Classification (thermosets, thermoplastics, semi-crystalline, amorphous), major modifications (fibre reinforced, impact modified, etc.). Properties, characteristics advantages and disadvantages of common plastics.
The barriers to structured selection include many plastics types and thousands of grades to choose from. Numerous options and variations will be presented to facilitate 'decoding the data sheet'. Equally important there will be advice on drawing up the specification; the hidden requirements, often overlooked, which can result in failure. Finally there is a participative case study using computer software.
Design for Performance
The structural performance of plastics (creep, stress relaxation, fatigue, effect of temperature, ageing, chemical attack), allowable design stresses and strains.
The differences betwen short and long term mechanical properties and their impact on application. Introduction of methodologies to use long term materials data to improve the confidence in the performance of a design and minimise the risk of product failure in the long term.
Common causes of failure, brittle fracture (stress cracking, embrittlement, effect of notches, uv degradation, hydrolysis), impact, fatigue
Many common faults including short shots, flashing, weld lines, sinking and voiding, thermal and hydrolytic degradation, etc. are discussed. Causes and remedies are suggested. How the part design contributes to the problems will be explained such that design can be optimised for manufacture as well as function.
Use of software simulation tools to optimise the moulded part in terms of processing quality, final part dimensions and residual stress.
Tensile stress-strain and creep tests, impact tests and stress relaxation.