When designing a product or component, it is worth considering – what, why and how – a product or component will go through during its day-to-day use or operation, as this will affect its design, function, operation and longevity. When designing any plastic injection moulding product, especially one we want to last, we consider behavioural design.
Behavioural design implements techniques and concepts taken from behavioural science: essentially the investigation and study of ‘what, why and how’ and the potential impacts. Understanding component behaviour is extremely useful in refining and improving product design.
The outcome of behavioural analysis can provide insight and awareness that will affect decision making and influence how products are designed, developed and manufactured to ensure they meet and exceed specific design and usage parameters. Understanding the behaviour of plastic components when subject to creep, fatigue, wear and weathering conditions is important when considering behavioural design.
Plastic can exhibit a memory effect. If a plastic component is stressed below its elastic limit for a short period of time, it will return to its original shape. If however the plastic is stressed for a prolonged period it will slowly deform and no longer return to its original shape. This condition is known as ‘creep’. Creep can be alleviated by the choice of materials and/or additives, or strengthening the part accordingly.
Fatigue occurs when physical/mechanical stress is repeatedly applied. Over time recurring strain can result in failure of a component if it has not been designed appropriately. Reciprocating and moving parts could be prone to fatigue failure, along with components subjected to continued vibration and shock.
Wear is most common in products like gears or bearings where they are subject to friction through physical contact, which results in the gradual erosion of the material. Physical wear can also increase the effects of fatigue, ultimately to the point where the component can no longer be used. It is important to consider the choice of material and/or additives that will produce very low friction, such as PTFE.
Repeated and long-term exposure to sunlight/UV will impact the material properties and colour of plastics. Adding specific additives can mitigate against weathering effects, although, some types of plastics, such as acrylics, are almost completely resistant to weathering, making them perfect for outdoor use.
Having a thorough understanding of the behaviour a plastic component or part that is used or implemented in a system, product or equipment is essential to ensuring the that the component can be designed to ensure enhanced reliability and continued longevity. Deliberately practicing behavioural design can produce valuable and worthwhile results.
For further enquiries or more detailed information please call us on 01473 828000 or email us at sales@skar.co.uk