Injection defect analysis and molding optimization of high⁃gloss grille for an automobile

doi:10.19491/j.issn.1001-9278.2022.09.011

Abstract

Abstract:

Aiming at the possible lack of material， air trapping and bleached appearance defects such as gradient in the free spray specular injection⁃molded grid with a complex curved surface， an optimization was conducted for the design methods based on the Moldflow software. These methods included the optimization of the local wall thickness and the placement sequence valve hot runner system as well as the change of the local melt flow direction. As a result， the production of appearance defects was eliminated， and the optimal surface quality of the product appearance was achieved. This greatly reduced the scrap rate of products and saved the manufacturing costs.

Key words: injection molding, highlight grille, moldflow software, appearance defect, gradient wall thickness

CLC Number:

TQ320.66⁺2

HU Xuechuan, FANG Jiahao, LI Youbing, ZHOU Jianjun, LI Li, ZHANG Jixiang, DENG Yajun, LIU Yuan. Injection defect analysis and molding optimization of high⁃gloss grille for an automobile[J]. China Plastics, 2022, 36(9): 70-73.

Figures/Tables 9

Fig.1. Graph of the automobile high gloss grille

材料牌号	模具温度/℃	熔融温度/℃	顶出温度/℃	最大剪切速率/s^-1	弹性模量/MPa	熔体流动速率/g·（10 min）^-1	密度/g·cm^-3
HAM8580	50~80	200~250	85	23 000	2 740	7	1.1603

Tab.1. Spray⁃free ultra⁃high gloss PMMA/ASA alloy material information and recommended process

Fig.2. Schematic diagram of hot runner of multi⁃gate sequential valve

Fig.3. Schematic diagram of filling at local area

Fig.4. Schematic diagram of air traps

Fig.5. Structural design optimization of V⁃shaped local defect area in Grid

Fig.6. Layout of the moving and stationary parts of an injection mold for manufacture high gloss grilles

Fig.7. Product appearance diagram with application of optimal technique

工艺	生产周期/s	返工人员数量/人	产品合格率/%
优化前	85	9	25
优化后	80	3	96

Tab.2. Comparison of product qualification rate and production efficiency before and after process optimization

References 8

1	余力.轻型载货汽车外饰塑料件涂装工艺［J］.电镀与涂饰，2021，40（20）：1 604⁃1 608.
	YU L. Process for painting exterior plastic parts of light⁃duty truck［J］. Electroplating and Finishing， 2021， 40（20）：1 604⁃1 608.
2	胡慧林，陆书来，陶悦.影响高光黑色ABS树脂光泽度因素分析［J］.塑料工业，2017，45（2）：112⁃114．
	HU H L， LU S L， TAO Y. The analysis of contributory factors to high⁃gloss black ABS resin［J］. Plastic Industry， 2017， 45（2）：112⁃114．
3	杨北京.免喷涂注塑件的成型品质及应用概述［J］.中国塑料，2020，34（6）：118⁃125.
	YANG Beijing. Processing qualities and applications of injection molded spray‑free plastic parts［J］. China Plastics， 2020， 34（6）：118⁃125.
4	傅莹龙，褚建忠，邵明朝.高光后盖热流道注塑模具结构设计［J］.工程塑料应用，2020，48（3）：104⁃108.
	FU Y L， CHU J Z， SHAO M C. Design of hot runner injection mold structure for high gloss back cover［J］. Engineering Plastics Application， 2020， 48（3）：104⁃108.
5	李又兵.汽车前保险杠顺序注射模流分析与工艺优化［J］.中国塑料，2017，31（3）：64⁃68.
	LI Y B. Moldflow analysis and process optimization for sequentially injection⁃molded auto front bumpers［J］. China Plastics， 2017， 31（3）：64⁃68.
6	李又兵.某汽车前保险杠顺序注射成型模具设计［J］.中国塑料，2017，31（2）：108⁃111.
	LI Y B. Design of injection molds for a sequentially injection⁃molded auto front bumper［J］. China Plastics， 2017， 31（2）：108⁃111.
7	杜西兰，龙雪彬，陈琳，等.PMMA/ASA合金的制备及性能研究［J］.塑料工业，2016，44（9）：37⁃39.
	DU X L， LONG X B， CHEN L， et al. Preparation and performance of PMMA/ASA alloy［J］. China Plastics Industry， 2016， 44（9）：37⁃39.
8	刘惠芬，黄瑶.基于顺序注塑的大型薄壁件的熔接线研究［J］.现代塑料加工应用，2015，27（1）：56⁃59.
	LIU H F， HUANG Y. Weld line of large thin⁃wall parts based on sequential injection molding［J］. Modern Plastics Processing and Applications，2015， 27（1）： 56⁃59.

