Molding

Professional Blow Molding Services for Your Business

Blow molding inflates heated plastic into a mold cavity to create hollow parts like bottles, containers, tanks, and ducts at high production rates.

Blow Molding manufacturing

About Blow Molding

Blow molding is a manufacturing process used to create hollow plastic parts. A heated tube of plastic material (called a parison or preform) is inflated with air pressure inside a mold cavity, forcing the plastic against the mold walls to form the desired shape. There are three main types: extrusion blow molding, injection blow molding, and injection stretch blow molding. The process is responsible for producing most of the world's plastic bottles, containers, fuel tanks, and industrial ducting. Blow molding machines can produce thousands of parts per hour, making it extremely cost-effective for high-volume hollow part production.

Tolerances

±0.010" (±0.25mm) typical; varies with part size

Lead Time

6-12 weeks for tooling; 2-4 weeks for production

Cost Range

$10,000-$80,000 for tooling; $0.05-$5 per part

Compatible Materials

HDPELDPEPETPolypropylenePVCABSNylon

Advantages

  • Ideal for hollow parts
  • Very high production rates
  • Low per-part costs at volume
  • Large parts possible (fuel tanks, drums)
  • Good wall thickness control
  • Seamless hollow construction

Limitations

  • Limited to hollow parts
  • Less precise than injection molding
  • Wall thickness uniformity can vary
  • Limited to certain plastics
  • Tooling still requires significant investment

Industries Served

Blow Molding FAQ

What products are made with blow molding?

Blow molding produces bottles, containers, fuel tanks, drums, automotive ducts, industrial tanks, watering cans, kayaks, playground equipment, and other hollow plastic products. Virtually every plastic bottle you encounter was blow molded.

What is the difference between blow molding and injection molding?

Blow molding creates hollow parts by inflating plastic inside a mold. Injection molding creates solid parts by injecting plastic into a mold cavity. Blow molding is used for bottles and tanks; injection molding is used for solid components, caps, and housings.

How large of a part can be blow molded?

Blow molding can produce parts from small bottles (a few ounces) to very large tanks and containers (hundreds of gallons). Industrial blow molding machines can produce parts several feet in diameter and length.

What is extrusion blow molding vs. injection blow molding?

Extrusion blow molding extrudes a continuous parison that is then captured in the mold and inflated. Injection blow molding first injection-molds a preform, then inflates it. Extrusion blow molding is better for larger and irregularly shaped parts; injection blow molding offers more precision for smaller parts.

Is blow molding cost-effective for small quantities?

Blow molding requires tooling investment, so it's most cost-effective at volumes of 1,000+ parts. For small quantities of hollow parts, rotational molding or 3D printing may be more economical alternatives.

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