scholarly journals The influence of blowing agent addition, talc filler content, and injection velocity on selected properties, surface state, and structure of polypropylene injection molded parts

2019 ◽  
Vol 39 (1) ◽  
pp. 3-30 ◽  
Author(s):  
Paweł Palutkiewicz ◽  
Milena Trzaskalska ◽  
Elżbieta Bociąga
Keyword(s):  
Tensile Strength ◽  
Impact Strength ◽  
Filler Content ◽  
Hold Time ◽  
Injection Velocity ◽  
Blowing Agents ◽  
Blowing Agent ◽  
Molded Parts ◽  
Injection Molded ◽  
Injection Cycle

The effects of blowing agent, talc, and injection velocity on properties of polypropylene molded parts were presented. Blowing agent was dosed to plastic in amounts 1–2% and talc 10–20%. The results of selected properties, such as weight, thickness, hardness, impact strength, tensile strength, and gloss, were presented. The article also presents microscopic investigations. The blowing agent and talc content have a large impact on mechanical properties and gloss of parts than addition of blowing agent. The use of the blowing agent in an amount of 2 wt% will allow the reduce injection cycle time by reducing the hold pressure and hold time. Addition of blowing agents lowers of tensile strength, hardness, impact strength, and significantly affected the gloss. Talc filler contributes to a significant increase in the weight of parts, a decrease in hardness, impact strength, and tensile strength. The injection velocity has no significant effect on parts properties.

scholarly journals Tensile and Bending Strength Improvements in PEEK Parts Using Fused Deposition Modelling 3D Printing Considering Multi-Factor Coupling

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2497 ◽  
Author(s):  
Yao Li ◽  
Yan Lou
Keyword(s):  
Tensile Strength ◽  
3D Printing ◽  
Tensile Properties ◽  
Bending Strength ◽  
Utilization Rate ◽  
Fused Deposition Modelling ◽  
Fused Deposition ◽  
Molded Parts ◽  
Injection Molded ◽  
Printing Direction

Compared with laser-based 3D printing, fused deposition modelling (FDM) 3D printing technology is simple and safe to operate and has a low cost and high material utilization rate; thus, it is widely used. In order to promote the application of FDM 3D printing, poly-ether-ether-ketone (PEEK) was used as a printing material to explore the effect of multi-factor coupling such as different printing temperatures, printing directions, printing paths, and layer thicknesses on the tensile strength, bending strength, crystallinity, and grain size of FDM printed PEEK parts. The aim was to improve the mechanical properties of the 3D printed PEEK parts and achieve the same performance as the injection molded counterparts. The results show that when the thickness of the printed layer is 0.1 mm and the printing path is 180° horizontally at 525 °C, the tensile strength of the sample reaches 87.34 MPa, and the elongation reaches 38%, which basically exceeds the tensile properties of PEEK printed parts reported in previous studies and is consistent with the tensile properties of PEEK injection molded parts. When the thickness of the printed layer is 0.3 mm, the printing path is 45°, and with vertical printing direction at a printing temperature of 525 °C, the bending strength of the sample reaches 159.2 MPa, which exceeds the bending performance of injection molded parts by 20%. It was also found that the greater the tensile strength of the printed specimen, the more uniform the size of each grain, and the higher the crystallinity of the material. The highest crystallinity exceeded 30%, which reached the crystallinity of injection molded parts.

Selected Properties and Shrinkage Compensating Effect by Injection Moulding of Origin and Recycled Thermoplastic Composites with Polypropylene (PP) Matrix, Talcum and Glass Fiber

2014 ◽  
Vol 1001 ◽  
pp. 187-193 ◽  
Author(s):  
Aneta Krzyżak ◽  
Marcin Drabik ◽  
Łukasz Zyśko ◽  
Ľudmila Dulebová
Keyword(s):  
Tensile Strength ◽  
Glass Fiber ◽  
Injection Moulding ◽  
Thermoplastic Composites ◽  
Recycling Process ◽  
Polypropylene Composites ◽  
Shrinkage Effect ◽  
Molded Parts ◽  
Injection Molded ◽  
Transverse Shrinkage

This article explains and demonstrates how to first and second injection moulding influence to shrinkage effect of polypropylene composites with talcum and cutting glass fiber. Results show that the longitudinal and transverse shrinkage changed by differend parameters of injection moulding. It was observed shrinkage compensating effect occurring at composite molded parts with a high glass fiber content. Recycling process has reduced the shrinkage and tensile strength. Caused an increase in elongation, but it has not noticed any major changes in the hardness of injection molded parts.

