and testing of dog-bone-shaped samples. Heat deflection temperature (HDT) was tested, as also was the crystallinity of the tested samples by differential scanning calorimetry.

The values for notched impact strength were higher upon water uptake in the case of injection-moulded specimens, which was not the case with 3D-printed specimens. Tensile properties of the specimens produced by both methods were reduced after water absorption tests. Values of the HDT were also lower after water absorption tests studied for both processing methods.

Morphology studies were done by SEM from fracture surfaces of tensile as well as notched impact specimens of injection-moulded and 3D-printed samples. The effect of water storage on various samples was tested. The two different production technologies were compared to each other owing to their influence of water storage. This study also dealt with NFC compounds and produced NFC composites and the influence of water storage on these samples.

Ault & Wiborg Paints are to close down manufacturing facilities at their Tyseley, Birmingham factory as part of a rationalisation programme which started with the merging of the Ault & Wiborg Group paint interests earlier this year.

The purpose of this article is the determination of the temperature fields in a weld region has always been an obstacle to the improvement of welding processes. As an alternative, the use of inverse problems to determine the heat flux during the welding process allows an analysis of these processes.

This paper studies an alternative for the thermal analysis of the tungsten inert gas welding process on a 6,060 T5 aluminum alloy. For this purpose, a C++ code was developed, based on a transient three-dimensional heat transfer model. To estimate the amount of heat delivered to the plate, the specification function technique was used. Lab experiments were carried out to validate the methodology. A different experimental methodology is proposed to estimate the emissivity (radiation coefficient).

The maximum difference between experimental and numerical temperatures is lower than 5 per cent. The determined emissivity value for the aluminum 6,060 T5 presented a good agreement with literature values. The thermal fields were analyzed as function of the positive polarity. The specification function method proved to be an adequate tool for heat input estimation in welding analysis.

The proposed methodology proves to be a cheaper way to estimate the heat flux on the sample. The estimated power curves for the welding process are presented. The methodology to calculate the emissivity (radiation coefficient) was validated.

This paper aims to develop a novel strategy to manufacture poly-lactic acid (PLA) filaments reinforced with Mg particles for fused filament fabrication of porous scaffolds for biomedical applications.

The mixture of PLA pellets and Mg particles was extruded twice, the second time using a precision extruder that produces a filament with zero porosity, constant diameter and homogeneous dispersion of Mg particles. The physico-chemical properties of the extruded filaments were carefully analysed to determine the influence of Mg particles on the depolymerisation of PLA during high temperature extrusion and the optimum melt flow index to ensure printability.

It was found that the addition of a polyethylene glycol (PEG) plasticizer was necessary to allow printing when the weight fraction of Mg was above 4%. It was possible to print porous face-centre cubic scaffolds with good geometrical accuracy and minimum porosity with composite filaments containing PEG.

The new strategy is easily scalable and seems to be very promising to manufacture biodegradable thermoplastic/metal composite filaments for 3D printing that can take advantage of the different properties of both components from the viewpoint of tissue engineering.