Wire cut electrical discharge machining working fluid replacement system and method

Abstract

The invention discloses a wire cut electrical discharge machining working fluid replacement system and method. The system comprises a box body with a filter cavity, a fluid supply cavity and a fluid preparation cavity which are internally separated; the liquid supply cavity supplies liquid to the processing area through a liquid supply pipeline with a pump and a valve; the liquid preparation cavity is connected in parallel with the liquid supply pipeline through a liquid preparation output pipeline with a valve; a partition structure is arranged in the filter cavity to divide the filter cavity into a liquid storage cavity and a circulation cavity, an openable and closable communication structure is arranged between the liquid storage cavity and the circulation cavity, and the circulation cavity is communicated with the liquid supply cavity; each cavity is provided with a controlled liquid discharge passage; through the separable design of the liquid storage cavity and the circulation cavity and the parallel liquid supply of the liquid preparation cavity and the liquid supply cavity, the system can temporarily store the new liquid in the closed liquid storage cavity, continuously supply the new liquid through the liquid supply pipeline and empty the old liquid at the same time, so that the non-stop continuous operation of replacing the working liquid is realized, and the liquid replacement efficiency and the processing stability are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to wire cut electrical discharge machining equipment, and particularly relates to a wire cut electrical discharge machining working fluid replacement system and method. BACKGROUND

[0002] In the wire cut electrical discharge machining process, the working fluid serves as a machining discharge medium and a cooling and chip removal carrier, and its cleanliness and physicochemical state directly affect machining stability, cutting precision and machining efficiency. The existing wire cut electrical discharge machining equipment usually adopts a centralized tank structure, filters the working fluid flowing back from the machining area and recycles it, and replaces the working fluid by emptying the tank and re-injecting new working fluid when the performance of the working fluid deteriorates or needs to be replaced. In this kind of technical solution, the filtering, storage and fluid supply functions are usually integrated in the same liquid cavity or realized through a fixed communication structure, and when the working fluid replacement operation is performed, the fluid supply usually needs to be stopped, the old fluid needs to be discharged and the machining needs to be resumed after the injection of new fluid is completed. Since the machining fluid supply system and the internal space of the tank lack isolable structural division, the old fluid discharge and the new fluid supplement cannot be performed in parallel, resulting in a long fluid supply interruption time during the replacement process, and even complete shutdown. In addition, in the continuous machining or high-precision machining scenarios, frequent shutdown and fluid replacement not only reduce the equipment utilization rate, but also easily cause machining state fluctuations, affect the machining quality and consistency, and are difficult to meet the application requirements of modern wire cut electrical discharge machining for continuousness, stability and increasing automation degree. SUMMARY

[0003] The present application relates to wire cut electrical discharge machining equipment, and particularly relates to a wire cut electrical discharge machining working fluid replacement system and method.

[0004] The wire cut electrical discharge machining working fluid replacement system provided by the present application comprises a tank, the tank is divided into a filtering cavity and a fluid supply cavity, the fluid supply cavity provides working fluid to the wire cut electrical discharge machining area through a fluid supply pipeline and a fluid supply pump arranged on the fluid supply pipeline, the filtering cavity receives the working fluid flowing back from the machining area and processes it through a back fluid pipeline, and is in communication with the fluid supply cavity; a fluid preparation cavity is further divided in the tank, a fluid preparation output pipeline of the fluid preparation cavity is in communication with the fluid supply pipeline of the fluid supply cavity; valves independently controlled are arranged on the fluid preparation output pipeline and the fluid supply pipeline; a partition structure is arranged in the filtering cavity, the partition structure divides the filtering cavity into an upstream storage cavity and a downstream flow-through cavity, an openable and closable communication structure is arranged between the storage cavity and the flow-through cavity; the flow-through cavity is in communication with the fluid supply cavity, the flow-through cavity and the fluid supply cavity are respectively provided with controlled open drain paths, and when the communication structure is in a closed state, the storage cavity is isolated from the flow-through cavity and the fluid supply cavity.

[0005] Preferably, an automatic liquid preparation unit connected with the liquid preparation cavity is further included, the automatic liquid preparation unit comprising a liquid preparation pump and a liquid preparation pipeline in communication with the output end of the liquid preparation pump; a liquid preparation valve is arranged on the liquid preparation pipeline; the liquid preparation pipeline is in communication with a working liquid raw liquid conveying branch and a dilution liquid conveying branch respectively, wherein a first mass flow meter and a first electromagnetic valve are arranged on the working liquid raw liquid conveying branch in sequence, and a second mass flow meter and a second electromagnetic valve are arranged on the dilution liquid conveying branch in sequence; a stirrer or a circulating pump for mixing liquid is further included in the liquid preparation cavity.

