scholarly journals Enhancing the weld line strength of injection molded components

2019 ◽  
Author(s):  
A. Geyer ◽  
C. Bonten
Keyword(s):  
Line Strength ◽  
Weld Line ◽  
Injection Molded

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.

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.

Reinforcement of micro injection molded weld line strength with ultrasonic oscillation

2009 ◽  
Vol 16 (3) ◽  
pp. 399-404 ◽  
Author(s):  
Lei Xie ◽  
Gerhard Ziegmann ◽  
Bingyan Jiang
Keyword(s):  
Line Strength ◽  
Weld Line ◽  
Ultrasonic Oscillation ◽  
Injection Molded

Improvement of Weld Line Strength in Injection Molded FRTP Articles

1988 ◽  
Vol 2 (3-4) ◽  
pp. 131-136 ◽  
Author(s):  
H. Hamada ◽  
Z. Maekawa ◽  
T. Horino ◽  
K. Lee ◽  
K. Tomari
Keyword(s):  
Line Strength ◽  
Weld Line ◽  
Injection Molded

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.

scholarly journals Effect of Melt Temperature on Weld Line Strength

2019 ◽  
Vol 801 ◽  
pp. 264-269
Author(s):  
Karel Raz ◽  
Frantisek Sedlacek
Keyword(s):  
Negative Impact ◽  
Line Strength ◽  
Flow Analysis ◽  
Weld Line ◽  
Melt Temperature ◽  
3D Printed ◽  
Injection Molded ◽  
Plastic Parts ◽  
Injection Molded Plastic ◽  
Mold Flow

This article deals with the influence of the melt temperature on weld line strength in injection-molded plastic parts. A special mold was created for this investigation to make specimens with a central weld line. The experimental material was polypropylene Sabic PP 90910. Its stress at break is around 16 MPa and its melting temperature is between 200°C and 260°C. In general, the presence of weld lines has a negative impact on mechanical properties. This investigation showed that the strength depends on the melt temperature (160–260°C in this case). Strength was measured using mechanical testing. It was found to increase with the melt temperature, up to 210°C. Above 210°C, degradation of the plastic led to decreasing strengths. A melt temperature range of 190–210°C is therefore optimal for this application. Shear forces and friction were found to play a great role, as they raise the melt temperature during molding. This was confirmed by mold-flow analysis. The melt temperature during molding was up to 18% higher than the initial melt temperature. This investigation has important consequences for the plastic industry. It is relevant to evaluations of the polymer matrix strength in composite materials and the strength of 3D printed parts with multiple weld lines.

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