What is the difference between bar, rod and tube?

Bar and rod are solid sections, with bar often flat, square or hexagonal and rod round. Tube is hollow and may be round, square or rectangular.

Why are bicycle frames made from tube rather than solid rod?

A tube places material far from its centre, where it best resists bending and twisting. A tube is therefore much stiffer for its weight than a solid rod.

Why are structural sections such as angle, channel and I-section used in construction?

The shape of each section places material where it resists bending, giving high stiffness for little weight. An I-section beam can carry the floor loads of a building.

What is bright drawn mild steel?

Bright drawn mild steel is drawn cold through dies to an accurate size. The steel has a clean, smooth, shiny surface ready for machining.

CCEA A-Level Technology and Design 8900

Material Selection and Wood

Topic overview Material selection criteria Physical and mechanical properties Hardwoods, softwoods and timber stock sizes Pine, ash, beech, oak and mahogany Manufactured boards Wood finishes, veneers and laminates

Metals

Topic overview Ferrous and non-ferrous metals and alloys Metal stock forms and sizes Aluminium, copper, brass and zinc Carbon steels and stainless steel Finishes for metals

Plastics

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Composite and Emerging Materials

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Processing Materials

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Product Analysis and Design Communication

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Design for Manufacture, Quality and Safety

Topic overview CAD modelling, virtual imaging and rapid prototyping CAM and CIM Factor of safety and tolerances Testing and inspection of products Risks in workshop and manufacturing processes

Electronic Control SystemsOption A

Topic overview Control systems, feedback and electronics safety Resistors, Ohm's law and power ratings Capacitors and RC timing Potential dividers, sensors and comparators Switches, pull-up and pull-down resistors Output devices and LEDs Transistors, Darlington pairs and thyristors Logic gates, truth tables and flip-flops 555 monostable and astable timers

Microelectronic Control SystemsOption A

Topic overview Microcontroller systems, ADCs and DACs Strain gauges and bridge circuits Optical switches, encoded discs and Schmitt triggers Op-amp amplifiers and gain Zener diodes and voltage regulators Karnaugh maps and binary counters Seven-segment, LCD and dot matrix displays PIC flowcharts and programming DC motors, stepper motors and driver circuits

Mechanical and Pneumatic ComponentsOption B

Topic overview Open and closed loop mechanical and pneumatic control Safe working with compressed air and mechanisms Levers, linkages and moments Gear types and gear trains Pulleys, belts, chains and shaft fixings Cams, cranks and converting motion Compressed air supply and pneumatic valves Cylinders, shuttle valves, restrictors and reservoirs Pneumatic circuits for logic, timing and speed control

Mechanical and Pneumatic SystemsOption B

Topic overview Hydraulics, system limitations and plant safety Torque, work, power and air consumption Vacuum handling, proximity sensors and 5/3 valves Sequential and cascade pneumatic circuits Cam profiles and follower displacement diagrams Gear geometry, pulley blocks and ratchets Toggles, treadles, shafts and couplings Friction, brakes and clutches Bearings, lubrication and seals

Designing and Manufacturing ProductsOption C

Topic overview Research, questionnaires and specifications Idea generation, critiques and computer simulation Manufacturing planning and product evaluation CFRP, GRP, Kevlar and tungsten carbide Smart materials, nanotechnology and biophotovoltaics Isometric, perspective and assembly drawing Laminating, steam bending, cutting and printing processes Risk assessment and product safety law Scales of production, JIT and cell production Quality assurance, ISO 9001 and continuous improvement Design influences and intellectual property rights

Product Design in Industry and SocietyOption C

Topic overview Life-cycle environmental impact and climate change The 6Rs, waste and environmental legislation Sustainable metals, plastics and degradable polymers Product life cycles, consumer types and relaunches CAD, CAM, 3D scanning and quick-change moulding Market pull, technology push and market strategy Price, place and promotion Jigs, fixtures and ICT in quality control Design for maintenance, inclusion and scale production Rendering, typography and presentation Dyson, Baylis, Memphis and Apple

Product Development

Topic overview Choosing a product to redesign Analysing the function and fitness for purpose of existing products Materials, manufacture and sustainability of existing products Ergonomic and aesthetic analysis Redesign modifications, sketching and viability Modelling, testing and evaluating a redesign

Product and System Design and Manufacture

Topic overview Clients, end users and design briefs Researching existing solutions and writing a specification Generating and appraising design proposals Developing a concept with numerical analysis, ergonomics and aesthetics Working drawings and planning manufacture Testing and evaluating a prototype

Metals

Metal stock forms and sizes

3 things to know
AS 1 Paper 1

Overview

Sheet, plate, bar, rod, tube and structural sections, bright drawn and black mild steel, specifying stock, gauges, extrusions, and stock cost and mass calculations.

What you need to know

Answer each one before you reveal it.

Your recallNot started

Key term

How do bright drawn and black mild steel differ, and when is black steel used?

Key term

What are the common forms in which metals are supplied?

Key term

What is the difference between sheet and plate?

Questions from this subtopic

Each one with the model answer underneath.

1
What are the common forms in which metals are supplied?
Model answer
Metals are supplied as sheet, plate, strip, bar, rod, tube and wire. Structural sections such as angle, channel and I-section are also common.
2
What is the difference between sheet and plate?
Model answer
Sheet and plate are both flat stock, but plate is thicker. Sheet bends and folds easily, while plate is used where stiffness and strength are needed.
3
What is the difference between bar, rod and tube?
Model answer
Bar and rod are solid sections, with bar often flat, square or hexagonal and rod round. Tube is hollow and may be round, square or rectangular.
4
Why are bicycle frames made from tube rather than solid rod?
Model answer
A tube places material far from its centre, where it best resists bending and twisting. A tube is therefore much stiffer for its weight than a solid rod.
5
Why are structural sections such as angle, channel and I-section used in construction?
Model answer
The shape of each section places material where it resists bending, giving high stiffness for little weight. An I-section beam can carry the floor loads of a building.
6
What is bright drawn mild steel?
Model answer
Bright drawn mild steel is drawn cold through dies to an accurate size. The steel has a clean, smooth, shiny surface ready for machining.

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Material Selection and Wood

Metals

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Composite and Emerging Materials

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