Saturday, March 3, 2007

Molding Methode

1. Injection molding
is a manufacturing technique for making parts from thermoplastic material. Molten plastic is injected at high pressure into a mould, Injection mouldings count for a significant proportion of all plastics products from micro parts to large components such as bumpers and wheelie bins. Virtually all sectors of manufacturing use injection moulded parts - the flexibility in size and and shape possible through use of this process have consistently extended the boundaries of design in plastics and enabled significant replacement of traditional materials thanks to light weighting and design freedom, which is the inverse of the product's shape, the product example is interior part of automotive, refrigerator part, printer part and other electronic parts
injection molding basically has two main part core and cavity that build the shape of product, core and cavity mounted in mold base, mold base arranged by plate , basically standard a mold have 10 plate, but a simple mold sometimes have only 6 plates.

2. Extrusion molding
This same with injection process but this like vertical injection with product specially tube shape, this method used for making pipes, pipe of cartridge in printer parts and insulation for electrical cables

3. Calendering
calendering methods use several pair of rolling part, plastic rolls of the material are passed between several pairs of heated rollers, to give a shiny surface. Extruded PVC sheeting is produced in this manner as well other plastics, this method used for making large sheets of plastic

4. Compression molding
compression molding is mostly used to make larger flat or moderately curved parts such as hoods, fenders, scoops, spoilers, lift gates and the like for automotive end-uses mostly used to shape thermosetting plastics

5. Blow moulding
in Extrusion Blow Molding (EBM), plastic is melted and extruded into a hollow tube (a parison). This parison is then captured by closing it into a cooled metal mold. Air is then blown into the parison, inflating it into the shape of the hollow bottle, container or part. After the plastic has cooled sufficiently, the mold is opened and the part is ejected.

Injection blow moulding is used for the Production of hollow objects in large quantities. The main applications are bottles, jars and other containers. The Injection blow moulding process produces bottles of superior visual and dimensional quality compared to extrusion blow moulding
Typical Materials Used for injection blow molding process

Polyethylene Low Density (LDPE, LLDPE), Polypropylene (PP), Polyethylene - Terephthalate (PET), Polyvinyl chloride (PVC), Polyethylene High Density (HDPE)