An Experimental Study on Copper Plates Using Friction Drilling.

Friction drilling is a novel hole-making method that can be performed on thin-walled sheets. In recent years of study, the thrust force and torque under numerous process conditions were performed to demonstrate the benefits. In recent years of study, the thrust force and torque under various process conditions were performed to demonstrate the benefits. Our objective is to review the behavior of the material with the use of friction drilling by variation of thickness, Spindle speed, and feed rate. Our objective is to study the behavior of the material with the use of friction drilling by variation of thickness, Spindle speed, and feed rate. The friction between a rapid rotating conical tool and a sheet metal workpiece generates heat to soften and displace the metal to form a whole. Friction drilling is a non-traditional hole-making process in which a conical rotating tool is applied to penetrate the workpiece and make the outlet in a single step, without generating chips. the process relies on the heat generated thanks to the resistance force between tool and workpiece, to soften, penetrate and deform the work material into a bushing shape. Generally, friction drilling is applied to thin-walled materials owing to increasing connection length and clamping strength. The generated resistance heat cause softening piece of work material, increase its ductility, and providing it to flow, that extruded onto both the front and back sides of the holes. Keywords: Friction Drilling, Conical Tool, Material Displace, Temperature, Hardness & Thickness.

INFLUENCE OF PROCESS PARAMETERS IN FRICTION DRILLING OF TITANIUM TI-6AL-4V ALLOY

Friction drilling is a process of using the friction between the rotating conical tool and the workpiece to generate heat and deform the work piece’s material and penetrate the hole. The softened material is pushed sideward and downward to make the bushing. This paper aimed to study the influence of friction drilling parameters. Thrust forces and torque forces were analysed. Experiments were carried out with a friction drill tool made of tungsten carbide on titanium grade Ti-6Al-4V. The parameters used in this study were spindle speed and feed rate. It was found that the thrust force and torque decreased with increased spindle speed and with decrease of feed parameters. The microstructure reveals that deformed grains at hole’s surface relate to hardness on the cross-section of workpiece. The highest value of microhardness was 813.2 HV and reduced to the original hardness of the matrix material.

Effects of process parameters on tensile strength of friction stir welded Al-Cu double-layer sheets

In this paper, friction stir welding (FSW) process was used to join double-layer sheets of pure copper and 1050 aluminum alloy produced by explosive welding (EXW). The double-layer sheets were arranged side by side to perform friction stir butt-welding. In this regard, rotary FSW tools with different geometries were used at rotational speeds of 800 and 1250 rpm and linear speeds of 8, 12, and 20 mm min‑1, in one and two number of passes. According to the results, the sample welded by a conical tool with a rotational speed of 800 rpm and a linear speed of 12 mm min‑1 in one pass offered the highest tensile strength, which was approximately equivalent to the 84% of the strength of the raw double-layer sheet. In addition, applying the second FSW pass and using a threaded tool from the aluminum side had negative effects on the tensile strength. The microstructural evaluation showed the presence of more intermetallic phases including Al4Cu9, AlCu, and Al2Cu in the sample welded by the threaded tool from the aluminum side in two number of passes, which was the responsible of the lower tensile strength and the higher microhardness.

Pressurization and Annealing Effect Analysis Through Hole Expansion

Due to continuous push towards environmental regulations to reduce the impact on the environment by reducing the fuel consumption, and concerns on limited resources, the more sustainable manufacturing is in demand. More abundance material like iron-carbon based alloy are higher strength and easily formable but ways are research to reduce the weight of created part by reducing the thickness due to density issue. Some low dense material is the alternatives but they miss the easy to deform spot. The present study is focused on how to make the material more deformable in the process by evaluating the parameters in deformation through the hole expansion process. For this study, four tests were chosen hemispherical dome test, cylindrical tool test, conical tool test, and biaxial test. In all tests, only the biaxial test machine does not use the rigid tool to deform the hole while all other test used the rigid tool punch to deform the hole. Cruciform specimen dimension was used to make the sample, which fits in all of the considered tests. A hole was created at the center of the specimen which will be expanded in all tests. In all tests the deformation mechanics and hole expansion was studied. Force-displacement curves were plotted and discussed. In addition, tests were also performed on annealed material to understand the hole expansion in ductile material. Based on the results it was observed that biaxial tests do not provide any pressurization effect and all test which includes the rigid tool to deform the hole does. Due to the pressurization effect, the hole was expanded more. It was also noted that the hole expansion was more in ductile material and pressurization effect increases with ductile material.

