Reciprocating vibration type multi-channel efficient electric spark machining method

Abstract

The invention discloses a reciprocating vibration type multi-channel efficient electric spark machining method, and belongs to the technical field of multi-channel electric spark machining. According to the method, through the synergistic effect of high-frequency reciprocating vibration of the electrodes and multi-channel discharging, the machining efficiency and the surface quality are remarkably improved. Specifically, under the driving of a reciprocating vibration device, the multi-channel electrode is additionally provided with high-frequency transverse reciprocating motion on the basis of longitudinal feeding, the inter-electrode chip removal, cooling and deionization characteristics are improved, and the machining stability is maintained. The discharge circuit adopts a group electrode and is formed by connecting parallel resistors and sub-electrodes in series, each sub-electrode is provided with a working solution inflow end and a discharge end, and an insulating layer is arranged on the outer wall of each sub-electrode, so that multi-channel discharge is realized. Energy is dispersed to multiple channels through multi-channel discharge, the energy density of a single channel is reduced, electrode loss is reduced, and the surface quality is improved. Compared with a traditional method, the method has the advantages that the pulse utilization rate and the material removal rate are increased, the electrode loss rate and the thickness of a recasting layer are reduced, and the surface roughness is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of multi-channel electrical discharge machining, that is, through the synergistic effect of small-amplitude reciprocating vibration of electrodes and multi-channel discharge, the purpose of efficiently etching difficult-to-machine materials is achieved, and specifically relates to a reciprocating vibration multi-channel efficient electrical discharge machining method. Background Art

[0002] Difficult-to-process materials in aviation, such as titanium alloys, high-temperature alloys, high-strength steels, composite materials and other new high-performance materials, are widely used in aerospace, military weapons, biomedicine and other fields due to their excellent performance. With the substantial improvement of equipment performance, the demand for their application will further increase, and structural parts will also develop in the direction of complexity, thin-walling and integration. Traditional processing methods such as CNC milling face problems such as large tool loss, high cost and long processing cycle in the processing of these difficult-to-process materials. In particular, problems such as low material removal rate and poor processing surface quality limit the accuracy and durability of parts. Therefore, the use of special processing methods to achieve high-efficiency, high-quality and low-cost forming processing of difficult-to-process materials has gradually developed into an inevitable trend.

[0003] Multi-channel EDM technology is a new special machining method based on traditional EDM, that is, multiple resistors are connected in parallel in the discharge circuit to maintain the open circuit voltage at each possible discharge channel, achieving multiple channel discharge in one pulse, breaking the technical barrier of traditional EDM technology that only one discharge channel can be formed in one pulse. Multi-channel group electrodes can generate multiple discharge channels in a single pulse cycle. The currents in each sub-electrode discharge branch are equal. The current in the total discharge circuit is equal to the superposition of the currents in the discharge branches of each unit sub-electrode, rising in a step-like manner. The number of steps is the number of discharge channels formed. This method not only keeps the overall discharge energy equal to that of traditional EDM by dispersing the discharge energy, but also effectively improves the surface quality of the workpiece.

[0004] In single-channel EDM, since the resistance of the metal is close to zero, that is, the two metal electrodes are approximately two equipotential bodies, only one discharge channel can be formed during one pulse discharge. Once the channel is established, the voltage between the two electrodes drops to the discharge maintenance voltage level, and cannot support the formation of additional discharge channels. However, in semiconductor EDM, due to the body resistance and the electrical contact resistance of the semiconductor, the electrode is no longer an equipotential body. Even after the main channel is formed during a pulse, other areas may still maintain a high enough voltage to form additional discharge channels. This allows the pulse energy to be dispersed and released through multiple channels, improving processing efficiency and surface quality, and reducing electrode loss.

[0005] When using traditional electric spark to process difficult-to-process materials, as the processing depth increases, the inter-electrode discharge environment deteriorates and the working medium flow rate slows down, resulting in the inter-electrode erosion products not being discharged in time, and even the erosion products reattaching to the substrate surface after the secondary discharge between the electrodes, which seriously affects the processing efficiency and the surface quality of the workpiece. Therefore, the present invention proposes a reciprocating vibration multi-channel high-efficiency electric spark machining method, which ensures that the electrode and the workpiece are always in a relative motion state during the machining process, improves the chip removal, cooling and deionization characteristics of the inter-electrode during the machining process, maintains the machining stability of difficult-to-process materials, and improves the machining efficiency and machining accuracy. Summary of the invention

[0006] The purpose of the present invention is to provide a reciprocating vibration multi-channel high-efficiency electrospark machining method, which can achieve continuous and stable machining of difficult-to-machine materials while taking into account both machining efficiency and machining surface quality, and effectively solve the technical problem of the difficulty in balancing machining efficiency and surface quality in existing discharge machining technology.

