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    May 16, 2022

    The 8 Pros and Cons of Injection Molding


    As you probably know, injection molding is a great way to mass-produce a part. This is the preferred way to manufacture consumer items like toothbrushes, remotes, and phone cases. There are a lot of pros and cons to using this technology, and we are going to discuss them in this guide.

    Pros of Injection Molding

    First, let’s discuss the major benefits of using injection molding. 

    Keeps Tolerances Tight

    An injection molding machine utilizes a metal mold that’s specifically designed. When the molten plastic goes into the mold, it takes up the entire cavity before cooling. This leaves very little room for error and allows parts to be dimensionally “perfect”.

    The simple truth is that these machines can achieve very tight tolerances time after time.

    Works With Multiple Colors and Materials

    There’s also a lot of versatility when it comes to material selection. As long as the material can melt, flow, and solidify when it cools, it makes for a viable option in an injection molding machine.

    You can create units that utilize hundreds of material options with colors that span across the color wheel.

    Highly Repeatable and Reliable

    A big benefit is that injection molders are highly repeatable and reliable. One injection molder can create a million units that are all nearly identical to one another. 

    Consider a water bottle cap, for example. Every cap threads perfectly onto the lid of the bottle. The cap is likely injection molded, proving how repeatable these machines can be.

    Very Fast Production Times

    Above everything else, an injection molding machine will churn out parts quickly. It’s common for dedicated facilities to make millions of units annually from a single machine.

    In your application, this means that you can order thousands or hundreds of thousand units and get them back very quickly. Injection molders can easily make a unit from scratch in less than a minute. Comparatively, 3D printing or traditionally machining the same part could take hours or even days.

    Keeps Costs Low

    When it comes to injection molding parts, you’re really just paying for the material cost and some operational cost. If you get a quote for a thousand injection molded parts versus a thousand 3D printed parts, you’ll be blown away by the difference.

    Why? An injection molding machine can run around the clock with very little human interaction. This means you can create a full production run of products without paying for manpower. In addition, it’s a lot quicker to injection mold a part, which adds to the low costs.

    Cons of Injection Molding

    Next, we’ll discuss some downsides associated with using injection molding machines.

    Initial Costs are High

    It’s fair to say that the upfront costs of running an injection molding machine are very expensive. One of the leading variables in the “cost per unit” in the beginning is the cost of tooling and calibrating the injection molding machines.

    For large, complicated molds, you might be charged tens of thousands of dollars. The price flattens out as you make more units, but there’s still the initial sticker shock.

    Long Turnaround Times in the Beginning

    Not only are the molds expensive, but they also take time to make. In a lot of cases, there are test units that are made and shipped before the mold is deemed fit for production. You might go through months of waiting just to get your first official part.

    The silver lining is that this long lead time ensures you don’t run into issues in the future. Once the mold is perfected, then you’ll be getting units delivered much quicker.

    Tough and Expensive to Change Unit Design

    Once the mold is finalized, it’s very difficult and expensive to make changes. Injection molding is not good for prototyping parts as you iron out the details — that’s where 3D printing comes in handy.

    Injection molding is for parts that have mature designs that won’t change as production parts are made. If you want to start printing a new iteration of the same part, it often involves creating brand-new tooling for the new units.


    As you can see, there are plenty of advantages and disadvantages when it comes to injection molding production parts. If you’re looking to mass-produce a consumer part, then injection molding is typically the best option.

    If you want to learn more about this technology, reach out to Rapid Axis today. Our team of injection molding experts can make you a mold and even create production-scale batches of units for you. Contact us today for a free quote.

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