Liquid filtering device and processing system

Abstract

The present invention relates to a liquid filtration device, comprising: a dirty liquid tank for storing a dirty liquid which is a liquid containing metal filings generated by machining a metal workpiece; a filter for filtering the dirty liquid; and a clear liquid tank for storing a clear liquid that has passed through the filter. The liquid filter device includes: an adjustment mechanism that adjusts a resistivity value of a liquid; a first sensor that detects a resistivity value of the liquid; a determination unit that determines whether or not the resistivity value has increased; and a mechanism control unit that causes the adjustment mechanism to adjust the resistivity value of the liquid when it is determined that the resistivity value has increased.

Description

Technical Field

[0001] This disclosure relates to liquid filtration devices and processing systems. Background Technology

[0002] Japanese Patent Application Publication No. 2021-167052 discloses an electrical discharge machining (EDM) machine comprising a sludge tank, a filter, and a cleaning tank. The sludge tank stores machining fluid containing machining chips. The machining fluid stored in the sludge tank is conveyed to the cleaning tank via the filter. The filter filters the machining fluid. Summary of the Invention

[0003] Filters have a lifespan (product lifespan). This refers to liquid filtration devices and processing systems where extending the filter's lifespan is desired.

[0004] This disclosure discloses a liquid filtration device comprising: a sludge tank for storing sludge, the sludge being a liquid containing metal shavings generated during the processing of a metal workpiece; a filter for filtering the sludge; and a clear liquid tank for storing the liquid that has passed through the filter, i.e., clear liquid. The liquid filtration device further comprises: an adjustment mechanism for adjusting the resistivity value of the liquid; a first sensor for detecting the resistivity value of the liquid; a determination unit for determining, based on the resistivity value detected by the first sensor, whether the resistivity value has increased; and a mechanism control unit for, if it is determined that the resistivity value has increased, causing the adjustment mechanism to adjust the resistivity value of the liquid.

[0005] Another aspect of this disclosure is a processing system comprising the aforementioned liquid filtration device and a processing machine for processing the metal workpiece. Attached Figure Description

[0006] Figure 1 This is a schematic diagram of the machining system.

[0007] Figure 2 This is a schematic diagram of the control device according to the first embodiment.

[0008] Figure 3A This is a chart used to illustrate the determination of the resistivity value in the first embodiment. Figure 3B This is a chart used to explain the determination of the pressure value in the first embodiment.

[0009] Figure 4 This is a schematic diagram of the control device according to the second embodiment.

[0010] Figure 5A This is a chart used to illustrate the determination of the resistivity value in the second embodiment. Figure 5B This is a chart used to explain the determination of the pressure value in the second embodiment.

[0011] Figure 6A This is a chart used to illustrate the determination of the resistivity value in the third embodiment. Figure 6B This is a chart used to explain the determination of the pressure value in the third embodiment.

[0012] Figure 7 This is a schematic diagram of the control device according to the fourth embodiment.

[0013] Figure 8A This is a chart used to explain the determination of the resistivity value in the fourth embodiment. Figure 8B This is a chart used to explain the determination of the pressure value in the fourth embodiment.

[0014] Figure 9A This is a chart used to illustrate the determination of the resistivity value in the fifth embodiment. Figure 9B This is a chart used to explain the determination of the pressure value in the fifth embodiment.

[0015] Figure 10 This is a schematic diagram of the control device in Modified Example 1.

[0016] Figure 11 This is a schematic diagram of the machining system in variation example 2. Detailed Implementation

[0017] When the filter mesh becomes clogged due to metal shavings generated during the processing of metal workpieces, the operator needs to replace the filter. Used filters are typically discarded and not reused. To reduce the frequency of filter replacements and the amount of filter waste, it is necessary to extend the filter's lifespan.

[0018] The subject of this disclosure is to provide a liquid filtration device and processing system that can extend the life of the filter.

[0019] In this disclosure, the term "resistivity value" is used. Generally, the reciprocal of the resistivity value [Ωm] is known to be the conductivity [S / m]. Therefore, the term "resistivity value" can be replaced by the term "conductivity." When the term "resistivity value" is replaced by "conductivity," "decreasing the resistivity value" is replaced by "increasing the conductivity." Conversely, "increasing the resistivity value" is replaced by "decreasing the conductivity."

