Ultrasonic vibration on metal forming has been studied since the 1950s and key work was done on ultrasonic die vibration dating back to the 1960s. There are many research publications that review the use of ultrasonic energy in forming processes, including wire and tube drawing.
|Amplitude of vibration (a）:|
What's is ultrasonic wire drawing
Ultrasonic Wire Drawing The Wire Drawing Process with Axial Ultrasonic Vibration consists of two systems of wire drawing and ultrasonic vibration. The wire drawing device consists of a rotating wire drawing drum (winch) and a die holder. The vibration system consists of an electric oscillation generator, a machine-electric transducer and a horn. The electric oscillation generator converts the 50 Hz AC power into a 6-60 kHz AC through a capacitor, an inductor, and a tube circuit. The machine-electric transducer converts the electrical oscillation into a magnetostrictive nickel or an electrostrictive ceramic. Mechanical vibration; the horn is a rod with a thick end and a thin end. The thick end is connected with the machine-electric transducer, and the vibration transmitted from the vibration source is received. The small end is used as the mold base, the fixed drawing die, the drawing force, and the vibration It is transmitted to the wire drawing die through the horn. In the case where the vibration frequency is fixed and the vibration energy is not lost, the effect of the horn is to increase the vibration amplitude when the cross-sectional area becomes small, and hence the name. There are two parameters of frequency and amplitude when vibration occurs. The particle has energy when it vibrates. When the mass of the particle is large, the frequency of the vibration is high, and the amplitude is large, the energy of the particle vibration is large. The propagation of vibration becomes a wave with two parameters of wavelength and amplitude. Vibration generally propagates in a traveling wave, but becomes a standing wave when subjected to a specific disturbance. The standing wave has two special positions: the node and the antinode. The amplitude of the particle at the antinode is the largest, and the amplitude of the node at the node is the smallest. When the ultrasonic frequency vibration propagates in the horn, the rod has ultrasonic waves whose wavelength can be calculated according to the vibration frequency and the elastic modulus of the rod material. The length of the rod should be such that a standing wave is generated within the rod. The mold as a vibrated particle point should be fixed at the antinode or at the node.
The direction of vibration to the wire drawing die can be axial, radial and tangential. Common axial vibration is applied. At this time, the wire drawing die should be placed at the antinode position of the standing wave, and the drawing direction is the same as the vibration direction. When radial vibration is applied, the wire drawing die should be placed on the node of the standing wave, and the outer circle of the mold faces the vibration source, that is, the wire drawing direction is perpendicular to the vibration direction.
|Maximum Output||100 Watt|
|Power Supply||220V / 50-60 Hz|
|Ultrasonic Generator||Size||250(W) x 310(L) x 135(H) mm|
|Feature||Ultrasonic Amplitude Adjustable|
ultrasonic energy can provide these distinct benefits:
Draw force can be reduced from 15% to 60%.
Draw speed may be increased from 20% to 200% or more depending on materials and conditions.
Surface finish can be improved.
It can eliminate stick-slip action (known as chatter).
Application of ultrasonic vibrations to most any metal forming process can offer these benefits to the process and finish.
Reduced friction between die and workpiece
Die temperature reduction
Reduced forming forces,
Reduced flow stress
Improved surface quality
Why combine ultrasonics with wire drawing?
The drawing of wire rods requires power to overcome friction and to reshape the material. In a conventional drawing line, this power comes from the rotating capstan, only. The tensile force on the wire rod rises with faster line speed, wire diameter and diameter reduction ratio. Tensile strength and yield strength are critical factors for the drawing of smaller wires, because the ratio of the circumference to cross-section is higher for smaller wire diameters. This limits the drawing line speed and the diameter reduction per drawing step. The ultrasonically assisted drawing of wires, pipes and profiles reduces the tensile forces and therefore the risk of fractures. ultrasonically vibrating wire die holder.
How does ultrasonically assisted wire drawing work?
Ultrasonically assisted drawing transmits a high frequency longitudinal vibration to the wire die. The typical vibration frequency is 20kHz, the wire die displacement can be up to 100 micron (pk-pk). The higher the ratio between the tool’s vibrational velocity and the wire rod speed is, the lower can be the tensile force on the wire line. Therefore ultrasonically powered drawing allows faster drawing line speeds or bigger size reduction in one drawing step for any given tensile stress limit. The reduction in tensile force makes ultrasonically powered drawing most favorable for small material diameters and for hollow strands, such as pipes.
What Is Required For Ultrasonically Assisted Drawing?
UAD uses your standard wire die. An ultrasonic resonator – also known as sonotrode – replaces the conventional die holder. This sonotrode is a special innovation of Hielscher Ultrasonics. It transmits the ultrasonic longitudinal vibrations efficiently onto the wire die. In order to save installation space, the ultrasonic driver – also known as transducer – agitates the sonotrode from the top. A typical UAD setup requires less than 250mm of line space. The ultrasonic vibrations are generated by our standard ultrasonic devices, such as: UIP1000hdT (1.0kW), UIP1500hdT (1.5kW), UIP2000hdT (2.0kW) or UIP4000 (4.0kW). These units drive various processes in 24h/7d operations around the world. The power required depends on the line speed, material and the dimensions. The ultrasonic unit are interchangeable, should developments in line speed make more power necessary. You can retrofit any existing drawing line with an ultrasonic system easily. Many wire line manufacturers are well familiar with the installation or the retrofit of our ultrasonic system. Some of the newer machines have space allocated for the ultrasonic system retrofit, already.