SU747675A1 - Method and tool-electrode for electro-erosion working of internal spaces - Google Patents

Description

one

The invention relates to mechanical engineering technology, in particular, to the EDM machining of shaped parts, mainly matrices of separator pieces.

There is a method of electroerosive treatment of cavities, according to which, to obtain a given accuracy and purity of the surface, as well as sufficient process performance, the parts are machined with a composite electrode tool in draft and finishing modes in series. isolated from each other and connected to separate power sources 1.

The disadvantage of the known method and the device implementing it 20 is the low productivity of the process / due to the fact that the black and white processing are performed sequentially. 25

The purpose of the invention is to increase the productivity of the process.

This goal is achieved by the fact that the processing is carried out simultaneously on the draft and finishing modes, the DA

the ratio between the parameters of which is chosen from the expression 5-Sr (UiV 5r, (Ut)

Uiti-CilUgii + eg).

where 5 is the total allowance for processing,

SH finishing allowance area, mm, as a function of draft mode performance;

 Draft Performance

U2- performance on the finishing mode, mm / min;

, 2 is the relative wear of the electrode on the draft and finishing modes, respectively.

The composite electrode tool DL of the sprasob is made in the form of a rod insulated with a dielectric layer of the draft element and at least one coaxial, hollow finishing element coaxial to it, the TC surfaces of which are located in one plane perpendicular to the axis of the electrode. -. the thickness of the dielectric layer is defined by the expression:

Claims (2)

 Iist Lchern where K is the thickness: a dielectric layer, mm; Mist the value of one-sided interelectrode gap on the finishing mode, mm; The ycern value of one-sided interelectrode gap on the draft mode, mm. FIG. 1 shows a general view of a composite electrode tool with an indication of rough and machining allowances and its wiring diagram; FIG. 2 is a section A-A of the tool electrode; The method is implemented using a composite electrode tool consisting of a rough electrode 1, made in the form of a Siberian Crane (n and a finishing electrode 2, which is a hollow cylinder. The electrodes are separated by a dielectric layer 3. The shaking of the electrodes is by key to one of the poles of the circuit 4 of the electric pulse generator. Other The second pole of each generator is connected to the processing part 5. In the central part, part 5 contains a through pre-cavity 6. The method allows the use of an electrode-tool, the total number of draft and finishing electrodes of which exceeds two. this roughness of the side surface of the part, and their increase accordingly increases the purity class. This is achieved by uniformly reducing the energy of the electrical discharges starting from the draft electrode 1, p laid in the central portion and terminating the finishing electrode located extremely 2 elektroddov number determines the number of contours 4. The ratio between processing modes determined from simultaneous processing conditions and on rough Num PTO mode x. This condition allows to determine the ratio between the modes at different initial processing allowances and is determined by the equality:) SrttUQ,) U2 (the conclusion of which is based on the equality of the rates of penetration of both parts of the composite electrode into the part), where 6-Snlbi is equal to the inverse i 4. from the speed of insertion1 into the detail on the black new mode; equal to the inverse of the rate of insertion of rhenium into the part in the finishing mode. With the same rate of introduction of both parts of the composite electrode into the part to the same depth, the time required for processing will be equal to -1k in the draft and finishing modes. An example of a specific method. Suppose we need to get pok-st in the matrix of the separation stamp, the workpiece of which is made of hard alloy grade VK-20. A composite power tool is made, the rough 1 and the finishing 2 elements of which are made of copper grade Ml. Such an electric tool is installed in the machine spindle, the black element 1 of which is connected to the rough contour of the electric pulse generator, and the finishing element 2 - to the finishing one - to the contour. For each of the elements, a mode is established that ensures the same rate of penetration of both parts into the workpiece 5. In the process of processing, the rough element 1 removes the allowance for roughing SqepH in the workpiece 5 In this case, part of the dielectric layer 3 of the tool electrode evaporates to a depth equal to one-sided interelectrode gap ycern A defective layer 0.13 mm thick with a roughness of the lateral surface corresponding to the third class h appears on the lateral surface of the cavity origins. Defective layer is removed by finishing element 2 at the same time as it originates from the draft mode, and the side surface roughness decreases to v7 - v 8 At the same time, another part of the dielectric layer 3 evaporates, the thickness remaining of which does not exceed the value of one-sided interelectrode gap A, The thickness of the dielectric layer is determined by the expression: Cd is the thickness of the dielectric layer, mm; The cnst value of the interelectrode gap in the finishing mode ,, mm; the black value of the interelectrode gap per when the thickness Kd is equal to the sum of the interelectrode gaps, it will completely evaporate, since the temperature in the discharge plasma is of the order of lOOOO C. If the thickness Kd is greater than the sum of the interelectrode gaps for the rough and the finishing direction , it is possible to partially preserve it, which can be an obstacle to the further electroerosion treatment.The erosion products are removed through the preliminary cavity 6 of the part 5 due to simultaneous pumping and suction of the working fluid. At the same time, the hose for suction of the working fluid is connected to the lower part of the cavity 6. The invention makes it possible to raise the technology of electroerosive cavity manufacturing to a higher level, for example, punch die templates. It is known that for small and medium areas, the duration of roughing is 20-25% of the finishing. In the invention, the roughing is carried out in parallel with the finishing. Thus, the reduction in cavity processing time by only 20-50% provides a significant economic effect. Claim 1. Electro-erosion treatment of cavities by a composite electrode tool, carried out in the black and clean modes, characterized in that, in order to increase productivity, the process is carried out simultaneously on the black and clean modes, the parameters of which are chosen from respect for the relation: 5-5n (U, l Sn (U,) uai e rUati eaV where S is the total allowance for processing; cn is the finishing allowance area; Uj is the performance when working in draft mode; Uj is the performance at pa6oie on clean mode; relative wear of the electrode when operating in draft mode; relative: wear of electrode when operating in finishing mode; 2. Electrode tool for carrying out the method; according to claim 1, consisting of separate draft and finishing elements, isolated from each other and connected to separate power sources, characterized in that the draft element is designed as a rod, and the finishing element is at least one coaxially mounted, hollow cylinder, with the end surfaces of the elements in the same plane perpendicular to the axis of the electrode, and the thickness of the dielectric layer between the elements is determined by the formula Lzerm is clean, - the thickness of the dielectric uqepH - the value of one-sided interelectrode; the gap when working on the black mode; the value of one-sided electrode gap when working on the true mode. Sources of information taken into account in the examination 1. Japanese Patent No. 27619, cl. 74 № 6, published 1964 D. Phi1.2.