Research On The High Temperature Friction Drilling

With the development and progress of modern manufacturing technology, the efficient environmental and economic processing methods will become more important., drilling is a large proportion of processing in machining some of which are sheet bored. We have a great demand of the retention of link, cost-effective, good quality, production processes less, no crumbs processing, and environmental clean sheet drilling methods. High temperature friction drilling can meet these requirements.With the requirements of the good quality processing quality and the efficiency of processing increasing the friction drilling will be more and more important in our life. Related studies should prepared for the application of the friction drilling. China's Manufacturing industrial development has a great promote and improve the quality of sheet bored and tapping processing. The studies of the hight temperature no crumbs molding friction drilling explore friction drilling technology, combined with the development of modern science and technology and the idea of technological innovation in achieving high-quality processing of sheet bored high efficiency for forward-looking research, useful exploration and practice.We also can enhance friction drilling level ,its economic and social benefitsand raise our technological level of manufacturing industries to meet the development of national economy. This processing method will be applied in many industries and can be widely used including furniture, cars and the exhaust pipe.The research on the no crumbs molding friction drilling have too many topics, The temperature is a very important factor in friction drilling processing and this is the main topic of friction drilling and the topic of this article.On the study of friction drilling, one of the important aspects is the study of the changes of temperature in friction drilling process, the biggest temperature curve in the drilling process according to the workpiece material and the same kinds of materials with different thickness in the certain feed rate is very important ;we can determine the best speed and the best speed. The basis research of friction drilling is very important, and the establishment of mathematical model of friction drilling in the process which make for the simulation of temperature also requires the temperature data collected in experiment.Following is a brief introduction of the main topicsof each chapters. we make a structural design of the sets of friction drilling in chapter three of this article. No litter molding high temperature drilling friction use the heat which is produceed by the friction of the tube and workpieces in processing to make a hole with bush in the pile or plane workpiece.On the begining in order to soften workpiece, we must increase friction heating power, the factors of the heating power are the spindle speed and axial pressure on the contact area. Axial pressure in the same spindle speed and certain feed rate can increase the friction heat of power with increasing the contact area, but in order to penetrate the workpiece the drill bit must have a certain cusp shape. So here we decide to use obtuse angle. We chosse 90°in the experiment and we make a very good effect. The basic requirements of material is the abrasion resistance, good-rigid so it can still maintain sufficient hardness in 900 ~ 1200℃hight temperatures and not easily melt-down. For ordinary sheets or thin-walled steel tube profiled obviously the carbide is more satisfactory material.In the experimental we use tungsten carbide-cobalt alloy which have gain a positive result.In the fourth chapter, we design a rapid response temperature testing device based on microcontroller . The design of hardware circuit includew temperature acquisition A / D converter circuits, microcontrollers , serial communication circuit and power supply. We have design the circuit between MCU and MAX6675 converter chip ,the interface circuit MCU and PC RS232, the circuit of the power supply.In the fifth chapter, we program for the rapid response temperature testing device including MCU programming and PC programming. MCU programming including the communication program between the MCU and MAX6675 through SPI interface. SCM program include serial data acquisition module and serial data transmission module. In the data acquisition module, single-chip microcomputer use the serial clock produced by programming to read out the 16-bit data acquisited by MAX6675. We transform the data into serial communications standards data which is suitable for PC serial asynchronous reading. Serial data transmission modules include serial port initialization subroutine and data transmission subroutine. Sending data use inquiring to determine whether sending is completed; data receiving use interrupt. when SCM receive a byte, it would generate an interrupt then the interrupt service subroutine will complete data collection and data transmission. After the temperature's A / D converter we shift the data to the metric system into the serial port of characters and send it to the PC. In this article, we design the experimental device based on the ARM microcontroller with the acquisition of the temperature data then send the results in serial to computer. every 0.2 S we send a sample data to the computer and computer receive the serial data and processing it, recording it,draw real-time rendering curve.In the sixth chapter,we do some experiment on no crumbs molding friction drilling. We design the experiment and prepared for the laboratory equipment needed and then make experiment.1) The experimentheat test the feasibility of drilling no crumbs molding friction drilling. This experiment show that friction drilling is a drilling methods with good quality.It is reliable and fast, no litter and environmental protection and low cost.2) The experiment show the influence of location of the thermocouple to the measurement of temperature . We known that the highest temperature is as highter than 700℃from the experiment in the friction drilling processing and the core bit can reach higher temperature. Bored temperature near the core is higher when the axial force maintain a certain stability to produced the heat. Test temperature test in the experiment should maintain a stable test location.3) We do some temperature experiment to gian the influence of the feed rate .The temperature will be lower when the feed rate is faster. the quality of drilling will be serious decline when the temperature is low;but if the feed rate was too slow it will affected processing efficiency. Therefore, to achieve better processing quality and processing efficiency integrated performance we must make a reasonable choice of feeding speed.4) We do some temperature experiment to gian the impact of spindle speed .We contrast the maximum temperature adopted when various conditions unchanged so we known that the higher the temperature when the higher the spindle speed. Take into account that the torque is too small when high-speed spindle in the running, so long as to make the workpiece temperature hinght enough to soften workpiece as far as a comprehensive performance in terms of speed. At the same time in the high speed condition the high temperature may damage the workpiece or softe the workpiece then the workpiece material will be welded on a bit part.5) The greater the thickness of the workpiece will make the higher the temperature in the same processing conditions. So we can apply the friction drill not only in plate but also thicker workpiece plate. it provide a convenient tool for drilling in thick wall pipe.