Prototyping an injection-molded component is necessary to ensure proper quality and performance. Rapid tool prototyping and prototyping for injection molding production are two standard prototyping options, and each has its own advantages — but which is right for your projects?
Custom injection molding projects are, by nature, an expensive undertaking. Part development and tooling design/build often account for the majority of the budget, particularly in the case of intricate components. The consistency, quality, and cost of the part produced largely hinge on optimizing these two aspects of the project. Missteps can lead to expensive setbacks, product defects, and lower profits.
Custom injection molding projects are understandably focused on plastics selection. After all, the materials used to construct the parts have the greatest influence over quality and performance.
However, the grade of injection molding tool steel chosen for production also has a major impact on project outcomes. Cycle times, part criteria, production volume, cost, and maintenance expectations all must be factored in to align the steel with the need.
Insert molding is a process that requires an insert — typically metal — to be pre-placed in the tool for injected plastic to flow around. Encapsulating the insert with plastic creates a single molded plastic piece that’s generally stronger than one created using secondary assembly.
Insert molding can be accomplished through two methods:
- Manual insert loading: The generally more cost-effective way to approach very low-volume applications or extremely complex part geometries
- Automated insert molding: A better choice for part consistency. It minimizes human error, improves efficiencies, and ensures optimal cycle times.
Securing an insert in plastic requires precision and a thorough knowledge of how each individual substrate reacts to conditions during the injection molding process.
Geometric dimensioning and tolerancing (GD&T) is a symbolic language that is used on engineering drawings and computer-generated models. It communicates geometric dimensions and allowable tolerances for various parts. Not only is this a useful exercise for product design, it’s also helpful on the manufacturing floor because engineers and operators can quickly see the degree of tolerance that is required for each part.
Surface finish on plastic composites can vary a great deal, depending on the physical and chemical properties of the polymer blend as well as the parameters of the injection molding process.
The first objective for a custom injection molder is working with the customer to determine how important the surface finish is for the appearance and/or performance of the final product. For example, does the product need to be eye-catching or simply functional? Depending on the answer, the material selected and the desired finish will determine the settings for the injection molding process, and any required secondary finishing operations.
Injection-molded and blow-molded plastic parts are so pervasive in everyday life that the two processes are sometimes thought of as interchangeable. While the two may be used in an individual application — perhaps a blow-molded fluid reservoir is attached to a custom injection-molded medical device — injection molding and blow molding serve different purposes and markets.
There are several prototype tooling options for your designs — the one you choose really depends on what you expect to accomplish with the prototype. For example, will the prototype be subjected to testing? Does it need to be "dressed up" for presentation? Will it need to meet tight tolerance requirements?
The most common prototyping options are SLA/SLS, urethane cast, soft tooling, and hard tooling. But which is right for your component? Read on to discover the advantages and disadvantages of each.
When you approach a custom injection molder to produce complex plastic parts or components, determining if the product is suitable for a streamlined injection molding process is one of the first steps.