What is meant by blow moulding?

Blow molding is the forming of a hollow object by inflating or blowing a thermoplastic molten tube (parison) in the shape of a mold cavity.

How is blow molding done?

The process involves heating a plastic tube (known as a preform or parison) to its melting point and then putting that into the cavity of a mold. They then use compressed air to inflate the molten plastic like a balloon so that it takes the shape of the mold but is hollow inside.

Why is blow molding important?

Blow molds have more design freedom between mold halves since each mold half forms its own wall shape. With blow molding, creating the mold is important but there are variables as well such as wall thinning, air leaks, flash, and streaks that must be monitored.

What is the difference between blow moulding and injection moulding?

The major difference between injection molding and blow molding is the kind of product produced. Typically, blow molding is designed to produce hollow, singular containers, such as bottles. On the other hand, injection molding is used to produce solid pieces, such as plastic products.

What is a parison used for?

Parison blow molding of intricate plastic bottles and other plastic parts requires air pressure control that is precise, repeatable and rapid responding. Proportion-Air offers electronic closed-loop pressure and flow controls that are used to improve processes in the plastics blow molding industry.

Why are blow molds so expensive?

When something is rare and there is a demand for it, it’s hard to come by and often very expensive. With the rarity of well-maintained blow molds also comes the fact that some of the original companies that made these products are out of business. This makes them even more collectible.

What are the disadvantages of blow Moulding?

Disadvantages of blow moulding

• Limited to hollow parts.
• Low strength.
• To increase barrier properties, multilayer parisons of different materials are used (thus not recyclable)
• Trimming is necessary to make wide neck jars spin.
• Limited to thermoplastics (rotational moulding can be used with thermosets)

What is parison made of?

(Counterclockwise from top) A molten polymer is extruded into a hollow tube-shaped parison. A split mold is closed around the parison, which is expanded against the sides of the mold by a stream of air. Once the plastic has solidified, the mold is opened and the shaped bottle released.

Are blow molds worth money?

Blow molds are seen as vintage Christmas decorations and started finding popularity in the early 1940s-1950s. You’ll see in a moment that these Christmas decorations can cost a few hundred dollars. If there is anything I’ve realized about all these vintage Xmas decorations is that they can be very rare.

Why did they stop making blow molds?

Plant assets were sold at a public auction in March 2018. As news and industry publications noted, like many other U.S. manufacturing firms, the company succumbed to foreign competition and aging facilities.

Is Blow Moulding sustainable?

Blow molding uses a large quantity of compressed air, which requires a lot of energy. Recycling this air can reduce energy use by up 40\%, resulting in big financial savings.

What products are made with blow molding?

Blow Molding. 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.

What does blow molding stand for?

Blow molding (BM) is a process for converting thermoplastics (TPs) into simple to intricate and complex shapes hollow objects. The process is especially amenable to the goal of consolidating as much function as possible into a single product.

What is the process of blow molding?

The process of injection blow molding (IBM) is used for the production of hollow glass and plastic objects in large quantities. In the IBM process, the polymer is injection molded onto a core pin; then the core pin is rotated to a blow molding station to be inflated and cooled.

How does a blow molding machine work?

Blow molding is a manufacturing process in which air is used to inflate soft plastic into a mold cavity. It is a two part manufacturing process. First a parison or starting tube of molten plastic is made and then the tube is inflated into the desired shape. The parison is made either by extrusion or injection molding.