What is the difference between injection and blow molding? When it comes to custom plastic carrying cases, you have two options for manufacturing methods. Knowing the fundamental differences between the two will help you when narrowing down choices for case design. Both ways of molding plastic offer benefits, such as high-quality products and cost-effective prices.
When comparing blow and injection molding, the most notable difference is that injection molding creates solid plastic parts, whereas blow molding creates hollow pieces. When rigid walls are needed, consider injection molding. Blow molding is considered more versatile of the two manufacturing methods.
When it comes to building custom carrying cases, there are two main types of manufacturing: blow molding and injection molding. Each molding type offers pros and cons. Choosing between production types is essential for getting the right case and staying within budget.
Injection Molding
Injection molding works by melting resin into a hollow mold. Once the mold is completely filled, the injection mold is then held together using extreme pressure. The pressure is enough to force the resin into all areas of the mold.
Injection Molding requires more upfront engineering than blow molding. Molds are formed from steel or aluminum, and then liquid polymers are added to the mold at high temperatures and under extreme pressure.
Individuals choose injection molding because:
- Multi-cavity molds can be made
- Highly detailed final products
- Possible to change material and colors being used
- Efficient use of materials and a low scrap rate
Blow Molding
Blow molding uses a plastic tube that is heated and filled with air until it becomes something akin to a balloon of hot plastic (parison). Molds are then clamped around the parison while air continues filling the parison to the shape of the part.
Individuals choose blow molding because:
- Is less expensive than injection molding
- Has machining costs that are also lower than injection molding
- A single-piece construction means there is no need to connect different parts
- Is capable of more design freedom than injection molding
When building custom plastic carrying cases, it is common to see blow molding as the first choice for manufacturing. Blow molding takes less time than injection molding, and it is typically more affordable. Blow molding is lightweight because parts are hollow. Injection molding creates solid pieces.