[0007] To achieve the above purpose, the specific technical solution of a reciprocating vibration multi-channel high-efficiency electrospark machining method of the present invention is as follows:

[0008] A specific technology of a reciprocating vibration multi-channel high-efficiency electrospark machining method, characterized in that: during the machining process, the synergistic effect of the small reciprocating vibration of the electrode and the multi-channel discharge significantly improves the machining efficiency and surface quality of the material. Specifically, driven by the reciprocating vibration device, the multi-channel electrode adds high-frequency lateral reciprocating motion on the basis of a single longitudinal feed motion. The high-frequency reciprocating vibration of the multi-channel electrode improves the chip removal, cooling and deionization characteristics between the electrodes during the machining process, and maintains the machining stability of the material; the multi-channel electrode in the discharge circuit adopts a group electrode, and the group electrode is composed of several resistors connected in parallel and connected in series with sub-electrodes respectively, each sub-electrode has a working medium inflow end and a discharge end, and the outer wall of the sub-electrode has an insulating layer to realize multi-channel discharge machining. Multi-channel discharge reduces the energy density of a single channel by dispersing the discharge energy into multiple channels, thereby reducing electrode loss and helping to improve the machining surface quality. Compared with traditional electrospark or multi-channel discharge machining, this reciprocating vibration multi-channel high-efficiency electrospark machining method greatly improves the pulse utilization rate and material removal rate, reduces the relative electrode loss rate and the thickness of the recast layer, and can achieve both surface quality and machining efficiency even when the machining depth increases.

[0009] Furthermore, the transverse reciprocating feeding distance of the multi-channel electrode is in the range of 0.1 to 5 mm, and the transverse reciprocating feeding frequency is in the range of 10 to 1500 times per minute.

[0010] Furthermore, during the processing, the working medium is kept to flow continuously and stably from the center of the sub-electrode to the processing area. Meanwhile, the pressure range of the working medium is 0.01-9 MPa.

[0011] Furthermore, the processing medium solution can be one or a combination of deionized water, spark oil, and working fluid, and the combination is configured in an equal volume ratio.

[0012] Furthermore, the resistance value of the resistor is 5Ω.

[0013] Furthermore, the multi-channel sub-electrode is a copper tube electrode with a diameter of 5 to 8 mm.

[0014] Furthermore, the insulating layer is a polyurethane coating with a thickness of 20 to 40 μm.

[0015] Furthermore, the material is titanium alloy, high-temperature alloy, high-strength steel and a composite material with electrical conductivity.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The present invention provides a reciprocating vibration multi-channel high-efficiency electrospark machining method, which increases the inter-electrode gap, reduces the inter-electrode energy density, and promotes the discharge of the erosion products through the reciprocating motion of the electrodes and the multi-channel discharge characteristics, thereby significantly improving the effective discharge probability and the erosion efficiency. While ensuring the machining quality and precision, the machining process is more stable and the efficiency is significantly better than conventional electrospark machining. In addition, the method has good controllability, can effectively eliminate surface residual stress, and is a macro-cutting force-free machining method, which is not limited by the mechanical properties of metal materials such as hardness and strength, and ensures the problem of residual tensile stress on the machining surface.

[0018] Compared with traditional EDM, the present invention can process difficult-to-process materials in a continuous, stable and efficient manner; compared with multi-channel EDM under the same electrical parameters, the processing efficiency is also greatly improved, and the processing time is significantly shortened. Especially when processing difficult-to-process metal materials such as titanium alloys, high-temperature alloys, and high-strength steel, the present invention effectively solves the problems of inefficient processing and poor surface quality, significantly reduces processing costs, and expands the application field. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of an application example of a reciprocating vibration multi-channel high-efficiency electrospark machining technology of the present invention;

[0020] Figure 2 This is a comparison chart of titanium alloy samples processed by EDM and reciprocating vibration multi-channel high-efficiency EDM.

[0021] Explanation of the numbers in the figure: 1. Pulse power supply, 2. Material, 3. Multi-channel electrode, 31. Sub-electrode, 32. Insulation layer, 33. Resistance, 4. Reciprocating vibration drive control unit, 5. PVC hose, 6. Working medium diverter, 7. Plunger pump, 8. Working medium. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] like Figure 1 As shown in the figure, a reciprocating vibration multi-channel high-efficiency EDM method is designed, and the specific steps are as follows:

[0024] Step 1: Prepare pulse power supply 1, material 2, sub-electrode 31, insulating layer 32, resistor 33, reciprocating vibration drive control unit 4, PVC hose 5, working medium diverter 6, plunger pump 7, working medium 8.

[0025] Step 2: Spray an insulating layer 32 on the outer wall of the sub-electrode 31, connect the insulated sub-electrode 31 in series with the resistor 33, and combine all the sub-electrodes in parallel to form a multi-channel electrode 3. The multi-channel electrode 3 is clamped on the reciprocating vibration drive control unit 4, and the working medium 8 is introduced into the processing area. The upper end of the multi-channel electrode 3 is connected to the lower end outlet of the working medium diverter 6 through the PVC hose 5, the water suction end of the plunger pump 7 is connected to the processing area, and the water outlet end is connected to the upper end inlet of the working medium diverter 6.

