Introduction
At the moment, most business owners in the manufacturing sector are seeking new ways to save money on injection molding while automating processes and increasing efficiency.
Although injection molding may seem quite expensive in the first instance, especially compared to other processes like 3D printing and CNC machining, its ability to scale and manufacture thousands of parts makes it the best solution for mass production.
However, manufacturers interested in small-scale production under 200k can also opt for micro-molding, a highly specialized process where micro-structured steel or aluminum molds are CNC, and EDM is machined within micron or even submicron scale tolerances.
In addition, micro-molding is cheaper and capable of replacing conventional injection molding in low-volume production.
How much does injection molding cost?
Determining the cost of injection molding generally depends on 3 primary factors, which include the following:
- The production volume
- The choice of mold materials.
- Machinery choice
Let’s take a detailed look at how these factors affect the cost of injection molding.
Production Volume
Molding operations are usually voluminous. Some of the projects lead to the production of hundreds of prototypes. This implies that during the production stage, lots of parts are molded in one shot when multi-cavity is used. This process is one way of saving costs on injection molding. However, it is vital to state that the mold of production must have as many cavities as possible to avoid compromising the quality of the parts produced.
However, a better alternative to injection molding is micro-molding which is perfect for low volume production. In fact, many of the molds could be small enough to fit in the micro mold projected area and not exceed micro injection shot volume. Micro molding also leads to lesser machine operating expenses, fewer mold cavities, and aluminum, which results in faster and cheaper machining, waste minimization and gives room for easy and flexible modification.
The types of material
Another key factor that determines the injection molding costs is the type of material used. Many plastic materials overlap in functionalities; while some are easier to mold, others are more difficult to reduce operation cost. Therefore, it is vital to experiment with different materials before opting for one. Also, keep in mind that all plastics made of fiberglass-filled material are capable of wearing down the most common mold, and only molds made of hardened tools can withstand injection molding with fiberglass-filled material.
Machinery Choice
Another important factor determining the injection molding cost is machinery choice which depends on the type of mold cavities that contributes to tooling costs. Opting for single cavity molds requires lighter, smaller and less complex machinery than for multi-cavity molds, which accounts for the highest difference in terms of costs of single cavity and multi-cavity molds injection molding tooling costs.
How do mold features affect the final costs?
Mold features are dependent on the project’s size, and they have effects on the final cost. For instance, single cavity molds used in low-volume production involve the use of lighter machines, smaller components, low tooling costs, and high cost per piece. In comparison, the multi-cavity molds, which are associated with high-volume production, heavier and more complex machines, bigger parts, high tooling costs, and leads to a low cost per piece.
However, it is best to opt for micro-molding, a highly specialized tool that is perfect for low scale production. Micromolding machines can inject a fraction of a gram with high precision as they have higher resolution feed options, resulting in even pressure distribution inside the cavity.
Micro molding demands extensive attention to packaging and quality management that can be viewed as secondary operations in conventional injection molding.
Other Ways to Reduce Injection Molding Costs
Other ways to reduce the cost of injection molding include the following:
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Opt for the maximum design optimization
One of the best ways to optimize mold design is by working with the molder who will intelligently design your mold. It is vital to collaborate and design out excess material usage, which translates to reduced cost. Also ensure that everything remains intact during the ejection process and that there would be no damage at the end to the product or mold design.
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Reconsider quality and tolerance requirements
Furthermore, put in mind that not all parts (molded part numbers, surfaces, company logo) require aesthetic surface finishing, which can lead to high costs. Instead, you must reconsider quality and ensure that your specific tolerance is truly necessary to meet your needs. Note that specifying tight tolerance that requires additional mold manufacturing steps could lead to high production costs. It is also vital to state that avoiding these cosmetics and features does not imply that you are going low on quality. Everyone understands that aesthetics is a good thing, but going too extra will add up more expenses. Therefore keeping your design simple by sticking strictly to what is necessary is one primary way of cutting down injection molding costs.
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Consider the time brackets for the relevant project.
Producing molds can be quite expensive and time-consuming due to the expertise and high level of customization required; however, before developing the right tooling solutions, it is vital to reconsider the overall system cost and not just the tooling or the molded parts but also the estimated annual usage, expected product lifespan, and the production quantities. These factors radically influence decisions like mold design, finishing, and material choice. For instance, it will be worth the effort for larger production quantities if you invest in producing long-lasting tools that are needed to streamline processes. In comparison, for smaller quantities, you may want to opt for tooling built with softer, less expensive metals.
Conclusion
Injection molding is an established process which makes it difficult to think that there are better ways to alter the process. However, injection molding costs can be reduced while saving lots of money through various means.
One of the best ways to reduce cost on injection molding is by opting for Micro molding which isn’t only cost-effective, leads to waste minimization and low machine expenses, it also gives room for the use of fewer mold cavities, among other benefits.
