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Working principle of slow wire processing

 Slow wire walking, also called low-speed wire walking, is a kind of CNC machining machine tool that uses continuously moving fine metal wire as an electrode to pulse spark discharge on the workpiece to generate a high temperature of over 6000 degrees, ablate metal and cut into a workpiece. The principle of wire processing is the phenomenon that there is a gap between the wire electrode and the workpiece, and the metal is removed by continuous discharge. Since the slow-moving wire cutting machine adopts the method of wire electrode continuous feeding, that is, the wire electrode is processed during the movement, so even if the wire electrode is worn out, it can be continuously supplemented, so it can improve the machining accuracy of the parts and slow the wire. The surface roughness of the workpiece processed by the cutting machine can usually reach Ra=0.8μm and above, and the roundness error, linear error and dimensional error of the slow-moving wire cutting machine are much better t

How Do Cnc Swiss Machines Work

How Do Cnc Swiss Machines Work Save 0 What Is Swiss Machine –The full name of the walking CNC lathe, it can also be called the spindle box mobile CNC automatic lathe, the economical turning and milling compound machine tool or the slitting lathe. It belongs to precision machining equipment, which can complete compound  machining such as turning, milling, drilling, boring, tapping, and engraving at one time. It is mainly used for batch  machining of precision hardware and special-shaped shafts. This machine tool first originated in Germany and Switzerland. In the early stage, it was mainly used for precision machining of military equipment. With the continuous development and expansion of industrialization, due to the urgent needs of the market, it was gradually applied to the  machining of civilian products; the development of similar machine tools in Japan and South Korea Earlier than China, it was mainly used in the military industry in the early days. After the war, it was gradually

Spring Design Attention And Roll Forming Method

Spring Design Attention And Roll Forming Method The coiling characteristics and methods of springs are divided into cold coiling method and hot coiling method. Cold winding method: When the diameter of the spring wire is less than 8mm, the cold winding method is adopted. High-quality carbon spring steel wire is usually first cold drawn and then heat treated. After winding, it is generally not quenched, but only tempered at low temperature to eliminate the internal stress during winding. Hot-rolling method: Springs with larger diameter (>8mm) spring wire should use hot-rolling method. Hot rolled springs must be quenched and tempered at medium temperature. The Design Process Of Various Springs ·          Installation space: When designing a  compression spring , it is necessary to have a clear understanding of the space required for the installation of the spring, in order to effectively grasp the basic manufacturing conditions of the compression spring, including the outer diam

Drive the preferential presetting of the spring frame of the vehicle

The secondary spring system of the original electric locomotive consists of 4 sets of the same ordinary cylindrical compression springs. Its parameters are: spring material diameter d=48mm, maximum working circle diameter D=230mm, effective working circle number n=6.6, free height H0= 528mm, working height H=431mm. The characteristic curve of the spring is approximately straight, with stable stiffness and simple structure. However, the spring stiffness is mainly along the axial direction, and its transverse shear and bending stiffness is very poor, and its anti-resonance ability is poor. After the train speeds up, its snake-like movement and shaking phenomenon intensify. Therefore, it is necessary to improve the spring system of electric locomotives.

Improvement of the spring system. The improved spring parameters and characteristics take into account the special position of the secondary spring (between the bogie and the car body) and specific functions (supporting the car body and damping), under the premise of ensuring equal free height , The cylindrical spiral compression spring is improved into a conical compression spring with equal pitch. The distance t can be calculated by the following formula: H0=6.6t+1.5dT=(528mm-1.548mm)/6.6=69.09mm*large working radius R2=115mm, *smallest working radius R1=101.8mm, and the pressing time distance d=d1 -R2-R1nd2=47.96mm The stiffness of the improved conical compression spring is increased, the characteristic curve is gradually increasing, and the anti-resonance ability is enhanced.

The effect of the bending moment at the end of the spring on any section A indicates the effect of the unit transverse force on any section A. The improved spring bending stiffness and transverse stiffness. The bending stiffness of the spring is set as the distance from any section A of the conical spring to the end of the spring, then = R1 +R2-R12ntan In the formula, is the polar angle of the helix; is the helix angle.

The effect of the spring end bending moment on any section A is as shown. The torque generated by the bending moment M of the spring force end on the section A and the bending moments in the two directions are respectively Tt=McoscosMb=-McossinMn=Msinds=R1+R2-R12ncosd where Tt is the torque on the section of the spring material; Mb, Mn is the bending moment on the section of the spring material; ds is the length of the tiny section of the spring material.

The effect of unit lateral force on any section A is shown in the figure. When Pr=1, the torque and bending moment produced by the unit force on the section A respectively, Ip is the polar moment of inertia; Ib and In are the moments of inertia; E is the elastic modulus of the material; is the Poisson’s ratio. Substitute the reference value R1=101.8mm, R2=115mm, n=6.6, d=48mm, E=2G(1+) (=0.25, G=80109Pa), Ip=2Ib=2In=d4/32 into the formula, after integration Get Fr=(544011.7/(EIn))MM=(EIn/544011.7)Fr=95798N, so the bending stiffness is 95798N.

The bending stiffness of the original cylindrical spring can be calculated according to the formula (7-42) in the literature <1>. M=Ed416D2nH(2+)Fr=42604.5N. Therefore, the bending stiffness of the original cylindrical spring is 42604.5N. This shows that the bending stiffness of the conical spring is Improved. The lateral stiffness is as shown, the torque and the bending moment of the A section caused by the lateral force Pr are respectively (because it is very small, sin=0, cos=1) Tt=PrR1+R2-R12ntancos3

From the literature <1> formula (7-51), the transverse stiffness of the original cylindrical spring is obviously, the transverse stiffness of the conical spring is higher than that of the cylindrical spring.

Conclusion At present, the spring system of most foreign locomotives is still cylindrical spring, but the railway quality is higher than that of our country. The cost of the same transformation of the railway system in our country will be very high. Therefore, in our country, the key to improving the stability and safety of vehicle operation is to improve the spring system of the locomotive. Through the theoretical derivation and quantitative calculation of the new design scheme in the article, it is proved that the transverse stiffness and bending stiffness of the improved spring system are significantly increased, thus realizing the active control of the resonance of the locomotive during high-speed operation, and greatly improving the high-speed operation of the locomotive. Safety and stability. This design has been used by Zhuzhou Electric Locomotive Factory in the manufacture of the new Shaoshan SS9 train.

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