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Guide to Foamcore Joining Techniques

Foamcore (also known as foam board or foam core) is a lightweight building material typically consisting of an inner foam layer sandwiched by paper or another thin, lightweight material. If you have put together a poster for a school project or a work-related presentation, odds are you’re familiar with rigid foam core poster board. Foamcore […]

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Engineering Fundamentals Refresh: Strength vs. Stiffness vs. Hardness

This article was originally published in February 2017 by Humberto Villasenor. The content has been updated. Understanding the differences between the mechanical properties of strength vs. stiffness vs. hardness is foundational in mechanical engineering, yet these properties are often confused. These properties are related, but they have important differences:  For this article, we’ll review the […]

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Types of Springs and their Applications: An Overview

Springs are common in all kinds of machines — from consumer products to heavy industrial equipment. Take apart anything that involves a mechanism, and chances are, you’ll find a spring inside. Springs are storage devices for mechanical energy, analogous to the electrical storage capacity of batteries. The earliest spring-driven clocks appeared in the 1400s. Fast-forward […]

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Fillets: When to Use ‘Em, When to Lose ‘Em

Fillets are one of those mysterious design features for which there seem to be no clearly defined rules. Either a part is entirely devoid of fillets, and most or all edges are well-defined, or the part’s designer decided to take the opposite route, and every single edge and corner is rounded with some size of […]

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Best Practices for Adding Ribs and Gussets to 3D Printed Parts for Structural Integrity

When designing plastic components, it’s often necessary to add ribs and gussets to improve the stiffness and strength of load-bearing features. This reduces material volume and optimizes print time for 3D printed parts, since it takes longer to make these features solid structures (print time is largely driven by the volume of material for a […]

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Thermoplastics vs. Thermoset Plastics: Material Properties Overview

Thermoplastics and thermoset plastics are classes of polymers used in injection molding, CNC machining, 3D printing, and urethane casting. Like elastomers, another class of polymer, thermoplastics and thermosets both consist of long, repeating chains of molecules. Under a microscope, the structure of a thermoplastic resembles a railroad track while a thermoset material looks like a […]

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3D Printed Light Pipes: Overview and Material Selection

The advent of 3D printable transparent materials has opened doors to new possibilities with rapid prototyping for optical applications. Now, we can consider how to use and manipulate light with 3D printed parts. Light pipes, sometimes referred to as light guides or light tubes, are physical components used to purposefully redirect or transport light from […]

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Let It Slide: Self-Lubrication in Mechanical Assemblies

Friction is one of the five contact forces along with tension, spring force, normal force, and air resistance. Friction is what gives us traction on the road, good brakes, and allows us to walk without looking like a baby giraffe. But sometimes we just want to let things slide, and that’s when friction frustrates — […]

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Threaded Locking Methods for Secure Connections

Threaded fasteners, such as bolts and nuts, are used in many applications, ranging from plastic toys to massive bridges. And all threaded fastener connections need to stay together when we want them to, but also come apart when needed. For example, the valve covers on an engine must remain in place while driving, but we […]

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How to Design for Part Stiffness Using a Geometric Approach

Designing products for load bearing applications is a complex and multifaceted task, so it’s important for a designer to have a “toolbox” of techniques that improve design quality. Designing for part stiffness through geometric controls is one of these important tools. While part stiffness can be modified with geometry, material stiffness is a property of […]