Hollow blow molding is the extrusion or injection molding obtained by the semi-melting plastic billet for a variety of shaped abrasive, closed abrasive, in the billet according to the air compression blowing, so that it meets the wall of the abrasive, after the cooling mold and hollow crafts. Can be used for the production of edible oil, drinks, drinks, seasonings, milk and other food packaging materials with plastic bottles, a variety of annular, square, shaped and with doorknob barrels, cans and other hollow crafts.
Hollow blow molding is the plastic deformation of plastic plastic blank placed in the grinding tool, air compression into the blank, blow it up, make it close to the mold cavity wall, after cooling to get a certain shape of hollow plastic parts production and processing. According to the molding way is not the same, can be divided into four ways.
1, extrusion blow molding
1 — Extrusion machine head 2 — blow molding die 3 — tubular billet 4 — air compression boiler blow tube 5 — plastic parts
The first extruder extruded tubular billet; Extract a section of finishing rolling pipe and put it into the grinding tool while it is hot, close the left and right sides of the other clamping type blank of the open grinding tool;
Then to the concave die into the air compression, so that the billet blowing and attached to the inner wall of the die core table;
Finally, after pressure retention, refrigeration and forming, it can remove the air compression and mold to remove the plastic parts.
Extrusion blow molding mold design is simple, the project investment is less, the actual operation is very easy, suitable for a variety of plastic hollow blow molding. Extrusion blow molding defects are not easy to symmetrical wall thickness, plastic parts need to be processed after the removal of burr.
2, injection blow molding
1 — Injector nozzle 2 — Needle type blank 3 — hollow mold base (core) 4 — Electric heater 5 — blow molding mold 6 — plastic parts
The first injection mold in the injection machine to make hollow spectral type blank;
Then the core and the billet are moved into the blow molding mold, the core is hollow and the inner wall contains microporous plate;
Subsequently, the mold is locked and compressed from the pipe of the core shaft into the air, so that the blank is blown and attached to the inner wall of the concave mold surface of the abrasive tool;
Finally, after pressure retention, refrigeration and forming, it can remove the air compression and mold to remove the plastic parts.
The advantage of injection blow molding is that the wall thickness of plastic parts is well-proportioned without flying edge, without production and processing. Because of the needle type blank spectrum, so there is no joint at the bottom of the plastic parts, high compressive strength, high production and manufacturing efficiency, but the project investment of machinery and equipment and abrasive tools is very large, mostly for the batch production of small and medium-sized plastic parts.
3, injection stretch blow molding
1 — Injector nozzle 2 — injection mold 3 — stretch mandrel (boiler blow tube) 4 — blow molding mold 5 — plastic parts
Injection stretching blow molding is the production and processing method that the injection molding spectral blank is heated to the appropriate temperature below the solution point and then placed in the abrasive tool. The extension rod is first carried out radial stretching and then into the air compression blow molding.
After stretching blow molded plastic parts of its clarity, impact resistance compressive strength, surface strength, bending stiffness and steam resistance characteristics are often very improved. Injection stretch blow molding the most typical commodity is linear polyester mineral water bottles. Injection stretch blow molding can be divided into hot billet method and cold billet method two molding methods.
The first injection molding hollow spectral blank; Move the billet to the stretching and blow molding fixture to carry out stretching and blow molding; After pressure retention, refrigeration out of the mold removed plastic parts.
This kind of molding method saves the reheating of cold billet and saves energy. In addition, the billet system and stretch blow molding are carried out on the same machine and equipment, which occupies a small area, is convenient for continuous development of production and manufacturing, and has a high level of automation technology.
Cold billet injection stretch blow molding is the injection of good billet temperature to a suitable temperature and then put it in the blow molding mold to carry out stretch blow molding molding. When selecting cold billet forming method, the injection of billet and stretch blow molding of plastic parts are carried out on different machines and equipment respectively. Before the stretching blow molding, in order to compensate for the heat released by the refrigeration of the billet, the secondary heating must be carried out to ensure the stretching blow molding of the billet.
4 plastic sheet blow molding
Plastic sheet blowing molding injection molding or extrusion molding plastic sheet heating, make it soft, into the concave mold, locked in the middle of the plastic plate into the air compression and forming a hollow plastic parts.
Post time: Sep-17-2021