Comparative study of chemical and physical foaming methods for injection-molded thermoplastic polyurethane

2016 ◽  
Vol 53 (4) ◽  
pp. 373-388 ◽  
Author(s):  
Hrishikesh A Kharbas ◽  
Jason D McNulty ◽  
Thomas Ellingham ◽  
Cyrus Thompson ◽  
Mihai Manitiu ◽  
...  
Keyword(s):  
Injection Molding ◽  
Thermoplastic Polyurethane ◽  
Polyurethane Foams ◽  
Average Cell Size ◽  
Average Cell ◽  
Blowing Agents ◽  
Blowing Agent ◽  
Microcellular Injection Molding ◽  
Injection Molded ◽  
Commercial Applications

Thermoplastic polyurethane is one of the most versatile thermoplastic materials being used in a myriad of industrial and commercial applications. Thermoplastic polyurethane foams are finding new applications in various industries including the furniture, automotive, sportswear, and packaging industries because of their easy processability and desirable customizable properties. In this study, three methods of manufacturing injection molded low density foams were investigated and compared: (1) using chemical blowing agents, (2) using microcellular injection molding with N2 as the blowing agent, and (3) using a combination of supercritical gas-laden pellets injection molding foaming technology and microcellular injection molding processes using co-blowing agents CO2 and N2. Thermal, rheological, microscopic imaging, and mechanical testing were carried out on the molded samples with increasing amounts of blowing agents. The results showed that the use of physical blowing agents yielded softer foams, while the use of CO2 and N2 as co-blowing agents helped to manufacture foams with lower bulk densities, better microstructures, and lower hysteresis loss ratios. Chemical blowing agent-foamed thermoplastic polyurethane showed an earlier onset of degradation. The average cell size decreased and the cell density increased with the use of co-blowing agents. A further increase in gas saturation levels showed a degradation of microstructure by cell coalescence.

Effect of Molding Parameters on the Interface Morphology of Metal Co-Injection Molding

2011 ◽  
Vol 189-193 ◽  
pp. 2939-2944
Author(s):  
Hao He ◽  
Yi Min Li ◽  
Guang Yao Wang
Keyword(s):  
Rheological Properties ◽  
Delay Time ◽  
Flow Direction ◽  
Injection Velocity ◽  
Interface Morphology ◽  
Key Factors ◽  
The Core ◽  
Molded Parts ◽  
Injection Molded ◽  
Injection Temperature

In the present study, the effect of injection temperature, velocity and delay time on the interface morphology of the co-injection molded plates was studied. The results showed that the core penetration parallel to the flow direction becomes less as the skin injection velocity and temperature increases and delay time decreases. Among the parameters, temperature was the most significant in affecting the interface morphology, followed by delay time, while injection velocity seemed to play no significant role. The results were analyzed by taking account of rheological properties of the two feedstocks. Calculations and comparisons of viscosity ratios encountered in experiments were made. It was demonstrated the differences in the rheological properties of the metal feedstocks involved are key factors in determining the interface morphology of the molded parts.

