In product development, testing is a critical factor. In some cases engineers need to demonstrate how a new design will perform as part of management approval for investment into production. In other cases, regulatory requirements require testing of products from representative materials and processes that correspond to those intended. As part of its prototyping methodology, manufacturers often use different strategies for executing prototypes depending on the purpose of the parts. When injection molding is involved in the final product, the use of specially engineered polymers in the product specification may result in the need to injection mold the parts being used in testing in order to get reliable results. Depending on the circumstances, the final production injection molds may be used or separate prototype tooling may be utilized. The goal is to ensure a superior prototype and timely testing, which helps identify design changes before taking a product into full production.
There are a number of key decisions, which go into the prototype tooling process, which enables a design team to select the appropriate build strategy. A key element to consider is the degree of uncertainty or uniqueness of a particular design. The more unique a given design is from a company’s previous manufacturing experience, the more critical it is to test process and product early. Likewise, overall program schedule plays a big factor. The component in need of testing may just be one part of an overall system being developed. Final production tooling timing may be aligned more with the overall system’s development schedule. If so, waiting for production tooling may be a costly risk delaying valuable testing time. In those cases, a simple prototype tool to allow early evaluation of the component or sub-system may be a great investment. Finally, the likelihood a product may change should also be a factor in considering if separate prototype tooling should be used. If a design change is likely or probable, it is better to identify this early rather than executing the change to final production tooling which could require welding on the tool steel or other changes which might compromise the integrity of the mold for long run use.
For both production and prototyping, every tool is different. Two factors, which strongly influence the distinction between the two, are as follows:
- Production Quantity – The degree of automation in a tool is often correlated with the production quantity intended. High production molds often are highly automated with wear maintenance provisions, sensing and process control capability built into the design. These factors add to the time and cost of the tooling but provide cost and processing efficiencies in the actual volume molding itself. Likewise high production molds are often multi-cavity allowing several parts of the same design to be molded simultaneously. Prototype molds by contrast, typically have limited automation and cavities, saving time and cost in fabrication and thus are suited to low volume molding with quicker development time.
- Hard vs. Soft Tooling – Another difference between the prototype tooling process and production tooling process has to do with tooling materials. Production tooling is often made from hardened P20, H13 or other tool steel suitable for repeated use and long tool life. Heat-treating and surface hardening or plating are also often utilized. Prototype tools are often called soft tools based on the fact that aluminum and or mild steel are often used. This tooling material can be cut quicker in the machining process allowing for faster and more cost effective prototype tools. The tradeoff however is that tool life may be limited depending on the plastic intended to be molded and processing is not optimized for shortest cycle time. Soft tooling can offer affordability for both production and prototyping. However, because it allows for quick turnarounds of samples, it is often the preferred choice for prototypes.
Tooling is a big investment and cost is always an important deciding factor. Therefore, a manufacturing company will determine which type of tooling makes the most sense from a financial perspective and any product based factors necessary to make the right choice.
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The JouleHub team of experts can assist your team in the process of making critical decisions about machines, material, and tooling and providing the support services needed regardless of choice. For a superior quality prototype or product, we would love the opportunity to help. Visit us online or call to speak with a company representative regarding your project.