Overmolding is often presented as a way to combine two materials into a single component. That description is technically correct, but it overlooks the real engineering challenge. The difficult part is rarely molding the second material. The difficult part is ensuring that the second material remains attached throughout the life of the product. In many
Many of the most useful features in plastic part design are also the ones most likely to complicate a mold. Snap fits eliminate screws. Living hinges eliminate assembly operations. Overmolded grips improve ergonomics. Bosses provide attachment points. Logos and molded text enhance product branding. From a product design perspective, these features often make perfect sense.
When an injection molded part shows short shots, weld lines, sink marks, flow hesitation, or cosmetic defects, the first reaction is often to adjust the molding process. Sometimes that works. More often, the root cause is already built into the tool. In many injection molding projects, gate location and gate design have a greater impact
Learn how to design molded threads for injection molded parts. Explore thread geometry, internal vs. external threads, inserts, tooling considerations, and DFM best practices.
During DFM reviews, wall thickness is one of the first things we evaluate. It is also one of the areas where we find the most preventable design issues. Many plastic parts look perfectly reasonable in CAD. The geometry may satisfy functional requirements, fit within the assembly, and meet cosmetic expectations. However, once the part moves
Many teams begin discussing injection molding costs after receiving tooling quotations. By that point, most of the important cost decisions have already been made. The geometry has been finalized. The material has been selected. The assembly strategy has been defined. The mold concept is largely determined. In other words, the majority of injection molding costs
Few design features have a greater impact on injection mold complexity than undercuts. From a product designer’s perspective, an undercut may appear insignificant: In CAD, these features are often created in seconds. In tooling, however, they can fundamentally change how a mold must be built. A small undercut can introduce: The undercut itself is rarely
When engineers evaluate manufacturing costs, the discussion often focuses on molding. Questions typically include: These are important questions. However, they often overlook a much larger cost driver. For many products, the most expensive operation does not occur during molding. It occurs after molding. Assembly labor, secondary operations, fastener installation, adhesive application, quality checks, and handling
A multi-cavity mold is an injection mold designed to produce multiple identical parts in a single molding cycle. While multi-cavity molds increase production efficiency, they require careful attention to runner balance, gate design, cooling, and process consistency to ensure uniform part quality across all cavities.
Learn how mold textures and surface finishes affect injection molded parts, including draft angle, ejection, material selection, tooling cost, and cosmetic appearance.
