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About Blow Molding

We manufacture the highest quality of Plastic Injection and Blow Molded products for many industries including, Aerospace, Medical, Commercial, Military, and Pharmaceutical. Our products span the globe and are used to save lives, provide preventative care, help the brave men and women in service accomplish their mission, and bring a smile to a child’s face.

Since our founding, we have helped inventors bring their ideas from concept to shelf. Our team of highly qualified experts is here to help and guide you with all phases of product development and delivery. This includes but is not limited to Product Design, Engineering, Project Management, Manufacturing, and Packaging and Distribution.

Advantages of Blow Molding

Production In large Quantities
  • Blow Molding is a process that can help the companies to produce large number of uniform units in a short period of time. This virtue makes this process all the more important.
Production of an Array of different products
  • Due to the efficiency of blow molding this process can utilized in many industries for manufacturing a variety of products such petrol tanks, flower pots and containers.
  • Due to the development of Placo X-Y machine which gave rise to 3D blow molding the automation of the entire process has been possible. The automation has increased the speed of production and made the process of assimilation and integration of various parts super easy.
Low Cost
  • This technology uses low pressure to make the molds and this technology also reduces the labor cost hence financially the process of blow molding is very efficient.


Blow molding is a multibillion-dollar business. In the late 1980s, the annual worldwide consumption of plastic resin by blow molding processes was about ten billion pounds. The packaging is the primary application for this resin and was used to produce approximately seventy billion bottles, drums, tanks, and other containers. Blow molding grade high-density polyethylene (HDPE) comprises about 69 percent of all materials that are blow molded.

The use of polyethylene terephthalate (PET) has increased rapidly in recent years and in 1990 claims about 21 percent of the blow molding market. About 25 percent of the total blow molding poundage goes into mild bottles. That is a tremendous market, but consumption for household chemical containers (bleach bottles, detergent bottles, etc.) is even larger: 33 percent. About 76 percent of the total resin usage goes into bottles, and the other 24 percent is in industrial items- gas tanks, bulk- goods drums, seats, toys, and other large items.

Overview of Blow Molding

What is Blow Molding?

Blow molding is a manufacturing process that is used to create hollow plastic parts by inflating a heated plastic tube until it fills a mold and forms the desired shape. The raw material in this process is a thermoplastic in the form of small pellets or granules, which is first melted and formed into a hollow tube, called the parison. There are various ways of forming the parison, as explained below. The parison is then clamped between two mold halves and inflated by pressurized air until it conforms to the inner shape of the mold cavity. Typical pressures are 25 to 150 psi, far less than for injection molding. Lastly, after the part has cooled, the mold halves are separated and the part is ejected. 

Parts made from blow molding are plastic, hollow, and thin-walled, such as bottles and containers that are available in a variety of shapes and sizes. Small products may include bottles for water, liquid soap, shampoo, motor oil, and milk, while larger containers include plastic drums, tubs, and storage tanks.

Several types of thermoplastic materials:

Blow-molded parts can be formed from a variety of thermoplastic materials, including the following:

  • Low-Density Polyethylene (LDPE)
  • High-Density Polyethylene (HDPE)
  • Polyethylene Terephthalate (PET)
  • Polypropylene (PP)
  • Polyvinyl Chloride (PVC)

How Does Blow Molding Work?

In order to produce the many single or multi-layer bottles and jars you package your products in or even use every day, the process first starts with the plastic pellets we mentioned earlier.

The Extrusion Blow Molding Process Broken Into 5 Steps:

  1. The extruder turns each plastic pellet into a molten material with the help of a heated barrel and sheer force. Both temperature (frictional and external heat are used) and pressure melt the plastic.
  2. The material is then moved through the extrusion tooling to create a parison.
  3. In order to be captured, the parison is closed into a water-cooled mold.
  4. Next, compressed air is blown into the parison. This blown air inflates the parison into the exact shape of the mold cavity, thus forming a hollow bottle, container, or part. If you’ve ever seen glassblowing, it’s very much like that.
  5. After the plastic has cooled enough, the mold is opened and the part or product is taken out!

Three forms of Blow Molding:

  • Extrusion blow molding – An extruder uses a rotating screw to force the molten plastic through a die head that forms the parison around a blow pin. The parison is extruded vertically between the two open mold halves, so they can close on the parison and blow pin. Pressurized air flows through the blow pin to inflate the parison. This is the most common type of blow molding and is used to manufacture large quantities of relatively simple parts.
  • Injection blow molding – The molten plastic is injection molded around a core inside a parison mold to form the hollow parison. When the parison mold opens, both the parison and core are transferred to the blow mold and securely clamped. The core then opens and allows pressurized air to inflate the parison. This is the least commonly used method because of the lower production rate but is capable of forming more complicated parts with higher accuracy. Injection blow molding is often preferred for small, complex bottles, such as those in medical applications.
  • Stretch blow molding – The parison is formed in the same way as injection blow molding. However, once transferred to the blow mold, it is heated and stretched downward by the core before being inflated. This stretching provides greater strength to the plastic. Stretch blow molding is typically used to create parts that must withstand some internal pressure or be very durable, such as soda bottles.

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