Stock Forms, Types & Sizes
Why Stock Forms Matter
Materials are supplied in standard stock forms. Knowing what is available helps a designer calculate how much material to order, minimise waste, and ensure the product can be manufactured efficiently. You need to know the common stock forms, standard sizes and standard components for each material category.
Papers & Boards
Paper and board are sold in sheets and rolls. Standard sheet sizes follow the A-series (A0, A1, A2, A3, A4, A5). Board is measured by thickness (microns or mm), weight (gsm — grams per square metre), and colour. Corrugated card uses a ply rating (single, double, triple wall) to indicate strength. Standard components include fasteners (staples, paper clips), seals (adhesive strips) and bindings (spiral, saddle stitch).
Every material category has its own stock forms, standard sizes and standard components. You must be able to name examples from at least one category in the exam.
Timber-Based Materials
Timber is sold as planks, boards and standard mouldings (skirting, architrave, dowel). Sizes are specified by length, width, thickness and diameter (for dowel). Manufactured boards (MDF, plywood, chipboard) come in standard sheet sizes, typically 2440 × 1220 mm. Standard components include standard components such as woodscrews, hinges and KD (knock-down) fittings used in flat-pack furniture (e.g. cam locks, barrel nuts).
Metal-Based Materials
Metals are available as sheet, rod, bar and tube. They are sold by length, width, thickness and diameter. Standard components include rivets, machine screws, nuts and bolts. Metals are also available in standard profiles such as angle iron, channel and I-beam.
Polymers
Polymers come in many forms: sheet (acrylic, HIPS), rod, powder and granules (for injection moulding), foam (expanded polystyrene) and film (polythene bags). They are sold by length, width, gauge (thickness of film) and diameter. Standard components mirror those for metals — plastic screws, nuts, bolts and hinges are available for non-metal assemblies.
Textile-Based Materials
Textiles are sold as yarns (by weight and ply) and fabrics (by the roll or metre). Fabric is measured by roll size, width (typically 90 cm, 115 cm or 150 cm) and weight (gsm). Standard components include zips, press studs (poppers), Velcro, buttons and elastic.
Electronic and mechanical components are sold by quantity, voltage and current rating. Standard components include the E12 resistor series (12 preferred values per decade), dual in-line IC packages (DIL), and microcontrollers (PIC). These are ordered from specialist suppliers in standard packages.
Calculating Material Quantities
Designers must calculate how much material they need. This involves working out surface area (for sheet materials and coatings) and volume (for solid components). Efficient material use means considering nesting — arranging pattern pieces closely together on a sheet to minimise offcuts. This applies to timber sheets, metal plates, fabric layouts and card nets.
Nesting and efficient pattern spacing reduce material waste and save money, especially in batch and mass production where even small savings per unit add up across thousands of items.
A product requires six identical panels, each 300 mm × 200 mm. Standard MDF sheet size is 2440 mm × 1220 mm. Fitting 300 mm panels along the 2440 mm length gives 8 columns (8 × 300 = 2400 mm). Fitting 200 mm panels along the 1220 mm width gives 6 rows (6 × 200 = 1200 mm). That is 48 panels per sheet — so one standard sheet is more than enough for six panels, with material left over for other projects. Good nesting reduces waste to just 40 mm × 1220 mm + 2440 mm × 20 mm of offcuts.