Property Information

Cost

Overview

• Materials are usually sold by weight or by size. Material costs are therefore given as cost per unit weight or cost per unit volume.
• Many materials are initially made in bulk (e.g. cast metal ingots). They are usually shaped into standard stock items (e.g. sheet or tube) before being bought by a manufacturer.
• As a result, the cost of a material to a manufacturer is often higher than the cost of the raw material. Also, as a general rule, the more a material is "improved", e.g. by alloying, the more expensive it becomes.
• Note that the cost of a product is not the same as its price. The cost is how much the manufacturer has to pay for it, while the price is what the product is sold for - the difference is the profit!

Design issues

• Cost is often one of the most important design considerations when choosing a material. In most designs the aim is to minimise the cost.
• For products such as consumer goods, building materials and transport, material cost dominates design. This makes it difficult to introduce expensive, high performance materials like CFRP into products suc has cars.
• Cost only becomes less important when product performance is everything to the customer and they are prepared to pay for it! Examples are top-of-the-range sports products (racing bicycles, Formula 1 cars, gold clubs etc.), medical implants (such as hip prostheses and heart valves). In some cases cost is virtually irrelevant, for example in satellites.

Measurement

• Material costs are not fixed properties, but are strongly affected by the marketplace and international trading, and by changes in the stability of the supply of the raw materials - which can be disrupted by wars and global politics.
• Some materials, e.g. steel, have had a very stable price for many years. Others, like aluminium, have varied by as much as a factor of 3 in the last decade. The cost of newer materials such as CRFP is steadily decreasing as their usage increases
• The most accurate information on material price can be obtained by phoning a supplier!
• Note that the price will depend on the form the material is supplied in (e.g. as raw material, or formed into sheet or tube), and that bulk discounts can be significant.

Units & Values