Real-Time Acoustic and Pressure Characterization of Two-Phase Flow for Quality Control of Expanded Polystyrene Injection Molding Processes

2015 ◽  
Vol 138 (5) ◽  
Author(s):  
James N. Magarian ◽  
Robert D. White ◽  
Douglas M. Matson
Keyword(s):  
Injection Molding ◽  
Real Time ◽  
High Speed ◽  
Expanded Polystyrene ◽  
Video Data ◽  
Injection Molding Process ◽  
Molding Process ◽  
Two Phase ◽  
Acoustic Data ◽  
Acoustic Standing Wave

A method is proposed for real-time process monitoring for expanded polystyrene (EPS) injection molding systems. The method employs measurement of two variables: vacuum pressure in the EPS supply hose and phase difference between two points along an acoustic standing wave generated within the EPS flow path. High-speed videography is utilized as a secondary means of monitoring the injection molding process. Video data are correlated with pressure and acoustic data to substantiate those variables’ validity as indicators of intended molding system performance. Data show recorded parameter curve shapes to be indicative of key injection molding milestone events, such as valve timing and changes in flow regime.

An effective approach to measuring real-time mold deflection during injection molding

2011 ◽  
Vol 31 (8-9) ◽  
Author(s):  
Chung-Ching Huang ◽  
Thanh-Cong Truong ◽  
Shen-Hong Chen
Keyword(s):  
Injection Molding ◽  
Real Time ◽  
Plate Thickness ◽  
Displacement Sensor ◽  
Injection Molding Process ◽  
Molding Process ◽  
Packing Pressure ◽  
Mold Deformation ◽  
Deflection Analysis ◽  
Injection Molded

Abstract This study develops an effective approach to measure real-time mold plate flexion, namely a displacement of a cavity plate. A mold-filling program was used to simulate the injection molding process. The predicted cavity pressure was then applied as an input for the subsequent mold deflection analysis. In this work, an amorphous polymethyl methacrylate (PMMA) was injection-molded into a 6-inch light guide plate (LGP) cavity, with cavity plate thicknesses of 35 mm, 55 mm, and 100 mm. To validate the predicted mold deflection, an inductive displacement sensor was placed underneath the cavity plate, and experiments were conducted using process variables identical to those of the simulation. Comparison between the simulated results and the experimental data shows that when the cavity plate thickness is reduced, the mold deformation increases significantly, and results in an increase in part thickness. In addition, an increase in packing pressure caused a rise in mold deformation. This study demonstrates that the proposed approach is able to measure the mold deflection.

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