The hottest intelligent EDM Technology

2022-08-24
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Intelligent EDM technology

EDM (electrical discharge machining for short) technology integrates the most advanced technologies in various periods, and gradually evolved into today's interdisciplinary, multidisciplinary, edge technology integrated agent. The demand for intelligence is entirely due to its elimination of human accidental factors, high reliability, low operation cost and high production efficiency

the "intellectualization" of electrical processing is also based on a huge system organization, and the completion of processing requires high efficiency and safety. At present, Switzerland and Japan are leading in the intelligent technology of EDM. Switzerland is the first country to study intelligent technology. All technologies aim to achieve the most efficient, reliable and lowest operating cost by the most direct and simple means. The recent development of Japanese technology shows that its investment in the research of dielectric and drive system technology of electrical processing (such as powder mixing processing and linear motor) is far greater than that of intelligent technology, which makes the recent intelligent technology inferior to Switzerland

the intelligent technology in Switzerland (especially Agie) is generally developing in the direction of intelligence like "human". Mainly in optimization, advanced intelligent expert technology (brain), perfect monitoring system (nervous system), rapid feedback, execution system (musculoskeletal), and so on

intelligent pulse power supply and control

optimization, advanced intelligent expert technology (brain), namely intelligent pulse power supply and control. The mechanism of EDM is to gasify conductive materials at high temperature generated by electric pulse discharging in the medium to form processing. The quality of electric pulse parameter selection directly affects the processing results. How to select the fastest and most suitable parameters depends on manual on-site adjustment, which is obviously time-consuming and inaccurate, so intelligent technology is used. Accurately studying the mechanism and theory of single pulse micro EDM process (Fig. 1) is a prerequisite for EDM intelligent technology

Fig. 1 micro EDM process of single pulse

the research results of Swiss Agie show that the micro EDM process of single pulse forms etch pits (referred to as etch pits) with the high-temperature vaporization and melting conductive machining body generated by the plasma beam formed by the dielectric breakdown with the pulse voltage, and the etch pit radius increases with the increase of the plasma beam radius. When the heat balance radius increases and stops, it is in the "progressive state". The "progressive state" is the lowest electrode loss and the maximum etching rate, and it is also the best time to stop the pulse voltage. At this time, the surface quality of the etch pit is good, the same discharge gap discharge energy is the most economical, and the finishing time is reduced (Fig. 2)

Fig. 2 research results of Rui n-octave (OCT) and Agie

processing results of uncontrollable etching period and controllable stable etching period are shown in Fig. 3

Fig. 3 processing results of two etching periods

with theory, we have technology, that is, detect the etching period, stabilize the etching period, and extend the etching period as far as possible

there are many factors affecting the erosion period, which are mainly controlled and solved by the following six means (Fig. 4)

1. Dynamic stability of voltage

2. Process control

3. Expert system optimization

4. Resolution of power pulse parameters

5, power pulse

6. Pls translation strategy

pls translation method has no effect on the stable extension of erosion period. This technology is to improve the translation efficiency

the application of intelligent technology integrates all the factors that affect EDM (discharge parameters, flushing and mechanical motion indicators, etc.) and the adjustment of these factors in different situations (such as deep and narrow slots, large areas, no flushing, etc.) into the "brain". Through real-time detection of discharge results, the best optimized combination of various factors can be selected in time to achieve high efficiency, high surface quality and low loss. This process does not require manual participation

the main solutions are as follows:

the perfect monitoring system (nervous system) provides accurate on-site information

the monitoring system monitors all useful information, including temperature, voltage, current, flushing pressure, movement position, speed, acceleration and physical quantities closely related to EDM. The corresponding results are obtained through calculation, for example, the lower edge slope is obtained through the calculation of discharge voltage pulse waveform, and controlling the lower edge slope can avoid arcing; There are also physical quantities required for special applications, such as the medium ion concentration required by the slow wire cutting machine, the tension of the electrode wire, the deflection of the electrode wire, etc

electrode wire deflection monitoring (Figure 4) method

Figure 4 electrode wire deflection monitoring

fast feedback and execution system (Jinchengli flesh skeleton, whose "muscle continuation creates maximum value for customers" is regarded as the company's mission), has been mentioned in the previous paragraph. Without fast feedback, millisecond discharge process means disaster. But there are priorities and rationality. Discussing the feedback and execution of electrical processing should be based on the feedback and execution speed of electrical parameters (please see the above power supply solution). For the application of mechanical speed improvement, there is a reason that the charging actions of enterprises involved are regular, supervised, evaluable or enough, and blindly increasing the speed is counterproductive

the relationship between tool lifting (electrode fallback) time and EDM time is shown in Figure 5

Fig. 5 Relationship between tool lifting time and machining time

when machining a 30mm deep cavity, lift the tool once in 0.8s and retreat 5m. Calculation:

4.5m/min speed, 2 m/s2 acceleration

wt = 83%

30m/min speed, 10 m/s2 acceleration (requires 20ms start and 30ms stability)

wt = 87%

on the surface, it is only 4% improved, But more importantly, the stability of the discharge circuit caused by the dynamic effect from the electrode to the vicinity of the discharge gap requires that when approaching the discharge gap, the smooth change of speed (that is, the acceleration must change with a certain slope) just reaches the position of the discharge gap (Fig. 6), and the speed must be adaptive to the discharge gap

Figure 6. The smooth change of discharge gap position

speed, that is, the acceleration must change with a certain slope. The time for circulating lubrication of all moving parts at high-speed knife lifting (30m/min) is much longer than that at low-speed knife lifting (4.5m/min), which is much larger than the above 4%

it is mentioned that the influence of dynamic effect on the stability of discharge circuit should be adaptive to the discharge gap, that is, the slope of acceleration must be adjusted according to the size of discharge gap. This technology is called intelligent power, and it is also another application of Swiss intelligent technology

to sum up, with the development of EDM today, intelligent technology is not only comprehensively upgraded in terms of technical content, but also more extensive in terms of intelligent control range. With the improvement of market requirements for EDM, intelligent technology will continue to develop. (end)

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