[0020] [First Implementation Method]

[0021] Figure 1 This is a schematic diagram of the machining system 10. The machining system 10 includes a machining machine 12, a liquid filtration device 14, and a control device 16. The machining machine 12 is a machine for machining metal workpieces. The machining machine 12 can also be an electrical discharge machining (EDM) machine that performs electrical discharge machining on metal workpieces in a machining fluid. The machining fluid is a liquid used for machining metal workpieces.

[0022] The liquid filtration device 14 includes a sludge tank 18, a clean liquid tank 20, a first pump 22, a filter 24, a second pump 26, and an adjustment mechanism 28.

[0023] The machining fluid used during processing by the machining machine 12 is discharged from the machining machine 12 through the drainage path 30 to the sludge tank 18. Sludge is mixed into the machining fluid discharged from the machining machine 12. The sludge contains metal shavings generated during the processing of the metal workpiece.

[0024] The processing fluid stored in the sludge tank 18 is transported to the clear fluid tank 20 through the filtration path 32. A first pump 22 and a filter 24 are installed in the filtration path 32. The first pump 22 draws the processing fluid from the sludge tank 18 and transports it to the clear fluid tank 20. The filter 24 filters the processing fluid transported from the sludge tank 18 to the clear fluid tank 20, removing metal shavings and other sludge from the processing fluid.

[0025] The processing fluid stored in the clear liquid tank 20 is transported from the clear liquid tank 20 to the processing machine 12 through the supply path 34. A second pump 26 is provided in the supply path 34. The second pump 26 draws the processing fluid from the clear liquid tank 20 and transports it to the processing machine 12.

[0026] The adjustment mechanism 28 is a mechanism for adjusting the resistivity value of the clear liquid stored in the clear liquid tank 20. In this embodiment, the adjustment mechanism 28 causes the processing fluid to pass through a container holding a reagent that reduces the resistivity value. For example, the adjustment mechanism 28 can be composed of a circulation path 28A, a valve 28B, and a reagent container 28C.

[0027] The circulation path 28A includes a destination path 28A_1 and a loop path 28A_2. Destination path 28A_1 connects the supply path 34, which is upstream of the second pump 26, to the reagent container 28C. Loop path 28A_2 connects the reagent container 28C to the clear liquid tank 20. A valve 28B is provided in destination path 28A_1. When valve 28B is open, a portion of the processing fluid stored in the clear liquid tank 20 circulates between the clear liquid tank 20 and the reagent container 28C. Alternatively, valve 28B may also be provided in loop path 28A_2.

[0028] The reagent container 28C is a container that holds a reagent that reduces the resistivity of the processing fluid, and is connected to the outgoing path 28A_1 and the return path 28A_2. The reagent container 28C reduces the resistivity of the processing fluid delivered from the outgoing path 28A_1 through the reagent, and then delivers the processed fluid with the reduced resistivity to the return path 28A_2.

[0029] Figure 2 This is a schematic diagram of the control device 16 according to the first embodiment. The control device 16 is a device for controlling the adjustment mechanism 28. The control device 16 can also be assembled into the numerical control device that controls the machining machine 12.

[0030] The control device 16 has one or more processors 50, such as a CPU or MPU, and one or more memories 52, such as ROM, RAM, or hard disk. The control device 16 causes the processors 50 to execute programs stored in the memories 52. When executing a program, the processors 50 function as a recording control unit 54, an acquisition unit 56, a determination unit 58, and a mechanism control unit 60. Furthermore, at least one of the recording control unit 54, the acquisition unit 56, the determination unit 58, and the mechanism control unit 60 can also be implemented using integrated circuits such as ASICs or FPGAs. Additionally, at least one of the recording control unit 54, the acquisition unit 56, the determination unit 58, and the mechanism control unit 60 can also be constructed using electronic circuits including discrete components.

