Prototype Injection Molds vs. Production Injection Molds

Prototype injection molds are useful when quickly producing limited test runs to identify and remove defects. Whether made of aluminum or steel, these molds take far less time to produce and are more economical for smaller runs to make prototypes used for evaluating and testing a design. Production injection molds require more testing, time, and stronger materials for the actual long-term use and final design of high-yield production runs. Both types of injection molds use state-of-the-art equipment in the production process. At Special Tool & Engineering, we offer six injection molding presses ranging in size from 120T to 1450T.

Rapid Prototype Injection Molds

The main benefit of rapid prototype injection molds is the short time frame they take to make and use. However, if your design is far enough along in the process that you need a number of pieces made in test runs, aluminum injection molds are an economical choice. The turnaround on standard prototype molds is usually two weeks to a month, a timing that allows for other kinks to be ironed out in the meantime. These molds are affordable and can produce parts that may be identical to the final production run, allowing for comprehensive testing for construction or operation flaws. Small inconsistencies in friction, materials, or temperature can be identified.

Using 3D printed prototypes is typically another low-cost option and allows for reproductions with a fast turnaround. However, it is important to remember that for what 3D prototyping boasts in speed, it lacks in complexity. A printed prototype does not match the exact surfacing and appearance of an injection molded part and cannot accurately reflect the expected warping and shrinking of materials. It also becomes more expensive and time-consuming if more than a few prototypes must be printed. Customers and engineers alike return to injected molds for prototypes because they better handle small details and can be used to identify even tiny flaws. Moreover, an injection mold can be used to create runs of 100 prototypes or more for more extensive testing, ultimately saving time and money in the long run.

Aluminum Prototype

While some manufacturers assume that aluminum is only suitable for prototype molds, in practice it can be used to construct either prototype or production molds. The customer request and product purpose can determine which will be most useful for the design.  

If customers request an aluminum prototype for their design or initial prototyping run, it will typically have fewer cavities to fulfill the smaller test order. Likewise, if the aluminum mold is designated for a high-quantity yield, it can be designed with more cavities for mass production instead. When it comes to this decision, it is usually best to leave it to the engineers and the customers, but we do offer aluminum for all design needs. 

Steel Production Injection Molds

Steel can withstand high heat temperatures and is resilient to the elements over the long term and for repeated use. Aesthetically, steel is both recognizable in the world of parts and production as it is a marker for quality. We offer steel as a standard production injection mold material. 

Steel molds hold up over time, maintaining integrity while mass-producing high quantities over long periods. While the molds are more costly than aluminum up front, they should be considered an investment that will likely pay you back for years to come. 


Regardless of skill, experience, or expertise, prototyping is the best practice for good design and engineering. Identifying bugs and fixing them is a key step of the production process. To iron out all the wrinkles with the prototypes, work with Special Tool and Engineering. We can help determine the type, quantity, and material that will be best for your production injection mold choice. 

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