Optimization and experimental verification of injection⁃molding parameters of leather back trim for vehicle

doi:10.19491/j.issn.1001-9278.2025.03.014

Abstract

Abstract:

Taking the rear trim strip of a certain type of car skin as the research object， feature point A on the strip was selected as the warpage observation point， and an “overflow loop” was added along the direction of the material flow at the buckle feature. Mold surface temperature， injection temperature， injection pressure， and pressure holding pressure were selected as the research objects to construct a four⁃factor four⁃level L₁₆ orthogonal experiment. The range analysis was carried out upon 16 groups of data to obtain the most sensitive factors and levels as well as the optimal combination of process parameters. With the optimal combination of parameters， the warpage quantity at the point A reached 5 mm under all effects， which was 30 % lower than that under the tenth group of parameters. The optimal parameters were verified by experiments. The main injection parameters were determined to be a mold surface temperature of 128 ℃， an injection temperature of 330 ℃， an injection pressure of 48 MPa， and a holding pressure of 95 % of the injection pressure. After molding， the appearance of the product was uniform. There was no silver grain， wire drawing， and white injection defects. The feature point A looks smooth over the all transition of the product， meeting the test expectations. After molding， the product can meet the requirement of application. The results verified the accuracy of the Moldflow⁃2023 analysis software and the scientificalness of range analysis.

Key words: mold surface temperature, injection molding temperature, injection pressure, holding pressure, orthogonal test, range analysis

CLC Number:

TQ320.66

HUANG Ke, ZOU Huajie, QIAN Zilong, LI Bingbing. Optimization and experimental verification of injection⁃molding parameters of leather back trim for vehicle[J]. China Plastics, 2025, 39(3): 77-80.

Figures/Tables 10

Fig.1. Leather back trim for a model car

Fig.2. Preset mode flow analysis results

Fig.3. Optimize the finished product structure

Fig.4. Analysis results of mold flow after product optimization

水平	因素
水平	I/℃	J/℃	K/MPa	L/%
1	80	300	40	85
2	104	310	43	90
3	128	320	46	95
4	150	330	48	100

Tab.1. Horizontal table of orthogonal test factors

Fig.5. Warp at point A for all effects in each group

因素	I	J	K	L
A_i₁	40.39	33.76	38.29	38.39
A_i₂	34.35	36.45	35.57	34.91
A_i₃	32.28	39.07	37.06	33.27
A_i₄	35.41	33.15	31.51	35.86
a_i₁	10.10	8.44	9.57	9.60
a_i₂	8.59	9.11	8.89	8.73
a_i₃	8.07	9.77	9.27	8.32
a_i₄	8.85	8.29	7.88	8.97
H	2.03	1.48	1.70	1.28

Tab.2. Range analysis of warpage for all effects（mm）

Fig.6. Modal flow analysis results under optimal parameters after range analysis

Fig.7. Testing site

Fig.8. Test product

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