Applications of Core Retraction in Manufacturing Low-Density Polypropylene Foams with Microcellular Injection Molding

2018 ◽  
Vol 37 (1) ◽  
pp. 1-20
Author(s):  
Hrishikesh Kharbas ◽  
Thomas Ellingham ◽  
Lih-Sheng Turng
Keyword(s):  
Mechanical Properties ◽  
Injection Molding ◽  
Tensile Properties ◽  
Weight Reduction ◽  
Low Density ◽  
Cavity Volume ◽  
The Core ◽  
Process Use ◽  
Incomplete Filling ◽  
Microcellular Injection Molding

Without modifying existing part and mold designs, the conventional microcellular injection molding (MIM) process can typically save about 5–10% material without encountering problems such as incomplete filling, excessive shrinkage, or deteriorating microstructure and mechanical properties. In this study core retraction was used in combination with the MIM process to produce thick polypropylene (PP) parts (up to 7.6 mm thick) with high density reductions of 30% and 55%. The cavity volume was modified by changing the retraction distance, which enabled control of density reductions. The lowest densities were achieved with this core retraction-aided microcellular injection molding (CR-MIM) process, the results of which could not have been achieved by the conventional MIM process alone. The effects of delay time in core retraction and weight reduction on the microstructure of the core and skin layers were investigated. It was shown that the CR-MIM process yielded better microstructure and tensile properties than the conventional MIM process. Use of core retraction also yielded more consistent densities and tensile properties throughout the length of the foamed parts.

LUCEFIN C20

Alloy Digest ◽  
2021 ◽  
Vol 70 (3) ◽  
Keyword(s):  
Mechanical Properties ◽  
Physical Properties ◽  
Tensile Properties ◽  
Alloy Steel ◽  
Heat Treating ◽  
Low Carbon ◽  
Wear Resistant ◽  
The Core

Abstract Lucefin C20 is a low-carbon, non-alloy steel that is used in the normalized, cold finished, or quenched and tempered condition. It may also be used in the carburized or carbonitrided, and subsequently quench hardened and tempered, condition for parts requiring a hard wear-resistant surface, but with little need for increased mechanical properties in the core. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on forming, heat treating, machining, and joining. Filing Code: CS-209. Producer or source: Lucefin S.p.A..

Effects of microcrystalline cellulose on the mechanical properties of low-density polyethylene composites

2018 ◽  
Vol 32 (3) ◽  
pp. 297-311 ◽  
Author(s):  
Yousef Ahmad Mubarak ◽  
Raghda Talal Abdulsamad
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Impact Strength ◽  
Tensile Properties ◽  
Microcrystalline Cellulose ◽  
Weight Fraction ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Ldpe Composites ◽  
The Impact

This work was intended to provide an understanding of the effect of microcrystalline cellulose (MCC) on the mechanical properties of low-density polyethylene (LDPE). The impact resistance and the tensile properties of low-density LDPE/MCC composites were investigated. The weight fraction of MCC was varied at (0, 0.5, 1, 2.5, 5, 10, 20, and 30 wt%). The obtained blends were then used to prepare the required tensile and impact testing samples by hot compression molding technique. It has been found that MCC has a strong influence on the mechanical properties of LDPE. At a low MCC weight fraction, there was a little improvement in the ultimate strength, fracture stress, and elongation at break, but at a high MCC weight fraction, the tensile properties were deteriorated and reduced significantly. The addition of 1 wt% MCC to LDPE enhanced the mentioned properties by 10, 25, and 6%, respectively. While at 30 wt% MCC, these properties were lowered by 36, 25, and 96%. The elastic modulus of LDPE composites was improved on all MCC weight fractions used in the study, at 20 wt% MCC, an increase in the elastic modulus by 12 folds was achieved. On the other hand and compared with the impact strength of pure LDPE, the addition of MCC particles enhanced the impact strength, the highest value obtained was for LDPE composites filled with 10 wt% MCC where the impact strength enhanced by two folds.