[0031] A first sensor 62 and a second sensor 64 are connected to the control device 16. The first sensor 62 is a sensor that detects the resistivity of the liquid. The first sensor 62 is, for example, installed inside the clear liquid tank 20 (see reference). Figure 1 Furthermore, the first sensor 62 can also be replaced with a sensor that detects the conductivity of the liquid. The second sensor 64 is a sensor that detects the pressure applied to the filter 24. The second sensor 64 is, for example, disposed in the filtration path 32 between the first pump 22 and the filter 24 (see reference). Figure 1 ).

[0032] The recording control unit 54 records resistivity data in the memory 52 at predetermined sampling intervals based on the signal output from the first sensor 62. Additionally, the recording control unit 54 records pressure data in the memory 52 at predetermined sampling intervals based on the signal output from the second sensor 64. The resistivity data represents at least the resistivity value detected by the first sensor 62 and the detection time. The pressure data represents at least the pressure value detected by the second sensor 64 and the detection time.

[0033] The acquisition unit 56 periodically acquires specific resistivity values ​​based on resistivity data stored in the memory 52. ​​Each time the acquisition unit 56 acquires a resistivity value, the determination unit 58 determines whether the resistivity value of the processing fluid has increased. The acquisition unit 56 periodically acquires pressure values ​​based on pressure data stored in the memory 52. ​​Each time the acquisition unit 56 acquires a pressure value, the determination unit 58 determines whether the pressure applied to the filter 24 has increased. Details of the acquisition unit 56 and the determination unit 58 will be described later.

[0034] The mechanism control unit 60 controls the adjustment mechanism 28. When the determination unit 58 determines that both the resistivity and pressure values ​​are rising, the mechanism control unit 60 causes the adjustment mechanism 28 to begin adjusting the resistivity of the processing fluid. If the adjustment mechanism 28 consists of a circulation path 28A, a valve 28B, and a reagent container 28C, the mechanism control unit 60 opens the valve 28B. Thus, the adjustment mechanism 28 can adjust the resistivity of the processing fluid.

[0035] The timing at which the mechanism control unit 60 stops the adjustment mechanism 28 is not particularly limited. For example, if a predetermined time has elapsed since the adjustment mechanism 28 began adjusting, the mechanism control unit 60 stops the adjustment mechanism 28. In the case where the adjustment mechanism 28 consists of a circulation path 28A, a valve 28B, and a reagent container 28C, the mechanism control unit 60 closes the valve 28B. Thus, the adjustment mechanism 28 stops adjusting the resistivity value of the processing fluid.

[0036] Next, use Figure 3A and Figure 3B The acquisition section 56 and the judgment section 58 are described in detail. Figure 3A This is a chart used to illustrate the determination of the resistivity value in the first embodiment. Figure 3B This is a chart used to explain the determination of the pressure value in the first embodiment.

[0037] like Figure 3A As shown, the acquisition unit 56 acquires resistivity values ​​at predetermined intervals PD based on resistivity data stored in the memory 52. ​​Whenever the acquisition unit 56 acquires the current resistivity value R1, the determination unit 58 compares the current resistivity value R1 with a past resistivity value R2. The past resistivity value R2 is the resistivity value detected by the first sensor 62 at a time T2, which is a predetermined interval PD earlier than the current time T1.

[0038] If the current resistivity value R1 exceeds the previous resistivity value R2 (R1>R2), the determination unit 58 determines that the resistivity value has increased. On the other hand, if the current resistivity value R1 is less than or equal to the previous resistivity value R2 (R1≤R2), the determination unit 58 determines that the resistivity value has not increased.

[0039] like Figure 3B As shown, the acquisition unit 56 acquires pressure values ​​at predetermined intervals PD based on pressure data stored in the memory 52. ​​Whenever the acquisition unit 56 acquires the current pressure value P1, the determination unit 58 compares the current pressure value P1 with a past pressure value P2. The past pressure value P2 is the pressure value detected by the second sensor 64 at a time T2, which is a predetermined interval PD earlier than the current time T1.

