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Global Polymer Demand Trends
The global polymer industry consumes raw materials worth more than US$500 billion per year and transforms them into plastics products valued at more than US$1 trillion
The period since 1983 has seen world demand grow from just over 45 million tonnes to an expected market demand of over 250 million tonnes for 2014
Plastic Consumption World-Wide
The Plastic Industry
Materials Properties Comparison
Product Design: it is the process of devising a product that fulfills as completely as possible the total requirements of the user, and at the same time satisfies needs in terms of cost-effectiveness or ROI (return on investment).Design Technology: It is the prediction of performance in its broadest sense, including all the characteristics and properties of materials that are essential and relate to the processing of the plastic.Engineering Properties: correlative properties, together with those that can be used in design equations
Industrial designer : Low processing cost, Appearance, Topical decorationsHuman Engineering
Engineering designer tool builders processors
Engineering design Graphic design Innovative design
Some basic definitions
Design Factors Influencing the Performance
ShapeMaterials selectionDesign constraints (Shrinkage, Stresses)-Eliminate those!Precautionary measures-ribs
The solution is the development/adoption of a Check List!1. Performance RequirementsColour, temperature, moisture, ultraviolet exposure, exposure to fungus, flammability, chemical, electrical resistance, arc resistance, light transmission, stability or permanency, physical property, mechanical property, optical property, heat and/or electrical insulation, resistance to scratching (mar resistance), and special requirements such as self-lubrication, lightness, hinging property, spring property, time of exposure, etc. Also important will be meeting existing government and/or industry regulation.
2. Determine tolerance requirements that are expected in the performance of the product. Shrinkage characteristics of the selectedplastic should be as small as possible so that tolerances can be anticipated with a reasonable degree of accuracy.
3. If required, determine the nature of the load to which the product will be exposed, such as impact, creep, deflection, stresses, bending, gliding, etc.
4. Color matching may be a factor.
5. Cost of plastic by volume and cost to fabricate.
Materials selection e.g., based on strengthThe required data are,1. Data sheets of the specific grade of material containing the properties required,2. Stress-strain curves at the conditions of product application. If applicable, this would usually indicate the toughness of material bysizing up the area under the curve. It would also show the proportional limit, yield point, corresponding elongations, and other relevant data.3. Curves showing change of tensile strength, flexural strength, and modulus with increasing temperatures or other environments.4. Creep data for periods at 100 and 1000 hours (or more, if available) covering stress and temperature conditions closely comparable to those of product application5. The allowable working stress, based on successful performance at conditions of product usage.6. Chemical and/or heat resistance at conditions in service.7. Others (fatigue, etc.)
Loads
type and duration of the load
the temperature conditions under which the load will be active the stress created by the load
Load is continuous when it remains constant for a period of 2 to 6 hours, whereas an intermittent load could be considered of up to two hours duration and is followed by an equal time for stress recovery
The relationships of machine capabilities, plastics processing variables, and product performance
machine conditions include the operating temperature and pressure, mold and die temperature, machine output rate, and so on.
Processing variables are more specific, such as the melt condition in the mold or die, the flow rate vs. temperature
It is the processing variables, properly defined and measured, not necessarily the machine setting, that can be correlated with product performance.
Advantage and Disadvantage of Plastics
products fail not because of its disadvantage(s). They failed becausesomeone did not perform in the proper manner
Plastics can be classified into various families
Cost of product= cost of plastic+ processing cost!
Low stiffness particularly at high temperature
Less density, strength through shape, good thermal insulation, high degree of mechanical dampening, high resistance to corrosion and
chemical attack, and exceptional electric resistance
Viscoelasticity: The behavior of most plastics is much more dependent on the time of application of the load, the past history of loading, the current and past temperature cycles, and the environmental conditions