Injection Molding Versus Blow Molding: Advantages and Disadvantages

September 20, 2021 | aic

When companies want to upgrade their manufacturing processes, they often have to decide between injection molding or blow molding. Both of these processes come with several benefits, making them an attractive option to manufacturers. However, it’s crucial to understand both their benefits and drawbacks before deciding on either, as one molding process may better suit your company’s unique needs.

While you attempt to improve your manufacturing processes, find out more about injection molding and blow molding. Additionally, you can learn more about their advantages and disadvantages to select the perfect option for your company.

What Is Injection Molding?

Injection molding is the process of producing solid plastic parts via precision tooling and molds. As the name suggests, the injection molding process involves a machine injecting molten material into a specified mold to produce products, versus blow molding which is a type of manufacturing process designed to produce hollow plastic objects. Many companies wanting to mass-produce various items turn to the injection molding method.

If you’re interested in adding injection molding into your manufacturing processes, find out more about the advantages and disadvantages of injection molding below.

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Injection Molding Advantages

As you decide between injection molding and blow molding, check out some of the following injection molding advantages:

  • Exceptional design flexibility: Since the injection molding process places a great deal of pressure on the mold, injection molding machines allow for greater design flexibility. Due to the high pressure, the machinery can press the mold harder, making it possible to add more detail to the product. Additionally, injection molding’s design flexibility can help you create more intricate and complex shapes.
  • Low labor expenses: Due to companies’ abilities to automate many injection molding processes with robotics and machines, manufacturers don’t have to spend much on labor costs. The high level of automation allows you to only devote a single operator to manage the production process. With the fewer labor costs associated with injection molding, you can reduce your overall manufacturing costs by lowering overhead.
  • Efficient and fast production: Many companies turn to injection molding because of its swift and efficient production. When you use an injection mold process, you can expect to produce a huge number of parts per hour. Additionally, your mold’s size and design complexity can affect the cycle time, with cycle times ranging from 15 to 120 seconds. Since injection molding machines can produce thousands of parts before their tooling needs maintenance, the process is very efficient.
  • Many materials: When you select injection molding, you can often pick from many polymer resins. With this manufacturing process, you can simultaneously use several plastic materials, giving you greater choice and flexibility.

Injection Molding Disadvantages

While injection molding comes with many benefits, it has some drawbacks for specific applications. Some of the main injection molding disadvantages include:

  • Expensive small runs: Since injection molding requires very complex tooling and the need to eliminate any previous material in the machinery, setting up injection molding machines for a small run can take a long time and cost a great deal of money. If you want to do a small part production run, injection molding may be too expensive to warrant the costs.
  • High upfront costs and long lead times: Injection molding requires high upfront costs due to the testing, tooling and design needed to function correctly. This manufacturing process can also take a while to set up, as the process requires a couple of design and prototype stages and in-depth testing before producing a part.
  • More design restrictions: Inject molding has a few design restrictions that might not be appropriate for some of the products you hope to produce. For example, injection molded parts generally need uniform wall thicknesses and can’t have sharp edges. Since there are some design restrictions, this manufacturing process may not be appropriate for certain products.

What Is Blow Molding?

Blow molding is a type of manufacturing process designed to produce hollow plastic objects. This process utilizes melted down plastic and a mold, with a machine blowing air into it. As the air blows into the mold, it pushes out the plastic, so the remaining plastic matches the mold. After the plastic hardens and cools, the mold will open up, producing the desired product.

Learn more about the advantages and disadvantages of blow molding below.

Blow Molding Advantages

Many manufacturers turn to blow molding for the benefits it provides them. If you’re interested in this manufacturing process, check out some of the following blow molding advantages:

  • Low machinery costs: When you’re looking at injection molding versus blow molding costs, blow molding tends to have the edge. Due to the low-pressure level required by blow molding, you can cut down on machinery expenses. You can also automate much of the process, helping you reduce your labor expenses.
  • High product variety: Blow molding allows manufacturers to produce many plastic containers. Since blow molding allows engineers to experiment with various designs and applications, you can manufacture a vast selection of products. For example, you can find blow molding used to produce everything from fuel tanks to flower pots.
  • Automated production: Much of the blow molding process can be automated, allowing users to speed up the production process and reduce labor costs. This automated production can also help you achieve higher levels of productivity. When you utilize blow molding machines with 3D moldings, you can significantly increase your production capability and speed up the process.
  • Many production methods: When you select blow molding, you’ll find you can choose from various production methods, such as extrusion blow molding, injection blow molding and stretch blow molding. Each of these methods can help you manufacture different types of products, giving you plenty of choices during the production process.

Blow Molding Disadvantages

Alongside knowing the many advantages of molding, you might also want to be aware of the primary drawbacks of blow molding:

  • Limited applications: While blow molding can produce various products, it can usually only manufacture products with hollow forms. Since blow molding is restricted to creating hollow objects, it has limited uses.
  • Highly petroleum dependant: Blow molding needs lots of petroleum to manufacture plastic products. As oil supplies diminish, you might see increased petroleum costs. Additionally, petroleum can harm the environment, making blow molding unattractive to companies looking to go green.
  • More material waste: What is the difference between blow molding and injection molding? Waste is a significant factor. Since blow molding has to hollow out plastics to create products, it tends to waste more material than more precise injection molds.

Contact AIC Plasti-Co® for Molding Machines and Components

Now that you know more about blow molding versus injection molding, you might be interested in utilizing them for your production needs. At AIC Equipment and Controls, we can provide you with several molding machines designed to handle your manufacturing needs. Additionally, Plasti-Co® can outfit your equipment with various processing components to assist with efficient production and ensure your machinery works smoothly. Some of our most popular components include feed screws, barrels, nozzles and end caps.

Whatever your needs, our high-quality engineering solutions can help you increase your productivity and minimize downtime. Take a moment to review our molding machines to see how we can help outfit your facility with plastic processing equipment. If you have any questions or want to partner with us, please feel free to contact us.

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