Study of Frozen Layer Development with an iMFLUX Process

2022-PLET

The objective of this project is to find the change in frozen layer thickness between a pressure-limited process and a conventional molding process.

 

Team Members

Nicholas Johnson | Noah Sekerski | Tyler Zellers | |

Project Poster

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Project Summary

 

Overview

The frozen layer of an injection molded part can be affected by many different factors and can reduce affect the formation of sinks and warpage. iMFLUX has created a pressure-limited process that changes velocity throughout the injection phase of the process to maintain a set pressure. The change in frozen layer is the primary concern with each process and multiple other factors to see if there is a significant change.

Objectives

  • To find how much change in frozen layer this new process has on injection molded parts compared to other factors such as mold and melt temperature
  • Mold parts with blowing agents using both processes to see what affect the change has on foaming distribution
  • Compare surface roughness and weight with blowing agent molded parts to see how they change with different processes

Approach

  • Research the fundamentals of frozen layer development and the factors that influence the thickness along with review iMFLUX patents
  • Develop an optimized process for conventional and pressure-limited processes
  • Create two DOEs with factors that were determined to affect frozen layer thickness the most
  • Mold test specimens and record physical dimensions
  • Parts cut every 25 mm from the gating location to view multiple sections of a part
  • Frozen layer thickness data collected and recorded under a polarized light optical microscope
  • Surface roughness data collected using a Perthometer
  • Results interpreted and displayed using Minitab to evaluate significant factors and interactions

Outcomes

  • The iMFLUX pressure-limited process produced a minimal increase in frozen layer increase when compared to a conventional process, with melt temperature and mold temperature having greater effects
  • The pressure-limited process showed a relatively thinner frozen layer close to injection of the part, and thicker towards the end of fill in a gradient pattern
  • An increase in blowing agent content gave a rougher surface finish with the pressure-limited process giving no change