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Awareness on Plastics &Moulds

H & GT - GTCI - Bangalore - July 2005

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Contents

> > > > > > > > >H & GT - GTCI - Bangalore - July 2005

Introduction Materials Mould Manufacturing Advanced Moulding Technology Injection Moulding Machine Moulding defects and remedies Design Considerations Design Guidelines Design for Manufacturing and Assembly Guidelines

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Introduction to MouldsWhat is mould? Moulding is a manufacturing technique for making parts from plastic material. Molten plastic is injected at high pressure into a mold, which is the inverse of the desired shape. The mould is made by a mold maker from metal, usually either steel or aluminum, and precision-machined to form the features of the desired part. Injection moulding is very widely used for manufacturing a variety of parts, from the smallest component to entire body panels of cars.

4 Ms to be consideredMan Material Manufacturing Machine

Why is injection moulding awareness needed for Product Designing ? Considerable thought should be put into the design of moulded parts and their moulds, to ensure that the parts will not be trapped in the mould, that the moulds can be completely filled before the molten resin solidifies, and to minimize imperfections in the parts, which can occur due to peculiarities of the Design Process.

H & GT - GTCI - Bangalore - July 2005

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H & GT - GTCI - Bangalore - July 2005

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Materials

> General Definition of MaterialsMaterial is the substance or matter from which something is or can be made, or also items needed for doing or creating something. Materials for moulding: 1. Natural Rubber. 2. Synthetic Rubber 3. Thermoset Plastic. 4. Thermo Plastic.

H & GT - GTCI - Bangalore - July 2005

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Materials

> Criteria for selecting MaterialsPhysical & Mechanical Considerations What are the overall part dimensions (diameter, length, width, thickness)? What load will the part have to carry? Will the design carry high loads? What will the highest load be? What is the maximum stress on the part? What kind of stress is it (tensile, flexural, etc.)? How long will the load be applied? Will the load be continuous or intermittent? Does the part have to retain its dimensional shape? What is the projected life of the part or design

H & GT - GTCI - Bangalore - July 2005

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Materials

> Criteria for selecting MaterialsThermal Considerations What temperatures will the part see and for how long? What is the maximum temperature the material must sustain? What is the minimum temperature the material will sustain? How long will the material be at these temperatures? Will the material have to withstand impact at the low temperature? What kind of dimensional stability is required (is thermal expansion and contraction an issue)? Bearing and Wear Considerations Will the material be used as a bearing? Will it need to resist wear? Will the material be expected to perform as a bearing? If so, what will the load, shaft diameter, shaft material, shaft finish, and rpm be? What wear or abrasion condition will the material see?

Note: Materials filled with friction reducers (such as PTFE, molybdenum disulfide, or graphite) generally exhibit less

H & GT - GTCI - Bangalore - July 2005

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Materials

> Criteria for selecting MaterialsChemical Considerations Will the material be exposed to chemicals or moisture? Will the material be exposed to normal relative humidity? Will the material be submerged in water? If so, at what temperature? Will the material be exposed to steam? Will the material be painted? If so, what kind of paint? Will the material be glued? If so, what kind of adhesive will be used? Will the material be submerged or wiped with solvents or other chemicals? If so, which ones? Will the material be exposed to chemical or solvent vapors? If so, which If so, which ones? Will the material be exposed to other materials that can outgas or leach detrimental materials, such as plasticizers or petroleum-based chemicals?

H & GT - GTCI - Bangalore - July 2005

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Materials

> Criteria for selecting MaterialsOther Miscellaneous Considerations Will the part have to meet any regulatory requirements? Is UL94 Flame retardant rating required? What level? Should the material have a special color and/or appearance? Natural | White | Black | Other Colors Color match to another part or material? Window-Clear | Transparent | Translucent | Opaque Smooth | Polished | Textured | One-Side or Both Will the part be used outdoors? Is UV Resistance needed? Is static dissipation or conductivity important? Insulator | Static Dissipative | Conductive

H & GT - GTCI - Bangalore - July 2005

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Materials

> Rubber1. A naturally gifted plastic. 2. Has many applications in industrial and consumer goods. 3. Only group of materials able to provide elastic properties across a wide range of temperatures. The rubber family includes a diverse range of materials - as varied as "metals" or "plastics".

