Weld line strength factors in a reinforced injection molded part: Relationship with predicted fiber orientation

2019 ◽  
Vol 39 (5-6) ◽  
pp. 219-230
Author(s):  
Maria C Quintana ◽  
Patricia Frontini
Keyword(s):  
Fiber Orientation ◽  
Line Strength ◽  
Weld Line ◽  
Process Condition ◽  
Simulation Software ◽  
Process Conditions ◽  
Significant Variable ◽  
Orientation Factor ◽  
Molded Part ◽  
Injection Molded

In this work, the residual strength of a fiber-reinforced injection molded part containing a hot weld line—or meld line—was evaluated. Injected plates were generated using a double-gated mold under four different process conditions. Quantification of the weld line detrimental effect was made in base on a fracture mechanics experiment. Specimens with and without the weld line—obtained from the same plates—were tested under a clamped single edge notched tension (SENT) configuration. For each set of process conditions, a relative weld line strength factor was defined in terms of the maximum applied stress intensity factor (KImax) as: KImax of specimens with weld line/KImax of specimens without weld line. In parallel, the fiber distribution pattern was obtained by process simulation software Moldex3D. An orientation factor was determined from simulation in order to quantify the effect of the local fiber orientation around the weld line. Optimal process condition and the most significant variable influencing the weld line strength were calculated via statistical analysis. Results showed a clear correlation between the weld line strenght factors and the orientaion factor. It was demonstrated that the fracture performance of the weld line region is controlled by the fiber orientation arrangement developed on that zone.

Weld Lining Strength of Injection Molded Jute/PLA and Jute/PP

2012 ◽  
Author(s):  
Cuntao Wang ◽  
Yuqiu Yang ◽  
Masuo Urakami ◽  
Hiroyuki Hamada
Keyword(s):  
Fiber Orientation ◽  
Line Strength ◽  
Weld Line ◽  
Fiber Bundles ◽  
Interfacial Property ◽  
Fiber Distribution ◽  
Molded Parts ◽  
Injection Molded ◽  
Hybrid Mixtures ◽  
Better Than

Weld lines are formed inevitably when two separate melt fronts rejoin during injection molding. It has been reported that weld lines greatly weaken the strength of injection-molded parts. Therefore, in this paper the weld property of injection molded jute /PLA and jute/PP dumbbell shape specimen with weld line was investigated by changing pellets materials. In the study pultrusion technique was adopted to fabricate jute/PLA and jute/PP long fiber pellets (LFT) and it was found that fiber bundles in LFT specimens were not separated and dispersed well. As a result, in this paper re-compound pellets of LFT, i.e. RP was made. Then LFT, RP, and hybrid mixtures with the hybrid ratios of LFT50:RP50 were used to mold dumbbell shape specimens with or without weld line. In particular, the influence of different pellets on weld line strength of injection molded jute/PLA and jute/PP dumbbell shape specimens with weld line was discussed based on tensile test and SEM observation. It was found that tensile strength of RP specimens was higher than that of LFT both for jute/PLA and jute/PP, because fiber distribution and interfacial property of RP was much better than that of LFT. Weld line strength of RP was improved than that of LFT both for jute/PLA and jute/PP. RP of jute/PLA was more effective to improve the weld property than that of jute/PP. Weld line strength of jute/PP LFT increased as holding pressure increased from 44 to 88 MPa and decreased at 132 MPa holding pressure. It depends on the co-effect of fiber orientation and voids content.

Development of the layered structure in a double-gated glass fiber-reinforced polypropylene injection molding: Experimental and simulated results

2018 ◽  
Vol 37 (14) ◽  
pp. 945-959 ◽  
Author(s):  
MC Quintana ◽  
MP Frontini
Keyword(s):  
Glass Fiber ◽  
Layered Structure ◽  
Fiber Orientation ◽  
Flow Direction ◽  
Weld Line ◽  
Orientation Distribution ◽  
Simulation Software ◽  
Distribution Data ◽  
Melt Temperature ◽  
Fiber Orientation Distribution

The present study aims to experimentally validate numerical simulation of fiber orientation distribution performed by molding simulation software Moldex3D in a double-gated injection-molded glass fiber-filled (40 wt%) polypropylene box, by making a detailed comparison of predicted and experimentally measured fiber orientation distribution data. The modeling approach evaluated in this work consists in the implementation of the Folgar–Tucker rotary diffusion model with the invariant-based optimal fitting closure approximation for the fourth-order orientation tensor. The specimen used has a weld line in the center and sharp corners. This investigation characterizes in detail the development of the through-thickness layered structure at distinctive locations of the specimen. The sensitivity of fiber orientation distribution and the layered structure to changes upon injection time and melt temperature is also evaluated. The boxes display the typical layered laminate structure, with fibers aligned in the main flow direction near the walls (shell layer) and less oriented in the middle plane (core layer). The boxes injected at the lowest melt temperature display an additional skin layer. Unfortunately, simulation fails in predicting the five layers structure developed under these latter conditions. The grade of fiber orientation is deemed to be independent of process parameters but not the layered structure.

scholarly journals Effect of Melt Temperature and Hold Pressure on the Weld-Line Strength of an Injection Molded Talc-Filled Polypropylene

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Yuanxin Zhou ◽  
P. K. Mallick
Keyword(s):  
Line Strength ◽  
Weld Line ◽  
Yield Strain ◽  
Stress Strain ◽  
Melt Temperature ◽  
Strain Behavior ◽  
The Core ◽  
Nonlinear Constitutive Model ◽  
Softening Behavior ◽  
Injection Molded

