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The purpose of this study is to determine the material extrusion (MEX) printability envelope of a new kind of low-viscosity powder-binder feedstocks using rheological properties.

Formulation of 13 feedstocks (variation of solid loading 60–67 Vol.% and thickening agent proportion 3–15 Vol.%) that were characterized and printed at different temperatures.

Three rheological models were successfully used to define the viscosity envelope, producing stable and defect-free printing. At a shear deformation rate experienced by the feedstock in the nozzle ranging from 100 to 300 s^–1, it was confirmed that metal injection molding (MIM) feedstocks exhibiting a low viscosity between 100 and 150 Pa s could be printed using an extrusion temperature as low as 85 °C.

MEX can be used in synergy with MIM to accelerate mold development for a new injected part or simply as a replacement for MIM when the cost of the mold becomes too high for very small production volumes.

Correlation between the rheological properties of this new generation of low-viscosity feedstocks and MEX printability has been demonstrated for the first time.

G. D. GALVIN enlarges on tribological conditions determining the specification, terminology and use of various types of lubricant involving petroleum products.

A series of articles dealing, in as simple a way as possible, with the basic facts of lubrication, lubricants, their selection and prescription, specification, application, and testing. This series is primarily intended for students, engineering personnel who may be unfamiliar with certain aspects and others who, one way or another, are interested in this important subject. Part One in our March Issue dealt with Friction, Lubrication and Wear. Part Two in our July Issue dealt with Mineral Oils and their Additives. Part Three, in our September and October Issues dealt with Lubricating Greases. Part Four commenced in our December Issue and is concluded here. Part Five will deal with Non‐Newtonian Flow, Grease Consistency and Shear Stability.

The aim of this work is to synthesize neopentyl glycol oligoesters based on adipic acid and rapeseed oil (NOAR) which may be used as the renewable and environmentally acceptable base fluids to replace mineral oils in the future.

Oligomeric intermediates were synthesized in the first esterification of neopentyl glycol with adipic acid and characterized by Gas Chromatography-Mass Spectrometer (GC-MS) to calculate the average oligomerisation degree. NOAR were synthesized in the second esterification of oligomeric intermediates with rapeseed oil fatty acid. The effects of average oligomerisation degree on the viscosity, viscosity index, pour point, oxidative stability and biodegradability of NOAR were investigated; the tribological properties and thermal stability of NOAR were evaluated by four-ball tribometer and TGA, respectively.

Results show that with the increase of average oligomerisation degree from 2.10 to 4.34, the viscosity of NOAR increased from 101.1 to 182.0 (mm2/s) at 40°C and 18.3 to 30.1 (mm2/s) at 100°, respectively, and their oxidation stability can be improved as well. The yields of NOAR were 83.3-89.4 per cent, and the evaluated properties were as follows: viscosity index of over 200, pour point of below −43°C, biodegradation rate of more than 96 per cent, maximum non-seizure load (PB value) of 784 N, wear scar diameters of 0.40 mm and thermal decomposition temperature of higher than 300°C.

This work provides a method to synthesize rapeseed oil-based oligoesters which can serve as the renewable and environmentally acceptable base fluids with tunable viscosity by controlling the oligomerisation degree of esterification.

The purpose of this paper is establishing a general mathematical model and theoretical design rules for 3D printing of biomaterials. Additive manufacturing of biomaterials provides many opportunities for fabrication of complex tissue structures, which are difficult to fabricate by traditional manufacturing methods. Related problems and research tasks are raised by the study on biomaterials’ 3D printing. Most researchers are interested in the materials studies; however, the corresponded additive manufacturing machine is facing some technical problems in printing user-prepared biomaterials. New biomaterials have uncertainty in physical properties, such as viscosity and surface tension coefficient. Therefore, the 3D printing process requires lots of trials to achieve proper printing parameters, such as printing layer thickness, maximum printing line distance and printing nozzle’s feeding speed; otherwise, the desired computer-aided design (CAD) file will not be printed successfully in 3D printing.

Most additive manufacturing machine for user-prepared bio-material use pneumatic valve dispensers or extruder as printing nozzle, because the air pressure activated valve can print many different materials, which have a wide range of viscosity. We studied the structure inside the pneumatic valve dispenser in our 3D heterogeneous printing machine, and established mathematical models for 3D printing CAD structure and fluid behaviors inside the dispenser during printing process.

Based on theoretical modeling, we found that the bio-material’s viscosity, surface tension coefficient and pneumatic valve dispenser’s dispensing step time will affect the final structure directly. We verified our mathematical model by printing of two kinds of self-prepared biomaterials, and the results supported our modeling and theoretical calculation.

For a certain kinds of biomaterials, the mathematical model and design rules will have unique solutions to the functions and equations. Therefore, each biomaterial’s physical data should be collected and input to the model for specified solutions. However, for each user-made 3D printing machine, the core programming code can be modified to adjust the parameters, which follows our mathematical model and the related CAD design rules.

This study will provide a universal mathematical method to set up design rules for new user-prepared biomaterials in 3D printing of a CAD structure.

Discusses the various methods that are used for measuring the viscosity of paints and inks in the laboratory environment and suggests what equipment is most suitable for different applications. Identifies the most common sources of errors in making measurements and emphasizes the importance of calibration in obtaining accurate and reproducible results.

Cellobond HEC is the new trade name for BP Chemicals hydroxyethyl cellulose. It is described as a versatile water soluble polymer produced in 19 standard grades covering a wide viscosity range. Cellobond HEC is manufactured from ethylene oxide and cellulose to high standards at BP Chemicals factory at Antwerp, Belgium, and is available in 25 kg extra strong bags.

The market for ultraviolet curing technology has been growing at double‐digit rates in the last 10 years. The main reason for such a rapid technological growth of UV curing is its unique process characteristic, which allow UV‐coating to be applied on virtually any substrates, including plastic, metal, composite, wood, paper, leather, vinyl, glass, magnetic recording tape and even human teeth. The original driving forces behind the commercialisation of UV‐technology were energy saving and freedom from solvents. These benefits are complemented by high productivity and subsequently higher profits that can be achieved with the increased line speed, just‐in‐time benefits and immediate “pack and ship” capabilities. This paper gives a review of the development of the UV curing technology, with emphasis placed on relevant chemistry.

The results of the corrosion of metals and alloys with the use of solvent mixtures covering a wide range of compositions are limited in the literature. These mixed solvent systems possess a wide range of viscosity, dielectric constant and acid‐base properties. With this view, a kinetic study on the corrosion of metals in different aquo‐organic solvent systems has been undertaken. The corrosion of metals and alloys is strongly affected by the presence of water, the latter being found to have a passivating effect and sometimes a passivity breakdown effect. It is therefore of much interest to study the influence of varying water concentration on the corrosion and electrochemical behaviour of metal and alloys. The present work is a continuation of our studies on the kinetic of corrosion of metals in mixed aqueous‐organic solvents. Also, the corrosion rates are correlated to the dielectric constant and the total number of moles (n1 + n2) of water and ethylene glycol. This latter new correlation is described by El‐Shazly et al. for calculating the chemical potential (Δμ*) from kinetic data and molar thermodynamic excess functions for binary mixtures.

This paper was first given at a seminar in London on 12th May, 1981 on techniques using electrically insulating resins. It was organised by Liquid Control Ltd. and Emerson & Cuming (UK) Ltd. and was chaired by Peter Kershaw of Shell Chemical Ltd. The papers from Liquid Control executives dealt with equipment used and application practice.