Blow moulding machine for forming a bottle having a calibrated neck finish
Blow moulding machine for forming a bottle having a calibrated neck finish
An extrusion blow moulding machine for forming a bottle having a calibrated neck finish from an extruded parison, including a blow pin assembly comprising a blow pin tip that comprises (a) a plurality of orifices around the circumference of the blow pin and adjacent the base of the bottle neck to help spread the parison material around the neck and assist in cooling and (b) oval cut-outs positioned in line with the parting line of the mold to receive excess material and reduce push-down of excess material at the base of the bottle neck.
Containers and other hollow articles are frequently formed by blow molding. The blow molding process involves providing a tube of heated and softened plastics material (parison) about which a two-piece mold is closed. Air or another gas is introduced under pressure into the parison to expand it against the walls of the mold, forming the desired hollow article. Such blow molding machines can be of various types, the most common of which are extrusion-blow mold machines and injection-blow molding machines.
More specifically, in the extrusion-blow molding process, the blow moulding machinery is closed over the parison pinching off (closing) the ends of the tubular parison. Air or another gas is injected inside the parison through a blow pin, expanding the parison to match the mold cavity. Obviously, the mold in this process controls only the shape of the outer surface of the bottle, including the neck. Since the outer surface of the neck has an irregular contour to facilitate use in dispensers or water coolers, the corresponding inner surface is also irregular since the material forming the inside wall is not constrained, resulting in varying wall thickness that further distorts as the bottle cools to ambient temperature.
In summary, the method and apparatus defined by the present blow moulding machine facilitate production of economical, easily cleaned water bottles from a wide range of materials. Advantages to the water bottle industry are the wide range of plastic materials that can be used and the range of neck sizes that can be suitably formed. Another achievement is producing the straight inner diameter of the neck that facilitates total cleaning during bottle recycle.
An extrusion blow moulding machine for forming a bottle having a calibrated neck finish from an extruded parison, including a blow pin assembly comprising a blow pin tip that comprises (a) a plurality of orifices around the circumference of the blow pin and adjacent the base of the bottle neck to help spread the parison material around the neck and assist in cooling and (b) oval cut-outs positioned in line with the parting line of the mold to receive excess material and reduce push-down of excess material at the base of the bottle neck.
Containers and other hollow articles are frequently formed by blow molding. The blow molding process involves providing a tube of heated and softened plastics material (parison) about which a two-piece mold is closed. Air or another gas is introduced under pressure into the parison to expand it against the walls of the mold, forming the desired hollow article. Such blow molding machines can be of various types, the most common of which are extrusion-blow mold machines and injection-blow molding machines.
More specifically, in the extrusion-blow molding process, the blow moulding machinery is closed over the parison pinching off (closing) the ends of the tubular parison. Air or another gas is injected inside the parison through a blow pin, expanding the parison to match the mold cavity. Obviously, the mold in this process controls only the shape of the outer surface of the bottle, including the neck. Since the outer surface of the neck has an irregular contour to facilitate use in dispensers or water coolers, the corresponding inner surface is also irregular since the material forming the inside wall is not constrained, resulting in varying wall thickness that further distorts as the bottle cools to ambient temperature.
In summary, the method and apparatus defined by the present blow moulding machine facilitate production of economical, easily cleaned water bottles from a wide range of materials. Advantages to the water bottle industry are the wide range of plastic materials that can be used and the range of neck sizes that can be suitably formed. Another achievement is producing the straight inner diameter of the neck that facilitates total cleaning during bottle recycle.