In part one of this two-part blog series, we went over some basics on two somewhat similar plastic manufacturing processes: Injection molding and blow molding. And while these do have some notable similarities, even beyond their use for plastic parts, there are also several distinct areas that separate them.

At EnviroTech Custom Injection Molders, we’re happy to provide a wide range of plastic injection molding services, from custom molding to bulk molding and more for a huge variety of industries. For those who are wondering whether our processes or the blow molding process might be best for the kinds of products you’re looking to produce and other factors like your budget, what are some of the major differences between the two? Today’s part two in our series will go over everything you need to know here.

Basic Process Differences

As we discussed to some degree in part one of our series, the actual process of manufacturing is very different between these two parts. In fact, the presence of plastic is one of the only true similarities.

For starters, the injection mold process features a sealing of plastic in the injection chamber for the entirety of the manufacturing, start to finish. Blow molding, however, doesn’t actually begin until the mold has already been removed from plastic – the blowing process is actually used to expand the product once it’s outside a mold.

Air or No Air?

Another major difference in the manufacturing and finishing processes of these two formats: Air. One process relies on it, while the other must not be exposed to it to remain viable.

The former, as we discussed in part one, is blow molding. This process requires air to be forced into the mold, pushing out and expanding the desired product to its final state. Injection molding, on the other hand, must not have air present during manufacturing – this can create air pockets and eventual weak spots, leading to products that are defective and often simply wasted.

Final Products

And based on these differences and more, these two processes produce a whole host of different product types. Blow molding is the more limited of the two, producing only hollow, single-form containers like bottles. Injection molding is much more versatile, though, creating solid pieces that are not hollow and can take on a variety of shapes or sizes. While the injection molding process can be the more expensive of the two up-front, its advanced capabilities make it worth this additional cost in numerous circumstances.

For more on the differences between injection molding and blow molding for plastics, or to learn about any of our custom molding services, speak to the staff at EnviroTech Custom Injection Molders today.