20Khz 500W Ultrasonic Vibration applied in Friction stir welding

Take your machining capabilities to the next level, along with your bottom line, with ultrasonic milling: the latest in ultrasonic machining technology. Experience unprecedented machining efficiency with high performance ultrasonic milling, grinding, core drilling and light weighting of optical glasses and ceramics. Ultrasonic oscillation of the tool promotes free cutting of material, greatly reducing the force applied to the tool as well as the work piece during processing. This reduction in force allows for rapid material removal and faster cycle times as well as reduced tool wear and longer tool life.

Ultrasonic machining, or strictly speaking the "Ultrasonic vibration machining", is a subtraction manufacturing process that removes material from the surface of a part through high frequency, low amplitude vibrations of a tool against the material surface in the presence of fine abrasive particles. The tool travels vertically or orthogonal to the surface of the part at amplitudes of 0.05 to 0.125 mm (0.002 to 0.005 in.). The fine abrasive grains are mixed with water to form a slurry that is distributed across the part and the tip of the tool. Typical grain sizes of the abrasive material range from 100 to 1000, where smaller grains (higher grain number) produce smoother surface finishes.

Ultrasonic vibration machining is typically used on brittle materials as well as materials with a high hardness due to the micro-cracking mechanics.

Parameter

Rotary ultrasonic vibration machining

Measured forces in these experiments are downward force and welding force (in feed direction). For observing the effect of ultrasonicvibrationsonfloatingstageofthetool,dataacquisition ofdynamometerwasadjustedon10,000Hz.AsshowninFig.7, tool was put into the workpiece in floating stage, and after 15 s, ultrasonicvibrationswereappliedonthetoolfor35sformaking sure that ultrasonic equipment works well, and vibrations will notbedampedbyforce.Whenmagnifying(about0.002s)apart of the chart where ultrasonic vibrations were applied, it can be seen that in floating stage, the tool vibrates very good.

the effect of ultrasonic vibrations (applied to pin direction)onFSWofAA6061-T6 workpieces was investigated. Studied parameters included downward force, welding force(inweldingdirection),temperature,strength,andmicrohardness,andtheirchangesbyrotaryandfeedspeedsforboth FSWand UAFSW were studied. The achieved results can be summarized as follows:
– Ultrasonic vibrations can reduce downward force about 25 % because they can improve penetration. Enhancement of feed speed increases downward force slightly, and reduction of rotary speed decreases this force. – Ultrasonic vibrations do not have any drastic effect on welding force in feed direction, and they can reduce this force less than 10 %. Increase of feed speed increases welding force since material should move from the front of the tool toward its back, faster. By enhancing rotary speed, the slope of the force increase with feed speed increase diminishes and causes a small enlargement in welding force. – Adding ultrasonic vibrations to FSW increases temperature because they enhance stirring. Enhancing of feed speed reduces tool temperature because tool can pass through welding path faster, but increase of rotary speed increases tool temperature since it enhances friction (between shoulder and tool) and stirring. – Ultrasonic vibrations enhance strength and also elongation less than 10 %. Using UAFSW does not have any drasticeffectonthehardnessofweldedpartsinretreating path compared to FSW, but hardness increases about 15 % in advancing path.

Advantages

Ultrasonic vibration machining is a unique non-traditional manufacturing process because it can produce parts with high precision that are made of hard and brittle materials which are often difficult to machine.[1] Additionally, ultrasonic machining is capable of manufacturing fragile materials such as glass and non-conductive metals that can not be machined by alternative methods such as electrical discharge machining and electrochemical machining. Ultrasonic machining is able to produce high-tolerance parts because there is no distortion of the worked material. The absence of distortion is due to no heat generation from the sonotrode against the work piece and is beneficial because the physical properties of the part will remain uniform throughout. Furthermore, no burrs are created in the process, thus fewer operations are required to produce a finished part

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