[0006] Preferably, the liquid supply cavity and the liquid preparation cavity are in communication with the input end of the liquid supply pipeline through connecting pipelines respectively, the liquid supply pump is used to extract the working liquid in the liquid supply cavity and the liquid preparation cavity and then convey the working liquid to the wire cut electrical discharge machining area; the valve on the liquid preparation output pipeline is a first valve, and the valve on the liquid supply pipeline is a second valve; the output end of the liquid supply pipeline is divided into at least two machining liquid supply branches through a three-way connecting pipeline.

[0007] Preferably, the liquid supply pipeline is a straight pipeline segment, the input end of the straight pipeline segment is in communication with the liquid supply cavity and the liquid preparation cavity through corresponding connecting pipelines respectively, and the liquid supply pump is arranged on the straight pipeline segment and used to extract the working liquid from the liquid supply cavity or the liquid preparation cavity when the corresponding valve is opened.

[0008] Preferably, the output end of the liquid supply pipeline is divided into two machining liquid supply branches arranged symmetrically above and below through a three-way structure, and the two machining liquid supply branches supply liquid to the upper and lower machining areas of the workpiece respectively to form symmetrical flushing and cooling conditions.

[0009] Preferably, the liquid supply pump is a variable speed pump, and the flow rate of the variable speed pump can be adjusted among the liquid supply from the liquid supply cavity alone, the liquid supply from the liquid preparation cavity alone, or the liquid supply from the two cavities simultaneously according to the machining condition.

[0010] Preferably, the partition structure is a partition plate with at least one side being inclined and detachably fixed in the filter cavity, and the openable and closable communication structure is a sealing plug which is sealingly inserted into a through hole of the partition plate and connected with an operating rod.

[0011] Preferably, a multi-stage filter assembly is arranged in the filter cavity, the multi-stage filter assembly comprising a first filter screen arranged at the input end of the liquid storage cavity, a funnel-shaped water collecting groove arranged below the partition plate and used for flow guiding, and a third filter screen arranged in the flow passage cavity, a second filter screen is arranged in the water collecting groove, the output end of the water collecting groove extends below the third filter screen, a fourth filter screen is arranged in the liquid supply cavity, the flow passage cavity is in communication with the liquid supply cavity through a communication pipeline, the input end of the communication pipeline extends above the third filter screen, and the output end of the communication pipeline extends below the fourth filter screen.

[0012] Preferably, the slope of the inclined partition is used to guide the working fluid after settling to flow along the surface of the partition to the position of the communication structure.

[0013] Preferably, when the communication structure is in an open state, the working fluid enters the flow-through cavity from the storage cavity through the partition hole, and is further filtered by the multi-stage filtering assembly before being delivered to the supply cavity.

[0014] Preferably, a pre-filter is provided on the return pipeline, and the output end of the return pipeline is connected to the input end of the storage cavity through an energy recovery device; the energy recovery device includes an impeller provided on the output end of the return pipeline and a generator connected to the impeller.

[0015] Preferably, a liquid level meter is provided in the supply cavity for detecting the liquid level, and the liquid discharge passage includes a controlled discharge valve provided at the bottom of the flow-through cavity and the bottom of the supply cavity.

[0016] Preferably, the system is provided with a detection unit for characterizing the arrival state of new working fluid on the supply pipeline or the supply branch of the processing area, and the detection unit includes but is not limited to a liquid conductivity sensor, a concentration sensor, or a flow stability detection device.

[0017] Preferably, after detecting that the new working fluid from the liquid preparation cavity has been stably delivered to the processing area, the control system opens the liquid discharge passage of the flow-through cavity and the supply cavity to discharge the original working fluid.

[0018] Preferably, the opening and closing of the liquid discharge passage is linked to the detection results of the detection unit, so as to avoid the premature discharge of the original working fluid and the interruption of the processing supply when the new working fluid has not arrived.

[0019] Preferably, the opening and closing of the valve, the supply pump, the liquid preparation pump, and the liquid discharge passage are controlled by a controller, and the controller automatically executes the working fluid replacement process according to the feedback signals of the liquid level meter and the detection unit.

[0020] A wire cut electrical discharge machining working fluid replacement method based on the above system, comprising the following contents:

[0021] Step one, preparation for replacement: new working fluid is prepared in the liquid preparation cavity;

[0022] Step two, parallel replacement and buffering: while the supply pump is simultaneously extracting working fluid from the liquid preparation cavity and the supply cavity to supply the processing area, the openable and closable communication structure between the storage cavity and the flow-through cavity is closed.

[0023] Step three, waste liquid discharge: under the condition of maintaining continuous liquid supply to the machining area, the second valve on the pipeline connecting the liquid supply cavity is closed, the liquid supply is switched to be provided only by the liquid preparation cavity, and the liquid discharge passage of the flow-through cavity and the liquid supply cavity is opened to discharge the original working liquid;

[0024] Step four, system reconstruction: after the original working liquid in the flow-through cavity and the liquid supply cavity is discharged to a predetermined state through the liquid discharge passage, the openable and closable communication structure is opened;

[0025] Step five, normal state recovery: after the liquid level in the liquid supply cavity is restored to the working liquid circulation condition, the valve on the liquid preparation output pipeline is closed, and the liquid supply from the liquid supply cavity to the machining area is restored.

[0026] Preferably, the predetermined state includes at least one of the following: the liquid level in the flow-through cavity or the liquid supply cavity is lowered to a set lower limit; the discharge time reaches a preset time length; or the original working liquid is confirmed to be basically discharged through liquid parameter detection.

[0027] Preferably, the process of introducing new working liquid into the liquid preparation cavity includes: introducing the working liquid stock solution and the dilution liquid into the liquid preparation cavity through the automatic liquid preparation unit, respectively, and after the flow rates of the working liquid stock solution and the dilution liquid are measured and controlled, the working liquid stock solution and the dilution liquid are delivered to the liquid preparation cavity through the liquid preparation pump, and are mixed in the liquid preparation cavity through the stirrer or the circulating pump.

[0028] Preferably, the process of supplying liquid to the machining area includes: extracting working liquid from the liquid supply cavity or the liquid preparation cavity by the liquid supply pump, delivering the working liquid to the machining area through the liquid supply pipeline, and splitting the flow through a three-way connecting pipe at the output end of the liquid supply pipeline to form at least two machining liquid supply branches.

[0029] Beneficial effects: Compared with the prior art, the present application has the following significant advantages: by arranging the mutually isolable liquid storage cavity and the flow-through cavity inside the box body, and combining the liquid preparation cavity and the liquid supply cavity connected in parallel to the liquid supply pipeline, a working mode of discharging old working liquid and supplementing new working liquid while maintaining continuous liquid supply to the machining area is formed, continuous liquid operation during working liquid replacement is realized, the liquid replacement efficiency and the continuous operation ability of the equipment are improved, the problem of having to stop during liquid replacement due to the non-isolable structure of the liquid cavity in the prior art is solved, and the stability and machining reliability of the wire cut electrical discharge machining process are significantly improved. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 It is a schematic diagram of the overall structure of the system of the present application;

[0031] Figure 2 It is a schematic diagram of the energy recovery device structure of the present application. DETAILED DESCRIPTION

[0032] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0033] Example 1:

[0034] like Figures 1-2 As shown, this invention provides an electrical discharge wire cutting working fluid replacement system. The system utilizes a cooperating liquid preparation chamber 4, a liquid supply chamber 3, and a filter chamber 2 with isolating function, all housed within the same casing 1. This allows for the orderly and parallel completion of the introduction of new working fluid, the discharge of old working fluid, and the continuous supply of fluid to the processing area within the same system, thereby achieving uninterrupted working fluid replacement during electrical discharge wire cutting. The system mainly includes a casing 1, which is internally divided to form at least a filter chamber 2, a liquid supply chamber 3, and a liquid preparation chamber 4. The liquid preparation chamber 4 is used to pre-prepare and buffer new working fluid during system operation. The liquid supply chamber 3 serves as the main liquid supply chamber during processing, and the filter chamber 2 receives and processes the working fluid returning from the processing area. These three components are structurally independent but controllably connected in the fluid path, collectively forming the fluid circuit foundation supporting continuous fluid replacement.

[0035] The liquid mixing chamber 4 is connected to the liquid supply pipeline 31 via a liquid output pipeline 41. A first valve 43 is installed on the liquid output pipeline 41 to control whether the liquid mixing chamber 4 participates in the liquid supply to the processing area. The liquid supply chamber 3 is also connected to the input end of the liquid supply pipeline 31 via a connecting pipeline, and a second valve 33 is installed on the liquid supply pipeline 31. The liquid supply pump 32 is installed on the liquid supply pipeline 31. When the first valve 43 and the second valve 33 are in different open states, the liquid supply pump 32 can selectively draw working fluid from the liquid supply chamber 3, the liquid mixing chamber 4, or both simultaneously and deliver it to the EDM wire cutting processing area. Through the above parallel connection method, the system can smoothly switch between new and old working fluids during the fluid change process without interrupting the liquid supply. The system is equipped with an external power supply interface to provide working power to the liquid supply pump 32, the liquid mixing pump 51, the control unit, the detection unit, and each controllable valve. The external power supply can be AC ​​mains power or a converted DC power supply, and its power supply method is conventional technology in this field.

[0036] like Figure 1As shown, the output end of the liquid supply pipeline 31 is branched into at least two machining liquid supply branches through a three-way connecting pipe 37, and the machining liquid supply branches are respectively communicated with the upper nozzle and the lower nozzle of the wire electrical discharge machining area. The upper nozzle and the lower nozzle are respectively arranged on the upper side and the lower side of the workpiece, and are cooperatively arranged with the electrode wire guiding structure, so that the working liquid is sprayed into the discharge machining gap between the electrode wire and the workpiece from top to bottom or from bottom to top under the driving of the liquid supply pump 32, thereby continuously cooling, medium renewing and flushing discharging the machining products to the machining area in the discharge process. Through the above-mentioned symmetrical liquid supply mode, the working liquid flow field in the machining gap is kept relatively stable, and the discharge instability or the machining precision decline caused by insufficient local liquid renewal is avoided.

