Visualization Study on Gas Injection Process of A New Type of Micro⁃foaming Gas Injector

doi:10.19491/j.issn.1001-9278.2021.09.020

Abstract

Abstract:

The gas injector is an important device in the micro?foam injection molding process. This article investigated the gas injection process of a new type of gas injector. The gas injection process was analyzed using a high?speed camera and the pressure curve collected by a computer data acquisition system. The results indicated that the gas entered the visualization device from the gas injector in a dispersed state. This was advantageous to the dispersion and mixing of gas and melt during the micro?foaming process. The gas injection flow rate was calculated by using the pressure data and combined with a high?speed camera image analysis. It was found that the gas injection pressure difference and initial water pressure had a great influence on the gas injection flow rate. Through investigating the gas injection process and the amount of gas injection， the gas injection process of this new type of micro?foaming gas injector was found to be stable and controllable， and it could be used for the micro?foaming injection molding experiments.

Key words: micro?foam injection molding, visualization, the new type of gas injector, high?speed camera, pressure curve

CLC Number:

TQ320.66

QIAO Linjun, XIN Chunling, HE Yadong, ZHAI Yujiao, YAN Baorui. Visualization Study on Gas Injection Process of A New Type of Micro⁃foaming Gas Injector[J]. China Plastics, 2021, 35(9): 128-135.

Figures/Tables 15

Fig.1. Schematic diagram of the new gas injector principle

Fig.2. Schematic diagram of micro?foam injection molding gas injection system

Fig.3. Schematic diagram of the current limiting element

Fig.4. 3D evice imensional model of visualization

Fig.5. Visual experiment platform

Fig.6. High?speed images at different time after the start of gas injection

Fig.7. High?speed image 3 s after gas injection

Fig.8. Flow curve of different injection pressure at 1 MPa of water pressure

Fig.9. Different initial water pressure flow curves with a pressure difference of 2 MPa

Fig.10. Relationship between initial gas injection volume and initial water pressure and pressure difference

Fig.11. Relationship between subsequent gas injection volume and initial water pressure and pressure difference

限流元件孔径/um	熔体压力/MPa	注气压差/MPa	注气时间/s
200	8	1	1
250	9	1.5	2
300	10	2	3

Tab.1. Experimental parameter range of micro?foam injection molding

Fig.12. Relationship between weight loss ratio and influencing factors

Fig.13. The relationship between the proportion of gas injection and influencing factors

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