Tag: fundamentals

Torsten’s Training Tip: Deformation Behavior and Reversing PVT Curves

Plastic part designers have an abundance of polymer materials to choose from, ranging from commodity to technical or engineered polymers. Selecting the optimal material for each design is key to a successful molding project. Polymer materials must be heated to their melt temperature ranges to be injection molded. Polymer strength, stiffness, and deformation behavior are […]

Torsten’s Training Tips: Warpage Due to Fiber Orientation

Fiber orientation plays a significant role in the shrinkage and warpage of a molded part. Let’s look at why. Fiber -filled composite plastic materials will induce anisotropic mechanical properties. Fiber reinforced parts have directional mechanical properties that are stronger in the direction (or parallel) to the flow and weaker transverse (or perpendicular) to the flow. […]

Torsten’s Training Tips: Understanding Shrinkage and Warpage Behaviors

Minimizing volumetric shrinkages and reducing part warpage are important considerations when designing injection molded parts. By understanding the interaction of part and mold designs, polymer material, and the molding process, preventative measures can be designed into the molding system to minimize shrinkage and warpage. Polymer materials naturally expand when they are heated and shrink as […]

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: Mold Design — Pin-Point Gates

Gate placement is an important aspect of mold design to achieve optimal part quality. Let’s look at some advantages and disadvantages to using pin-point (pinpoint) gates in mold design. Because gate placement options are often limited by design restrictions and other part-related constraints, understanding and utilizing industry best-practices can be helpful in achieving the desired […]

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: 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 common 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 […]

New Processing Lessons: Cooling and Packing

We are excited to announce our latest lessons in the Processing category. There are six brand new lessons focused on the Cooling and Packing phase. These lessons continue to build on our foundational level of injection molding training. Filling Phase Lessons Include: Lesson 1 – Packing Pressure Profiles: Amorphous Materials This lesson reviews the internal […]

Torsten’s Training Tips: Ejector Pin Sub-Gates

Gate design and placement are key factors in mold design. Because parts often need to be molded without surface marks or gate vestige, certain gate styles are more appropriate than others. Although many gate systems will leave behind a witness mark, selecting a gate that can be hidden inside the ejector pin with an automatically […]

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 […]