BGCSE Design & Technology flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Design brief

A short statement of the problem to be solved, naming the client, the intended purpose, and the main constraints, written before any design ideas are produced.

Design specification

A list of measurable criteria a successful solution must meet, covering function, size, cost, safety, materials, and finish, used later as the basis for evaluation.

Weighted decision matrix

A table scoring each design option against weighted criteria, multiplying score by weight and summing totals so the chosen solution is justified by numbers rather than preference.

Anthropometric data

Body measurement data from population surveys, such as reach and grip span, used to size products for a stated percentile range of intended users.

Ductility

The ability of a material to be stretched or drawn into wire without fracturing, shown by a large amount of plastic extension before the material breaks.

Thermoplastic

A polymer that softens on heating and hardens on cooling, can be reshaped repeatedly, and is generally recyclable, for example acrylic, HDPE, and polystyrene.

Thermosetting plastic

A polymer that cures by chemical cross-linking into a rigid permanent network; it cannot be remelted or reshaped and chars on strong heating, for example epoxy and polyester resin.

Young's modulus

A measure of stiffness calculated as stress divided by strain within the elastic region; a higher value means the material deflects less under the same load.

Tenon saw

A woodworking saw with a stiffened back and fine teeth, used for accurate straight cuts and joint shoulders because the back keeps the blade rigid.

Marking gauge

A woodworking tool with a spur that scribes a line parallel to a face side or face edge, used to mark joint positions accurately and repeatedly.

Centre punch

A pointed metalworking punch struck with a hammer to make a small indentation, preventing a drill bit from wandering from the marked hole position.

Face edge

A true, flat, square edge prepared on timber and marked with a symbol; all subsequent marking and joint layout is measured from it.

Injection moulding

A high-volume process in which heated thermoplastic is forced into a closed steel mould, cooled, and ejected, requiring draft angles and costly tooling.

Vacuum forming

A process that heats a thermoplastic sheet, clamps it over a former, and draws out the air beneath so the sheet takes the former's shape; undercuts are not possible.

Jig

A device that holds the workpiece and also guides the cutting tool, giving repeated identical results and reducing marking-out time in batch production.

Tolerance

The permitted upper and lower limits of a dimension; a part made within tolerance will fit and function as intended when assembled.

Third-angle projection

An orthographic layout in which the plan is placed above the front elevation and the end view to the left, as if the object were viewed through the paper.

Isometric projection

A pictorial drawing with vertical edges true and the two other axes at 30 degrees to the horizontal, showing three faces without perspective foreshortening.

Hidden detail line

A broken line of short dashes used on a technical drawing to show an edge or feature that is not visible from the viewing direction.

Scale

The ratio of drawing length to real length; a scale of 1:5 means one unit on the drawing represents five units on the actual object.

Triangulation

Bracing a frame with diagonals to form triangles; because a triangle cannot change shape without a side changing length, the structure becomes rigid.

Mechanical advantage

The ratio of load to effort in a machine or mechanism; a value greater than one means the machine multiplies the applied force.

Velocity ratio

The ratio of the distance moved by the effort to the distance moved by the load; efficiency equals mechanical advantage divided by velocity ratio.

Gear ratio

The number of teeth on the driven gear divided by the number on the driver gear; a ratio above one reduces speed and increases output torque.

Ohm's law

The relationship that voltage equals current multiplied by resistance (V = I x R), valid for a conductor at constant temperature.

Potential divider

Two resistors in series across a supply, giving an output voltage equal to supply voltage multiplied by the second resistance divided by the total resistance.

Light-emitting diode

A semiconductor component that emits light when current flows in the forward direction only; it needs a series resistor to limit the current.

Energy efficiency

The useful energy output of a device or system divided by its total energy input, expressed as a percentage; losses usually appear as heat and sound.

Life cycle assessment

A structured evaluation of a product's environmental impact across raw material extraction, manufacture, distribution, use, and end of life.

Design for disassembly

Designing products with reversible fasteners, standard fixings, and material labels so parts can be separated for repair, reuse, or recycling at end of life.

Inclusive design

Designing so a product is usable by the widest practical range of people, regardless of age, size, or ability, without needing special adaptation.

Production plan

A sequenced list of manufacturing operations stating the tools, jigs, quality checks, and time needed for each stage, used to control making in the project.