[0040] If the current pressure value P1 exceeds the past pressure value P2 (P1 > P2), the determination unit 58 determines that the pressure value has increased. On the other hand, if the current pressure value P1 is less than or equal to the past pressure value P2 (P1 ≤ P2), the determination unit 58 determines that the pressure value has not increased.

[0041] Furthermore, preferred Figure 3A PD during the scheduled period Figure 3B The scheduled periods (PD) are the same, but they can also be different. That is, Figure 3A Time T2 and Figure 3B The time T2 can also be a different time.

[0042] In this way, the determination unit 58 compares the current resistivity value R1 with the past resistivity value R2 at predetermined intervals PD, and compares the current pressure value P1 with the past pressure value P2. Therefore, compared with comparing average values, the processing load of the processor 50 can be reduced.

[0043] Furthermore, the determination unit 58 can also determine whether the resistivity value has increased based on whether the subtraction result (R1-R2) obtained by subtracting the past resistivity value R2 from the current resistivity value R1 exceeds a predetermined threshold. Similarly, the determination unit 58 can also determine whether the pressure value has increased based on whether the subtraction result (P1-P2) obtained by subtracting the past pressure value P2 from the current pressure value P1 exceeds a predetermined threshold.

[0044] By determining whether the resistivity or pressure value has increased based on whether the result of the subtraction operation exceeds a predetermined threshold, the impact of noise can be reduced. Furthermore, when the change in resistivity or pressure value is small, the control of the adjustment mechanism 28 by the mechanism control unit 60 can be suppressed. As a result, the processing load on the processor 50 can be reduced.

[0045] [Second Implementation]

[0046] In the second embodiment, descriptions that are repeated in the first embodiment are omitted. Figure 4 This is a schematic diagram of the control device 16 according to the second embodiment. In the second embodiment, the acquisition unit 56 is replaced by an average value calculation unit 66. When the program stored in the memory 52 is executed, the processor 50 operates as the average value calculation unit 66. Furthermore, the average value calculation unit 66 can be implemented by an integrated circuit or constituted by an electronic circuit containing discrete components.

[0047] like Figure 5AAs shown, the average value calculation unit 66 periodically calculates a first average value AV1 and a second average value AV2 based on the resistivity data stored in the memory 52. ​​The first average value AV1 is the average of the resistivity values ​​detected by the first sensor 62 in a first period PD1. The second average value AV2 is the average of the resistivity values ​​detected by the first sensor 62 in a second period PD2. The start time of the second period PD2 is earlier than the start time of the first period PD1. The length of the second period PD2 is greater than or equal to the length of the first period PD1.

[0048] In this embodiment, the second period PD2 is longer than the first period PD1 and includes the entire first period PD1. In other words, the start time of the second period PD2 is before the start time of the first period PD1, and the end time of the second period PD2 is equal to the end time of the first period PD1.

[0049] Furthermore, the second period PD2 only needs to be longer than the first period PD1. Therefore, the second period PD2 may not include all or part of the first period PD1. Additionally, the end time of the second period PD2 may be before the end time of the first period PD1. In this case, the end time of the second period PD2 may also be before the end time of the first period PD1 and after the start time of the first period PD1. Furthermore, the end time of the first period PD1 may also be the current time T1.

[0050] Whenever the average value calculation unit 66 calculates the first average value AV1 and the second average value AV2, the determination unit 58 compares the first average value AV1 and the second average value AV2. If the first average value AV1 exceeds the second average value AV2 (AV1 > AV2), the determination unit 58 determines that the resistivity value has increased. On the other hand, if the first average value AV1 is less than or equal to the second average value AV2 (AV1 ≤ AV2), the determination unit 58 determines that the resistivity value has not increased.

[0051] like Figure 5B As shown, the average value calculation unit 66 periodically calculates a third average value AV3 and a fourth average value AV4 based on the pressure data stored in the memory 52. ​​The third average value AV3 is the average of the pressure values ​​detected by the second sensor 64 during the first period PD1. The fourth average value AV4 is the average of the pressure values ​​detected by the second sensor 64 during the second period PD2.

