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Pros And Cons Of Handling Plastic Injection Molding In-House

Written by RevPart

If you’re considering plastic injection molding for your product or products, the accessibility and relative ease of the process can make it seem appealing to invest in an in-house solution. Given the high volume of parts that can be efficiently produced, the path to recouping your initial investment in in-house plastic injection molding can look clear and relatively painless. Before jumping feet first into an in-house custom injection molding solution, however, it’s important to consider the cons along with the pros — and there are several of each.

As a process, injection molding advantages are readily visible for most applications. If you’ve settled on the process but are deciding whether or not to invest in in-house, be sure to carefully consider each point below.


Cost-efficient production: Injection molding is, in general, a cost-efficient production process. While material choices, part complexity and part design (among other factors) can affect pricing, injection molding will typically offer a favorable price point when compared with other processes, all other factors being equal (or equivalent). An in-house solution can further boost the cost-efficiency advantages by cutting out shipping costs and the built-in overhead costs that would otherwise go to your supplier. Of course, that overhead cost is then shifted to you, which can attenuate some of the advantages detailed here.

Speed of output and fulfillment: Whether you carry out injection molding in-house or via a service provider, high production speed is one of the advantages that you’ll enjoy. With an investment in in-house processes, you eliminate shipping and other fulfillment time from your supplier to you, with products ready to distribute as soon as they’re completed and inspected (depending on whether you choose to package items in-house as well).

Low material waste and increased material re-use: If you use thermoplastic material in your in-house injection molding, any excess material, or material from defective pieces, is available to you for recycling and reclamation. With outsourced injection molding, you should only be charged for the material used to manufacture your products, but you do not get the advantage of this flexibility of use. With in-house processes, you can also be certain that you are reducing material waste through recycling and reclamation.

Flexibility in timing and production: The versatility of injection molding is one major factor that draws many entrepreneurs and engineers to it. A broad range of product types and materials can be used in, and produced with, injection molding. In-house production adds an aspect of flexibility with the ability to totally control your production schedule.


High initial investment: As mentioned above, you can certainly do the math on your ROI for in-house molding equipment and see an easy path to value — in theory. In practice, it can be more difficult to achieve. Any way you look at it, injection molding equipment is a costly investment, requiring years — and many, many pieces produced — to pay back.

There is no guarantee that your financial forecasting will prove accurate, given the complexities of most markets. With an in-house solution, you are stuck with your equipment, even if you are unable to move inventory and thus can no longer keep it running. Moreover, injection molding startup costs are more than just one machine — they cover automation equipment, QA machinery, personnel and more.

High overall costs for tooling: Tooling is another aspect of injection molding that just isn’t cheap. The high quality of the material used, as well as the expertise required to design and manufacture tooling properly, can often make the price seem prohibitive. With an in-house solution, these costs are amplified — in addition to tooling, you’re paying the full cost of the personnel and equipment.

Repairs and downtime are costly: Once you own injection molding machinery, it’s yours — for better and for worse. Machinery breakdowns, miscalibrations, errors and other negative aspects are now your responsibility. Thus, you must repair — or pay the costs of diagnostics and repair — yourself. While injection molding can, on the surface, seem to be a simple, straightforward process, it is quite complex and must be constantly monitored and fine-tuned to operate correctly and acceptably. Beyond the costs of repair personnel and labor, machinery downtime is also expensive, especially through the prism of repaying your initial investment: Your machinery uptime is literally money.

Limitations of plastic injection molding: While plastic injection molding is incredibly versatile and cost-effective — meeting the needs of a vast number of applications, industries and products — it’s simply not able to meet every single need out there. In those cases, you’ll still need to work with a service provider when another process might be better. In addition, you may wish to use your injection molding machinery for more complex processes such as overmolding of machined or 3D printed parts. In those cases, you’ll be working with another supplier — and paying for shipping, waiting for fulfillment and so on — while only using your in-house machinery for a portion of the process.

Outsourcing your plastic injection molding can often provide a solution to most, if not all of the “cons” mentioned above. Outsourced plastic injection molding advantages include:

  • No upfront investment — the burden of machinery costs lies completely with the supplier
  • For tooling, pay only for the mold, not the full cost of personnel required to design and manufacture it
  • Overhead costs are spread among all customers of a service provider, and are no longer just yours
  • Repairs are the responsibility of the machinery owner, not you
  • Machine downtime is not your concern when the machinery is not yours
  • An outsourced injection molding service provider will often have ready access to other processes, such as machining and 3D printing, when advanced molding techniques are the right solution
  • Keeping all services under one roof can help smooth the process from design to prototyping to manufacturing
  • An experienced injection molding can assist you with all steps of your process, from design and concepting to inventory and fulfillment

For more information about the advantages of outsourcing plastic injection molding, or to discuss your project, contact RevPart today.

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