[0037] A detection unit for characterizing the state of the working liquid is arranged at the liquid inlet position of the machining liquid supply branch or the upper nozzle and the lower nozzle, and the detection unit is used for detecting the working liquid entering the machining area, so as to judge whether the new working liquid from the liquid preparation cavity 4 has reached the machining area and formed stable liquid supply. The detection unit can select an electric conductivity sensor, a concentration sensor or a detection device related to the physicochemical properties of the working liquid, and the detection signal is used to distinguish the newly configured working liquid from the original circulating working liquid. Here, it is the common detection technology known in the art, which will not be described in detail. When the detection unit confirms that the new working liquid has been stably delivered to the nozzle through the liquid supply pipeline 31 and the machining liquid supply branch and enters the machining gap, the control system allows to open the liquid discharge passage of the flow passage 23 and the liquid supply cavity 3, so as to discharge the original working liquid, thereby avoiding the premature liquid discharge which leads to the interruption of the liquid supply to the machining area or the fluctuation of the discharge state when the new working liquid has not actually participated in the machining.

[0038] In the wire electrical discharge machining process, after the working liquid completes the cooling, medium renewal and flushing of the discharge machining gap, the working liquid flows back to the filter cavity 2 in the tank 1 through the liquid return pipeline 21 from the machining area. The inlet of the liquid return pipeline 21 is arranged at the low backflow position of the machining area, and is used to collect the overflow working liquid from the upper nozzle, the lower nozzle and the periphery of the workpiece, so that the working liquid carrying metal chips, discharge products and suspended particles enters the liquid return system under the driving of gravity and flow.

[0039] In order to avoid that the large particle machining debris directly enters the filter cavity 2 and causes subsequent filtering burden or blockage, a pre-filter 211 is arranged on the liquid return pipeline 21, and the pre-filter 211 is a detachable filter screen structure with a filter aperture larger than that of the fine filtering component in the filter cavity, which is used for the first coarse filtration of the backflow working liquid to intercept the electrode wire chips, the larger size metal particles and other impurities. The working liquid filtered through the pre-filter continues to flow along the liquid return pipeline 21 to the filter cavity 2. A Y-type filter or other detachable filter can be arranged on the liquid return pipeline 21 to further filter the working liquid flowing to the filter cavity 2.

[0040] An energy recovery device 212 is arranged between the output end of the liquid return pipeline 21 and the inlet of the filter cavity 2, and the energy recovery device 212 comprises an impeller 2121 arranged below the liquid return pipeline 21 and a generator in transmission connection with the impeller 2121. A gear speed increasing mechanism is further arranged between the impeller 2121 and the generator. The working liquid flowing back is used to drive the impeller 2121 to rotate by using its own flow rate and potential energy before entering the filter cavity 2. The impeller 2121 converts the kinetic energy of the liquid into mechanical energy of the impeller 2121, and the mechanical energy is further increased in speed by the gear speed increasing mechanism to drive the generator to generate electric energy, so as to realize the recovery of the energy of the working liquid flowing back. The electric energy generated by the generator can be used to power the detection unit, the controller or the auxiliary electrical components in the system, or as a standby energy recovery output, so as to reduce the energy consumption in the operation process of the whole machine. The output end of the generator can be connected with the electrical components through a rectification, voltage stabilization and energy buffer circuit, so as to convert the unstable mechanical power generation output into stable low-voltage electric energy suitable for the detection unit or the control unit. The electric energy conversion and voltage stabilization circuit is a common technical means in the art.

[0041] The flow rate of the working liquid after the energy recovery device 212 is properly adjusted, and then enters the liquid storage cavity 22 located upstream in the filter cavity 2. In this area, the preliminary settlement of small particles is realized by reducing the flow rate and expanding the space, so as to create stable flow conditions for further filtration through the flow-through cavity 23 and the multi-stage filter assembly.

[0042] A partition structure is arranged inside the filter cavity 2, and the partition structure divides the filter cavity 2 into the liquid storage cavity 22 located upstream and the flow-through cavity 23 located downstream in the vertical direction. The partition structure is a partition plate 24 fixedly arranged in the filter cavity 2, and at least one side of the partition plate 24 is arranged as an inclined structure for guiding the working liquid to the through hole on the partition plate. The partition plate 24 is provided with a through hole, and a sealing plug 25 is sealingly inserted into the through hole. The sealing plug 25 is connected with an operating rod, and the sealing plug 25 can be opened or closed by external operation, so as to form an openable and closable communication structure between the liquid storage cavity 22 and the flow-through cavity 23. The opening and closing of the sealing plug 25 can be realized by manual operation, electromechanical actuator or a combination thereof, and the specific driving mode is coordinated and controlled by the control unit.

