The influence of friction stir welding tool shape on quality of AZ31 Magnesium welding product

Magnesium is one type of material that can be used as a base metal in welding. Magnesium has superior properties, including low density, good ductility, medium strength and excellent corrosion resistance. Because of its properties, the metal is widely used, ranging from household goods to aircraft components. These base metals are categorised as mild when viewed from the specific gravity of magnesium (1.74 g/cm3 and 1.83 g/cm3). Welding is the process of merging two or more base metals which are merged at the contact surface with or without additives or fillers. Welding is divided into two main categories, Liquid and Solid-State Welding. Friction Stir Welding (FSW) is an example of Solid-State Welding (Non-Fusion Welding). FSW is a friction welding process that twists the tool by utilising heat energy and pressing without additives or fillers until the base metal is in a phase change. The welding process in this study used the cone and spiral shape with a tool rotation at 2000 rpm and a welding speed of 16 mm/min. The tests carried out are tensile and hardness testing. This study found that the tool shape, tool rotation, and welding speed significantly affect the mechanical properties of the welded AZ31 magnesium. The spiral shape will make the welding area wider. Although the cone shape will have a small area, the weld will look perfect with good tensile strength, while the hardness values for the two tool shapes are almost the same, but the cone shape is better.

THE USE GUIDED DRILLING PIPES FOR VARIOUS PURPOSES

The proposed installation provides control and monitoring of the parameters of the cutting tool during deep drilling of pipes for various purposes due to the controller and sensors, which are mounted on special equipment designed for processing deep holes. Installed sensors control such parameters as tool rotation, feed, part rotation, runout on the outer surface of the part, and the wall thickness of the part during processing. Movement of the cutting tool of the drilling head, in which a sensor for monitoring the thickness difference is installed using a lubricating and cooling liquid supplied to the head as a contact medium, which ensures the operation of the sensor for monitoring the wall thickness. The controller processes the data received from all sensors, and sends a pulse signal, thereby making appropriate adjustments to the operation of the entire installation.

Friction Stir Welding of Wrought Aluminium Alloy EN AW- 6082

The article presents results of the friction stir welding of 6 mm thick plates made of wrought aluminium alloy EN AW-6082. Tests discussed in the article involved the identification of the effect of primary welding process parameters on the quality of welds. Test welds were subjected to visual tests, measurements of temperature (inside the weld), tensile strength tests as well as macro and microscopic metallographic tests and structural tests (performed using a scanning electron microscope). The application of the appropriate values of the primary welding process parameters (i.e. the tool rotation rate and the welding rate) enabled the obtainment of the high and repeatable quality of FSW joints made of aluminium alloy EN AW-6082. The test results presented in the article can offer technological solutions for potential

Effect of tool rotation on the fabrication of micro-tool by electrochemical micromachining

Electrochemical micromachining (EMM) uses anodic dissolution in the range of microns to remove material. Complex shapes that are difficult to machine on hard materials can be fabricated easily with the help of EMM without any stresses on the workpiece surface and no tool wear. Fabrication of microfeatures on microdevices is a critical issue in modern technologies. For the fabrication of microfeatures, precise micro-tools have to be fabricated. In this present study, EMM milling is used for the fabrication of micro-tools. For this, an EMM setup has been designed. Tungsten carbide tools with an initial diameter of 520 µm have been selected and are electrochemically machined to reduce their diameter. The tool and workpiece are connected as anode and cathode, respectively. The electrolyte solution used for this investigation is sodium nitrate. A comparative analysis of the effect of tool rotation over both machining accuracy and surface finish has been performed.

The Effect of Tool Rotation Speed on Hardness, Tensile Strength, and Microstructure of Dissimilar Friction Stir Welding of Dissimilar AA5083 and AA6061-T6 Alloys

The welding between two different grades of aluminum alloy, specifically AA5083 and AA6061-T6, is very difficult to obtain optimal results when using conventional welding methods such as TIG/MIG welding. Therefore, a solid-state joining technique is highly recommended to overcome these problems, one of which is friction stir welding (FSW). The effect of rotation speed on microstructure, microhardness, and tensile properties of dissimilar Friction Stir welded AA5083 and AA6061-T6 aluminum alloys were investigated. Three different rotation speeds (910, 1500, and 2280 rpm) were used to weld the dissimilar alloys. The metallographic analysis of joints showed the presence of various zones such as BM (base material), HAZ (heat affected zone), TMAZ (thermo-mechanically affected zone), and NZ (nugget zone) were observed and analyzed by mean of optical and scanning electron microscope. The results showed that increasing the rotation speed from 900 to 2280 rpm made grain coarsening in NZ and the mass distribution of the material is more evenly distributed, as well as increased hardness and tensile strength of the joint. The highest values in microhardness in NZ and tensile strength at the join were founded at the speed of 2280 rpm and 1500 rpm which was similar to 2280 rpm, respectively.

Performance Evaluation of Robot Polishing in Macro-Micro System Based Polishing Robot

Polishing is an important process performed in the finishing and repair processes of mechanical parts and is still a manual work of skilled workers. However, in addition to the time and cost required for manual polishing, there are also problems such as a decrease in the number of workers and health hazards due to dust generated during polishing. From these problems, the demand for automatic polishing is increasing at manufacturing sites. To automate polishing process, a macro-micro system based polishing robot which consists of a functional end-effector and industrial robot has been proposed. Regarding end effectors, mechanical design aiming for high rigidity and motion control methods for keeping the contact force constant is being researched. Meanwhile, the tool rotation speed of the spindle is independently controlled typically. Therefore, in this research, a functional polishing module capable of polishing force control and tool rotation control according to the tool feed rate is developed as the end effector. For the polishing automation, the macro-micro system based polishing robot is constructed attaching the polishing module to the industrial robot. From the viewpoint of Preston’s law, the effectiveness of the robot polishing is investigated through polishing experiments and measuring the shape of the polished surface.

Effect of Process Parameters on Mechanical Properties of Aluminum Composite Foam Developed by Friction Stir Processing

The underwater friction stir processing is used for development of aluminum metal matrix composite (AA2219-Y2O3) foam. For development of foam, holes with different diameter in the mid thickness of plate were filled with a mixture of TiH2 and aluminum powder and underwater friction stir processing was used to mix this mixture in aluminum metal matrix composite. Then precursors extracted from the processed zone and heated upto 650°C in a furnace for development of foam. The effect of diameter of hole, number of passes and the tool rotation direction has been studied on the foam cell size and static and dynamic compressive behavior of the foam. It is found that as the diameter of hole increases, the size of pores increases. The distribution of pores is better with higher number of passes and increasing the hole diameter. The quality of foam further improves by reversing the tool rotation direction. The developed foam has different pore size varies from 0.7 to 2.7 mm depends on the FSP parameters. Based on the size of pores and their distribution the relative density ranges from 0.1 to 0.78. The foam produced with 4 mm hole diameter has best static and dynamic compression properties.