Classifications of Blow Molding | Types of Blow Molding
Verfasst: Do 23. Jul 2020, 05:19Each plastic part requires a specific manufacturing process which can be significantly different from one product to another. Injection molding is used to manufacture solid components while PET Blowing Machine is used to make plastic products with hollow areas, such as bottles and containers
Injection stretch blow molding combines the injection molding and blow molding processes.The plastic is first molded into a solid preform, to create a threaded bottle neck. Once the preform cools it is fed into a stretch blow mold machine. The preform is then reheated using an infrared heater and blown into a plastic bottle with forced compressed air.
Injection molding and blow molding are two core processes in plastic manufacturing. Products made through these processes are used in a wide range of industries such as automotive, food service packaging, electronics, medical devices, irrigation, dental, firearms, energy and environmental industries.
To help you better understand the different manufacturing methods available for your project, we have compiled an overview of the main types of injection and blow molding methods used by plastics manufacturers.
Injection blow molding
Injection blow molding is normally used to make bottles in large quantities. The method is actually two processes combined. The first step is to injection mold a plastic pre-form. The pre-form typically looks like a test tube, with the thread detail that will be used on the finished bottle neck molded into the open end of the tube.
The injection molded pre-forms are moved (sometimes over long distances) to the blow molding machine where they are reheated, placed into the blow molds, and blown into the finished shape of the bottle. The largest market currently uses the material polyethylene terephthalate (PET).
This method has both advantages and drawbacks. On the plus side, it’s ideal for making very precise bottlenecks, thanks to the core rod used in the injection portion of the process.
However, you can’t use injection blow molding to make more complicated items, such as complex bottle shapes with handles, most consumer goods, or industrial parts.
Stretch blow molding
Stretch blow molding is a variation of injection blow molding, which is also primarily used to make clear PET bottles. Two-liter soda bottles are one of the most common stretch blow molded products.
In the stretch blow molding variation of injection blow molding, the pre-form is both blown and stretched. The core rod increases the length of the pre-form as air is forced into it so that the product lengthens and widens at the same time to fill the mold cavity. The core rod stops lengthening near the opposite wall of the mold.
Stretch blow molding allows you to make the same bottle using less material than in regular injection blow molding. Though this provides an economic advantage, it is counterbalanced by the fact that stretch blow molding machinery is relatively expensive.
Extrusion blow molding
For this process, the plastic is melted and then extruded into the parison. The parison is then closed, and then air is blown into the desired shape while it is still warm. Then once the piece is completely cooled, the plastic is ejected. There are two parts of extrusion blow molding: continuous and intermittent. Continous is when the parison is extruded continuously and each piece of plastic is cut off by a knife, and intermittent is when there is a stop between each mold.
Master Packing Co.,Ltd focus on Bottle Blowing Machine , if you interested in petblowingmachine, please visit PETBLOWINGMACHINE
Injection stretch blow molding combines the injection molding and blow molding processes.The plastic is first molded into a solid preform, to create a threaded bottle neck. Once the preform cools it is fed into a stretch blow mold machine. The preform is then reheated using an infrared heater and blown into a plastic bottle with forced compressed air.
Injection molding and blow molding are two core processes in plastic manufacturing. Products made through these processes are used in a wide range of industries such as automotive, food service packaging, electronics, medical devices, irrigation, dental, firearms, energy and environmental industries.
To help you better understand the different manufacturing methods available for your project, we have compiled an overview of the main types of injection and blow molding methods used by plastics manufacturers.
Injection blow molding
Injection blow molding is normally used to make bottles in large quantities. The method is actually two processes combined. The first step is to injection mold a plastic pre-form. The pre-form typically looks like a test tube, with the thread detail that will be used on the finished bottle neck molded into the open end of the tube.
The injection molded pre-forms are moved (sometimes over long distances) to the blow molding machine where they are reheated, placed into the blow molds, and blown into the finished shape of the bottle. The largest market currently uses the material polyethylene terephthalate (PET).
This method has both advantages and drawbacks. On the plus side, it’s ideal for making very precise bottlenecks, thanks to the core rod used in the injection portion of the process.
However, you can’t use injection blow molding to make more complicated items, such as complex bottle shapes with handles, most consumer goods, or industrial parts.
Stretch blow molding
Stretch blow molding is a variation of injection blow molding, which is also primarily used to make clear PET bottles. Two-liter soda bottles are one of the most common stretch blow molded products.
In the stretch blow molding variation of injection blow molding, the pre-form is both blown and stretched. The core rod increases the length of the pre-form as air is forced into it so that the product lengthens and widens at the same time to fill the mold cavity. The core rod stops lengthening near the opposite wall of the mold.
Stretch blow molding allows you to make the same bottle using less material than in regular injection blow molding. Though this provides an economic advantage, it is counterbalanced by the fact that stretch blow molding machinery is relatively expensive.
Extrusion blow molding
For this process, the plastic is melted and then extruded into the parison. The parison is then closed, and then air is blown into the desired shape while it is still warm. Then once the piece is completely cooled, the plastic is ejected. There are two parts of extrusion blow molding: continuous and intermittent. Continous is when the parison is extruded continuously and each piece of plastic is cut off by a knife, and intermittent is when there is a stop between each mold.
Master Packing Co.,Ltd focus on Bottle Blowing Machine , if you interested in petblowingmachine, please visit PETBLOWINGMACHINE