Specialist technical principles

In addition to the core technical principles, all students should develop an in-depth knowledge and understanding of the following specialist technical principles:

• selection of materials or components
• forces and stresses
• ecological and social footprint
• sources and origins
• using and working with materials
• stock forms, types and sizes
• scales of production
• specialist techniques and processes
• surface treatments and finishes.

Each specialist technical principle should be delivered through at least onematerial category or system. Not all of the principles outlined above relate to every material category or system, but all must be taught.

The categories through which the principles can be delivered are:

• papers and boards
• timber based materials
• metal based materials
• polymers
• textile based materials
• electronic and mechanical systems.

Selection of materials or components

In relation to at least one material category or system, students should be able to select materials and components considering the factors listed below.

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Potential links to maths and science

Functionality: application of use, ease of working.

Aesthetics: surface finish, texture and colour.

Environmental factors: recyclable or reused materials.

Availability: ease of sourcing and purchase.

Cost: bulk buying.

Social factors: social responsibility.

Cultural factors: sensitive to cultural influences.

Ethical factors: purchased from ethical sources such as FSC.

Calculation of material costs.

Selection and use of materials considering end of life disposal.

Forces and stresses

In relation to at least one material category or system, students should know and understand the impact of forces and stresses and the way in which materials can be reinforced and stiffened.

Materials and objects can be manipulated to resist and work with forces and stresses

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Potential links to maths and science

Tension, compression, bending, torsion and shear.

Changing the magnitude and direction of forces.

Materials can be enhanced to resist and work with forces and stresses to improve functionality

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Potential links to maths and science

How materials can be reinforced, stiffened or made more flexible: eg lamination, bending, folding, webbing, fabric interfacing.

Ecological and social footprint

In relation to at least one material category or system, students should have a knowledge and understanding of the ecological and social footprint left by designers.

Ecological issues in the design and manufacture of products

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Potential links to maths and science

Deforestation, mining, drilling and farming.

Mileage of product from raw material source, manufacture, distribution, user location and final disposal.

That carbon is produced during the manufacture of products.

Selecting appropriate materials.

Understanding of how to choose appropriate energy sources.

The six Rs

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Potential links to maths and science

Reduce, refuse, re-use, repair, recycle and rethink.

Social issues in the design and manufacture of products

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Potential links to maths and science

Safe working conditions; reducing oceanic/atmospheric pollution and reducing the detrimental (negative) impact on others.

Ethical factors and the social footprint of materials used in products.

Sources and origins

In relation to at least one material category, students should know and understand the sources and origins of materials.

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Potential links to maths and science

Primary sources of materials and the main processes involved in converting into workable forms for at least one material area.

• Paper and board (how cellulose fibres are derived from wood and grasses and converted into paper).
• Timber based materials (Seasoning, conversion and creation of manufactured timbers).
• Metal based materials (extraction and refining).
• Polymers (refining crude oil, fractional distillation and cracking).
• Textile based materials (obtaining raw material from animal, chemical and vegetable sources, processing and spinning).

Life cycle assessment and recycling ie the basic principles in carrying out a life cycle assessment of a material.

Using and working with materials

In relation to at least one material category or system, students should know and understand in addition to material properties (page 15), the factors listed below.

Properties of materials

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Potential links to maths and science

Students must know and understand how different properties of materials and components are used in commercial products, how properties influence use and how properties affect performance.

Students must know and understand the physical and mechanical properties relevant to commercial products in their chosen area as follows:

• Papers and boards (flyers/leaflets and card based food packaging).
• Timber based materials (traditional timber children’s toys and flat pack furniture).
• Metal based materials (cooking utensils and hand tools).
• Polymers (polymer seating and electrical fittings).
• Textile based materials (sportswear and furnishings).
• Electronic and mechanical systems (motor vehicles and domestic appliances).

How physical and working properties are selected related and used in commercial products when designing and making.

The modification of properties for specific purposes

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Potential links to maths and science

• Additives to prevent moisture transfer (paper and boards).
• Seasoning to reduce moisture content of timbers (timber based materials).
• Annealing to soften material to improve malleability (metal based materials).
• Stabilisers to resist UV degradation (polymers).
• Flame retardants reduce combustion and fire hazards (textile based materials).
• Photosensitive PCB board in PCB manufacture and anodizing aluminium to improve surface hardness (electronic and mechanical systems).

