SACE Stage 2 Design, Technology and Engineering flashcards

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

Design brief

A short statement defining the client, target user, purpose, key requirements and constraints of a design task. It sets the boundaries against which all later solutions are judged.

Functional requirement

A statement of what a product must do or achieve in service, such as supporting a stated load or fitting a specified space. It is distinct from a constraint, which limits how it may be achieved.

Constraint

A fixed limit imposed on a design, such as budget, deadline, available machinery, relevant standards or safety rules. Constraints eliminate otherwise workable options and must be identified early.

Success criteria

Measurable statements used to judge whether a finished design meets its brief. They must be observable or testable, for example a maximum mass or a minimum load before permanent deformation.

Design process cycle

An iterative sequence of investigating and defining, generating concepts, developing and testing, producing, and evaluating. Evidence from each stage is documented and informs the next.

Anthropometric percentile data

Body measurement data expressed as percentile values. Design for the fifth percentile where reach limits clearance, and the ninety-fifth percentile where body size limits openings.

Ergonomics

The application of human physical and cognitive capabilities to product design. It covers reach, posture, force limits, visibility and control layout so users can operate a product safely and comfortably.

Factor of safety

Failure stress or load divided by working stress or load. A value greater than one indicates reserve capacity beyond expected service conditions; higher values suit uncertain loads or brittle materials.

Mechanical advantage

For a lever, the effort arm length divided by the load arm length. A ratio above one means the applied effort is multiplied, though the effort must then move through a greater distance.

Velocity ratio

The distance moved by the effort divided by the distance moved by the load. For a pulley system it equals the number of rope segments supporting the moving load.

Mechanical efficiency

Work output divided by work input, expressed as a percentage. It equals mechanical advantage divided by velocity ratio, and is always below one hundred percent because friction dissipates energy.

Third-angle projection

An orthographic drawing convention where each view is placed on the side of the object from which it is viewed. The top view sits above the front view and the right side view to its right.

First-angle projection

An orthographic convention where each view is projected onto the plane beyond the object. The top view appears below the front view and the right side view appears on the left.

Section view

A drawing view showing the internal form of an object as if cut by a defined plane. Hatching indicates cut material and hidden detail is exposed rather than shown dashed.

Material strength-to-weight ratio

A material's strength divided by its density. It is a key selection criterion where mass matters, favouring materials such as aluminium alloys and composites over mild steel.

Design for disassembly

A sustainability strategy in which joints, fasteners and materials are chosen so a product can be separated for repair, reuse or recycling at end of life.

Sustainability hierarchy

An ordered preference in design: avoid or reduce material, use renewable or recycled stock, design for repair and disassembly, then plan end-of-life recovery. Earlier options deliver greater benefit.

Marking out

The process of transferring dimensions from a drawing onto raw stock using rules, squares, scribers or centre punches. Accurate marking out precedes cutting and reduces scrap from misplaced features.

Primary shaping

The first manufacturing operation that changes raw stock into a rough form, such as sawing, turning, milling, drilling or moulding. Finishing and joining follow it.

Tolerance

The permitted range of variation on a nominated dimension. A tight tolerance gives precise fit but raises machining cost and time; loose tolerances suit non-critical features.

Tolerance stack-up

The accumulation of individual component tolerances along a dimension chain. Total variation equals the sum of the contributing tolerances, so critical fits need tighter control.

Clearance fit

A fit in which the shaft is always smaller than the hole, leaving a gap. It allows free movement or easy assembly and is suited to bearings, pivots and sliding parts.

Interference fit

A fit in which the shaft is always larger than the hole and must be pressed or shrunk in. It transmits torque without fasteners but requires careful tolerance control.

Risk control hierarchy

The ordered approach to hazards: eliminate, substitute, apply engineering controls such as guards and extraction, then administrative controls, with personal protective equipment last.

Safe work procedure

A documented sequence of steps, hazards, controls and required equipment for a workshop task. It is consulted before work begins and reviewed when the process changes.

Fair test design

A test in which only the intended variable is changed while all others are held constant. It specifies the measuring instrument, its resolution, the number of repeats and the acceptance threshold.

First-article inspection

Measurement and checking of the first component produced after a setup change, confirming the machine, tooling and program are correct before the batch continues.

In-process inspection

Checks made at intervals during production to detect drift in dimensions or process conditions. It catches variation early, before a whole batch is made outside specification.

CAM toolpath

The calculated path a cutting tool follows, generated from a CAD model. It defines feed rate, spindle speed, depth of cut and safe rapid moves between cutting passes.

Break-even quantity

Fixed costs divided by the difference between unit selling price and variable cost per unit. It is the number of units that must be sold before the project returns no loss.

Design evaluation

A documented judgement of a finished design against the brief's success criteria, drawing on user trials and function tests. It records measured results and lists modifications for the next iteration.