Pancyprian Design & Tech key terms

A short written statement agreed with the client that sets out the problem to be solved, the target user, the constraints and the criteria the finished product must meet.

A detailed list of measurable requirements a product must satisfy, covering function, size, materials, cost, safety and appearance, used to judge whether design ideas are acceptable.

A working method in which a solution is sketched, built, tested and improved through repeated cycles, so that each version corrects the weaknesses found in the previous one.

The study of how people interact with products and workplaces, using body dimensions, reach, posture and force limits so that designs fit the user comfortably and safely.

The collection and use of measurements of the human body, such as height, grip span and seated reach, to size products for a chosen range of users.

An approach that studies the real needs, abilities and tasks of the people who will use a product, and tests ideas with them before final decisions are made.

A physical or digital early version of a product built to test function, fit or appearance before production, ranging from rough card models to working pre-production samples.

A material's resistance to being scratched or permanently indented by a harder object; measured by tests such as Brinell or Mohs and important for wear surfaces.

The ability of a material to absorb energy and deform plastically without fracturing, so a tough material resists impact and crack growth rather than snapping suddenly.

The property that lets a material be drawn out or stretched permanently into thin wire or sheet without breaking, typical of copper and mild steel.

The ability of a material to be hammered or rolled into thin sheets without cracking, a property used in press forming and hand beating of metals.

The ability of a material to return to its original shape after a load is removed, provided the stress stays below the elastic limit.

A permanent change of shape that remains after a load is removed, occurring once stress passes the yield point and the material can no longer spring back.

The tendency of a material to fracture with little or no plastic stretching beforehand, so failure is sudden; common in glass, ceramics and cast iron.

A material made by combining two or more distinct constituents so that their properties combine, for example glass fibres bonded in a polyester resin matrix.

A metallic material produced by melting and mixing a base metal with other elements to improve properties, such as adding carbon to iron to make steel.

A polymer that softens when heated and can be reshaped repeatedly because its long-chain molecules are not chemically cross-linked; examples include polythene and acrylic.

A polymer whose molecular chains cross-link permanently during curing, so it cannot be remelted or reshaped; examples include epoxy resin and melamine.

A high-volume process in which heated thermoplastic granules are forced under pressure into a closed steel mould, then cooled and ejected as a finished part.

A slight taper built into the vertical walls of a moulded or cast part so it can be released from the mould without dragging or scuffing the surface.

A process where a heated thermoplastic sheet is drawn over a former by suction, then cooled and trimmed, suited to shallow, low-volume enclosures and packaging trays.

A work-holding device that locates the workpiece and guides the cutting tool, so repeated operations such as drilling holes in the same place are accurate.

A device that holds and supports a workpiece securely in the correct position during machining or assembly, without guiding the tool itself as a jig does.

Identical components made to tight tolerances so that any one of them fits any assembly of the same product, enabling fast repair and mass production.

A drawing method that shows a three-dimensional object as separate front, plan and side views arranged in fixed positions, with hidden detail shown as dashed lines.

A standard layout in which each view is placed on the side of the drawing nearest to the face it shows, with the plan below the front view and the right side view to the right.

A pictorial drawing using three axes at 30 degrees to the horizontal, where all three dimensions are drawn to the same scale to give a quick three-dimensional impression.

The permitted range between the largest and smallest acceptable size of a dimension, written on a drawing so that parts still fit when made within limits.

A physical representation of a design made at a fixed ratio to the real object, used to check proportions, appearance and space requirements before full-size making.

A load that is applied steadily and does not change with time, such as the weight of a roof resting permanently on its beams.

The internal force carried per unit area of a material, calculated by dividing the applied load by the cross-sectional area and measured in newtons per square millimetre.

The change in length of a member divided by its original length, giving a ratio that shows how much a material stretches under load.

A measure of stiffness found from the slope of the straight part of a stress-strain graph; a high value means the material stretches very little under load.

A bracing technique in which diagonal members divide a frame into triangles, preventing it from racking because triangles cannot change shape without a side changing length.

The ratio of the output force a mechanism delivers to the input force applied to it, showing how much a lever, gear train or pulley system multiplies effort.

The ratio of the distance moved by the effort to the distance moved by the load in a mechanism, fixed by its geometry and independent of friction.

The ratio of the number of teeth on a driven gear to the number on the driving gear, which sets the change in speed and turning force through a gear train.

A control system that carries out a set sequence without measuring the result, so it cannot correct errors caused by disturbance or wear.

A control system that uses feedback from a sensor to compare the actual output with the target value and adjust its action to reduce the difference.

A device that detects a physical quantity such as temperature, light, pressure or position and converts it into an electrical signal a control system can use.

The total energy consumed in extracting raw material, processing, manufacturing and transporting a product, used to compare the true energy cost of material choices.

A structured method of adding up the environmental impacts of a product from raw material extraction through manufacture, use and disposal or recycling.

A design philosophy in which materials are treated as nutrients that circulate endlessly through reuse, remanufacture or safe biological breakdown, so nothing becomes waste.

Designing products with reversible joints, standard fasteners and labelled parts so they can be taken apart easily for repair, material recovery and safe disposal.

A commercial strategy in which a product is deliberately given a short useful life, through styling, limited durability or unavailable spares, so buyers replace it sooner.

Designing products to meet present needs while limiting resource use and pollution, for example by choosing renewable materials, cutting energy in use and extending product life.

Designing mainstream products so that as many people as possible can use them, including those with limited sight, hearing, mobility or strength, without special separate versions.

A structured judgement of a finished design against its specification, using testing, user feedback and comparison with rival products to decide what should be improved.

The checks and measurements carried out during and after production to confirm that parts and assemblies meet the tolerances and standards set in the design.