[0043] When the sealing plug 25 is in the closed state, the liquid storage cavity 22 is completely isolated from the flow-through cavity 23 and the liquid supply cavity 3, so that the liquid storage cavity 22 can be used as a temporary storage space for new working liquid. When the sealing plug 25 is in the open state, the working liquid in the liquid storage cavity 22 can enter the downstream structure through the through hole on the partition plate 24 to participate in the system circulation again.

[0044] In the storage cavity 22, the working liquid returned from the processing area is firstly filtered by the first filter screen 26 arranged at the input end of the storage cavity 22 after passing through the pre-filter 211 and the Y-type filter on the return liquid pipeline 21, so as to further intercept the larger-sized particle impurities. The internal space of the storage cavity 22 is relatively open, and the flow rate of the working liquid is low, so that the fine metal chips and particle impurities are naturally settled under the action of gravity, thereby realizing the preliminary clarification of the returned working liquid.

[0045] A funnel-shaped water collecting groove 27 is arranged below the partition plate 24, which is located between the storage cavity 22 and the flow-through cavity 23, and the inlet thereof is arranged in correspondence with the through hole of the partition plate 24. When the sealing plug 25 is opened, the working liquid in the storage cavity 22 that has been preliminarily settled and filtered by the first filter screen 26 flows into the water collecting groove 27 through the through hole of the partition plate, and is further filtered by the second filter screen 271 in the water collecting groove 27. The water collecting groove 27 has a funnel-shaped structure, and the outlet thereof is a downwardly extending flow guide pipe section. The water collecting groove 27 is fixed below the partition plate 24 by a threaded connecting piece, and the filter cavity 2 and the liquid supply cavity 3 are vertically detachable partition plates, and all the filtering structures are detachably fixed in the device, which is convenient for replacement.

[0046] The outlet of the flow guide pipe section is located below the third filter screen 28 and is arranged in correspondence with the central region thereof, and maintains a predetermined distance from the bottom surface of the third filter screen 28, so that the working liquid uniformly passes through the filter screen from bottom to top, and the working liquid after passing through the second filter screen 271 passes through the third filter screen 28 from bottom to top into the internal region of the flow-through cavity 23. Through this reverse filtering mode from bottom to top, the third filter screen 28 can effectively prevent the impurities possibly existing in the lower part from entering the upper region of the flow-through cavity 23, thereby forming a relatively stable high-purity working liquid region in the flow-through cavity 23.

[0047] The flow-through cavity 23 is communicated with the liquid supply cavity 3 through the communication pipe 35, the input end of the communication pipe 35 extends into the clean working liquid region above the third filter screen 28, and the output end thereof extends into the lower part of the fourth filter screen 34 in the liquid supply cavity 3, so that the working liquid entering the liquid supply cavity 3 still maintains a stable clean state after passing through multiple stages of filtering. The liquid supply pump 32 extracts the working liquid from the clean working liquid region above the fourth filter screen 34 in the liquid supply cavity 3 through the liquid supply pipeline 31 and delivers it to the processing area, thereby avoiding that the bottom sediments or the liquid not sufficiently filtered are re-sent to the processing area.

[0048] The liquid level gauge 36 is arranged in the liquid supply cavity 3 to monitor the change of liquid level in real time. The bottom of the flow cavity 23 and the liquid supply cavity 3 are respectively provided with a controlled opening liquid discharge passage to discharge the original working liquid during the liquid replacement process. The system can also be provided with a detection unit on the liquid supply pipeline 31 or the processing liquid supply branch to detect whether the new working liquid has reached the processing area stably, and the detection result is used to control the opening time of the liquid discharge passage and the valve. The system further comprises a control unit which is in signal connection with the detection unit, the liquid supply pump 32, the first valve 43, the second valve 33, the corresponding actuator of the sealing plug 25 and the valve of each liquid discharge passage, and is used to coordinate and control the opening and closing of each valve and actuator according to the state signal output by the detection unit and the liquid level signal of the liquid level gauge 36. The control unit can be composed of a programmable logic controller, an industrial control board card or a single-chip microcomputer control module. It receives the signals of the liquid level gauge 36, the flow detection element and the detection unit through an analog input interface, and controls the action of the corresponding actuators of each electromagnetic valve, the liquid supply pump 32, the liquid preparation pump 51 and the sealing plug 25 through a digital output interface or a driving module. The control logic based on the liquid level state and the output signal of the detection unit is pre-set in the control unit to realize the liquid supply supplement, the liquid replacement stage determination and the sequential interlocking control of each actuator. The above control method is a conventional automatic control means in the art, and the specific program implementation does not affect the technical effect of the present application. The liquid level signal output by the liquid level gauge 36 is one of the reference conditions for the liquid supply supplement, the liquid replacement process control and the running state judgment, and is used together with the detection result of the detection unit to control the working state of each valve and actuator, but not as the only control basis.

