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Science, Maths & Technology
Electrochemical Machining (ECM)
Works on the principle of anodic metal dissolution by electrical energy. An electrolyte medium separates the tool (cathode) from the electrically conductive metal workpiece (anode), creating an electrolytic cell. A high amperage, low voltage current is passed through the cell, selectively dissolving away the material to be removed. Produces ...
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Science, Maths & Technology
Extrusion of Powders
Hydrostatic compressive stresses and shear forces act on the powders. In hot extrusion, powder mixture is pre-compacted (‘canned’) by heat compression until all air has been removed. The sealed can is then rammed by a punch, until it adopts the shape of the die. Compacting pressure causes long sections of material to extrude from a small opening...
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Science, Maths & Technology
Cold isostatic pressing
Material in powder form is sealed into a flexible mould (or bag) situated inside a pressure vessel. Hydrostatic pressure is applied to the outside of the mould, until the powder molecules inside have bonded sufficiently. Subsequent finishing processes may be required.
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Science, Maths & Technology
Finding creativity in orbit?
Has space tourist Trevor Beattie got it wrong by suggesting that it's time to send creative people to space?
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Science, Maths & Technology
Pressureless sintering
A process where loose metal powders are poured into a metal die and vibrated until loosely compacted. When filled, the die is placed inside a furnace and sintered.
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Science, Maths & Technology
Hot isostatic pressing (HIP)
High temperature and pressure are applied simultaneously to pre-cast or sintered components. The addition of argon gas to the furnace helps to apply isostatic pressure to the component/s. The pressure and heat help to fill any pores on the surface of the component, thus optimising material properties and density.
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Science, Maths & Technology
What happens when you microwave an egg?
The New Scientist team have microwaved an egg, so you don't have to. Because you really, really shouldn't.
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Science, Maths & Technology
Download your free Matrix of Modern Life poster
A poster from The Open University that explores the colourful connections between different parts of science, engineering and technology - presented in the inimitable Bang style
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Money & Business
How is identity data creating headaches for large companies?
Increasingly the costs and risks of holding data are turning toxic for businesses. Bhargav Mitra and Robert McCausland explain why.
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Science, Maths & Technology
Cold Pressing and Sintering of Powders
A blend of powders is fed into a closed die, where upper and lower punches compact the powder using enough pressure to bind the powder particles together. The formed component is ejected from the die and heated at low temperature to burn off any residual lubricant. The component then moves to a protected environment where it is sintered before ...
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Science, Maths & Technology
Powder Forging / Hot pressing
A custom blended mix of powders is poured into a cavity mould, and compacted under pressure into a ‘preform’. The preform is heated to forging temperature then rapidly transferred into a forging press, where it is hot pressed into the final cast shape.
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Science, Maths & Technology
Slip-casting
The casting slip is a suspension of fine particles in a liquid medium. Slip is poured into a permeable mould, where liquid is drawn out of the slip, via a capillary action. A layer of solid slip (‘clay’) remains adhered to the walls of the mould. Once the required wall thickness of the casting has been achieved, the residue liquid is drained out...