Mechanical behavior analysis of a Friction Stir Welding (FSW) for welded joint applied to polymer materials

Welding is a technique of fusion joining the material involving a process of inter-molecular diffusion adhesion. Polymer welding is an assembly method among several known assembly techniques such as gluing. This welding process applies to thermoplastics; they have the rheological or softening characteristics during melting. This process is fast and controlled in order to obtain a solid and durable mechanical connection on the series parts. This study focuses on the weldability of high density polyethylene (HDPE) using the friction stir welding technique. A parametric choice was made to optimize the operating parameters namely the shape of the welding tool, the speed of rotation and the speed of advance of the tool. Monotonic tensile tests were used to compare the mechanical characteristics between a HDPE test specimen and a specimen taken from an FSW weldment. It emerges from this study that the FSW welding introduces a weakening of the joints characterized by a clear decrease of the deformation at break

Parametric Study Of Friction Stir Spot Welding (FSSW) For Polymer Materials Case Of High Density Polyethylene Sheets: Experimental And Numerical Study

Friction stir spot welding (FSSW) is a very important part of conventional friction stir welding (FSW) which can be a replacement for riveted assemblies and resistance spot welding. This technique provides high quality joints compared to conventional welding processes. Friction stir spot welding (FSSW) is a new technology adopted to join various types of metals such as titanium, aluminum, magnesium. It is also used for welding polymer materials which are difficult to weld by the conventional welding process. In various industrial applications, high density polyethylene (HDPE) becomes the most used material. The parameters and mechanical properties of the welds are the major problems in the welding processes. In this paper, we have presented a contribution in finite element modeling of the friction stir spot welding process (FSSW) using Abaqus as a finite element solver. The objective of this paper is to study the HDPE plates resistance of stir spot welding joints (FSSW). First, we show the experimental tests results of high-density polyethylene (HDPE) plates assembled by friction stir spot welding (FSSW). Three-dimensional numerical modeling by the finite element method makes it possible to determine the best representation of the weld joint for a good prediction of its behavior. Comparison of the results shows that there is a good agreement between the numerical modeling predictions and the experimental results

LARVICIDAL EFFECT OF THE SEED OILS OF TWO INDIGENOUS PLANTS FROM THE ALGERIAN SAHARA ON THE DESERT LOCUST

The lethal and sublethal effects of the seed oils of two indigenous plants of the Algerian Sahara, Peganum harmala L. (Zygophyllaceae) and Datura stramonium L. (Solanaceae), were investigated. Administration of 60 μl of oil by forced oral injection using a micropipette to the L5 larvae of Schistocerca gregaria Forsk. (Orthoptera: Acrididae) revealed the deterrent effect of these oils on treated larvae. The treatment resulted in various toxicological symptoms, such as intense defecation, diarrhea, weight loss, reduction in motor activity, delay and difficulty in molting and, in the most extreme cases, the death of treated individuals. During the treatment of L5 larvae of S. gregaria with P. harmala seed oil, various toxicological symptoms appeared: 81.81% of individuals presented with diarrhea; 68.18% of individuals lost weight; 72.72% exhibited reduced motor activity, and 100% of surviving individuals experienced a delay in their molt. On the other hand, in L5 larvae treated with D. stramonium seed oil, 77.27% of individuals had diarrhea, 100% showed weight loss and 100% of individuals reduced their motor activity. D. stramonium seed oil has been shown to be more toxic than P. harmala seed oil. The oral administration of 60 μl of D. stramonium seed oil caused the blocking of the phenomenon of exuviation in 100% of the treated L5 larvae, resulting in death after 16 days. While P. harmala seed oils caused 50% mortality after 12 days, the 50% surviving individuals were able to complete their imaginal molt with difficulties, which resulted in malformations. The estimated lethal time 50 (LT50) in larvae (L5) treated with D. stramonium seed oil was 3.67 days. It was more toxic than the LT50 obtained in larvae (L5) treated with the oil of P. harmala seeds, which was 12 days. The food intake in L5 larvae of S. gregaria treated with D. stramonium seed oil was 0.28 ± 0.18 g/day, it was lower than the average daily consumption recorded in the L5 larvae treated with P. harmala seed oil, which was 0.67 ± 0.36 g/day, D. stramonium seed oil appears to be more toxic, and profoundly affects food intake. The values of the apparent digestive utilization coefficient (DUC a) reported for L5 larvae treated with seed oil of P. harmala and D. stramonium were 39.32 ± 13.07% and 34.23 ± 29,07%, respectively. These values were significantly lower compared to the control group value, which was 70.63 ± 19.56%. Likewise, the digestive conversion coefficients (CCD) recorded in the L5 of S. gregaria treated with the seed oils of P. harmala and D. stramonium were -75.07 ± 54.45% and -3.08 ± 1.18, respectively. However, in the control group of L5 larvae, the noted CCD was 1.004 ± 0.073. Values of the consumption index (CI) reported for L5 larvae treated with the seed oils of P. harmala and D. stramonium were low, 6.74 ± 4.45 and 3.82 ± 2.45, respectively, while for the L5 larvae of the control group, it was 15.74 ± 3.51

