Plastic milk bottles are manufactured through a process called blow molding. The blow molding machine begins when heated high-density polyethylene (HDPE) pellets are extruded to form a hollow plastic tube, known as a parison. This soft, hot tube is then enclosed within a mold. Once the mold clamps shut, air is injected, inflating the plastic so that it conforms to the mold’s interior shape. The plastic quickly cools and solidifies against the chilled mold walls. After hardening, the newly formed bottle is ejected, any excess plastic is trimmed away, and the finished bottle is sent for filling and sealing.

Why HDPE Material?

High-density polyethylene is a very popular packaging material, especially for milk, because it offers the following advantages:

• Excellent chemical resistance: Does not react with the fats and acids in milk.
• High strength and rigidity: Can be stacked and withstand the pressures of transportation.
• Lightweight: Reduces transportation costs and raw material usage.
• Good moisture resistance: Effectively prevents water loss in milk.
• Recyclability: HDPE is recognized as a type 2 recyclable plastic.

Blow Molding Machine Process:

• Material preparation: Plastic pellets, typically virgin HDPE or a blend of recycled (rHDPE) and virgin material, are heated until they melt.

• Extrusion: The molten plastic is pushed through an extruder to form a hollow tube, known as a parison.
• Molding: The parison is placed into a bottle-shaped mold. The mold closes around the tube.
• Inflation: Air is blown into the parison, inflating it like a balloon to fill the mold and form the final bottle shape.
• Cooling: The plastic cools and solidifies as it presses against the cool walls of the mold.
• Ejection and finishing: The mold opens, and the new bottle is pushed out. Excess plastic is trimmed off, and quality checks are performed, such as blowing air into the bottle to detect any pinhole leaks.

Milk Bottle Blow Molding Machine Video:

About Suzhou Bestar Blow Molding Machinery Co., Ltd:

Beier Group and Bestar company are same owner And Bestar has been established for more than 19years. Bestar provides customers high efficiency, innovative, energy saving blow molding machinery solutions. Bestar blow molding machines sold to more than 60 countries.

Series blow molding machine is used for blowing 100ml-1250L HDPE PE PP products like milk bottles, daily chemical packaging bottles, jerry cans, pesticide bottles / medicine bottles and stacking barrels.

Please write your machine inquire Email, Phone Number and Company Name here, we will respond within 12h. Or you can directly contact us: Email: sales@bestarmachinery.com or at Whatsapp/Wechat +86 18862609888.