When commissioning plastic components or containers, one of the first questions to answer is which manufacturing process best fits your product requirements. Blow moulding and injection moulding are two of the most widely used techniques in the industry, but they produce fundamentally different results.

Blow Moulding

Blow moulding is used to create hollow plastic parts — typically bottles, jerrycans, tanks, and containers. The process works by inflating a heated plastic tube (called a parison) inside a mould until it takes the desired shape. It is ideal for producing large volumes of lightweight, hollow containers.

The key advantages of blow moulding include: - Cost-effective tooling for high-volume runs - Seamless, one-piece construction for superior leak resistance - Flexibility in producing various sizes and neck finishes - Suitability for both food-grade and industrial applications

Injection Moulding

Injection moulding involves injecting molten plastic into a mould under high pressure. It is used to produce solid or complex-shaped parts with tight tolerances — such as caps, fittings, trays, and structural components.

Key advantages include: - Exceptional dimensional accuracy and repeatability - Ability to produce complex geometries and fine surface detail - High production speeds for large volumes - Wide material compatibility

Choosing the Right Process

If your product is a hollow container that needs to hold liquids, blow moulding is almost always the right choice. If you need precision-engineered solid parts, injection moulding delivers the accuracy required. Many products — such as a jerrycan with a threaded cap — require both processes working together.

At Sarah Plastic, we operate both blow moulding and injection moulding machinery, giving our customers the flexibility to source complete product assemblies from a single trusted partner.