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 […]
Training Tip: The Five Stages of DOE
Design of Experiments, or DOE, is a powerful mathematical tool that can be successfully applied to areas of new mold trials and to trouble-shoot potentially challenging processes. Experimental design techniques can be utilized by anyone with a fundamental understanding of injection molding. There are five primary stages for conducting a designed experiment. These are planning, […]
Torsten’s Training Tip: Mold Functionality
An important step in the molding process is preparing the mold for optimal functionality. Every plastic injection mold is unique and requires a tailored set-up strategy. There are several important steps to take prior to beginning the molding process development phase. These include setting up and checking the functionality of the following: Molding machine Mold Ejector […]
Torsten’s Training Tip: Thermal Properties
During the injection molding process, a polymer is heated in different ways, beginning inside the machine cylinder. Electric heater bands around the cylinder create heat which is transferred through convection from the cylinder to the polymer. Then, the rotating screw creates shear heat which transfers to the polymer on top of the convection transfer. In […]
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: Short Shots
Injection molding is a complex scientific manufacturing process. By following a methodical set-up process, molders aim to minimize or eliminate common molding defects that affect part quality. Generally, molding defects are either part design, mold design, or process related. This training tip focuses on short shots. There are various potential design-related causes for short shots. […]