[0052] Whenever the average calculation unit 66 calculates the third average value AV3 and the fourth average value AV4, the determination unit 58 compares the third average value AV3 and the fourth average value AV4. If the third average value AV3 exceeds the fourth average value AV4 (AV3 > AV4), the determination unit 58 determines that the pressure value has increased. On the other hand, if the third average value AV3 is less than or equal to the fourth average value AV4 (AV3 ≤ AV4), the determination unit 58 determines that the pressure value has not increased.

[0053] Furthermore, preferred Figure 5A The first period PD1 and Figure 5B The first period PD1 is the same, but it can also be different. Similarly, it is preferred that... Figure 5A The second period PD2 and Figure 5B The second period PD2 is the same, but it can also be different.

[0054] In this way, the determination unit 58 determines whether the resistivity value and the pressure value have increased based on the calculation results of the average value calculation unit 66. Therefore, even if an unexpected abrupt change (interference) occurs in at least one of the resistivity value and the pressure value, the erroneous determination of the determination unit 58 can be suppressed.

[0055] Furthermore, the determination unit 58 can also determine whether the resistivity value has increased based on whether the subtraction result (AV1-AV2) obtained by subtracting the second average value AV2 from the first average value AV1 exceeds a predetermined threshold. Similarly, the determination unit 58 can also determine whether the pressure value has increased based on whether the subtraction result (AV3-AV4) obtained by subtracting the fourth average value AV4 from the third average value AV3 exceeds a predetermined threshold.

[0056] [Third Implementation Method]

[0057] In the third embodiment, descriptions that are repeated in the above embodiments are omitted. For example... Figure 6A As shown, the average value calculation unit 66 calculates the average resistivity based on the resistivity data stored in the memory 52 for each predetermined period of PD. The average resistivity is the average of the resistivity values ​​detected by the first sensor 62 during the predetermined period of PD. Whenever the average value calculation unit 66 calculates the current average resistivity AV5, the determination unit 58 compares the current average resistivity AV5 with the past average resistivity AV6.

[0058] The current resistivity average value AV5 is the average resistivity value detected by the first sensor 62 during a predetermined period PD (first period PD1), and is equivalent to the first average value AV1. The past resistivity average value AV6 is the average resistivity value detected by the first sensor 62 during a predetermined period PD (second period PD2) preceding the current resistivity average value AV5, and is equivalent to the second average value AV2. Furthermore, in this embodiment, the first period PD1 and the second period PD2 do not overlap.

[0059] The end time of the past resistivity average AV6 coincides with the start time of the current resistivity average AV5, but it can also be earlier than the start time of the current resistivity average AV5. In other words, the past resistivity average AV6 and the current resistivity average AV5 can also be separated in time.

[0060] If the current average resistivity AV5 exceeds the past average resistivity AV6 (AV5 > AV6), the determination unit 58 determines that the resistivity value has increased. On the other hand, if the current average resistivity AV5 is less than or equal to the past average resistivity AV6 (AV5 ≤ AV6), the determination unit 58 determines that the resistivity value has not increased.

[0061] like Figure 6B As shown, the average value calculation unit 66 calculates the average pressure value for each predetermined period (PD) based on the pressure data stored in the memory 52. ​​The average pressure value is the average of the pressure values ​​detected by the second sensor 64 during the predetermined period (PD). Whenever the average value calculation unit 66 calculates the current average pressure value AV7, the determination unit 58 compares the current average pressure value AV7 with the past average pressure value AV8.

[0062] The current average pressure value AV7 is the average pressure value detected by the second sensor 64 during a predetermined period PD (first period PD1), which is equivalent to the third average value AV3. The past average pressure value AV8 is the average pressure value detected by the second sensor 64 during a predetermined period PD (second period PD2) prior to the current average pressure value AV7, which is equivalent to the fourth average value AV4.

[0063] The end time of the past pressure average AV8 coincides with the start time of the current pressure average AV7, but it can also be earlier than the start time of the current pressure average AV7. In other words, the past pressure average AV8 and the current pressure average AV7 can also be separated in time.

[0064] If the current average pressure AV7 exceeds the past average pressure AV8 (AV7 > AV8), the determination unit 58 determines that the pressure value has increased. On the other hand, if the current average pressure AV7 is less than or equal to the past average pressure AV8 (AV7 ≤ AV8), the determination unit 58 determines that the pressure value has not increased.