H & GT - GTCI - Bangalore - July 2005

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Materials Rubber

> Introduction to Rubber ManufacturingThe two types of rubber in common use today are Natural and Synthetic. Natural rubber comes from the rubber tree (Hevea brasiliensis). When a tree matures at the age of six or seven years, the latex is collected from a diagonal incision in the tree trunk. The tapping process does not affect the health of the tree and the tree wound later heals itself. Synthetic rubber is made by man from petrochemical feedstock. Crude oil is the principal raw material.

H & GT - GTCI - Bangalore - July 2005

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Materials Rubber

> Uses of RubberDesigners choose rubber because of its wide range of properties It can be used over a temperature range from -80C to +300C

It can be electrically insulated, conductive or anti-static

H & GT - GTCI - Bangalore - July 2005

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Materials Rubber

> Uses of RubberIt is available in a wide range of colors and textures

It can withstand extremes of weather and outdoor environment

H & GT - GTCI - Bangalore - July 2005

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Materials Rubber

> Uses of RubberIt can withstand exposure to fuels, oils and chemicals while retaining its properties It can be made flame retardant and self extinguishing, with halogen free and smoke suppressant types available

It can absorb vibration and noise and act as an insulator

H & GT - GTCI - Bangalore - July 2005

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Materials Rubber

> Uses of RubberIt can maintain tension and compression forces indefinitely - for example in seals. It can be gas tight and used as a fluid seal or separator

Gaskets and Oil Seals used in Engine

H & GT - GTCI - Bangalore - July 2005

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Materials Rubber

> Uses of RubberIt has low thermal conductivity and can be used to reduce heat transfer

It has friction properties similar to human skin and is comfortable to grip

H & GT - GTCI - Bangalore - July 2005

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Materials Rubber

> Uses of RubberIt can have a clean, smooth surface which is non-stick and suitable for hygienic applications

It is compatible with other engineering materials (e.g. metals, plastics and ceramics) and can be combined with them in many different ways, including bonding.

H & GT - GTCI - Bangalore - July 2005

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Materials

> PlasticsThe term plastics covers a range of synthetic or semi-synthetic organic condensation or polymerization products that can be molded or extruded into objects or films or fibers. Their name is derived from the fact that in their semi-liquid state they are malleable, or have the property of plasticity. Plastics vary immensely in heat tolerance, hardness, and resiliency. Combined with adaptability, the general uniformity of composition and lightness of plastics ensures their use in almost all industrial applications today. Plastic may also refer to any material characterized by deformation or failure under shear stress. Plastics offer extraordinary advantages in product manufacturing. Because they are easily softened or melted, they can be molded into almost any shape. Plastics have replaced traditional materials like metals and wood in countless applications because of their cost effectiveness and property attributes.

H & GT - GTCI - Bangalore - July 2005

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Materials Plastics

Plastics can be divided into two processing groups Thermoplastics and Thermosets

Thermoplastic1.It is heated and pressed into a mould. 2.No chemical reaction of any kind takes place. 3.Once the plastic has cooled and hardened in this shape, it could be reheated and remoulded without any perceptible change in its properties.

Granules

Products

H & GT - GTCI - Bangalore - July 2005

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Materials Plastics

Thermosets1. Undergo chemical change while they are being formed. 2. They react by polycondensation and cross-link to form a three-dimensional lattice. 3. Once a thermoset has achieved its final shape, it cannot be reformed. 4. Examples of thermosets are phenolic resins, melamines and urea resins

Granules

Products

H & GT - GTCI - Bangalore - July 2005

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Materials Plastics

Advantages of PlasticsPlastics can provide the following advantages for product designers and manufacturers: Design Flexibility High Strength and Toughness Corrosion Resistance Reduced Manufacturing Costs Almost Any Color or Surface Texture Waterproof Stiffness o