All About Injection Blow Molding

Commercial plastic jugs

Plastic remains one of the world’s most popular materials. Every year, approximately 600 billion pounds of it are made and used by the planet. This is expected to go up by 5% each year. In the United States about 107.5 billion pounds of plastics and resins were made in 2013. That represented an increase of about 106 billion pounds from the year before. Every hour, people across the nation use 2.5 million plastic bottles and commercial plastic jugs.

Three are a number of ways plastic products can be made. The main three techniques that plastic manufacturing businesses have at their disposal are stretch blow molding, injection blow molding and extrusion blow molding.

When making commercial plastic jugs, plastic storage jars or plastic handleware, injection blow molding is a popular way to go. This method is the most popular when it comes to making certain items in large quantities. This method can be used for both hollow plastic and hollow glass items.

The process is a simple and straightforward one. This is a slimmed down version of the process. There are three parts to the process. They are the injection, blowing and then the ejection.

  • A polymer will be injection molded to cover a core such as a pin.
  • The core pin will then be rotated and it goes to a blow molding station.
  • At the station, the core pin is inflated and cooled.

To elaborate on the process.

  • The extruder barrel and screw type assembly is the basis for the machine that is used in injection blow molding. Once the polymer has been melted, it is pushed into a heated runner manifold. At this point, it is injected using nozzles into a cavity that has been heated and into a core pin. That cavity mold has been made in the shape that the items, such as commercial plastic jugs, will be at the end of the process. This is then fastened around a core rod. This is what will create the internal shape of the products. The result will be the fully complete product and it will be attached to a thick tube of polymer.
  • The mold that is preformed will be cut. A core rod is rotated and fastened to the hollow part of the mold. The entire item is then cooled via the introduction of air. The compressed air is pushed through the entire mold through an opening that has been created on one end of the mold. This process inflates the plastic (or glass) to the proper shape, as may be needed for commercial plastic jugs.
  • Lastly, the entire product moves to the ejection position. An opening is made and the core is moved to the right space. The core rod is removed. In some instances, as when commercial plastic jugs are made, the product can be tested for leaks. This can be crucial. It all depends on the product that is being manufactured.
  • The finished article is stripped off the core rod and as an option can be leak-tested prior to packing. The preform and blow mold can have many cavities, typically three to sixteen depending on the article size and the required output. There are three sets of core rods, which allow concurrent preform injection, blow molding and ejection.

Plastic blow molded containers are crucial for a number of processes and for many different uses. It can be very hard to look around a work space or a home and not see items that were made with a blow molding process. The vast number of products that can be created by blow molding makes it an important process for plastics manufacturing.

Plastics have gotten a bad name by a number of people in recent decades. The industry is very important to the United States economy. At least one million people owe their jobs to it. It contributes at least $375 billion to the American economy. The material is also better for the environment than many people realize. With two pounds of plastic, about ten gallons (or 1,300 ounces) of liquid can be moved from one place to another. It would take three pounds of aluminum to do the same thing, eight pounds of steel and more than 40 pounds of glass. Plastic products make our lives better.

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Sarah Todd

Sarah Todd

Sarah Todd, an investment banker, is a reporter and researcher for one of London’s leading media outlets. Formerly a trader and market maker at FTSE, she turned to media during the global recession. This website features some of her best and favourite articles, from all parts of the business world. Please let her guide you and your enterprise along the path to prosperity.