[0026] Step three: connect the positive electrode of the pulse power supply 1 to the material 2, and connect the negative electrode of the pulse power supply 1 to the multi-channel electrode 3; after the machine tool is aligned, start the reciprocating vibration drive control unit 4, and the reciprocating vibration drive control unit 4 drives the multi-channel electrode 3 to perform high-frequency reciprocating vibration in the horizontal direction; through the plunger pump 7, the working medium 8 is continuously and stably sprayed from the center of the multi-channel electrode 3 to the processing area, so that the difficult-to-process materials can be processed efficiently by reciprocating vibration multi-channel.

[0027] Specifically, the working medium 8 is deionized water.

[0028] Specifically, the pressure of the working medium is 4 MPa.

[0029] Specifically, the sub-electrode 31 is a copper tube electrode with a diameter of 5 mm, into which a working medium can flow, and the liquid filled therein can flush out the erosion products and improve the inter-electrode state.

[0030] Specifically, the insulating layer 32 is a 25 μm polyurethane coating.

[0031] Specifically, the resistance of the resistor 33 is 5Ω.

[0032] Specifically, the PVC hose 5 has an inner diameter of 4 mm and a wall thickness of 1 mm.

[0033] Specifically, the material is titanium alloy.

[0034] Specifically, the lateral reciprocating feeding distance of the reciprocating vibration driving control unit 4 is 1.5 mm, and the lateral reciprocating feeding frequency is 1200 times per minute.

[0035] like Figure 2 As shown, there is a comparison between traditional EDM and reciprocating vibration multi-channel high-efficiency EDM titanium alloy samples.

[0036] The present invention combines the characteristics of improving the inter-electrode state by combining the reciprocating motion of the electrode and dispersing the discharge energy by multi-channel discharge, thereby realizing efficient and high-quality processing of difficult-to-process materials, improving the stability of EDM processing, and reducing electrode loss. At the same time, the method is simple to implement, saves energy consumption, and is low in cost, and is particularly suitable for removing large excesses of difficult-to-process materials.

[0037] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A reciprocating vibration multi-channel high-efficiency electrospark machining method, characterized in that: During the machining process, the synergistic effect of the small reciprocating vibration of the electrode and the multi-channel discharge significantly improves the machining efficiency and surface quality of the material (2). Specifically, driven by the reciprocating vibration device, the multi-channel electrode (3) adds high-frequency lateral reciprocating motion on the basis of a single longitudinal feed motion. The high-frequency reciprocating vibration of the multi-channel electrode (3) improves the chip removal, cooling and deionization characteristics between the electrodes during the machining process, and maintains the machining stability of the material (2); the multi-channel electrode (3) in the discharge circuit adopts a group electrode, and the group electrode is composed of several resistors (33) connected in parallel and connected in series with sub-electrodes (31), each sub-electrode (31) has a working medium inflow end and a discharge end, and the outer wall of the sub-electrode has an insulating layer (32) to realize multi-channel discharge machining. Multi-channel discharge reduces the energy density of a single channel by dispersing the discharge energy into multiple channels, thereby reducing electrode loss and helping to improve the quality of the machined surface. This method for reciprocating vibration multi-channel high-efficiency EDM greatly improves the pulse utilization rate and material removal rate compared to traditional EDM or multi-channel EDM, reduces the relative electrode loss rate and recast layer thickness, and can achieve both surface quality and machining efficiency even when the machining depth increases.

2. A reciprocating vibration multi-channel high-efficiency electrospark machining method according to claim 1, characterized in that: The transverse reciprocating feeding distance of the multi-channel electrode is in the range of 0.1 to 5 mm, and the transverse reciprocating feeding frequency is in the range of 10 to 1500 times per minute.

3. A reciprocating vibration multi-channel high-efficiency electrospark machining method according to claim 1, characterized in that: During the processing, the working medium is always kept to flow steadily from the center of the sub-electrode to the processing area. At the same time, the pressure range of the working medium is 0.01~9MPA.

4. The reciprocating vibration multi-channel high-efficiency electrospark machining method according to claim 1, characterized in that: The working medium (8) can be one or a combination of deionized water, spark oil, and working fluid, and the combination is configured in an equal volume ratio.

5. The reciprocating vibration multi-channel high-efficiency electrospark machining method according to claim 1, characterized in that: The resistance value of the resistor (33) is 5Ω.

6. The reciprocating vibration multi-channel high-efficiency electrospark machining method according to claim 1, characterized in that: The multi-channel sub-electrode (31) is a copper tube electrode with a diameter of 5 to 8 mm.

7. The reciprocating vibration multi-channel high-efficiency electrospark machining method according to claim 1, characterized in that: The insulating layer (32) is a polyurethane coating with a thickness of 20 to 40 μm.

8. The reciprocating vibration multi-channel high-efficiency electrospark machining method according to claim 1, characterized in that: The material (2) is a conductive material such as titanium alloy, high-temperature alloy, high-strength steel and composite material.

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