Investigations on the Weldline Tensile Strength of Thin-wall Injection Molded Parts

2004 ◽  
Vol 23 (6) ◽  
pp. 575-588 ◽  
Author(s):  
Rean Der Chien ◽  
Shia-Chung Chen ◽  
Hsin-Shu Peng ◽  
Pao-Lin Su ◽  
Chun-Sheng Chen
Keyword(s):  
Tensile Strength ◽  
Thin Wall ◽  
Molded Parts ◽  
Injection Molded ◽  
Wall Injection

Quantitative Study of Shrinkage and Warpage Behavior for Microcellular and Conventional Injection Molding

Materials ◽  
2005 ◽  
Author(s):  
Adam Kramschuster ◽  
Ryan Cavitt ◽  
Don Ermer ◽  
Chris Shen ◽  
Zhongbao Chen ◽  
...  
Keyword(s):  
Injection Molding ◽  
Hold Time ◽  
Fractional Factorial ◽  
Injection Molding Process ◽  
Molding Process ◽  
Injection Speed ◽  
Microcellular Injection Molding ◽  
Molded Parts ◽  
Injection Molded ◽  
Factorial Design Of Experiments

This research investigated the effects of processing conditions on the shrinkage and warpage (S&W) behavior of a box-shaped, polypropylene part using conventional, microcellular, and microcellular co-injection molding. Three sets of 26-1 fractional factorial design of experiments (DOE) were employed to perform the experiments and proper statistical theory was used to analyze the data. After the injection molding process reached steady state, molded samples were collected and measured using an optical coordinate measurement machine (OCMM), which had been evaluated using a proper repeatability and reproducibility (R&R) measurement study. By analyzing the statistically significant main and two-factor interaction effects, the results show that the supercritical fluid (SCF) content (nitrogen in this case, in terms of SCF dosage time) and the injection speed affect the S&W of microcellular injection and microcellular co-injection molded parts the most, whereas pack/hold pressure and pack/hold time have the most significant effect on the S&W of conventional injection molded parts. Also, this study quantitatively showed that, within the processing range studied, a reduction in the S&W could be achieved with the microcellular injection molding and micro- cellular co-injection molding processes.

Microcellular Injection Molding of Gas-Laden Pellets Using Nitrogen (N2) and Carbon Dioxide (CO2) as Co-Blowing Agents

2013 ◽  
Author(s):  
Xiaofei Sun ◽  
Lih-Sheng Turng ◽  
Patrick J. Gorton ◽  
Pankaj Nigam ◽  
Sezen Buell
Keyword(s):  
Injection Molding ◽  
Foam Cell ◽  
Theoretical Background ◽  
Blowing Agents ◽  
Content Ratio ◽  
Microcellular Injection Molding ◽  
Molded Parts ◽  
Injection Molded ◽  
Combination Approach ◽  
Carbon Dioxide Co2

A novel combination approach to producing quality foamed injection molded parts has been investigated. By combining extruded, gas-laden pellets with microcellular injection molding, the processing benefits and material characteristics of using both N2 and CO2 blowing agents can be realized, thus yielding features superior to that of using either N2 or CO2 alone. Using an optimal content ratio for the blowing agents, as well as the proper sequence of introducing the gases, foamed parts with a much better morphology can be produced. In particular, extruding N2 gas-laden pellets, followed by microcellular injection molding with higher amounts of CO2, produces a cellular structure that is very fine and dense. In this paper, the theoretical background is discussed and experimental results show that this combined approach leads to significant improvements in foam cell morphology for low density polyethylene (LDPE), polypropylene (PP), and high impact polystyrene (HIPS) using two different mold geometries.

An Experimental Study of Metal Co-Injection Molding with Sequential Injection

2010 ◽  
Vol 97-101 ◽  
pp. 1116-1119
Author(s):  
Hao He ◽  
Yi Min Li ◽  
Jian Guang Zhang
Keyword(s):  
Experimental Study ◽  
Injection Molding ◽  
Phase Distribution ◽  
Relative Viscosity ◽  
Injection Velocity ◽  
Sequential Injection ◽  
Dissimilar Metal ◽  
Molded Parts ◽  
Injection Molded ◽  
Primary Variable

An experimental study of co-injection molding which involves sequential injection of dissimilar metal feedstocks into a mold has been carried out. The effect of skin temperature and injection velocity on the material distribution of co-injection molded plates has been studied. It was found that the molding temperature was important in controlling skin-core distribution, while injection velocity seemed to play no significant role. The experimental results were analyzed by taking account of the relative viscosity of the two melts. It was demonstrated that the differences in rheological properties of the metal feedstocks involved are the primary variable determining the phase distribution of the molded parts.

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