Blowing (expansion film) plastic (or hollow blow mouldi […]
Blowing (expansion film) plastic (or hollow blow moulding) refers to a moulding process in which a hot thermoplastic parison or sheet in a closed mould is inflated into a hollow product by means of fluid (compressed air) pressure.
A plastic container produced in this way. Such as various bottles, squares, round or flat barrels, fuel tanks, etc. have been widely used, newly developed various industrial parts and daily products, such as double-walled box-shaped products, L-ring large drums, pallets Surfboards, seat backs and desks, as well as front spoilers, belt covers, instrument panels, air conditioning ducts, etc., have been applied in practice. The materials processed are from daily plastics to engineering plastics. development of. Blow moulding has now become one of the important moulding methods in plastic processing.
But the basic steps of the blow moulding process are:
2. Forming a molten resin into a tube or parison
3. Sealing the hollow parison blow mould
4. Inflate the in-mould parison
5. Cooling blow moulding products
6. Remove the product from the mould
Injection blow moulding
Injection blow moulding is a blow moulding method. The plastic is first formed into a bottomed parison by injection moulding, and then moved into a blow mould to be blown into a hollow product.
This method can produce packaging containers for daily necessities, cosmetics, medicines, foods, etc., but its volume should not exceed 1L. Commonly used plastics are polyethylene, polystyrene and polyvinyl chloride.
Extrusion blow moulding
Extrusion blow moulding is a blow moulding method. Unlike injection blow moulding, its parison is manufactured by extrusion.
Stretch blow moulding
Stretch blow moulding is a blow moulding method. It is formed by extrusion, injection moulding, etc., and then the parison is heated to the stretching temperature, and longitudinally stretched by internal mechanical force (such as a mandrel) or external (such as a clamp), at the same time or slightly Later, it is inflated by compressed air to perform transverse stretching.