Influence of Injection Molding Parameters on Mechanical Properties of Low Density Polyethylene Filled With Multiwalled Carbon Nanotubes

2011 ◽  
Author(s):  
Catalin Fetecau ◽  
Felicia Stan ◽  
Daniel Dobrea ◽  
Dan Catalin Birsan
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Injection Molding ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Flow Direction ◽  
Mold Temperature ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Melt Temperature

In this paper, we investigated the effect of injection molding parameters such as melt temperature, mold temperature, injection speed and holding pressure on the mechanical properties of low density polyethylene reinforced with 2.5 wt% multi-walled carbon nanotubes. The Taguchi methodology with four factors and two levels was used for the design of the injection molding experiments. The mechanical properties were evaluated by tensile tests in the flow direction at room temperature (23 °C) at crosshead speeds of 1 and 5 mm/min. It was found that the mechanical properties can be modified by manipulating the injection molding parameters. The Young’s modulus of the LDPE-MWNTs composite decreased as the melt temperature increased, while mold temperature, injection molding speed and holding pressure have a moderate influence on the Young’s modulus.

scholarly journals Analysis of the Influence of Microcellular Injection Molding on the Environmental Impact of an Industrial Component

2014 ◽  
Vol 6 ◽  
pp. 793269 ◽  
Author(s):  
Daniel Elduque ◽  
Isabel Clavería ◽  
Ángel Fernández ◽  
Carlos Javierre ◽  
Carmelo Pina ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Environmental Impact ◽  
Injection Molding ◽  
Flexural Modulus ◽  
Green Manufacturing ◽  
Flexural Properties ◽  
Special Device ◽  
Injection Process ◽  
Microcellular Injection Molding ◽  
Green Manufacturing Technology

Microcellular injection molding is a process that offers numerous benefits due to the internal structure generated; thus, many applications are currently being developed in different fields, especially home appliances. In spite of the advantages, when changing the manufacturing process from conventional to microcellular injection molding, it is necessary to analyze its new mechanical properties and the environmental impact of the component. This paper presents a deep study of the environmental behavior of a manufactured component by both conventional and microcellular injection molding. Environmental impact will be evaluated performing a life cycle assessment. Functionality of the component will be also evaluated with samples obtained from manufactured components, to make sure that the mechanical requirements are fulfilled when using microcellular injection molding. For this purpose a special device has been developed to measure the flexural modulus. With a 16% weight reduction, the variation of flexural properties in the microcellular injected components is only 6.8%. Although the energy consumption of the microcellular injection process slightly increases, there is an overall reduction of the environmental burden of 14.9% in ReCiPe and 15% in carbon footprint. Therefore, MuCell technology can be considered as a green manufacturing technology for components working mainly under flexural load.

Influence of Packing Phase Parameters in the Optimization of Mechanical, Weight Reduction and Dimensional Properties of Microcellular Foaming Injection Molding of Polypropilene

2012 ◽  
Vol 445 ◽  
pp. 319-324 ◽  
Author(s):  
Angel Fernandez ◽  
Manuel Muniesa
Keyword(s):  
Mechanical Properties ◽  
Injection Molding ◽  
Weight Reduction ◽  
Mechanical Performance ◽  
Process Window ◽  
Foam Density ◽  
Microcellular Foam ◽  
Molded Part ◽  
Microcellular Foaming ◽  
Conventional Injection Molding

Microcellular foaming of injected plastics offers the possibility to manufacture parts with reductions in costs and weight if compared with conventional injection molding. For this reason there is an increasing interest in challenging applications such as HEV (hybrid and electrical vehicles) and lightweight material applications in general. Complexity of microcellular injection molding is very high because the final properties of the material obtained depend largely on the processing conditions and these in turn unalterable factors such as mold design and manufacturing. The shrinkage of the molded part must be applied as an oversize of the mold cavity in the design phase. Shrinkage of a microcellular foam depends on the reduction of foam density. Moreover, the piece is designed to get a mechanical performance and meet the dimensional tolerances. Knowing that the reduction of foam density implies a reduction of the mechanical properties and influences the final piece dimensions the conclusion is that the microcellular injection process has a very small process window to fit all these factors. This research focuses on two objectives. First is the variation of post-molding shrinkage in terms of reduction of weight to determine the process window. Second is the determination of mechanical properties which do not show a proportional reduction but exponentially with weight reduction components. The results obtained with a 750 Tons. injection moulding machine equipped with a MuCell plastication unit and a large spiral mold have shown small variations in the dimensions for a predetermined process window and smaller reduction of mechanical properties with weight reductions for 20% talc filled polypropylene. The goal of this applied research is that all experiments have been developed with scaled-industry tools (large injection molding machine, Mucell unit and mold and test parts) comparing with conventional injection molding.

