Selection of technological parameters for the hott

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Selection of wire cutting processing parameters

1, selection of pulse parameters

wire parallel interface is often used to connect extraction equipment (such as printers). Generally, transistor high-frequency pulse power supply is used for cutting processing, and pulse parameters with small single pulse energy, narrow pulse width and high frequency are used for positive polarity processing. During processing, the pulse parameters that can be changed mainly include current peak. This anti cutting glove contains three layers of elastic fabric, pulse width, pulse interval, no-load voltage and discharge current. It is required that the selected electrical parameters should be small when better surface roughness is obtained; If higher cutting speed is required, the pulse parameters should be larger. However, the increase of processing current is limited by chip removal conditions and electrode wire cross-sectional area. Excessive current is easy to cause wire breakage. See Table 1 for the selection of pulse parameters for WEDM. See Table 2 for the selection of pulse parameters for slow WEDM. Table 1 Selection of pulse parameters for fast WEDM

Table 2 selection of pulse parameters for slow WEDM

2. Determination of process size

in order to obtain the required processing size, a certain distance must be maintained between the electrode wire and the processing pattern, as shown in Figure 6.12. The double dotted line in the figure represents the trace of the electrode wire center, and the solid line represents the profile of the hole or punch. During programming, first, it is required to specify jgj/t 8 ⑼ 7 specification for deformation measurement of power transmission buildings (jgj/t 8 ⑼ 7). 2. The vertical distance △ R (gap compensation distance) between the electrode wire center track and the processing graphics. The electrode wire center track is divided into a single straight line or arc segment. After the intersection coordinates of each segment are calculated, the programming is carried out step by step. The specific steps are as follows:

(1) set the machining coordinate system

determine the machining coordinate system according to the clamping condition and cutting direction of the workpiece. In order to simplify the calculation, the symmetrical axis of the figure shall be selected as the coordinate axis as far as possible

(2) compensation calculation

according to the selected electrode wire radius r, discharge gap δ With the clearance Z / 2 of the convex and concave dies, the compensation distance △ R1 = R + of the machining concave die δ, As shown in Figure 1a. Compensation distance for machining punch △ R2 = R + δ- Z / 2, as shown in Figure 1b

(3) divide the electrode wire center track into smooth straight line and single arc line, and calculate the coordinate value of the intersection point of each line segment according to the average size of the hole or punch

a) female die b) male die

Figure 1 electrode wire center track

3. Selection of working fluid

working fluid has a great impact on cutting speed, surface roughness, machining accuracy, etc., so it must be selected correctly during machining. Commonly used working fluids mainly include emulsion and deionized water

1) deionized water is widely used in slow wire cutting. In order to improve the cutting speed, conductive fluid that is conducive to improving the cutting speed should be added during processing to increase the resistivity of the working fluid. Process quenched steel so that the resistivity is within 2 × 104Ω. Cm or so; Machining cemented carbide with resistivity of 30 × 104Ω. Cm or so

2) emulsion is the most commonly used for rapid WEDM Emulsion is prepared from emulsified oil and working medium (concentration is 5 ‰ ~ 10 ‰). The working medium can be tap water, distilled water, high-purity water and magnetized water. (end)

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