Category Archives: Tech Tips

The Screw Bounce Mystery Solved? One AIM Instructor’s Unexpected Discovery

Posted on 08-22-2025

David Hoffman, the director of Beaumont‘s American Injection Molding (AIM) Institute, recently published his research on Screw Bounce in Plastics Technology magazine!

If you’re an injection molding processor, you’ve undoubtedly encountered screw bounce and perhaps either ignored it or came up with an unproven reason in your head as to why it is happening…just like David used to do.

But shortly after a student in AIM’s hands-on Molders’ Series course asked a seemingly unrelated question about a more precise calculation of shot size and transfer position settings, Hoffman and his team initiated research that ultimately led to a new understanding of screw bounce and how it actually affects the calculations that the student was referring to.

Read about the research here → https://hubs.ly/Q03gqZQF0 (pages 18 to 24)

We applaud all the instructors at the AIM Institute for their passion for research. They embody our mission of advancing the injection molding industry by challenging accepted norms and never being satisfied with the status quo!

Measuring Viscosity: Capillary Rheometer vs. Injection Mold Rheometer

Posted on 02-28-2020

Thermoplastics viscosities are described as having a pseudo-plastic non-Newtonian behavior. This type of behavior means that as you push the material at a faster rate, the polymer exhibits a reduction in viscosity. There are two critical factors that affect the viscosity of plastics: temperature and shear rate.

In our material characterization lab we measure viscosity utilizing two primary, capillary based systems: Autodesk Moldflow Injection Molding Rheometer (IMR) and Capillary Rheometer. (We will touch on Therma-flo™ separately in a later article.) Each piece of equipment and associated test method has its own benefits and drawbacks, but the IMR remains the preferred method for material characterization to simulate the injection molding process.

Intro to iMFLUX Technology

Posted on 05-28-2019

An Introduction to iMFLUX Technology: Welcome to the Green Curve

By: Jason Travitz, Sr. Processing Instructor, AIM

iMFLUX’s process control technology is becoming more widely recognized. The organization, a wholly owned subsidiary of Procter & Gamble, has installed their process control technology on an increasingly large number of machines, and we are receiving more and more questions regarding the technology and how it can be beneficial. This article takes a high-level look at iMFLUX process controls and answers just a few of the most common questions we receive regarding the industry’s latest advancement.

Questioning the Science in Injection Molding: What are you actually getting in a “Pressure Loss Study”?

Posted on 08-19-2016

Written by John Beaumont.

This article was originally published in SPE’s Plastics Engineering Magazine.

Determining Flow Groups in Multi-Cavity Molds, Part II

Posted on 11-16-2015

Determining the Regions of the Mold

In the last tech tip, we discussed determining patterns within the mold in order to analyze “random” filling patterns and how to determine flow groups. This tech tip will discuss how to determine regions in the mold.

Determining Flow Groups in Multi-Cavity Molds, Part I

Posted on 10-14-2015

Often times when we hear that there is a random filling imbalance related to a random part quality issue, we are skeptical that the problem is truly “random”. A majority of molds that we are asked to look at often times have a pattern to the data, and therefore, a common root cause behind the associated problems. These patterns may be a result of either non-uniform shear heating variations or steel related issues that affect a certain set of cavities. In order to first determine if there is a pattern, we need to break down a mold into flow groups and regions. By determining flow groups in a mold, not only can a person more easily find the true imbalance but it is also easier to determine the source(s) of the imbalances.

Beware of the “Naturally Balanced” Runner System

Posted on 08-11-2015

For years now the standard method designing a melt delivery (runner) system has been the naturally balanced runner system. A naturally balanced runner system is a runner configuration where there is an even flow length from the tip of the sprue to the end of each cavity with symmetrical cross-sectional shapes. While the naturally balanced runner system looks good from a visual standpoint, it is what lies underneath that leads to molding issues. This tech tip will explain the pitfalls of the naturally balanced runner system and how to avoid them.

Viscosity, Part 3- Therma-flo™

Posted on 04-24-2015

In the previous two tech tips, we began a three part discussion on how our industry looks at the viscosity of a polymer. We reviewed capillary rheometers and melt flow index machines up to this point. We pointed out various benefits and flaws for each method. Now we are going to take a look at a newer approach to evaluating a polymer’s viscosity called Therma-flo™.

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TESTIMONIALS

“Of all the training seminars that I have attended over the past 10 years, this one ranks at the top! The explanations of clamp tonnage, cooling strategies, viscosity, and key mold design components are just a few of the takeaways that will be very useful in my job function.”

THOGUS®

Russ Wolff, Business Development Manager

“I was amazed at the amount of expertise and knowledge presented in just two days. Many myths were debunked, numerous scientific explanations for the way we should be thinking about plastic flow were given, and various real-world examples were used to show how plastic flows.”

CAPLUGS®

Don Makowski, Design Engineer