Tag: polymer materials

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: 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: 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: 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 […]

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: Designing Cold Runner Systems

Designing effective cold runner systems is as important as designing a molded part. After optimizing the gate location for a new part design, the next step is to determine the best cold runner size. Cold runner size will influence overall part quality, molding cycle time, and overall profits. Identifying critical material process characterizations that will […]