Tensile stress-strain behavior coupled with fractography was used to investigate the weld-line strength of an injection molded 40 w% talc-filled polypropylene. The relationship between processing conditions, microstructure, and tensile strength was established. Fracture surface of the weld line exhibited skin-core morphology with different degrees of talc particle orientations in the core and in the skin. Experimental results also showed that the thickness of the core decreased and the thickness of the skins increased with increasing melt temperature and increasing hold pressure, which resulted in an increase of yield strength and yield strain with increasing melt temperature and increasing hold pressure. Finally, a three-parameter nonlinear constitutive model was developed to describe the strain softening behavior of the weld-line strength of talc-filled polypropylene. The parameters in this model are the modulus E, the strain exponent m, and the compliance factor β. The simulated stress-strain curves from the model are in good agreement with the test data, and both m and β are functions of skin-core thickness ratio.

The application of fuzzy theory for the control of weld line positions in injection-molded part

2008 ◽  
Vol 47 (1) ◽  
pp. 119-126 ◽  
Author(s):  
Mei-Yung Chen ◽  
Huan-Wen Tzeng ◽  
Yi-Cheng Chen ◽  
Shia-Chung Chen
Keyword(s):  
Fuzzy Theory ◽  
Weld Line ◽  
Molded Part ◽  
Injection Molded ◽  
Line Positions

scholarly journals Desulfurization Of The Dibenzothiophene (DBT) By Using Imidazolium-Based Ionic Liquids(Ils)

2019 ◽  
Vol 1 (2) ◽  
pp. 1
Author(s):  
Bilal Kazmi ◽  
Awan Zahoor ◽  
Hashmi Saud ◽  
Zafar Khan Ghouri
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Process Condition ◽  
Chemical Properties ◽  
Aspen Plus ◽  
Extraction Process ◽  
Simulation Software ◽  
Liquid Fuels ◽  
Process Conditions ◽  
Model Diesel

In this work we examined the industrial scale extraction process of ultra-low sulfur diesel with the help of simulation software ASPEN Plus®. This work focuses on the [Cnmim] [BF4] (imidazolium-based) ionic liquid and employed it in the extractive desulfurization of the dibenzothiophene (DBT) from the model diesel fuel under a very mild process condition. UNIFAC (uniquasi functional activity) was chosen as the thermodynamic method to model the ionic liquid on ASPEN Plus® and different physical and chemical properties were then taken from the literature to be incorporated in the simulation model. Different parametric analysis was studied for the removal of thiophene-based compounds from the model diesel. The results acquired shows the significance of imidazolium-based ionic liquids (ILs) for the extraction of S-contents from the liquid fuels at an optimal process conditions of 40 ℃ and 2 bar pressure with the 2.8: 1 ratio of ionic liquid and model diesel which validates the experimental results obtained previously in the literature.

scholarly journals The simulation of volume shrinkage for double-injection molding with PC and ABS

2018 ◽  
Vol 192 ◽  
pp. 01053
Author(s):  
Pichai Leklong ◽  
Wipoo sriseubsai
Keyword(s):  
Injection Molding ◽  
Weld Line ◽  
Acrylonitrile Butadiene Styrene ◽  
Volume Shrinkage ◽  
Melt Temperature ◽  
Double Injection ◽  
Molded Part ◽  
Packing Pressure ◽  
Injection Molded ◽  
Plastic Injection

The objective of this paper was to study and analyze the plastic injection molding parameters to reduce the volume shrinkage of double injection molded part. The specimen was molded with Acrylonitrile-butadiene-styrene (ABS) after Polycarbonate was molded as a half part. The weld line occurred at the haft of the molded part. The simulation with Moldex 3D R13 and the design of experiment with Taguchi method was used to perform the experiments and analyze the data to get the optimum of volume shrinkage. The results showed that melt temperature and packing pressure was significant to the volume shrinkage. When using low melt temperature and high packing pressure, the shrinkage was low and related to the thermal expansion of the material. It would be one of the parameters to the design of double injection molding.

Fiber Orientation State Depending on the Injection Mold Gate Variations during FRP Injection Molding

2006 ◽  
Vol 321-323 ◽  
pp. 938-941 ◽  
Author(s):  
Jin Woo Kim ◽  
Dong Gi Lee
Keyword(s):  
Fiber Orientation ◽  
Weld Line ◽  
Polymeric Composite ◽  
Mold Temperature ◽  
Flow Speed ◽  
Intensity Difference ◽  
Injection Mold ◽  
Line Formation ◽  
Orientation State ◽  
Injection Molded

Because of orientation and separation, injection molded products are heterogeneous and anisotropic. These heterogeneousness and anisotropy have a vast influence on mechanical properties of molding material and product characteristics. It is well known that fiber orientation state in fiber-reinforced polymeric composite has a profound effect on dynamic qualities like intensity, rigidity, and etc. To measure the fiber orientation of injection molded product's weld part, we first X-rayed moldings and recognized this photo by using an image scanner. Then, image processing method, which uses intensity difference in measuring fiber orientation state, is applied. Through these procedures, we can analyze the influence of molding's fiber orientation state according to mold gate changes. Fiber orientation is related mainly with the mold gate positions than with fiber content or mold temperature. When the distance from the gate increases, by matrix and reinforcement's flow speed differences, fiber orientation occurred. As diversion flow occurred at the end of fluid flow, fiber oriented at a right angle to the flow, and this is the same effect of weld line formation.

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