Blow molding process

    Edit:China Manufacturing      View times      Time:6/23/2021 7:39:59 PM    Print


Blow ( Blow Molding ), also known as blow molding , a method of producing a hollow article of thermoplastic .


Well-known blow molding objects are bottles, barrels, cans, boxes, and all containers for packaging food, beverages, cosmetics, medicines and daily necessities. Large blow-molded containers are commonly used for packaging of chemical products, lubricants and bulk materials. Other blow-molded products include balls, bellows and toys. For the automotive industry, fuel tanks, car shock absorbers, seat backs, center brackets, armrests and headrest coverings are all blow molded. For machinery and furniture manufacturing, blow-molded parts include shells, door frames, racks, clay pots, or boxes with an open face.


Advantages of blow molding :

( 1 ) Advantages of the product: The product has no joints, high strength at the bottom, precise mouth size, and clear surface text and patterns.
( 2 ) Technical advantages:

a . The wall thickness distribution of the parison can be accurately controlled by the injection mold , so that the wall thickness of the obtained container is more uniform , and the thinning phenomenon that is easy to occur in the corner part of the general blow molded product is avoided .

b . The parisons made by injection can all enter the blow mold for inflation molding, which reduces the waste of molding materials and saves the trimming man-hours of the product.


Commonly used materials for blow molding include: PE , PET , PVC , PP , PC and POM , which are mainly used for containers and structural parts that require high molding accuracy and small volumes; commonly used materials for injection stretch blow molding include: PETP , PVC , PP , PAN , especially PETP is the most commonly used, and PC , PS , PA can also be used in this process.


Blow molding equipment :

Conventional plastic blow molding machines can be divided into three categories, including extrusion blow molding machines, injection blow molding machines and a blow molding machine with a special structure, while stretch blow molding machines can be classified as extrusion blow molding machines. One of the blow molding machine, injection blow molding machine and special structure blow molding machine, and the common extrusion blow molding machine is a combination of blow molding machinery and mold clamping machinery, which is generally composed of the parison die of the extrusion machinery and the blow molding machine. The device and the structure of the mold clamping, the thickness control system of the parison and the transmission machine are composed. The parison die is an important component that determines the quality of the blow molded product. Under normal circumstances, the side feed die and the central feed Material type die head.

According to the production method of the parison, blow molding can be divided into extrusion blow molding and injection blow molding, and the newly developed multi-layer blow molding and stretch blow molding.


Blow mold:

Blow molds are generally made of aluminum and copper alloys ; injection molds are generally made of 718 , S136 , MEK 4 , ELMAX and other materials.

For corrosive compounds such as PVC and POM , beryllium copper or copper-based alloys are also used; for molds with higher life requirements, such as blow molding engineering plastics such as ABS , PC , POM , PS , PMMA, etc., stainless steel is required Make molds.

Blow molding process: