scholarly journals A Design of Experiment Approach for Surface Roughness Comparisons of Foam Injection-Moulding Methods

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2358
Author(s):  
Gethin Llewelyn ◽  
Andrew Rees ◽  
Christian Griffiths ◽  
Martin Jacobi
Keyword(s):  
Surface Roughness ◽  
Injection Moulding ◽  
Surface Defects ◽  
Mechanical Performance ◽  
Processing Parameters ◽  
Melt Temperature ◽  
Foaming Agents ◽  
Pressure Surface ◽  
Blowing Agent ◽  
Physical And Chemical

The pursuit of polymer parts produced through foam injection moulding (FIM) that have a comparable surface roughness to conventionally processed components are of major relevance to expand the application of FIM. Within this study, 22% talc-filled copolymer polypropylene (PP) parts were produced through FIM using both a physical and chemical blowing agent. A design of experiments (DoE) was performed whereby the processing parameters of mould temperatures, injection speeds, back-pressure, melt temperature and holding time were varied to determine their effect on surface roughness, Young’s modulus and tensile strength. The results showed that mechanical performance can be improved when processing with higher mould temperatures and longer holding times. Also, it was observed that when utilising chemical foaming agents (CBA) at low-pressure, surface roughness comparable to that obtained from conventionally processed components can be achieved. This research demonstrates the potential of FIM to expand to applications whereby weight saving can be achieved without introducing surface defects, which has previously been witnessed within FIM.

Production of components through microcellular processing

2021 ◽  
Author(s):  
◽  
Gethin John Llewelyn
Keyword(s):  
Surface Roughness ◽  
Injection Moulding ◽  
Mechanical Performance ◽  
Processing Parameters ◽  
Experimental Results ◽  
Simulation Accuracy ◽  
Foaming Agents ◽  
Blowing Agents ◽  
Blowing Agent ◽  
Microcellular Foams

The manufacture of light weight plastic components is gaining relevance within the polymer industry as component weight savings of up to 15% can be achieved. Foam Injection Moulding (FIM) is one technology solution that delivers weight saving through the introduction of microcellular structures within components. FIM differs from conventional injection moulding whereby blowing agents are added to the polymer during processing to create a cellular structure. The first part of this research aims to benchmark Unfilled and Talc-filled Copolymer Polypropylene (PP) samples through low-pressure FIM. The research analyses the process response when utilising a chemical blowing agent, a physical blowing agent and a novel hybrid foaming (combination of said chemical and physical foaming agents). The experimental results concluded that Unfilled PP foams produced through chemical blowing agent exhibited superior mechanical characteristics due to larger skin wall thicknesses. However, the hybrid foaming produced superior microcellular foams for both PP variations due to calcium carbonate (CaCO3) enhancing the nucleation phase. The next section of research initially varied then subsequently optimised the main processing parameters to determine their effect on Surface Roughness, Young’s Modulus and Tensile Strength. The experimental results show that the mechanical performance can be improved when processing with higher Mould Temperatures and longer Holding Times. Also, when utilising the CBA, surface roughness is comparable to conventionally processed components. The final stage of the research investigated the ability of an industry standard simulation package to accurately predict the process response when processing with a variety of blowing agents. Initial simulations results failed to accurately replicate physical mouldings which can be attributed to microcellular structure overestimations within the simulation. Through an iterative process, simulation settings have been identified that provide clear correlations to improve the simulation accuracy of FIM.

An empirical study of gas penetration in full-shot gas-assisted injection moulded parts

2002 ◽  
Vol 216 (12) ◽  
pp. 1549-1559 ◽  
Author(s):  
S-J Liu ◽  
K-H Chang
Keyword(s):  
Injection Moulding ◽  
Bending Strength ◽  
Hold Time ◽  
Gas Injection ◽  
Processing Parameters ◽  
Melt Temperature ◽  
Relative Significance ◽  
Short Shot ◽  
Gas Penetration ◽  
Sink Mark

Full-shot gas-assisted injection moulding has increasingly become one of the most important methods used to produce plastic components. It has the advantage of eliminating the switchover mark, which usually occurs on the surface of short-shot gas-assisted injection moulded parts. This paper is devoted to an investigation of the effects of different processing parameters on the length of gas penetration in full-shot gas-assisted injection moulded parts. The first part of this report shows how the gas penetration of moulded parts is optimized. An L'18 experimental matrix design based on the Taguchi method was conducted to investigate the processing factors that affect the length of gas penetration in full-shot moulded parts. The second part of this paper identifies the relative significance of each processing parameter on the gas penetration of moulded products. The materials used were general-purpose polystyrene and polypropylene. Experiments were carried out on an 80 ton injection-moulding machine equipped with a high-pressure nitrogen gas injection unit. For the factors selected in the main experiments, melt temperature, gas injection delay time and gas hold time were found to be the key processing parameters affecting the length of gas penetration in full-shot gas-assisted injection moulded parts. In addition, the sink mark of full-shot moulded parts decreases with the length of gas penetration. Bending strength of full-shot gas-assisted injection moulded parts is higher than that of short-shot moulded parts.

scholarly journals Processing parameters Optimization of Injection Moulding in DN20 Vent of Water Meter Manufacturing

2020 ◽  
Vol 184 ◽  
pp. 01008
Author(s):  
N. Sateesh ◽  
S. Devakar Reddy ◽  
Ram Subbiah ◽  
D. Siva Nagaraju ◽  
BCh Nookaraju
Keyword(s):  
Cycle Time ◽  
Injection Moulding ◽  
Processing Parameters ◽  
Volumetric Shrinkage ◽  
Shop Floor ◽  
Quality Prediction ◽  
Injection Time ◽  
Mould Temperature ◽  
Melt Temperature ◽  
Water Meter

The conventional optimization process in Injection Moulding includes actual shop floor trials in which melt temperature, mould temperature, injection time, injection pressure, pattern, feeder size, shape and location cores, mould layout, gating etc. are changed in each iteration which involves high machining cost, tooling cost, modification cost, melting cost, and transportation cost as well as, materials, energy, time are wasted in each trial until and unless the required results are obtained. Water meter component (DN20 Vent) is designed in CREO 5.0, and then components are 3D printed to cross check the dimensions and also to confirm whether all the other components can be accommodated or not. Then the mould flow analysis will be performed on a water meter components using different materials and changing the processing parameters. The input processing parameters considered are melt temperature, mould temperature and injection time, whereas the responses are warpage, volumetric shrinkage, cycle time and quality prediction. Grey relational analysis is carried out to determine the optimum injection moulding processing parameters.. The effort has been made to minimize the warpage, volumetric shrinkage, cycle time and maximize the quality prediction mould cavity and core for the components are designed in CREO 5.0 and manufactured using P20 tool steel. Then the water meter components are manufactured by inputting the optimal processing parameters in injection moulding machine to achieve high productivity and quality.

A new method for quantifying the blocking of coated paperboard

TAPPI Journal ◽  
2010 ◽  
Vol 9 (5) ◽  
pp. 29-35 ◽  
Author(s):  
PAULINE SKILLINGTON ◽  
YOLANDE R. SCHOEMAN ◽  
VALESKA CLOETE ◽  
PATRICE C. HARTMANN
Keyword(s):  
Surface Roughness ◽  
Fatty Acid ◽  
Surface Energy ◽  
Film Thickness ◽  
External Factors ◽  
Additive Concentration ◽  
Pressure Surface ◽  
Fatty Acid Amides ◽  
Coated Surfaces ◽  
Definite Period

Blocking is undesired adhesion between two surfaces when subjected to pressure and temperature constraints. Blocking between two coated paperboards in contact with each other may be caused by inter-diffusion, adsorption, or electrostatic forces occurring between the respective coating surfaces. These interactions are influenced by factors such as the temperature, pressure, surface roughness, and surface energy. Blocking potentially can be reduced by adjusting these factors, or by using antiblocking additives such as talc, amorphous silica, fatty acid amides, or polymeric waxes. We developed a method of quantifying blocking using a rheometer. Coated surfaces were put in contact with each other with controlled pressure and temperature for a definite period. We then measured the work necessary to pull the two surfaces apart. This was a reproducible way to accurately quantify blocking. The method was applied to determine the effect external factors have on the blocking tendency of coated paperboards, i.e., antiblocking additive concentration, film thickness, temperature, and humidity.

OPTIMISATION OF SAND CASTING PROCESS FOR IMPELLER USING TAGUCHI METHODOLOGY

2020 ◽  
Vol XVII (2) ◽  
pp. 23-33
Author(s):  
Faisal Hafeez ◽  
Salman Hussain ◽  
Wasim Ahmad ◽  
Mirza Jahanzaib
Keyword(s):  
Surface Roughness ◽  
Surface Defects ◽  
A356 Alloy ◽  
Casting Process ◽  
Sand Casting ◽  
Gate Length ◽  
Taguchi Methodology ◽  
Confirmatory Tests ◽  
Binder Ratio ◽  
Response Measures

This paper presents the study to investigate the effects of binder ratio, in-gate length and pouring height on hardness, surface roughness and casting defects of sand casting process. Taguchi methodology with L9 orthogonal array was employed to design the experimentation. Sand casting of six blade impeller using A356 alloy was performed and empirical models for all the above response measures were formulated. Confirmatory tests and analysis of variance results confirmed the accuracy of the model. Binder ratio was found to be the most significant parameter affecting casting surface defects and surface roughness. This was followed by pouring height and in-gate length.

scholarly journals Smoothing additive manufactured parts using ns-pulsed laser radiation

2021 ◽  
Author(s):  
Florian Kuisat ◽  
Fernando Lasagni ◽  
Andrés Fabián Lasagni
Keyword(s):  
Surface Roughness ◽  
Mechanical Performance ◽  
State Of The Art ◽  
Pulsed Laser ◽  
Industrial Applications ◽  
Laser Source ◽  
Pulsed Laser Radiation ◽  
Current State ◽  
The Impact

AbstractIt is well known that the surface topography of a part can affect its mechanical performance, which is typical in additive manufacturing. In this context, we report about the surface modification of additive manufactured components made of Titanium 64 (Ti64) and Scalmalloy®, using a pulsed laser, with the aim of reducing their surface roughness. In our experiments, a nanosecond-pulsed infrared laser source with variable pulse durations between 8 and 200 ns was applied. The impact of varying a large number of parameters on the surface quality of the smoothed areas was investigated. The results demonstrated a reduction of surface roughness Sa by more than 80% for Titanium 64 and by 65% for Scalmalloy® samples. This allows to extend the applicability of additive manufactured components beyond the current state of the art and break new ground for the application in various industrial applications such as in aerospace.

scholarly journals Chemical and physical interactions of regenerated cellulose yarns and isocyanate-based matrix systems

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bernhard Ungerer ◽  
Ulrich Müller ◽  
Antje Potthast ◽  
Enrique Herrero Acero ◽  
Stefan Veigel
Keyword(s):  
Mechanical Performance ◽  
Tensile Force ◽  
Tensile Modulus ◽  
Tensile Tests ◽  
Size Exclusion ◽  
Regenerated Cellulose ◽  
Hydrolytic Cleavage ◽  
Yarn Twist ◽  
Exclusion Chromatography ◽  
Physical And Chemical

AbstractIn the development of structural composites based on regenerated cellulose filaments, the physical and chemical interactions at the fibre-matrix interphase need to be fully understood. In the present study, continuous yarns and filaments of viscose (rayon) were treated with either polymeric diphenylmethane diisocyanate (pMDI) or a pMDI-based hardener for polyurethane resins. The effect of isocyanate treatment on mechanical yarn properties was evaluated in tensile tests. A significant decrease in tensile modulus, tensile force and elongation at break was found for treated samples. As revealed by size exclusion chromatography, isocyanate treatment resulted in a significantly reduced molecular weight of cellulose, presumably owing to hydrolytic cleavage caused by hydrochloric acid occurring as an impurity in pMDI. Yarn twist, fibre moisture content and, most significantly, the chemical composition of the isocyanate matrix were identified as critical process parameters strongly affecting the extent of reduction in mechanical performance. To cope with the problem of degradative reactions an additional step using calcium carbonate to trap hydrogen ions is proposed.

scholarly journals Enhanced Tensile Strength of Monolithic Epoxy with Highly Dispersed TiO2-Graphene Nanocomposites

2021 ◽  
Vol 5 (7) ◽  
pp. 191
Author(s):  
Yanshuai Wang ◽  
Siyao Guo ◽  
Biqin Dong ◽  
Feng Xing
Keyword(s):  
Tensile Strength ◽  
Epoxy Resin ◽  
Mechanical Performance ◽  
Chemical Properties ◽  
High Mechanical Property ◽  
Graphene Nanocomposites ◽  
Highly Dispersed ◽  
Dispersion State ◽  
Physical And Chemical

The functionalization of graphene has been reported widely, showing special physical and chemical properties. However, due to the lack of surface functional groups, the poor dispersibility of graphene in solvents strongly limits its engineering applications. This paper develops a novel green “in-situ titania intercalation” method to prepare a highly dispersed graphene, which is enabled by the generation of the titania precursor between the layer of graphene at room temperature to yield titania-graphene nanocomposites (TiO2-RGO). The precursor of titania will produce amounts of nano titania between the graphene interlayers, which can effectively resist the interfacial van der Waals force of the interlamination in graphene for improved dispersion state. Such highly dispersed TiO2-RGO nanocomposites were used to modify epoxy resin. Surprisingly, significant enhancement of the mechanical performance of epoxy resin was observed when incorporating the titania-graphene nanocomposites, especially the improvements in tensile strength and elongation at break, with 75.54% and 176.61% increases at optimal usage compared to the pure epoxy, respectively. The approach presented herein is easy and economical for industry production, which can be potentially applied to the research of high mechanical property graphene/epoxy composite system.

scholarly journals Long-fibre reinforced polymer composites by 3D printing: influence of nature of reinforcement and processing parameters on mechanical performance

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Francis Dantas ◽  
Kevin Couling ◽  
Gregory J. Gibbons
Keyword(s):  
Carbon Fibre ◽  
Polymer Composites ◽  
Mechanical Performance ◽  
Flexural Modulus ◽  
Matrix Material ◽  
Processing Parameters ◽  
Fibre Reinforcement ◽  
Reinforced Polymer ◽  
Unreinforced Material ◽  
Fibre Reinforced Polymer

Abstract The aim of this study was to identify the effect of material type (matrix and reinforcement) and process parameters, on the mechanical properties of 3D Printed long-fibre reinforced polymer composites manufactured using a commercial 3D Printer (Mark Two). The effect of matrix material (Onyx or polyamide), reinforcement type (Carbon, Kevlar®, and HSHT glass), volume of reinforcement, and reinforcement lay-up orientation on both Ultimate Tensile Strength (UTS) and Flexural Modulus were investigated. For Onyx, carbon fibre reinforcement offered the largest increase in both UTS and Flexural Modulus over unreinforced material (1228 ± 19% and 1114 ± 6% respectively). Kevlar® and HSHT also provided improvements but these were less significant. Similarly, for Nylon, the UTS and Flexural Modulus were increased by 1431 ± 56% and 1924 ± 5% by the addition of carbon fibre reinforcement. Statistical analysis indicated that changing the number of layers of reinforcement had the largest impact on both UTS and Flexural Strength, and all parameters were statistically significant.

The Use of Metallography for Examination of Causes of Surface Defects on Visual Parts

2017 ◽  
Vol 270 ◽  
pp. 107-111
Author(s):  
Zuzana Andršová ◽  
Pavel Kejzlar
Keyword(s):  
Sample Preparation ◽  
Cross Section ◽  
Surface Defects ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Visual Appearance ◽  
Visual Defects ◽  
Physical And Chemical ◽  
Microscopic Techniques ◽  
And Chemical Properties

Many of currently manufactured components intended for automotive, must not only meet the requirements on functionality, but also considerable demands on the visual appearance. Parts are subjected to thorough inspection and suppliers are forced to deal with causes of a very slight visual defects. When examining the defects, it is necessary to use a whole range of advanced analytical methods and procedures previously used only for identification of the physical and chemical properties and structure of the material. This paper deals with several examples which have been solved. It focuses especially on the use of demanding metallographic sample preparation from components with surface defects, examining the defects on the cross-section using mainly microscopic techniques and determining the causes of their generation. These results then serve as a basis for modification of the technology and thus they are the tool for significant reduction of amount of NOK parts.

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