plastic cylinder bottles

Blow molding and injection molding are both common plastic manufacturing processes. While injection molding and blow molding may seem similar, there are three major differences between the two methods: the mold used in the process, the process in which the parts are made, and the products themselves. Let’s take a closer look at these processes.

Molds
Injection molds are more difficult to make and work with. Injection molds take two halves that require an exact match so the material can flow flawlessly. In injection molding, making sure the mold lineup is perfection is crucial to the entire process.

In blow molding, each half of the mold is separate, so it’s much easier to work with. Manufacturers can spend more time making sure the product is flawless since they can spend less time working on the mold.

Processes
During the injection molding process, melted material is injected into a mold, which is held under intense pressure. Once the material has solidified, it is ejected and the mold is filled again.

Most blow molding machines consist of three major parts: the extruder, accumulator die and molds from which products of different shapes and sizes can be processed. Blow molded containers are produced through a process which requires a plastic tube being heated and filled with air, called a “parison”. The parison is inserted into the blow molding machine and the mold is clamped around the tube until the parison is formed in the shape of the part.

Products
One major difference in the products produced by both processes is the material used. Injection molding uses materials in Polypropylene and Polystyrene and blow molding uses PETE and HDPE materials.

To make things simple, injection molding creates solid products like lids and electrical switches and blow molding creates hollow products like plastic jars or plastic cylinder bottles.

Choosing Between Blow Molding and Injection Molding
There are some factors to consider when trying to decide between the two processes:

  • Does your product have more than one part?
  • How is the product going to function?
  • What kind of conditions is the product going to be in?
  • Does it need to be food safe or adhere to any other specificities?
  • What size does the product need to be?

If you’re looking to get custom made bottles produced, whether it be plastic cylinder bottles, plastic chemical jars, or even plastic packaging, contact a manufacturer near you to find out the best materials and process to use.