The Effects of Time on Polymers

Last month we briefly discussed the influence of temperature on the mechanical properties of polymers and reviewed some of the structural considerations that govern these effects.
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The Effects of Stress on Polymers

Previously we have discussed the effects of temperature and time on the long-term behavior of polymers. Now let's take a look at stress.
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How Backpressure Optimization Affects Melt Preparation

Backpressure is often the least understood of the settings in an injection molding process, even though it can play a significant role in the final quality of the part. Let’s start with understanding what backpressure is and then learn how to optimize it for a given mold.

Tracing the History of Polymeric Materials, Part 27: Liquid-Crystal Polymers

Liquid-crystal polymers debuted in the mid-1980s, but the history of the chemistry associated with this class of materials actually starts a century earlier.  

How Screw Design Can Boost Output of Single-Screw Extruders

Optimizing screw design for a lower discharge temperature has been shown to significantly increase output rate.

21 Tips to Slash Energy Costs in Molding

This checklist can provide injection molders a good starting point on the path to reduced energy consumption and can generate some money savings on that journey.  

The Impact of Hydraulics on Tool Design, Practical Uses -- Part 2 of 2

Here are more tips on using hydraulically actuated devices on your tools.

How to Configure Your Twin-Screw Barrel Layout

In twin-screw compounding, most engineers recognize the benefits of being able to configure screw elements. Here’s what you need to know about sequencing barrel sections.  

Tracing the History of Polymeric Materials, Part 26: High-Performance Thermoplastics

The majority of the polymers that today we rely on for outstanding performance — such as polysulfone, polyethersulfone, polyphenylsulfone and PPS — were introduced in the period between 1965 and 1985. Here’s how they entered your toolbox of engineering of materials.    

The Impact of Hydraulics on Tool Design -- Part 1 of 2

Get a better understanding of their use, proper sizing, and how the tool design and setup in the machine can impact failures in manufacturing.

Troubleshooting Vent Flow Problems in Single-Screw Extruders

Vent flow can be a costly problem and a housekeeping nuisance. Here is some advice on how to eliminate it.  

Improving Twin-Screw Compounding of Reinforced Polyolefins

Compounders face a number of processing challenges when incorporating a high loading of low-bulk-density mineral filler into polyolefins. Here are some possible solutions.

How Important is Minimizing Residence Time in Injection Molding?

Does a focus on the concept of “minimum residence time” distract attention from areas of injection molding that have more of a direct impact on melt quality?

How to Select the Right Tool Steel for Mold Cavities

With cavity steel or alloy selection there are many variables that can dictate the best option.

Tracing the History of Polymeric Materials, Part 25: Silicones

The long road to the development of silicone resulted in a chemistry that is remarkably versatile.  

The Right Way to Design Vents in Single-Screw Extruders

Designing vents for single-screw extruders requires understanding of polymer flow in the screw channels. Some designs are more effective than others. Here are some guidelines.

The Importance of Melt & Mold Temperature

Molders should realize how significantly process conditions can influence the final properties of the part.
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Extruder Alignment: Important, but Only Half the Equation

The other half? Aligning and supporting downstream equipment. Here are best practices.

Understanding Flow Fronts and Defects

Flow-front behavior and corrections are key to solving many common molding problems —what is your process’s flow trying to tell you about your part?

Tracing the History of Polymeric Materials: Silicones

More properly known as siloxanes, silicones are a class of materials where no carbon is present in the polymer backbone.  

How Do You Estimate Cycle Time?

Molders price jobs based on  estimated press time, and that is where you can either be very profitable or lose your shirt. But there’s a new, free resource to help you out.  

Hot Runners: A View from the Bottom Up

Addressing hot-runner benefits, improvements, and everyday issues from the perspective of decades of experience with probably every brand on the market. Part 1 of 2.