With the continuous development of science and technology, the hole processing technology in the field of machinery manufacture for the use of more and more widely, but at the same time, the machining accuracy and surface quality of hole is also put forward higher requirements, especially in stainless steel, heat-resistant steel, titanium alloy, high temperature alloy hard machining materials such as precision micro deep hole. Practice shows that if the traditional method of processing, a series of difficult to solve the difficulties, such as high cutting temperature, cooling, leads partial, broken, into the drill bit easy centering, poor chip removal and exit burr. And rotating axial ultrasonic vibration drilling technology as a kind of special composite processing technology, in the precision deep hole machining practice has been shown to ordinary drilling incomparable process effect. It is in order to solve the difficulties of ordinary deep drilling micro holes, the precision micro deep hole rotating axial ultrasonic vibration drilling technology were studied.
According to the principle of high frequency vibration cutting, designed a set of maximum output power is 500 W, maximum output amplitude is 25 mm, resonance frequency of the rotation of the (+ 1) 20 kHz axial ultrasonic vibration drilling device, it is mainly composed of digital phase locked loop frequency automatic tracking type transistor acoustics system of ultrasonic generator, half wavelength (1/4 l cylindrical piezoelectric transducer and 1/4 l type resonant tapered amplitude), rotary joints, tools, system and tooling system of five parts. The device design, first of all, realize the function of vibration and rotation, and then solves the precision centering and good heat dissipation performance problems. Work, ultrasonic generator will first 220 V, 50 Hz alternating current into a super audio frequency electric oscillation signal, and then through the rotary joint can pass the signal with the handle system of high-speed rotation of the half wave acoustics system, acoustic system will be super audio frequency electric oscillation signal transformation for ultrasonic frequency of mechanical vibration and its amplitude amplification system, and then passed on to the tool bit in the final tool system can be carried out in at a certain frequency, amplitude and speed rotary ultrasonic machining.
The designed rotating axial ultrasonic vibration drilling device after installation, commissioning and performance test, with the frequency automatic tracking, automatic output power adjustment, high energy conversion efficiency and stable vibration speed, etc. Process experiment, install it on the high precision vertical machining center, and the aperture f0.2, respectively f0.5, f0.8, f1.0, f1.5, f2.0, length to diameter ratio L/D = 15 aluminum, copper, polycarbonate specimen of vibration drilling. Results show that as long as the vibration parameters (the vibration amplitude and frequency) and the cutting parameters (cutting speed and feed, cutting depth) choose reasonable, total axial ultrasonic vibration drilling can significantly improve the machining accuracy and surface quality of hole, also can improve the cutting condition, such as lower cutting force, cutting heat, eliminate or reduce inhibition of cutting vibration, improve the bit durability.
Thus, this technique is especially suitable for deep hole precision and ultra-precision machining, has wide application prospect.