How do designers calculate material quantities, waste and the cost of a product?
Calculating material quantities and cost: areas and volumes, percentage material waste, material and total cost (materials, labour, overheads), mark-up and selling price, with worked calculations applied to manufacture.
A focused answer to OCR A-Level Product Design on costing and quantities: calculating areas and volumes, percentage material waste, material and total cost (materials, labour, overheads), and mark-up and selling price, with worked calculations applied to manufacture.
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What this dot point is asking
OCR wants you to calculate material quantities (areas and volumes), percentage waste, the cost of a product (materials, labour and overheads) and the selling price after a mark-up. These are the applied-maths calculations that connect a design to its economics, and they carry marks in Component 01.
Areas, volumes and quantities
Percentage waste
The exam trap is the circle area: use the radius (half the diameter), and remember to multiply one part's area by the number of parts.
Cost: materials, labour and overheads
Mark-up and selling price
Exam-style practice questions
Practice questions written in the style of OCR exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
OCR 20194 marksA rectangular sheet of plywood measures 1200 mm by 600 mm. Six circular discs of diameter 200 mm are cut from it. Calculate the percentage of the sheet wasted, taking pi as 3.14.Show worked answer →
A Component 01 percentage-waste calculation. Marks for the sheet area, the used area, and the percentage waste.
Sheet area square mm. One disc area square mm; six discs square mm. Waste area square mm. Percentage waste (about ).
A common dropped mark is using the diameter instead of the radius in the disc area (the radius is 100 mm, half of 200 mm), or forgetting to multiply one disc by six.
OCR 20226 marksA product costs 4.50 pounds in materials, 3.00 pounds in labour and 1.50 pounds in overheads per unit. The company applies a 60 percent mark-up. Calculate the total cost per unit, the selling price, and the profit per unit.Show worked answer →
A Component 01 costing calculation. Marks for the total cost, the selling price and the profit.
Total cost per unit = materials + labour + overheads = pounds. The mark-up is 60 percent of the cost: pounds. Selling price = cost + mark-up = pounds. Profit per unit = the mark-up = pounds (the selling price minus the total cost).
A common dropped mark is applying the mark-up to only the material cost rather than the total cost, or confusing mark-up (a percentage of cost) with margin (a percentage of selling price).
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