A Numerical Study on Rotational Tube Flaring Process

A substantial increase in demand on the sheet metal part usage in aerospace and automotive industries is due to the increase in the sale of these products to ease the transportation. However, due to increase in the fuel prices and further environmental regulation had left no choice but to manufacture more fuel efficient and inexpensive vehicles. These heavy demands force researchers to think outside the box. There are many advanced manufacturing processes to produce optimized part are single and double point incremental forming, Reuleaux forming, hydroforming, explosive forming, electrically assisted manufacturing. In this project, a numerical study on rotational tube flaring process will be studied. Tube flaring is one of the most commonly used processes under tube forming. In this process, a conical tool contacts and forces the end of the tube while another end of the tube is fixed. This is called conventional flaring process. In contrast to this process, a tool rotational technique was utilized for this work. The rotation and the feed of the tool will be analyzed to have the best formability of the tool. The strain path and failure will be analyzed. The strain and thinning pattern will be discussed.

Outer Diameter to Thickness Ratio Effect on Tube Flaring Behavior

Tube forming is one of the main manufacturing techniques for processing of tubular components. This process is subdivided depending on the processing i.e., tube end forming either to expand or reduce the section. One of these tube end forming techniques is a flaring process. Most applications for flaring tube ends, utilizes a conical tool for flaring the tube either till a particular deformation to achieve a desired shape or till failure to characterize the material properties. The relationship between the flaring behavior during the process based on the outer diameter and thickness of the tube was experimentally characterized in this paper for variety of tube sizes. Further flaring limits were analyzed in these considered tube sizes. For this four outer diameter to thickness ratio were experimented and results were analyzed. Further numerical simulations were performed to match the results. A closer look on the required force-displacement curve is presented and unique regions were identified. Based on the data an empirical equation is proposed. This equation provides a concept based on material or process stiffness. It is believed that once an equation is established and variables are linked to the parameter a more better prediction can be carried out for flaring the tubes.

Investigation of Friction Conditions in Dry Metal Forming of Aluminum by Extended Conical Tube-Upsetting Tests

In cold forming of aluminum, various lubricants and coatings are typically used to reduce friction and wear, resulting in higher workpiece surface quality. The preparation of the workpiece surfaces and the cleaning of the products after the forming step generate a significant amount of environmentally hazardous residues. Therefore, current research focuses on the realization of dry metal forming processes. Instead of lubricants, modified tool surfaces can also optimize tribological conditions in the interaction zone of forming tool and workpiece. The applicability of these surfaces needs further examination before usage within an industrial manufacturing process. In this paper, different surface modifications are examined by using a conical tube-upsetting test setup that is based on the concept of the well-known ring-compression test. The conical tool surface homogenizes the relative displacement between tool and workpiece and suppresses the appearance of a neutral point. Conical tools from AISI H11 / DIN 1.2343 and AISI D2+ / DIN 1.2379+ are laser polished and functionalized with self-assembled monolayers. Friction conditions resulting from different surface modifications are analyzed and evaluated by the use of nomograms. Moreover, the applicability of different friction laws for dry metal forming of aluminum is investigated.

Role of Threaded Tool Pin Profile and Rotational Speed on Generation of Defect Free Friction Stir AA 2014 Aluminium Alloy Welds

<p class="abstract">Influence of threads on tool pin and rotational speeds on defect occurrence in friction stir welding (FSW) of aluminum alloy AA 2014 T6 plates has been studied. The effect of FSW forces on the evolution of mechanistic defects, caused in turn through a variation in heat generation during the process has also been examined. In case of conical tool pin, relatively lower rotational speeds resulted in unbounded zones and micro defects while high speeds caused excessive flash, thereby resulting in surface defects and voids inside the weld. The FSW joints were defect-free at moderate speeds, hinting an optimum heat generation and flow. Reaction forces on the tool pin, in the welding direction, were correlated with the defect formation. Tools equipped with a threaded conical pin profile resulted in sound welds, irrespective of the tool rotational speeds in the entire range of 400 rpm - 2400 rpm. The threaded conical pin, with a relatively larger frictional area, may be contributing to higher levels of heat generation compared to a plain conical pin. Further, positive displacement of the hot plasticised material by the threads will carry away excess heat from the advancing-to-the-retracting side and simultaneously downwards, thus confining all heat within the weld zone.</p><p class="abstract"><strong>Defence Science Journal, Vol. 66, No. 1, January 2016, pp. 57-63, DOI: http://dx.doi.org/10.14429/dsj.66.8566</strong></p>