Injection Molding of Bulk Molding Compound (BMC)
Injection molding of Bulk Molding Compound (BMC) is a manufacturing process used to form thermoset composite materials into strong, dimensionally stable parts with tight tolerances and repeatable quality. Because BMC is a thermosetting system, it cures irreversibly in the mold, meaning the finished component will not soften or re-melt when reheated, which is a major […]
Air Blast Systems in Injection Molding
Air blast systems are auxiliary devices integrated into injection molding machines to support tooling-related operations such as part ejection, localized cooling, and mold-surface cleaning. They work by delivering short, controlled bursts of compressed air through nozzles, ports, or dedicated air channels in the mold. When properly designed and tuned, these air jets help stabilize the […]
The Toggle Clamp (Injection Molding)
An injection molding machine’s clamping unit is responsible for one essential job: keeping the mold securely closed while plastic is injected, packed, and cooled. During these stages, internal cavity pressure can become extremely high. If the mold halves separate even slightly, the result is typically flash, dimensional variation, surface defects, and premature mold wear. A […]
DOE— A Methodical Approach to Understanding Cause-and-Effect Behaviors in Injection Molding
Torsten Kruse explains how Design of Experiments (DOE) is used to systematically understand cause-and-effect relationships in injection molding processes. In a highly competitive manufacturing environment, success depends on more than trial-and-error adjustments; it requires a deep understanding of how multiple process variables interact and influence part quality, cycle time, and overall performance. Injection molding projects […]
Packing Flow Visualization During Compression of the Mold Cavity
The packing phase is a critical stage of the injection molding process, occurring immediately after cavity filling and before gate freeze-off. During this phase, additional material is forced into the mold cavity to compensate for volumetric shrinkage as the polymer cools and solidifies. Precise control of packing pressure and time is essential, as these parameters […]
Understanding Cause and Effect Behavior in Injection Molding
This presentation, delivered by Torsten Kruse of Kruse Training, provides a structured, practical introduction to the core principles needed to achieve robust, predictable, and scalable injection molding processes. It integrates three foundational disciplines—Design for Manufacturability (DFM), Design of Experiments (DOE), and systematic cause-and-effect analysis—to establish a disciplined framework for process understanding and control. The presentation […]
Torsten’s Training Tips: Nozzle Tip Designs
Molding high-quality parts is dependent on many factors, including skillful part and mold design, an understanding of polymer material behavior, and an optimized process. The three standard nozzle tip designs found in the injection molding industry are general purpose, reverse taper, and free flow. Nozzle tip design and size will impact mold filling, process behavior, […]
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 […]