[0065] In this way, the determination unit 58 compares the current average resistivity AV5 with the past average resistivity AV6 at predetermined intervals PD, and compares the current average pressure AV7 with the past average pressure AV8. Therefore, even if an unexpected abrupt change (interference) occurs in at least one of the resistivity and pressure values, the determination unit 58 can suppress misjudgments. Furthermore, with Figure 5A and Figure 5B Compared to the situation shown, the setup can be simplified. As a result, the processing load on processor 50 can be reduced, and errors during program creation can also be reduced.

[0066] Furthermore, the determination unit 58 can also determine whether the resistivity value has increased based on whether the result of the subtraction operation (AV5-AV6) obtained by subtracting the past resistivity average value AV6 from the current average resistivity value AV5 exceeds a predetermined threshold. Similarly, the determination unit 58 can also determine whether the pressure value has increased based on whether the result of the subtraction operation (AV7-AV8) obtained by subtracting the past pressure average value AV8 from the current average pressure value AV7 exceeds a predetermined threshold.

[0067] [Fourth Implementation Method]

[0068] In the fourth embodiment, descriptions that are repeated in the above embodiments are omitted. Figure 7 This is a schematic diagram of the control device 16 according to the fourth embodiment. In the fourth embodiment, the average value calculation unit 66 is replaced by a cumulative value calculation unit 68. When the program stored in the memory 52 is executed, the processor 50 operates as the cumulative value calculation unit 68. Furthermore, the cumulative value calculation unit 68 can be implemented by an integrated circuit or constituted by an electronic circuit containing discrete components.

[0069] like Figure 8A As shown, the cumulative value calculation unit 68 periodically calculates a first cumulative value IG1 and a second cumulative value IG2 based on the resistivity data stored in the memory 52. ​​The first cumulative value IG1 is the cumulative value of the resistivity detected by the first sensor 62 during the first period PD1. The second cumulative value IG2 is the cumulative value of the resistivity detected by the first sensor 62 during the second period PD2. The start time of the second period PD2 is earlier than the start time of the first period PD1. The length of the second period PD2 is greater than or equal to the length of the first period PD1.

[0070] In this embodiment, the second period PD2 is longer than the first period PD1 and includes a portion of the first period PD1. In other words, the second period PD2 does not include the entire first period PD1. However, the second period PD2 may also not include a portion of the first period PD1. Furthermore, the end time of the first period PD1 may also be the current time T1.

[0071] Whenever the cumulative value calculation unit 68 calculates a first cumulative value IG1 and a second cumulative value IG2, the determination unit 58 compares the first cumulative value IG1 and the second cumulative value IG2. If the first cumulative value IG1 exceeds the second cumulative value IG2 (IG1 > IG2), the determination unit 58 determines that the resistivity value has increased. On the other hand, if the first cumulative value IG1 is less than or equal to the second cumulative value IG2 (IG1 ≤ IG2), the determination unit 58 determines that the resistivity value has not increased.

[0072] like Figure 8B As shown, the cumulative value calculation unit 68 periodically calculates a third cumulative value IG3 and a fourth cumulative value IG4 based on the pressure data stored in the memory 52. ​​The third cumulative value IG3 is the cumulative value of the pressure value detected by the second sensor 64 during the first period PD1. The fourth cumulative value IG4 is the cumulative value of the pressure value detected by the second sensor 64 during the second period PD2.

[0073] Whenever the cumulative value calculation unit 68 calculates the third cumulative value IG3 and the fourth cumulative value IG4, the determination unit 58 compares the third cumulative value IG3 and the fourth cumulative value IG4. If the third cumulative value IG3 exceeds the fourth cumulative value IG4 (IG3 > IG4), the determination unit 58 determines that the pressure value has increased. On the other hand, if the third cumulative value IG3 is less than or equal to the fourth cumulative value IG4 (IG3 ≤ IG4), the determination unit 58 determines that the pressure value has not increased.

