IRANIAN JOURNAL OF MANUFACTURING ENGINEERING
Year:2024 | Volume:11 | Issue:3|Papers Count:6

In the present research, the effective parameters of ultrasonic horns in the ultrasonic-assisted simple shear extrusion process and the selection of the best choice are discussed. At first, the main input parameters (horn type, material, and dimensions) were determined to be used in the design of the experiments. Then, the experiments for input parameters were designed using the Taguchi method in Minitab software. The output results of the forming force for each level were obtained using finite element simulation in Abaqus/Explicit software. The optimization of the input values was investigated based on the-lower-the-better condition of the signal-to-noise (S/N) ratio. The optimal levels of the horn input variables were determined to achieve the minimum forming force during the ultrasonic-assisted simple shear extrusion process. After the design of experiments and the finite element simulations, the proposed horn was manufactured according to the optimal input values and then it was connected to the simple shear extrusion die. In the presence of ultrasonic vibrations, an 11% reduction in forming force was reported compared to the process without ultrasonic vibrations. A comparison of experimental and simulation results in the ultrasonic-assisted simple shear extrusion process showed a 9% error, which validated the numerical simulation.

In the present study, the effective parameters of injection stage of the metal injection molding process (MIM) is investigated in order to make a sound industrial part from the AISI-4605 low-alloy steel. In order to design of experiments and also to optimize different parameters of injection, statistical method of response surface method (RSM) and five-variable Box-Behnken Design (BBD) have been used assuming a quadratic model. Using this software, 46 experiments were designed. Then the samples are made and their density is measured. After that, the importance of the injection parameters as well as the interaction between each parameter have been investigated using analysis of variance (ANOVA). Finally, this research has shown that the injection temperature of 155°C, the injection speed of 80 mm/s, the holding pressure of 83 bar, the holding time of 9 seconds and the injection pressure of 132 bar led to the maximum density of the green body, which is equivalent to 4.892 g/cm2. Finally, after producing a new sample using the optimal parameters a piece with a density of 4.9 g/cm2 was obtained, and it was observed that the results were very close to the predicted value, which presented the model has good accuracy in prediction.

Mechanical seals are among the most widely used components of pumps and compressor. These parts consist of stationary and rotary sections with proper hardness and surface quality. The rotary surface is moving on the stationary surface while sealing should be performed between them. Hence, surface quality of the mechanical seals is critical for their performance. Lapping is a suitable finishing process used to improve the flatness and smoothness of mechanical seal surfaces. However, there is a lack of sufficient and extensive researches in the field of optimizing the lapping parameters of mechanical seals made of tungsten carbide. This study aimed to optimize the lapping time and pressure for tungsten carbide material to improve the flatness and roughness of the mechanical seals. To achieve this aim, a novel approach was used that combines anodizing and lapping. Experiments were conducted on both anodized and non-anodized samples. The results showed that anodizing reduces the surface hardness of tungsten carbide by 50%, which can reduce the maximum lapping time from 17 hours to less than 4 hours. The oxide layer on the surface of the samples was also completely removed after lapping, as confirmed by scanning electron microscopy. Moreover, the results of 2D and 3D topography showed that the surface roughness and flatness of the anodized samples were both improved compared to the non-anodized samples.

Various industries widely use forming processes to produce parts. The phenomenon of spring-back is an important issue related to forming process, which has a direct effect on the dimensional and geometric accuracy of the final part. In the present study, the preform force is used as a new approach to control and reduce the spring-back angle. To optimize the input parameters, the Taguchi test design method was used. In this design, preform force, annealing temperature, anisotropic and preform punch radius were considered as input variables and spring-back angle as quality index. The designed tests were carried out with the help of finite element model and experimental tests, and the spring-back angle was extracted for each test. By examining the results, it was found that the preform force and annealing temperature have the greatest effect on reducing the spring-back angle. The results of the experimental tests show that by choosing the optimal levels of the process parameters, the angle of the spring-back decreases significantly.

Owing to the increasing demand in the industry for materials possessing favorable mechanical properties and a high strength-to-weight ratio, the utilization of laminated composites has seen a surge in popularity. Nevertheless, laminated composite materials are susceptible to delamination because of their inadequate out-of-plane strengths and poor adhesion at the interface of composite laminated layers. This research aimed to enhance the mode II critical strain energy release rate in glass/epoxy laminated composites by using the inter-layering method and polyvinyl alcohol as the interlayer. To achieve this purpose, end-notch flexure samples (ENF) were fabricated using the hand lay-up technique. The experimental results indicate that the presence of a polyvinyl alcohol interlayer led to a significant increase of 177% in the initiation fracture toughness and 36% in the propagation fracture toughness. The reason for this is to increase the adhesion between the composite layers and reduce their tendency to slide relative to each other. Furthermore, the examination of the fracture surface of ENF samples demonstrated that the utilization of the interlayer induced a transition in the failure mechanism from adhesive failure to cohesive failure, thereby generating a rougher fracture surface in comparison to the neat sample. It is important to note that examining the crack growth resistance curve and comparing the strain energy release rate obtained from the CCM and CBBM methods demonstrated a favorable agreement.

Titanium metal matrix composite (Ti-MMC) is a suitable alternative for titanium alloys in various products and industrial sectors. Due to the presence of hard and abrasive ceramic particles in the matrix of such material, machining of Ti-MMc is generally conducted under lubrication conditions. The size and composition of particles and dust resulting from machining processes are among the critical and primary factors in determining the toxicity of environmental pollution. Aerosol emission of 2.5-10 microns remains in the trachea and bronchioles, and particles larger than 10 microns are usually located in the chest and nose. Considering limited studies in this domain, the effects of cutting parameters and lubrication conditions on the concentration of ultrafine and fine particles during machining Ti-MMC were studied in this work. The effects of coating and flow rate on dust emission reduction were tangible based on experimental observations. Regardless of the coating type, using a higher flow rate in the cutting fluid led to reduced fine particles and vice versa; no significant effect was observed on ultrafine particles. In similar cutting conditions, higher levels of fine particles were observed when using uncoated tools. In addition, on the coated tool, except for the low levels of cutting speed, the lowest values of ultrafine particles were observed in addition to high levels of cutting speed and flow rate.