[0049] In the present embodiment, the box body 1 is provided with a separate automatic liquid preparation unit 5 on one side. The automatic liquid preparation unit 5 is used to prepare the new working liquid meeting the processing requirements in advance without interrupting the processing liquid supply, and deliver it to the liquid preparation cavity 4 for standby use.

[0050] The automatic liquid preparation unit 5 comprises a liquid preparation pump 51, a liquid preparation pipeline 52 in communication with the output end of the liquid preparation pump 51, and a liquid preparation valve 53 arranged on the liquid preparation pipeline 52. The liquid preparation pipeline 52 is divided into an original liquid delivery branch and a dilution liquid delivery branch at the inlet side of the liquid preparation pump 51. The original liquid delivery branch is used to deliver high-concentration working liquid original liquid, and the dilution liquid delivery branch is used to deliver deionized water or softened water and the like dilution liquid.

[0051] A first mass flowmeter 54 is arranged on the original liquid delivery branch in sequence to detect the flow of the working liquid original liquid entering the liquid preparation system in real time, and a first electromagnetic valve 55 is arranged to open or close the original liquid delivery according to the liquid preparation control requirement. A second electromagnetic valve 57 is correspondingly arranged on the dilution liquid delivery branch to control the on-off of the dilution liquid, and a second flow detection meter 56 is arranged on the dilution liquid delivery branch to monitor the flow of the dilution liquid.

[0052] The automatic liquid preparation unit 5 reads the raw liquid flow signal collected by the first mass flow meter 54 through the control module, and coordinates the opening timing and opening time of the first electromagnetic valve 55 and the second electromagnetic valve 57 according to the pre-set working liquid concentration parameter, so that the raw liquid and the diluent enter the liquid preparation pump 51 according to the set proportion. After the raw liquid and the diluent are preliminarily mixed during the conveying process of the liquid preparation pump 51, they are conveyed to the liquid preparation cavity 4 through the liquid preparation pipeline 52.

[0053] The liquid preparation cavity 4 is provided with a stirrer 42 or a circulating pump, so that the raw liquid and the diluent entering the liquid preparation cavity 4 are further fully mixed, so as to obtain new working liquid with uniform concentration and stable performance. During the liquid preparation process, the liquid preparation valve 53 is in an open state to ensure that the new working liquid can smoothly enter the liquid preparation cavity 4; after the liquid preparation is completed, the liquid preparation valve 53 is closed, so that the new working liquid in the liquid preparation cavity 4 is in a standby state.

[0054] Through the above structure and working mode, the automatic liquid preparation unit 5 can complete the metering, proportioning and mixing of the new working liquid in parallel during the processing process, so that the new working liquid meets the processing requirements before entering the liquid replacement process, thereby providing a stable and reliable liquid source basis for the subsequent uninterrupted working liquid replacement process.

[0055] Example 2:

[0056] In this embodiment, based on the wire electrical discharge machining working liquid replacement system of example 1, the supply, circulation and replacement of the working liquid are carried out in the following manner.

[0057] In the initial state of the system, the filter cavity 2, the liquid supply cavity 3 and the liquid preparation cavity 4 in the box body 1 are in an uncharged state. First, the automatic liquid preparation unit 5 is started, and the working liquid raw liquid and the diluent are introduced through the liquid preparation pump 51 from the working liquid raw liquid conveying branch and the diluent conveying branch respectively, wherein the raw liquid flow is metered by the first mass flow meter 54 and controlled by the first electromagnetic valve 55, and the raw liquid and the diluent are conveyed to the liquid preparation cavity 4 through the liquid preparation pipeline 52. In this process, the liquid preparation valve 53 is opened, and the stirrer 42 or the circulating pump arranged in the liquid preparation cavity 4 is used to mix the liquid entering the liquid preparation cavity 4 to form working liquid meeting the processing requirements.

[0058] When the working liquid preparation in the liquid preparation cavity 4 is completed, the first valve 43 is opened, and the liquid supply pump 32 is started to draw the working liquid from the liquid preparation cavity 4 through the liquid supply pipeline 31 to supply the working liquid to the machining area. The output end of the liquid supply pipeline 31 is divided into at least two machining liquid supply branches through the three-way connecting pipe 37 to supply the working liquid to the upper and lower machining areas of the workpiece respectively to meet the needs of the working liquid flushing and cooling in the wire electrical discharge machining process.

[0059] During the machining process, the used working fluid is returned to the filtering cavity 2 through the return fluid line 21. During the return process, the working fluid first passes through the pre-filter 211 to intercept larger particle impurities, and enters the storage cavity 22 through the energy recovery device 212. The kinetic energy of the returning working fluid drives the impeller 2121 to rotate and drives the generator to work, thereby achieving energy recovery. In the storage cavity 22, the flow rate of the returning working fluid is reduced, and preliminary sedimentation is completed, and the working fluid is filtered by the first filter screen 26.