[0074] In this way, the determination unit 58 determines whether the resistivity and pressure values ​​have increased based on the calculation results of the cumulative value calculation unit 68. Therefore, it is possible to capture the actual trend of the detected values. As a result, compared with the average value, it is possible to strictly determine the increase in resistivity and pressure values.

[0075] Furthermore, the determination unit 58 can also determine whether the resistivity value has increased based on whether the subtraction result (IG1-IG2) obtained by subtracting the second cumulative value IG2 from the first cumulative value IG1 exceeds a predetermined threshold. Similarly, the determination unit 58 can also determine whether the pressure value has increased based on whether the subtraction result (IG3-IG4) obtained by subtracting the fourth cumulative value IG4 from the third cumulative value IG3 exceeds a predetermined threshold.

[0076] Furthermore, in this embodiment, the cumulative value calculation unit 68 can also calculate an approximation line that approximates the change in resistivity value detected by the first sensor 62 during the first period PD1, and calculate the cumulative value of resistivity values ​​on this approximation line as the first cumulative value IG1. Similarly, the cumulative value calculation unit 68 can calculate the second cumulative value IG2, the third cumulative value IG3, and the fourth cumulative value IG4. In this way, compared with the case where only the actual detected value is accumulated, the misjudgment of the determination unit 58 caused by interference can be suppressed.

[0077] Furthermore, there are no particular limitations on the method for calculating the approximate line. For example, linear approximation, exponential approximation, logarithmic approximation, polynomial approximation, power approximation, and moving average can all be applied to the calculation of the approximate line. Additionally, the calculated approximate line can be expanded into a series.

[0078] [Fifth Implementation]

[0079] In the fifth embodiment, descriptions that are repeated in the above embodiments are omitted. For example... Figure 9A As shown, the cumulative value calculation unit 68 calculates the cumulative resistivity value for each predetermined period of the PD based on the resistivity data stored in the memory 52. ​​The cumulative resistivity value is the cumulative value of resistivity detected by the first sensor 62 during the predetermined period of the PD. Whenever the cumulative value calculation unit 68 calculates the current cumulative resistivity value IG5, the determination unit 58 compares the current cumulative resistivity value IG5 with the past cumulative resistivity value IG6.

[0080] The current cumulative resistivity value IG5 is the cumulative resistivity value detected by the first sensor 62 during a predetermined period PD (first period PD1), and is equivalent to the first cumulative value IG1. The past cumulative resistivity value IG6 is the cumulative resistivity value detected by the first sensor 62 during a predetermined period PD (second period PD2) prior to the current cumulative resistivity value IG5, and is equivalent to the second cumulative value IG2. Furthermore, in this embodiment, the first period PD1 and the second period PD2 do not overlap.

[0081] The end time of the past resistivity accumulation value IG6 coincides with the start time of the current resistivity accumulation value IG5, but it can also be earlier than the start time of the current resistivity accumulation value IG5. In other words, the past resistivity accumulation value IG6 and the current resistivity accumulation value IG5 can also be separated in time.

[0082] If the current cumulative resistivity value IG5 exceeds the previous cumulative resistivity value IG6 (IG5 > IG6), the determination unit 58 determines that the resistivity value has increased. On the other hand, if the current cumulative resistivity value IG5 is less than or equal to the previous cumulative resistivity value IG6 (IG5 ≤ IG6), the determination unit 58 determines that the resistivity value has not increased.

[0083] like Figure 9B As shown, the cumulative value calculation unit 68 calculates the cumulative pressure value at predetermined intervals (PD) based on the pressure data stored in the memory 52. ​​The cumulative pressure value is the cumulative value of the pressure values ​​detected by the second sensor 64 during the predetermined interval (PD). Whenever the cumulative value calculation unit 68 calculates the current cumulative pressure value IG7, the determination unit 58 compares the current cumulative pressure value IG7 with the past cumulative pressure value IG8.

[0084] The current pressure cumulative value IG7 is the cumulative pressure value detected by the second sensor 64 during the predetermined period PD (first period PD1), which is equivalent to the third cumulative value IG3. The past pressure cumulative value IG8 is the cumulative pressure value detected by the second sensor 64 during the predetermined period PD (second period PD2) prior to the current pressure cumulative value IG7, which is equivalent to the fourth cumulative value IG4.

