Ultrasonic machining is the removal of material by the abrading action of grit-loaded liquid slurry circulating between the workpiece and a tool vibrating perpendicular to the workface at afrequency above the audible range.
|Amplitude of vibration (a）:|
|Gap overcut :|
In rotary ultrasonic vibration machining , the vertically oscillating tool is able to revolve about the vertical center line of the tool. Instead of using an abrasive slurry to remove material, the surface of the tool is impregnated with diamonds that grind down the surface of the part. Rotary ultrasonic machines are specialized in machining advanced ceramics and alloys such as glass, quartz, structural ceramics, Ti-alloys, alumina, and silicon carbide. Rotary ultrasonic machines are used to produce deep holes with a high level of precision.
Rotary ultrasonic vibration machining is a relatively new manufacturing process that is still being extensively researched. Currently, researchers are trying to adapt this process to the micro level and to allow the machine to operate similar to a milling machine.
Rotary ultrasonic machining technology is one of the effective methods for processing engineering ceramics, but there are problems such as complicated tool making and serious tool wear during processing, which seriously limits its application in the processing of complex cavity ceramic parts. Rotating ultrasonic forming with a simple tool like a milling cutter is a viable method for solving complex cavity machining in ultrasonic waves in recent years.
Parameters of Ultrasonic Machining:
The ultrasonic vibration machining method is an efficient cutting technique for difficult-tomachine materials. It is found that the USM mechanism is influenced by these important parameters.
Amplitude of tool oscillation(a0)
Frequency of tool oscillation(f)
Type of abrasive
Grain size or grit size of the abrasives – d0
Feed force - F
Contact area of the tool – A
Volume concentration of abrasive in water slurry – C
Ratio of workpiece hardness to tool hardness; λ=σw/σt
|Abrasive||Boron carbide, aluminium oxide and silicon carbide|
|Grit size(d0)||100 – 800|
|Frequency of vibration (f)||19 – 25 kHz|
|Amplitude of vibration (a）||15 - 50 µm|
|Tool material||Soft steel titanium alloy|
|Wear ratio||Tungsten 1.5:1 and glass 100:1|
|Gap overcut||0.02-0.1 mm|
Improve the surface integrity of the material being processed for true cold cutting
Reduce the cutting resistance during tool processing and reduce the residual stress on the surface of the machined material
High-speed machine tool processing can be used to improve machining efficiency in low-speed machine applications
Customized JT, BT, HSK, straight shank and other specifications according to the user's machine tool spindle
Suitable for hard and brittle materials, such as: glass, ceramic lamps are more difficult to process materials.
What's the Principle of ultrasonic machining?
Through ultrasonic to achieve a very large impact acceleration (about 104-105 times the acceleration of gravity) under the action of a vibration frequency of 20-50KHz (ie, 2000-50,000 times per second), and the cutting direction of the machine is combined with the main motion of the machine. High frequency vibration, the material is first crushed and then removed.
Ultrasonic milling is microscopically a pulse cutting. The effective cutting time of the tool is very short. The tool is completely separated from the workpiece more than 80% of the time, and the workpiece is intermittently contacted by the machined surface, which greatly reduces the cutting resistance of the tool and avoids the common cutting. The phenomenon of letting the knife phenomenon is greatly reduced on the surface residual stress of the workpiece.
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 machining is suitable for machining of hard, brittle materials including: