Both injection molding and blow molding are common methods of creating plastic parts—and while certain parts require both injection-molded and blow-molded components, the two methods mainly serve different markets.

Let’s look at how injection molding and blow molding are different.

Molder capabilities

If OEMs need highly reliable, high-performance devices and components developed under advanced processing, including DfM (Design for Manufacturability) and scientific molding to optimize every facet of production, choosing injection molding will make more sense. Clear ongoing communication, comprehensive testing, guidance in materials selection, and engineering support are important and prioritized to ensure quality and accuracy. This underscores the need for OEMs to partner with an injection mold maker that’s experienced and accessible.

However, blow molding is perfect for low-tech, single-piece products. A blow molder must be able to prevent common blow molding obstacles like blowouts and poor welds. However, the components it produces and the process itself aren’t very complex. Often, OEMs feel comfortable using blow molders that are located overseas or with which they don’t have a rich history since the risk presented by potential defects and the need for close supervision is quite low.


Injection molding combines scientific molding and deep materials knowledge of an experienced injection mold maker to precisely control material flow for detailed, exceptionally small components. To ensure elements like tight tolerances and wall thickness are maintained to margins as little as +/-0.001, the precision of the tooling is critical. This will help parts work well independently and with others for no-fail, consistent performance.

custom plastic injection molding

On the other hand, blow molding uses hollow-shaped tools and air to create a product. This process achieves unique shapes and completes one-piece construction as the resin is blown into each side of the tool, forming its own wall. However, you’ll need secondary processes to create openings or remove excess material. While blow molding is quite efficient, it’s not very technical.

General uses

Injection molding is perfect for applications requiring precise repeatability in production, tight tolerances, and intricate part geometries.

Blow molding is ideal for relatively rugged, hollow, and single-piece commodity parts like carrying cases, component housings, traffic safety products, children’s outdoor toys, stadium seating, and plastic bottles.

PTMS strives to be your plastic injection mold maker in China

PTMS specializes in custom plastic injection molding. With experienced employees and advanced mold manufacturing equipment, PTMS would like to grow as one of China’s best plastic injection mold makers.

Reach out to them directly for more information on their plastic injection molding service!