Category: Fundamentals

Torsten’s Training Tips: Mechanical Material Behavior

Injection molding is a widespread manufacturing process used to create various everyday items, ranging from pipette tips to car bumpers, using different polymer materials. These parts can be made from either pure, unfilled polymers or those that are enhanced with reinforcements and additives. It’s crucial for designers of these parts to understand the mechanical behaviors […]

Torsten’s Training Tips: Mechanical Material Behavior

Injection molding manufacturing produces many everyday parts, from pipet tips to car bumpers in a variety of polymer materials. Some parts are produced from neat, unfilled materials and some from materials that are filled with reinforcements and additives. Part designers should be able to evaluate the mechanical material behavior and properties of these different polymers […]

Torsten’s Training Tips: Nominal Wall Thickness

What is the “Nominal Wall Thickness,” and how is it relevant in designing functional plastic parts?  Although parts can have various wall thicknesses to accommodate form, fit, and function, designers are generally tasked with minimizing thickness to lessen material consumption, achieve a faster cycle time, and reduce manufacturing costs. Nominal Wall Thickness However, parts with […]

Torsten’s Training Tips: Fill Speed Profiles

Evaluating and understanding fill speed profiles is an essential aspect of injection molding. Polymer materials can flow by heating them to their melting range. Every polymer has a melt and mold temperature range; within that range, the polymers flow and can be injected into a mold. The molten polymer is injected into the mold by […]

Torsten’s Training Tip: Jetting

Injection molding polymer through small gates creates complex three-dimensional fluid flow behaviors. Jetting occurs in injection molding when polymer material is injected through a nozzle, runner, or gate at high velocity, into open, thicker areas, without forming contact with the mold wall.  The jetting effect is like water flowing through a hose. If you place your thumb on […]

Torsten’s Training Tip: Parallel and Serial Coolant Circuits

An injection mold is effectively a heat exchanger. Molten polymer material that is injected must be cooled by the mold cooling system. As part designs become more complex, cavitation requirements increase, and larger overall mold bases are needed. Mold designers have several options when designing effective heat removal systems. Coolant circuits can be parallel or […]

Torsten’s Training Tip: Understanding Flow-Induced Molded-In Stress

Injection molding is a complex manufacturing process involving temperature and pressure. During the molding process polymer materials experience complex molecular chain deformation while undergoing temperature and pressure changes. Molded part properties and performance are dependent on, and influenced by, design complexity and the molding process. Understanding molded-in stress, specifically flow induced molded-in stress, is an […]

Torsten’s Training Tip: Polymer Materials Overview

It is important for part and mold designers not only to understand design principles, but also to understand the fundamentals of plastics. The choice of a plastic, or polymer, has a strong impact on the outcome of a molded part. Polymers are categorized by processing methods and temperature behavior. The major groups are thermoplastics, thermosets, […]

Torsten’s Training Tip: Cold Runner Types and Designs

Cold runner systems are an important aspect of mold design. By optimizing cold runner shapes and sizes, important molding processes such as pressure drops, polymer shearing, packing and cooling behavior, gate sealing time, and overall cycle time can be made more efficient. Cold runners are simply unheated channels that transport molten polymer material from a […]

Torsten’s Training Tip: Gate Seal Time

Gate seal time is an important aspect of the packing phase that needs to be understood to produce high quality molded parts.  Setting proper gate seal time plays a key role in packing parts. Properly packed parts will have even internal polymer molecular structure, fewer volumetric shrinkage differences, optimized part dimensions, and fewer sink marks […]