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Blow Molding Basics

Blow Molding Basics
April 15, 2020 Valencia Plastics

Blow Molding Basics


Blow molding has the capacity to create an expansive variety of hollow plastic objects. Similar to glass blowing in methodology, the blow molding process heats plastic to a molten or liquid state while pressure within forces the molten material into the desired shape using a die or a mold cavity. 

The most common types of blow molding include extrusion blow molding (EBM) and injection stretch blow molding (ISBM), each of which produce slightly different products. Production using EBM usually includes mass-producing a large volume of objects in the same size and shape, while ISBM is most commonly used for producing preforms of plastic bottles.


Blow Molding Process

While blow molding can produce a variety of complex geometries, the process itself is actually fairly simple. The blow molding process involves six basic steps:

  1. A mold or die is fabricated to the specifications of the design.
  2. Resin or polymer plastic is mixed, melted, and then extruded into a tube called a parison.
  3. The mold or die closes around the parison.
  4. Air blown inside the parison inflates and stretches the plastic into the contours of the mold.
  5. The plastic cools and hardens into the shape of the mold.
  6. The finished part is removed from the mold and the parison/flash is removed.


Materials Used

A variety of resins or polymers are compatible with the blow molding process, including:

  • LDHE polyethylene
  • HDPE polyethylene
  • Thermoplastics
  • Thermoset plastics
  • Polypropylene
  • Nylon
  • Polyethylene terephthalate (PET)


Considerations for Choosing a Blow Molding Supplier

When sourcing plastic parts, blow molded parts provide a variety of benefits like durability, visual appeal, high capacity for customization, and cost-efficient production. 

Five considerations to keep in mind when choosing a blow-molding supplier should include:

  • Blow molding is highly versatile, used for parts ranging from bottles to medical devices to stadium seats.
  • Unlike many fabrication processes, larger molds ultimately result in a lower cost-per-unit that can help to offset the initial capital investment.
  • A domestic blow molder with their own distribution capabilities will facilitate shorter lead times and reduced logistics costs.
  • Blow molding offers an infinite amount of color choices to accommodate company branding, regulatory requirements, aesthetic needs, and more. 
  • Standard molds can offer significant project savings, while custom molds will increase the upfront cost of the project.


Advantage of Using a Single Blow Molding Supplier

A single turnkey blow molding supplier provides a number of advantages for your company, including:

  • Eliminating delays and costs associated with vetting, meeting, and partnering with multiple vendors and suppliers.
  • Working with a team already familiar with your projects and preferences.
  • Providing customization suggestions based on previous projects
  • Streamlining required vendors to eliminate inefficiencies and shorten lead times.
  • Superior value and effort in order to maintain the business relationship.


Why Choose Valencia Plastics?

We are a full-service provider of blow molding and injection molding services. Valencia Plastics provides quality plastic products for a variety of industries, including:

  • Medical
  • Military
  • Pharmaceutical
  • Aerospace
  • Commercial

Our global manufacturing services offers services from concept to part production while including services like product design, engineering, project management, packaging and distribution. The materials we use for our blow molding processes include:

  • Acrylonitrile butadiene styrene (ABS)
  • HDPE
  • LDPE
  • Polypropylene (PE)
  • Polystyrene
  • Polyurethane
  • Santoprene
  • Kostrate
  • K-Resin

At Valencia Plastics, our capabilities include large parts up to 5 pound shots, small parts as low as 5 grams, and multi-component parts using overmolding and insert molding. We fabricate single-cavity blow molds of 70/75 aerospace aluminum, multiple-cavity beryllium pinch blow molds, air needle and blow pin blow molds, and molds that require inserts over molded components. 

Valencia Plastics manufactures all parts in the United States. We own and operate a variety of state-of-the-art equipment within our ISO 9001:2015-certified facility and offer highly competitive pricing on projects and materials. 

Contact us to learn more about the blow molding solutions available from Valencia Plastics.