Irregular Shape Effect of Brass and Copper Filler on the Properties of Metal Epoxy Composite (MEC) for Rapid Tooling Application

Due to their low shrinkage and easy moldability, metal epoxy composites (MEC) are recognized as an alternative material that can be applied as hybrid mold inserts manufactured with rapid tooling (RT) technologies. Although many studies have been conducted on MEC or reinforced composite, research on the material properties, especially on thermal conductivity and compressive strength, that contribute to the overall mold insert performance and molded part quality are still lacking. The purpose of this research is to investigate the effect of the cooling efficiency using MEC materials. Thus, this research aims to appraise a new formulation of MEC materials as mold inserts by further improving the mold insert performance. The effects of the thermal, physical, and mechanical properties of MEC mold inserts were examined using particles of brass (EB), copper (EC), and a combination of brass + copper (EBC) in irregular shapes. These particles were weighed at percentages ranging from 10% to 60% when mixed with epoxy resin to produce specimens according to related ASTM standards. A microstructure analysis was made using a scanning electron microscope (SEM) to investigate brass and copper particle distribution. When filler composition was increased from 10% to 60%, the values of density (g/cm3), hardness (Hv), and thermal conductivity (W/mK) showed a linear upward trend, with the highest value occurring at the highest filler composition percentage. The addition of filler composition increased the compressive strength, with the highest average compressive strength value occurring between 20% and 30% filler composition. Compressive strength indicated a nonlinear uptrend and decreased with increasing composition by more than 30%. The maximum value of compressive strength for EB, EC, and EBC was within the range of 90–104 MPa, with EB having the highest value (104 MPa). The ANSYS simulation software was used to conduct a transient thermal analysis in order to evaluate the cooling performance of the mold inserts. EC outperformed the EB and EBC in terms of cooling efficiency based on the results of thermal transient analysis at high compressive strength and high thermal conductivity conditions

Potential of New Sustainable Green Geopolymer Metal Composite (GGMC) Material as Mould Insert for Rapid Tooling (RT) in Injection Moulding Process

The investigation of mould inserts in the injection moulding process using metal epoxy composite (MEC) with pure metal filler particles is gaining popularity among researchers. Therefore, to attain zero emissions, the idea of recycling metal waste from industries and workshops must be investigated (waste free) because metal recycling conserves natural resources while requiring less energy to manufacture new products than virgin raw materials would. The utilisation of metal scrap for rapid tooling (RT) in the injection moulding industry is a fascinating and potentially viable approach. On the other hand, epoxy that can endure high temperatures (>220 °C) is challenging to find and expensive. Meanwhile, industrial scrap from coal-fired power plants can be a precursor to creating geopolymer materials with desired physical and mechanical qualities for RT applications. One intriguing attribute of geopolymer is its ability to endure temperatures up to 1000 °C. Nonetheless, geopolymer has a higher compressive strength of 60–80 MPa (8700–11,600 psi) than epoxy (68.95 MPa) (10,000 psi). Aside from its low cost, geopolymer offers superior resilience to harsh environments and high compressive and flexural strength. This research aims to investigate the possibility of generating a new sustainable material by integrating several types of metals in green geopolymer metal composite (GGMC) mould inserts for RT in the injection moulding process. It is necessary to examine and investigate the optimal formulation of GGMC as mould inserts for RT in the injection moulding process. With less expensive and more ecologically friendly components, the GGMC is expected to be a superior choice as a mould insert for RT. This research substantially impacts environmental preservation, cost reduction, and maintaining and sustaining the metal waste management system. As a result of the lower cost of recycled metals, sectors such as mouldmaking and machining will profit the most

