PLASTIC FURNITURE MANUFACTURING PROCESS I N T D 3 0 1 F U R N I T U R E A N D F I T T I N G S
COMMON MANUFACTURING METHODS FOR PLASTIC FURNITURE 1. MOLDING 1. Extrusion molding 2. Injection molding 3. Blow molding 4. Rotational molding 2. FORMING 1. Thermo forming 2. Vacuum Forming 3. CASTING 4. FOAMING
INJECTION MOLDING Injection molding process is used for making single work piece without joints. With injection molding, parts with very complex shapes can be molded very easily.
INJECTION MOLDING Molten polymer is first forced into a mold cavity where it cools and hardens to take the shape of the final product. Sometimes automated rams are used to push the molten material into the cavity.
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THERMO FORMING In this process, a thermoplastic sheet is heated to become softer, and is pressed against a mold and allowed to cool until it retains the shape of the mold. Applications of thermoforming are spas, bathtubs, sinks, swimming pools, furniture and housewares, point-of-purchase displays, amusement park rides, automotive components, signs, aircraft components, molds, lighting fixtures etc
VACUM FORMING The process involves heating a plastic sheet until soft. The softened sheet is draped over a mould. A vacuum sucks the sheet into / onto the mould. The newly shaped sheet is taken off the mould.
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FOAMING Foaming process is used for making foams or cellular plastics. Eg: thermocol, styrofoam cups, packaging materials, insulating materials etc.
FOAMING Foaming processes cause tiny bubbles to form within the plastic, solidifies the bubbles, or at least the holes created by the bubbles, remain. The solidified bubblecontaining material can be thought of as a cellular structure.
Process Plastics used Marks left Tooling cost Blow Moulding High density polythene Line along the join of mould parts Production Volume Uses High High Hollow products with smaller openings than the body Extrusion Foaming Injection moulding high density polythene; polystyrene and polyvinyl chloride polystyrene, polyurethane, polyvinyl chloride all thermoplastics none moderate high but restricted to minimum order lengths anything with a constant cross section: curtain rails or window frames none Medium High packaging; sponges; soles of shoes; steering wheels; vending cups, insulation; foam furniture the plastic enters the mould through what is known as a gate which leaves a 'sprue' which is then broken off but leaves a slightly rough, often circular area; there are sometimes also smooth circular marks left by the ejector pins used to help release the warm moulding from the mould High High precision technique capable of complicated shapes: e.g. medical components; Airfix kits; cheap products produced in very large numbers: Lego; plastic cutlery; machine housings; washing-up bowls
Process Plastics used Marks left Tooling cost Rotational moulding Thermoforming low or medium density polythene most sheet thermoplastic materials Same as Injection moulding Relatively low Production Volume Medium None Low suitable for low quantities or even one offs, but can be mechanised to speed up process Uses only for products with uniform wall thickness and where the inner surface of the product can be inferior to its outer surface which replicates the surface of the mould. Usually large simple forms: storage tanks; traffic bollards shallow forms: baths and boat hulls, bowls, margarine and yogurt pots
FINISHING OF PLASTIC FURNITURE After the plastics are molded or cast to their desired shape, they require additional finishing before they are in their final use form. Common finishing operations are as follows; 1. Flash removal 2. Shaping (postmold forming) (used if the molded part is at an intermediate shape) 3. Mechanical joining and assembly (by using rivets, metal screws, or designing snap joints and internal hinges) Adhesive bonding (with adherents and adhesives) Non-adhesive bonding (i.e. fusion bonding, ultrasonic welding, Radio frequency welding, friction welding, and induction welding) 4. Coating and decorating (painting, printing, metallizing, etc.)
WOODWORKING FLOWCHART Purchase of Timber Molding machine Carving Wood cutting Shaper machine to shape Assembly Seasoning in factory Furniture Design in CAD Polishing
Wood cutting automated saw
Wood lathe machine
Wood bending Wood bending is one of the technique in furniture manufacturing process. This adds the value of the product. Wood with good grain conditions (little loose grains), highly ductile and free of defects can be used for bending.
Wood carving- manual or automated: CNC machine
METALS Joining of metals can be done precisely by screwing, riveting, bolting or welding.