Torsten’s Training Tips: PVT
The Pressure-Volume-Temperature (or PVT) relationship of different materials is a calculation of the compressibility of material during the packing and cooling phase. Since this affects a parts’ shrinkage and warpage after ejection, having a clear understanding of PVT is essential for success. Polymer material shrinkage inside a mold must be compensated for with packing and […]
Torsten’s Training Tips: Packing Pressure Profiles (Amorphous and Semi-Crystalline Materials)
One of the key steps in the injection molding process is the packing and holding phase, sometimes also referred to as the compensation phase. During the packing phase material is continuously “packed” into a cavity, thereby compensating for the shrinkage that occurs due to material cooling inside the mold. To optimize a packing profile, it […]
Torsten’s Training Tips: Ejector Pin Sub-Gates
The design and placement of gates are crucial elements in mold design, mainly because manufacturing parts often necessitate the absence of surface marks or gate remnants. To achieve this, certain gate styles are preferable over others. While many gate systems inevitably leave a witness mark, opting for a gate that integrates seamlessly with the ejector […]
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 […]
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 […]