Potential of Rapid Tooling in Rapid Heat Cycle Molding:A Review

Rapid tooling (RT) and additive manufacturing (AM) are currently being used in several parts of industry, particularly in the development of new products. The demand for timely deliveries of low-cost products in a variety of geometrical patterns is continuing to increase year by year. Increased demand for low-cost materials and tooling, including RT, is driving the demand for plastic and rubber products, along with engineering and product manufacturers. The development of AM and RT technologies has led to significant improvements in the technologies, especially in testing performance for newly developed products prior to the fabrication of hard tooling and low-volume production. On the other hand, the rapid heating cycle molding (RHCM) injection method can be implemented to overcome product surface defects generated by conventional injection molding (CIM), since the surface gloss of the parts is significantly improved, and surface marks such as flow marks and weld marks are eliminated. The most important RHCM technique is rapid heating and cooling of the cavity surface, which somewhat improves part quality while also maximizing production efficiencies. RT is not just about making molds quickly; it also improves molding productivity. Therefore, as RT can also be used to produce products with low-volume production, there is a good potential to explore RHCM in RT. This paper reviews the implementation of RHCM in the molding industry, which has been well established and undergone improvement on the basis of different heating technologies. Lastly, this review also introduces future research opportunities regarding the potential of RT in the RHCM technique

Warpage optimisation on the moulded part with straight drilled and conformal cooling channels using Response Surface Methodology (RSM), Glowworm Swarm Optimisation (GSO) and Genetic Algorithm (GA) Optimisation Approaches

It is quite challenging to control both quality and productivity of products produced using injection molding process. Although many previous researchers have used different types of optimisation approaches to obtain the best configuration of parameters setting to control the quality of the molded part, optimisation approaches in maximising the performance of cooling channels to enhance the process productivity by decreasing the mould cycle time remain lacking. In this study, optimisation approaches namely Response Surface Methodology (RSM), Genetic Algorithm (GA) and Glowworm Swarm Optimisation (GSO) were employed on front panel housing moulded using Acrylonitrile Butadiene Styrene (ABS). Each optimisation method was analysed for both straight drilled and Milled Groove Square Shape (MGSS) conformal cooling channel moulds. Results from experimental works showed that, the performance of MGSS conformal cooling channels could be enhanced by employing the optimisation approach. Therefore, this research provides useful scientific knowledge and an alternative solution for the plastic injection moulding industry to improve the quality of moulded parts in terms of deformation using the proposed optimisation approaches in the used of conformal cooling channels mould

Lattice Boltzmann Method for Fluid Flow

In the last few years, a rapid development in the method known as the Lattice Boltzmann Method (LBM) has been achieved. It demonstrated its ability to simulate hydrodynamic systems, multiphase and multicomponent fluids. The main advantages of the LBM are the parallelism of the method, the simplicity of programming and the capability of incorporating model interactions. The use of the LBM to understand the flow structure inside the Gas Diffusion Layer (GDL) of a fuel cell is a particular active topic, motivated by the need of finding alternative energy conversion devices. In the present work we developed a rigorous initial base of a flow solver based on the LBM, the BGK model is used to approximate the collision term in the Boltzmann equation. We used the bounce back scheme to simulate the boundary conditions and the flow solver is validated against three benchmarking cases. The process of applying the boundary conditions was automated to handle complicated flow structures. We simulated the flow in a 2D structure surface extracted from a 3D reconstructed GDL, using both non-parallel and parallel code. The results for a single phase flow show the flow structure expected, the convergence of the parallel code is faster and its parallelism is easier comparing to the traditional Navier-Stokes solver

Optimization parameters to reduce the warpage defect of plastic injection molding process for a thin-shell part using design of experiment

Development of light, small and thin plastic products that possess high strength characteristic such as electronic devices have become one of the tremendous demands in the plastic injection molding industry nowadays. However, smaller and thinner wall part design has increased the possibility for the parts to warp. The aim of this study is therefore to determine the best set combination of molding parameters that could reduce the warpage defect. There are six parameters that have been selected in this study which are mold temperature, melt temperature, packing time, cooling time, injection time and packing pressure. Taguchi orthogonal array is used to simplify the experimental runs. The analysis is done by applying S/N ratio approach and ANOVA method. Based on the results obtained from the analysis, it is found that the best set combination parameters give out the smallest warpage value