Effects of Filler Incorporation Routes on Mechanical Properties of Low Density Polyethylene/Natural Rubber/Silica (LDPE/NR/Si) Composites

2014 ◽  
Vol 679 ◽  
pp. 154-157 ◽  
Author(s):  
Pei Ying Teoh ◽  
Abdulbaset Mohamed Erfeida ◽  
Xuan Viet Cao ◽  
Du Ngoc Uy Lan
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Tensile Properties ◽  
Low Density Polyethylene ◽  
Tensile Fracture ◽  
Low Density ◽  
Tensile Fracture Surface ◽  
Roll Mill ◽  
Typical Morphology ◽  
Internal Mixer

Low density polyethylene (LDPE) and natural rubber (NR) filled silica composites were prepared by using internal mixer (Brabender) at 150°C and 50 rpm for 10 minutes. Silica was incorporated into polymer matrix by three mixing routes by using Brabender. In mixing I, filler was added into LDPE/NR blend. In mixing II, filler was added prior to LDPE, which was further compounded with NR. In mixing III, filled was pre-dispersed into NR using two-roll mill, after that the compound is blended with LDPE. The effects of filler incorporation routes on the morphological and tensile properties of prepared composites were studied. Observation from SEM result showed that silica tended to localize in NR phase than LDPE phase in the composite. In addition, silica filled LDPE/NR composite exhibited the highest tensile strength in mixing II and lowest in mixing III. Tensile fracture surface of the composites showed typical morphology of LDPE and NR phase depending on mixing methods. KEYWORDS: LDPE/NR, silica, mixing order, tensile properties, morphology

LUCEFIN C16E (1.1148), C16R (1.1208)

Alloy Digest ◽  
2021 ◽  
Vol 70 (1) ◽  
Keyword(s):  
Mechanical Properties ◽  
Physical Properties ◽  
Tensile Properties ◽  
Heat Treating ◽  
Case Hardening ◽  
Low Carbon ◽  
The Core

Abstract Lucefin C16E and C16R are low-carbon, non-alloy case-hardening steels that are used in the carburized or carbonitrided, and subsequently quench hardened and tempered, condition. These steels are, in general, used for parts requiring a hard wearresistant surface, but with little need for increased mechanical properties in the core. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on forming, heat treating, machining, and joining. Filing Code: CS-208. Producer or source: Lucefin S.p.A.

Mechanical Recycling of Low-Density Polyethylene/Carbon Nanotube Composites and its Effect on Material Properties

2019 ◽  
Author(s):  
Felicia Stan ◽  
Nicoleta-Violeta Stanciu ◽  
Catalin Fetecau ◽  
Ionut-Laurentiu Sandu
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotube ◽  
Injection Molding ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Mechanical Recycling ◽  
Multi Walled Carbon Nanotube ◽  
Nanotube Composites ◽  
Carbon Nanotube Composites ◽  
The Impact

Abstract In this paper, the impact of recycling and remanufacturing on the behavior of low-density polyethylene/multi-walled carbon nanotube (LDPE/MWCNT) composites is investigated. LDPE/MWCNT composites with 0.1–5 wt.%, previously manufactured by injection molding, were mechanically recycled and remanufactured by injection molding and 3D filament extrusion, and the rheological, electrical, and mechanical properties were analyzed and compared with those of virgin composites under the same conditions. Experimental results demonstrate that the recycled LDPE/MWCNT composites have similar rheological, electrical, and mechanical properties to virgin composites, if not better. Therefore, the recycled LDPE/MWCNT composites have a great potential for being used in engineering applications, while reducing the environmental impact.

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