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Resistant MaterialsManufacturing Processes

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For more detailed instructions, see the Getting Started presentation.© Boardworks Ltd 20051 of 15

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Learning objectives

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Lear

ning

obj

ectiv

es To understand how reforming and deforming processes change the shapes of materials.

To know how to deform wood, metals and plastics.

To know how to reform metals and plastics.

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Deforming materials

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Wood can be bent – gently and carefully!

If you make small cuts part way through the wood it is easier to produce a curve.

The process of making small cuts part way through the wood in this way is called kerfing.

Deforming wood

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Laminating

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Thermoplastics can easily be bent when they are heated.

Thermoplastics can be bent using the heated wire strip in a line bender or strip heater.

Deforming plastics

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Vacuum forming is a process which deforms thermoplastics into new shapes. Press play to see a video of the vacuum forming process.

Deforming plastics

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Vacuum forming

Vacuum forming is often used to produce packaging items such as the insides of boxes of chocolates.

A sheet of plastic is forced down over a mould to create the desired shape.

The sides of the mould need to be tapered.Corners must be smooth curves so that the plastic does not get punctured. Holes are drilled to allow air to be extracted.

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Blow moulding

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Metals can be beaten or folded to change their shapes.

The process of re-shaping metal in this way is called deforming.

Mild steel sheet being bent into an angled shape.

Copper being beaten with a hammer into a curved shape.

Deforming metal

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Reforming plastics

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Sand casting

Reforming metals – casting

Metals are reformed using casting processes. There are two main types of casting:

Die casting

can be done in schools uses an aluminium alloy that has a low melting point is labour intensive.

is used in industry uses metal moulds which are expensive but re-usable is very accurate and quick is expensive to initially set up.

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Sand casting

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Die casting is used in industry for producing large quantities of very accurate castings for machinery such as engines.

Die casting

The molten metal is forced into the mould by a piston. It is then cooled before the mould is opened.

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Key points

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Key

poi

nts

Deforming involves changing the shape of a material by bending, squashing, heating or bending. Reforming involves melting a material before making it into a new shape.

Wood can be curved using a kerfing technique or by laminating strips of wood to produce plywood.

Thermoplastics can be bent using a line bender or strip heater. They can also be deformed using vacuum forming and blow moulding processes. Plastics can be reformed using injection moulding.

Metals can be bent or folded, and reformed using sand or die casting processes.