What is blow molding used for?

Blow molding (or moulding) is a manufacturing process for forming and joining together hollow plastic parts. It is also used for forming glass bottles or other hollow shapes.

How does a blow molding machine work?

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.

What does a blow mold look like?

What companies still make blow molds?

Leading Manufacturers

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

Is blow molding expensive?

The costs in blow molding are lower as compared to injection molding. Machinery costs are typically lower as well. One-piece construction so that there’s no need to connect part halves, which can achieve shapes that injection molding cannot produce.

What is the difference between blow molding and injection molding?

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 type of plastic is used in blow molding?

Looking for technical blow-moulders?

Polyethylene (Low Density) LDPE, LLDPE
Polypropylene PP
Polyethylene – Terephthalate PET
Polyvinyl chloride PVC
Polyethylene (High Density) HDPE

How do you tell if a product has been blow Moulded?

Extrusion Blow Moulding is the simplest type of blow moulding. Evidence of the process can often be identified on bottles by a thin rim running vertically around the surface of the bottle left by the split mould.

What is a blow mold decoration?

Blow mold decorations are 3D figures created by connecting hollow pieces of plastic together. They became popular in the 1930’s and have been a favorite vintage decoration ever since. You can find vintage blow molds or new reproductions of your favorite classic holiday characters.

Why are they called blow molds?

The figures were called blow molds because they were made of hollow hard plastic that was formed in a mold. … Blow molds first appeared in the 1940s and were two dimensional until the 1950s when Empire Plastics and Union started making the famous pink flamingo yard ornaments.

Are blow mold decorations still made?

If you want to add them to your display, good news: There are retailers who still make and sell these, as well as websites that make it easy to purchase ones from generations ago. Here’s where you can find—and purchase—blow mold Christmas items, from bearded Santa to reindeer to nativity scenes.

Why did they stop making blow molds?

Due to dramatically decreasing sales in the 90s, Empire downsized in 2001 and no longer began producing blow molds. Its molds and machinery were sold in an auction and another company called General Foam Plastics purchased many of them.

Are blow molds making a comeback?

Believe it or not, blow mold decorations are making a comeback. If you reflect on your childhood, chances are you might remember seeing homes in your neighborhood illuminated with these plastic figures. … Plus, they delight those who long for vintage and nostalgic Christmas decor.

Can blow molds be repainted?

If the paint on your blow mold appears faded or scratched, Sansing says you can freshen it up with plastic-friendly spray paint, such as Fusion All-in-One by Krylon ($5, amazon.com). … Then, apply the paint using a steady side to side sweeping motion.

What happened to blow molds?

Sadly, after 60 years of plastics production in the USA, the most recognized and largest U.S. maker of blow molds closed its doors in 2017. General Foam Plastics, headquartered in Virginia Beach, shut down its production facilities in Norfolk, Virginia and Tarboro, North Carolina.

Is General Foam still in business?

In January 2018, GFP sold all of its remaining merchandise, and in March, the company officially went defunct and all of its employees were laid off. The Norfolk factory was shut down after 60 plus years of work. In 2018, Cado Products revealed that they had been present at the GFP auction and purchased several molds.

What is the advantages of injection blow Moulding?

Injection blow molding provides manufacturers with a number of benefits: No unwanted scrap material is generated during the process. Better, tighter part tolerances that are safe and secure are created. The procedure produces good surface finishes.

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.

Is Blow Moulding bad for the environment?

The Disadvantages of Blow Molding The biggest disadvantage may be the negative environmental effect associated with plastic use. Plastic isn’t biodegradable and it typically makes its way in massive quantities into landfills. There is also the concern caused by such a wide use of petroleum.

How much does a blow mold cost?

A single cavity, extrusion blow mold suitable to produce up to 100M units per year may cost as little as $3,000. An eight cavity, extrusion blow mold with automatic detabbing equipment may cost as much as $25,000 but may generate sufficient cost savings to return the investment within a short period.

How much does roto molding cost?

Is Rotomolding Right for You?

Cost Drivers Roto Molding Blow Molding
Tooling $150,000 / yr $200,000 / lifetime
Production Rate 2 parts / hr 70 parts / hr
Piece Price $35 $22

What are blow molds made of?

Both blow molding and injection molding involve the use of liquid material — typically plastic — that’s forced into a mold cavity.

Which is not an advantage of compression Moulding?

It is not suitable for all complex designs. The material used in compression molding operations may be subject to some limitations of flow within the mold cavity. … This quality makes the process unsuitable for some complex part and product designs.

Can you blow mold acrylic?

Acrylic. Acrylic can be difficult to work with in blow molding operations. Its low cost and clarity make it a popular option for the manufacture of optical parts and products. High-density polyethylene (HDPE).

What products are blow Moulded?

Everyday hollow plastic objects like milk cartons, shampoo bottles, storage drums and watering cans all have a specific manufacturing process in common – blow moulding.

Why pet Cannot be extrusion blow molded?

Some materials such as PET and standard PP homopolymer are difficult to impossible to extrusion blow mould on a commercial basis due to their low melt viscosities. … The parison (hot hollow plastic tube) is extruded through an annular die.