[0060] When the sealing plug 25 is in the open state, the working fluid in the storage cavity 22 enters the funnel-shaped water receiving groove 27 through the through hole on the partition plate 24, and then passes through the second filter screen 271 and the third filter screen 28 to complete multi-stage filtration, and then enters the clean liquid area of the flow-through cavity 23. The filtered working fluid enters the liquid supply cavity 3 through the communication pipe 35, and is further filtered by the fourth filter screen 34 to form the effective liquid supply liquid in the liquid supply cavity 3.

[0061] During the normal circulation operation of the system, the liquid level meter 36 in the liquid supply cavity 3 is used to monitor the liquid level state in the liquid supply cavity 3, and serves as a reference basis for liquid supply replenishment and operation state adjustment. When the liquid level in the liquid supply cavity 3 decreases to a set range, the system opens the first valve 43, and replenishes the working fluid from the liquid preparation cavity 4 through the liquid supply pump 32; when the liquid level in the liquid supply cavity 3 recovers to the working state range, the first valve 43 is closed, and the system recovers to the circulation liquid supply mode mainly using the working fluid in the liquid supply cavity 3.

[0062] When the detection unit detects that the working fluid parameter entering the machining area deviates from the preset range, or the control unit comprehensively judges that the working fluid needs to be replaced as a whole according to the cumulative information of the machining condition and the liquid level change of the liquid level meter 36, the system enters the liquid replacement operation stage. In this stage, first, the communication structure between the storage cavity 22 and the flow-through cavity 23 is closed, so that the sealing plug 25 is in a closed state, thereby isolating the storage cavity 22 from the flow-through cavity 23 and the liquid supply cavity 3. The opening of the drain passage is premised on the detection unit confirming that the new working fluid from the liquid preparation cavity 4 has stably reached the machining area. Before the above condition is met, the control unit prohibits the opening of the drain passage. Subsequently, under the condition of maintaining continuous liquid supply to the machining area, the drain passage at the bottom of the flow-through cavity 23 and the liquid supply cavity 3 is opened, so that the original working fluid is gradually drained; at the same time, the new working fluid continuously supplies the machining area from the liquid preparation cavity 4 through the liquid supply line 31, and is temporarily stored in the area above the sealing plug 25 in the filtering cavity 2.

[0063] After the original working liquid is discharged, the liquid discharge passage is closed, and the communication structure between the liquid storage chamber 22 and the flow passage 23 is opened, so that the temporarily stored new working liquid enters the flow passage 23 and the liquid supply chamber 3, and the normal filtering and circulating path is restored. The determination that the original working liquid is discharged can be based on at least one of the liquid discharge time of the liquid discharge passage, the liquid level change detected by the liquid level meter 36, or the liquid discharge working condition parameter preset by the control unit. When the liquid level in the liquid supply chamber 3 returns to the normal operating state, the first valve 43 is closed, the system exits the liquid replacement stage and returns to the normal circulating liquid supply and processing.

[0064] Through the above method, the smooth switching of new and old working liquids is realized without stopping the processing liquid supply, and the continuity of the processing process and the stability of the system operation are ensured.

Claims

1. An electrical discharge wire cutting working fluid replacement system, comprising a housing (1), the housing (1) being divided into a filter chamber (2) and a supply chamber (3), the supply chamber (3) supplying working fluid to the electrical discharge wire cutting processing area via a supply pipeline (31) and a supply pump (32) installed on the supply pipeline (31), the filter chamber (2) receiving and processing the working fluid returning from the processing area via a return pipeline (21), and being connected to the supply chamber (3); characterized in that, The housing (1) is also divided into a liquid preparation chamber (4), and the liquid preparation output pipeline (41) of the liquid preparation chamber (4) is connected to the liquid supply pipeline (31) of the liquid supply chamber (3); the liquid preparation output pipeline (41) and the liquid supply pipeline (31) are each equipped with independently controlled valves; the filter chamber (2) is provided with a partition structure, which divides the filter chamber (2) into an upstream liquid storage chamber (22) and a downstream flow chamber (23), and there is an openable and closable communication structure between the liquid storage chamber (22) and the flow chamber (23); the flow chamber (23) is connected to the liquid supply chamber (3), and the flow chamber (23) and the liquid supply chamber (3) are respectively provided with a controlled opening drainage passage. When the communication structure is closed, the liquid storage chamber (22) is isolated from the flow chamber (23) and the liquid supply chamber (3).

2. The electrical discharge wire cutting working fluid replacement system according to claim 1, characterized in that: It also includes an automatic liquid mixing unit (5) whose output end is connected to the liquid mixing chamber (4). The automatic liquid mixing unit includes a liquid mixing pump (51) and a liquid mixing pipeline (52) connected to the output end of the liquid mixing pump (51). A liquid mixing valve (53) is provided on the liquid mixing pipeline (52). The liquid mixing pipeline (52) is connected to a raw liquid conveying branch for conveying the raw working liquid and a diluent conveying branch for conveying the diluent. A first mass flow meter (54) and a first solenoid valve (55) are provided in sequence on the raw liquid conveying branch. A second mass flow meter (56) and a second solenoid valve (57) are provided in sequence on the diluent conveying branch. The liquid mixing chamber (4) also includes a stirrer (42) or a circulation pump for mixing liquids.