[1]	XU Yuxuan, DANG Kaifang, FU Nanhong, JIAO Xiaolong, XIE Pengcheng, YANG Weimin. Research progress in adaptive optimization technology for injection molding process [J]. China Plastics, 2022, 36(9): 180-186.
[2]	WANG Xiaodong, WANG Quan, CHEN Tuo, ZHENG Yue. Optimization of multi⁃objective parameters for double color injection⁃molding based on grey relational analysis and entropy weight method [J]. China Plastics, 2022, 36(7): 115-120.
[3]	LIU Yi, SUN Wei, QU Guoxing, WANG Ye, YUAN Ning, YANG Shaolin, XU Xia, CHANG Xiaoyi, ZHANG Yufei. Structure and performance analysis of transparent polypropylene special material for thin⁃wall injection molding [J]. China Plastics, 2022, 36(7): 37-43.
[4]	DENG Shixin, WANG Jian, YANG Weimin. Simulation and analysis of fluid high⁃pressure and high⁃speed collision in mixing head cavity of enhanced reaction injection molding machine [J]. China Plastics, 2022, 36(6): 130-136.
[5]	SUN Wenbo, XIN Chunling, HE Yadong, ZHAI Yujiao, YAN Baorui. Influence of micro⁃foaming injection molding process on cell structure of glass⁃fiber⁃reinforced PBT products [J]. China Plastics, 2022, 36(5): 1-7.
[6]	ZHAI Yujiao, XIN Chunling, HE Yadong, YAN Baorui, QIAO Linjun. Study on process parameters for filling process of polypropylene microcellular injection molding under supercritical N₂ [J]. China Plastics, 2022, 36(3): 69-74.
[7]	LIU Ganhua, TANG Naifu, MA Ruiwu. Multi⁃objective optimization for MIM process parameters of equal⁃distance spiral bevel gear [J]. China Plastics, 2022, 36(3): 96-103.
[8]	ZHANG Xiang, YAN Zhenhao, KONG Xiaoya, ZHU Jianxiao, GUAN Guotao, ZHAO Na, LI Qian. Study on structural optimization of disc screw in micro injection machine [J]. China Plastics, 2022, 36(2): 147-156.
[9]	ZHAI Yujiao, XIN Chunling, HE Yadong, YAN Baorui, QIAO Linjun. Study on surface quality optimization of microfoaming injection⁃molded products [J]. China Plastics, 2022, 36(2): 19-26.
[10]	HUANG Wei, LIU Hesheng, HUANG Xingyuan, ZHANG Wei, KUANG Tangqing, CHEN Zhongshi. Study on high⁃pressure water penetration behavior of square cross⁃sectional pipes based on short⁃glass⁃fiber⁃reinforced polypropylene [J]. China Plastics, 2022, 36(2): 82-88.
[11]	REN Lihui, LI Fuzhu, WANG Yun, DAI Yachun, YANG Hui, XU Zhenying. Multi⁃objective optimization of injection molding quality based on TOPSIS⁃grey relational analysis [J]. China Plastics, 2022, 36(2): 96-102.
[12]	ZHENG Fangli, FU Nanhong, JIAO Xiaolong, YANG Weimin, XIE Pengcheng. Research progress in applications and optimization of artificial intelligence technology in injection molding parameters setting [J]. China Plastics, 2022, 36(1): 84-91.
[13]	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.
[14]	ZHA Yan, ZHENG Fangli, XIAO Jian, YANG Weimin, XIE Pengcheng. Research on the Application of Co⁃simulation in the Reduced Design of Automotive Injection Parts [J]. China Plastics, 2021, 35(8): 112-116.
[15]	WANG Yanqing, KUANG Tangqing, LAI Jiamei, LIU Hesheng, LIU Tian. Preliminary Research on Gas⁃Water⁃assisted Injection Molding Technology [J]. China Plastics, 2021, 35(7): 69-73.