How to shape and form using cutting, abrasion and addition

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Potential links to maths and science

• Papers and boards (how to cut, crease, score, fold and perforate card).
• Timber based materials (how to cut, drill, chisel, sand and plane).
• Metal based materials (how to cut, drill, turn, mill, cast, bronze and weld).
• Polymers (how to cut, drill, cast, deform, print and weld).
• Textile based materials (how to sew, pleat, gather, quilt and pipe).
• Electronic and mechanical systems (how to cut, drill and solder).

Stock forms, types and sizes

In relation to at least one material category or system, students should know and understand the different stock forms types and sizes in order to calculate and determine the quantity of materials or components required.

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Potential links to maths and science

Commercially available types and sizes of materials and components.

Papers and boards:

• sheet, roll and ply
• sold by size eg A3, thickness, weight and colour
• standard components eg fasteners, seals and bindings
• cartridge paper and corrugated card.

Timber based materials:

• planks, boards and standard moldings
• sold by length, width, thickness and diameter
• standard components eg woodscrews, hinges, KD fittings.

Metal based materials:

• sheet, rod, bar and tube
• sold by length, width, thickness and diameter
• standard components eg rivets, machine screws, nuts, and bolts.

Polymers:

• sheet, rod, powder, granules, foam and films
• sold by length, width, gauge and diameter
• standard components eg screws, nuts and bolts, hinges.

Textile based materials:

• yarns and fabrics
• sold by roll size, width, weight and ply
• standard components eg zips, press studs, velcro.

Electrical and mechanical components:

• sold by quantity, volt and current rating
• standard components eg E12 resistor series, dual in line IC packages (DIL), microcontrollers (PIC).

Calculation of material quantities and sizes.

Calculate surface area and volume eg material requirements for a specific use.

Efficient material use, pattern spacing, nesting and minimising waste.

Scales of production

In relation to at least one material category or system, students should be able to select materials and components considering scales of production and referencing the processes listed in Specialist Techniques and processes.

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Potential links to maths and science

How products are produced in different volumes.

The reasons why different manufacturing methods are used for different production volumes:

• prototype
• batch
• mass
• continuous.

Specialist techniques and processes

In relation to at least one material category or system, students should know and understand the factors listed below.

The use of production aids

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Potential links to maths and science

How to use measurement/reference points, templates, jigs and patterns where suitable.

Scaling of drawings, working to datums.

Material quantities required.

Tools, equipment and processes

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Potential links to maths and science

A range of tools, equipment and processes that can be used to shape, fabricate, construct and assemble high quality prototypes, as appropriate to the materials and/or components being used including:

wastage, such as:

• die cutting
• perforation
• turning
• sawing
• milling
• drilling
• cutting and shearing

addition, such as:

• brazing
• welding
• lamination
• soldering
• 3D printing
• batik
• sewing
• bonding
• printing

deforming and reforming such as:

• vacuum forming
• creasing
• pressing
• drape forming
• bending
• folding
• blow moulding
• casting
• injection moulding
• extrusion.

How materials are cut shaped and formed to a tolerance

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Potential links to maths and science

The manufacture to minimum and maximum measurements.

Extracting information on tolerances and using it to control quality and make a prototype.

Commercial processes

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Potential links to maths and science

• Papers and boards (offset lithography and die cutting).
• Timber based materials (routing and turning).
• Metal based materials (milling and casting).
• Polymers (injection molding and extrusion).
• Textile based materials (weaving, dying and printing).
• Electrical and mechanical systems (pick and place assembly and flow soldering).

The application and use of Quality Control to include measurable and quantitative systems used during manufacture

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Potential links to maths and science

• Papers and boards (registration marks).
• Timber based materials (dimensional accuracy using go/no go fixture).
• Metal based materials (dimensional accuracy using a depth stop).
• Polymers (dimensional accuracy by selecting correct laser settings).
• Textile based materials (dimensional accuracy checking a repeating print against an original sample).
• Electrical and mechanical systems (UV exposure, developing and etching times in PCB manufacture).

Surface treatments and finishes

In relation to at least one material category or system, students should have knowledge and understanding of surface treatments and finishes.

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Potential links to maths and science

The preparation and application of treatments and finishes to enhance functional and aesthetic properties.

• Papers and boards (printing, embossing and UV varnishing).
• Timber based materials (painting, varnishing and tanalising).
• Metal based materials (dip coating, powder coating and galvanizing).
• Polymers (polishing, printing and vinyl decals).
• Textile based materials (printing, dyes and stain protection).
• Electronic and mechanical systems (PCB lacquering, and lubrication).

Surface treatments to inhibit corrosion and oxidation.