ISO 20457 gives the general tolerances for plastic molded parts. Plastics shrink and warp, so molded parts need much wider tolerances than machined parts. The standard sorts them into tolerance groups TG1 to TG9, and a drawing names one group as the general tolerance, for example General tolerances ISO 20457 – TG6. Use the tables
Two mold quotes for the same plastic part can arrive with very different prices, and the first instinct is to assume one supplier is overcharging. Often the real reason is simpler: they are quoting different molds. One may be pricing a hardened-steel tool built for a million shots. The other may be pricing a pre-hardened
T0 The mold’s health check Does the mold work mechanically? Look at: mold function, water lines, cavity fill. Not part dimensions. T1 First trial, first real samples What problems does the design still have? Look at: samples, trial report, dimensional report. T2 Fix and verify Did the fixes work? Is the process stable? Look at:
Overmolding is one of the most powerful techniques in modern injection molding — allowing engineers to combine multiple materials into a single, high-performance component without adhesives, fasteners, or secondary assembly. From the soft-touch grips on surgical instruments to the waterproof seals of consumer electronics, overmolding is quietly behind some of the most functional and elegant
The plastic injection molding gate directly affects polymer flow behavior, part quality, and process efficiency. It connects the runner system and the cavity. The gate regulates melt flow rate, shear conditions, and pressure distribution during filling. Its geometry and placement not only determine how the cavity is filled but also influence weld line formation, shrinkage,
Choosing between insert molding and overmolding is one of the most common decisions engineers face when designing multi-material plastic injection molding parts. Both techniques eliminate secondary assembly and improve part strength — but they work in fundamentally different ways, suit different applications, and carry very different cost profiles. This guide breaks down exactly how each
Types of Injection Molding Tolerances In injection molding, different types of tolerances are used to control the dimensions and quality of molded parts. Each type of tolerance impacts specific aspects of the part’s geometry and ensures that the final product meets precise standards. The key types of injection molding tolerances are: 1. Dimensional Tolerances These
DFM (Design for Manufacturability) for injection molding is the process of reviewing and optimizing a plastic part design before mold cutting begins. Done correctly, DFM reduces tooling costs by 20–40%, cuts T1 sampling iterations from 5+ down to 1–2, and prevents the most expensive type of problem: discovering a design flaw after steel has been
What is the dimensional stability of plastics? During the process of plastic parts processing, assembly, and product application, a series of external conditions such as processing and environment will affect whether the product functions well from materials to parts throughout the entire life cycle. The most commonly affected by dimensional stability is the size of
Table of Contents Add a header to begin generating the table of contents Plastic injection molding has been widely used in automotive, aerospace, consumer electronics, medical devices. It is ideal for producing high-volume, highly detailed plastic parts with tight tolerances at relatively low cost. The cost of injection molding depends on numerous factors. What is
