1. Tecnologie di fabbricazione di plastiche La tecnica utilizzata dipende dal tipo di materiale, i.e. termoplastico o termoindurente

2. Formatura di materiali termoplastici (thermosofting plastic) Stampaggio a caldo (Thermoforming) Stampaggio a iniezione (Injection moulding) Estrusione (Extrusion) Soffiatura (Blow moulding) Colaggio (Casting)

3. Estrusione PVC – Polyvinyl Chloride PE – (HDPE & LDPE) Polyethylene PP – Polypropylene PS – Polystyrene PC – Polycarbonate ABS – Acrylonitrile Butadiene Styrene EVA – Ethylene Vinyl Acetate TPE – Thermoplastic Elastomer PMMA (Acrylic) – Polymethyl Methacrylate PA (Nylon) – Polyamide

4. Extrusion is used to produce a variety of products ranging from spaghetti to garden hose. It is the most common process used to manufacture long strands of anything. A variety of materials can be extruded including aluminium, clay, rubber, various foods and plastics. Plastic pellets are fed and placed into a hopper, from which they drop into a heated barrel. They are moved and kneaded in the barrel by a screw until they reach a molten state (this is then referred to as the melt.) The melt is then extruded or forced out of the end of the barrel through a shaping die as a long, continuous line of shaped plastic. This line is then pulled by a haul-off (puller) through a cooling trough, where it solidifies and then is cut to length or coiled. Advantages Extrusion is a highly efficient process (high speed process, little waste) Extrusion allows some of the most complex shapes to be formed in high volume Allows for precise cross sectional dimensions to be produced. Disadvantages Parts must be cut to finished length The cross-sectional shape of the product must remain the same Characteristics Continuous cross section Virtually unlimited length is possible!

5. Stampaggio a iniezione

6. Injection molding is a method of producing parts with plastic material (thermoplastic and thermosetting resins). This is done by the use of an injection molding machine. The shape which is produced is controlled by what is called a mold. This is a reverse image of the part desired and can be compared to the familiar "Jell-O®" mold. The injection molding machine has two basic parts; the injection unit, which melts the plastic and then injects or moves it into the mold, and the clamping unit, which holds the mold. The unit clamps the mold in a closed position during injection, opens the mold after cooling, and ejects the finished part. Injection molding is the most common plastic manufacturing process. It is used to produce high volumes of parts. Advantages Complex geometry and fine features are easily produced, because very high pressures are possible. Cycle times are relatively low, and many parts can be made from a single mold, making extremely high volumes (millions per year) possible. Relatively low labor cost: Injection molding is commonly automated. Many machines can be run by a single operator. Little or no finishing of parts is required. Able to process a wide variety of materials. Minumum scrap losses. Disadvantages Large undercuts cannot be formed (such as bottles) Mold cost is high, so low part volumes are not recommended (usually less than 1000 parts is considered low; most volumes for injection molded parts are well over 10,000 pieces per year) Characteristics The parts are thin-walled (walls greater than 0.125" are not common) Thermoplastic materials are used in this process (thermoplastics can be remelted, as opposed to thermosets) All exterior surfaces of the part touch the mold (as opposed to blow molding, where air forms the inside) Mold cost is high, so low part volumes are not recommended (usually less than 1000 parts is considered low; most volumes for injection molded parts are well over 10,000 pieces per year)

7. Soffiatura Blow molding is the process of inflating a hot, hollow, thermoplastic preform or parison inside a closed mold so its shape conforms to that of the mold cavity. A wide variety of hollow parts, including plastic bottles, can be produced from many different plastics using this process. Advantages of blow molding Low tool and die costs (compared to other molds) Rapid production rates Able to mold complex shapes in one piece Disadvantages of blow molding Limited to the forming of hollow or tubular shapes Characteristics of blow molded parts are Usually have thin walls Range in size and shape from small bottles to automotive fuel tanks

8. Granules of plastic powder (polystyrene, nylon, polypropylene and polythene) are poured or fed into a hopper which stores it until it is needed. T he heater is turned on. This warms up and melts the granular plastic. A motor turns a screw thread which pushes the granules along the heater section causing it to change to a liquid. The liquid plastic is forced into a mould by pressure. Pressurised air is ‘blown’ into the mould. This forces the liquid plastic against the sides of the mould. In this example it forms the shape of a plastic bottle. The plastic is allowed to cool and the mould is ‘split’ and the plastic bottle removed. The entire process is repeated hundreds or thousands of times.

9. Stampaggio: Vacuum forming & Pressure forming Vacuum Forming is the process of creating 3-D objects from a flat plastic sheet by heating the sheet, draping it over a form, and then evacuating air from between the sheet and form. Vacuum forming is especially useful in creating large products. Vacuum forming uses thermoplastic materials. Advantages Very low tooling costs (compared to injection or blow molding) Short lead time (able to move from concept to production rapidly) Disadvantages Unable to mold parts with negative draft There are limits to the depth of part based on the material's elasticity