3. The electrical discharge wire cutting working fluid replacement system according to claim 1, characterized in that: The liquid supply chamber (3) and the liquid distribution chamber (4) are respectively connected to the input end of the liquid supply pipeline (31) through connecting pipelines. The liquid supply pump (32) is used to extract the working fluid in the liquid supply chamber (3) and the liquid distribution chamber (4) and deliver it to the electrical discharge wire cutting processing area. The valve on the liquid distribution output pipeline (41) is the first valve (43), and the valve on the liquid supply pipeline (31) is the second valve (33). The output end of the liquid supply pipeline (31) is divided into at least two processing liquid supply branches through a three-way connecting pipe (37).

4. The electrical discharge wire cutting working fluid replacement system according to claim 1, characterized in that: The partition structure is a partition (24) that is detachably fixed in the filter chamber (2) with at least one side being inclined. The openable and closable communication structure is a sealing plug (25) that is sealed and inserted into the through hole of the partition (24) and connected to an operating rod.

5. The electrical discharge wire cutting working fluid replacement system according to claim 4, characterized in that: The filter chamber (2) is provided with a multi-stage filtration assembly, which includes a first filter screen (26) disposed at the input end of the liquid storage chamber (22), a funnel-shaped water receiving trough (27) disposed below the partition (24) for guiding flow, and a third filter screen (28) disposed in the flow chamber (23). The water receiving trough (27) is provided with a second filter screen (271). The output end of the water receiving trough (27) extends below the third filter screen (28). The liquid supply chamber (3) is provided with a fourth filter screen (34). The flow chamber (23) and the liquid supply chamber (3) are connected by a connecting pipe (35). The input end of the connecting pipe (35) extends above the third filter screen (28), and its output end extends below the fourth filter screen (34).

6. The electrical discharge wire cutting working fluid replacement system according to claim 1, characterized in that: The return pipeline (21) is equipped with a pre-filter (211), and the output end of the return pipeline (21) is connected to the input end of the storage chamber (22) through an energy recovery device (212); the energy recovery device (212) includes an impeller (2121) located at the output end of the return pipeline (21) and a generator connected to the impeller (2121).

7. The electrical discharge wire cutting working fluid replacement system according to claim 1, characterized in that: The liquid supply chamber (3) is equipped with a level gauge (36) for detecting the liquid level, and the liquid discharge passage includes a controlled discharge valve located at the bottom of the flow chamber (23) and the bottom of the liquid supply chamber (3).

8. A method for changing the working fluid in wire electrical discharge machining based on the system described in any one of claims 1-7, characterized in that: Includes the following: Step 1, Replacement preparation: Prepare new working solution in the solution preparation chamber (4); Step 2, Parallel replacement and buffering: While the working fluid is simultaneously drawn from the liquid preparation chamber (4) and the liquid supply chamber (3) by the liquid supply pump (32) and supplied to the processing area, the openable and closable communication structure between the liquid storage chamber (22) and the flow chamber (23) is closed. Step 3, waste liquid discharge: Under the condition of maintaining continuous liquid supply to the processing area, close the valve on the pipeline connected to the liquid supply chamber (3) so that the liquid supply is switched to be provided only by the liquid distribution chamber (4), and open the drainage passage of the flow chamber (23) and the liquid supply chamber (3) to discharge the original working liquid; Step 4, System Reconstruction: After the original working fluid in the flow chamber (23) and the supply chamber (3) is discharged to the predetermined state through the drainage passage, the openable and closable communication structure is opened; Step 5, Normal Restoration: After the liquid level in the supply chamber (3) is restored to the working fluid circulation condition, close the valve on the liquid distribution output pipeline (41) and restore the supply of liquid only from the supply chamber (3) to the processing area.

9. The method for replacing the working fluid in wire electrical discharge machining according to claim 8, characterized in that: The process of introducing new working fluid into the mixing chamber (4) includes: introducing the working fluid stock solution and diluent through the automatic mixing unit (5), measuring and controlling the flow rate of the stock solution, and then transporting the stock solution and diluent to the mixing chamber (4) through the mixing pump (51), and mixing them in the mixing chamber (4) by the stirrer (42) or the circulation pump.

10. The method for changing the working fluid in wire electrical discharge machining according to claim 8, characterized in that: The process of supplying liquid to the processing area includes: the liquid supply pump (32) draws working liquid from the liquid supply chamber (3) or the liquid distribution chamber (4), and delivers it to the processing area through the liquid supply pipeline (31). At least two processing liquid supply branches are formed by splitting the liquid at the output end of the liquid supply pipeline (31) through the three-way connecting pipe (37).

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