[0085] The end time of the past pressure accumulation value IG8 coincides with the start time of the current pressure accumulation value IG7, but it can also be earlier than the start time of the current pressure accumulation value IG7. In other words, the past pressure accumulation value IG8 and the current pressure accumulation value IG7 can also be separated in time.

[0086] If the current accumulated pressure value IG7 exceeds the previous accumulated pressure value IG8 (IG7 > IG8), the determination unit 58 determines that the pressure value has increased. On the other hand, if the current accumulated pressure value IG7 is less than or equal to the previous accumulated pressure value IG8 (IG7 ≤ IG8), the determination unit 58 determines that the pressure value has not increased.

[0087] In this way, the determination unit 58 compares the current cumulative resistivity value IG5 with the past cumulative resistivity value IG6 at predetermined intervals PD, and compares the current cumulative pressure value IG7 with the past cumulative pressure value IG8. Therefore, even if an unexpected abrupt change (interference) occurs in at least one of the resistivity value and pressure value, the determination unit 58 can suppress misjudgments. Furthermore, with Figure 8A and Figure 8B Compared to the situation shown, the setup can be simplified. As a result, the processing load on processor 50 can be reduced, and errors during program creation can also be reduced.

[0088] Furthermore, the determination unit 58 can also determine whether the resistivity value has increased based on whether the result of the subtraction operation (IG5-IG6) obtained by subtracting the past resistivity value IG6 from the current resistivity cumulative value IG5 exceeds a predetermined threshold. Similarly, the determination unit 58 can also determine whether the pressure value has increased based on whether the result of the subtraction operation (IG7-IG8) obtained by subtracting the past pressure cumulative value IG8 from the current pressure cumulative value IG7 exceeds a predetermined threshold.

[0089] In addition, in this embodiment, the cumulative value calculation unit 68 can also calculate an approximation line that approximates the change in resistivity detected by the first sensor 62 during the first period PD1, and calculate the cumulative value of resistivity on this approximation line as the current cumulative resistivity value IG5. Similarly, the cumulative value calculation unit 68 can calculate the past cumulative resistivity value IG6, the current cumulative pressure value IG7, and the past cumulative pressure value IG8.

[0090] [Modified Implementation]

[0091] The above-described embodiments can also be modified as follows.

[0092] (Variation Example 1)

[0093] Figure 10 This is a schematic diagram of the control device 16 in Modified Example 1. In this modified example, the control device 16 of the first embodiment includes a notification control unit 70. The notification control unit 70 may be provided in the control device 16 of the second embodiment or the control device 16 of the third embodiment. Alternatively, the notification control unit 70 may be provided in the control device 16 of the fourth embodiment or the control device 16 of the fifth embodiment.

[0094] In this modified example, when the program stored in memory 52 is executed, processor 50 functions as notification control unit 70. Furthermore, notification control unit 70 can be implemented using an integrated circuit or constructed from electronic circuitry including discrete components.

[0095] If the determination unit 58 determines that both the resistivity and pressure values ​​have increased, the notification control unit 70 controls the notification unit 72 to issue a warning. For example, the notification control unit 70 controls the notification unit 72 to notify the user of a warning message. The notification unit 72 includes at least one of a display unit, a speaker, and a light-emitting unit. The notification unit 72 can be installed on the control device 16 or external to the control device 16, such as the processing machine 12.

[0096] By having a notification control unit 70, users can be prompted to perform maintenance such as adjusting the mechanism 28.

[0097] (Variation Example 2)

[0098] Figure 11 This is a schematic diagram of the processing system 10 in Modified Example 2. In this modified example, the structure of the adjustment mechanism 28 differs from that in the above-described embodiment. In this modified example, the adjustment mechanism 28 supplies a reagent or tap water that reduces resistivity to the clear liquid tank 20. For example, the adjustment mechanism 28 may consist of a supply section 28D for supplying the reagent or tap water, a communication path 28E connecting the supply section 28D and the clear liquid tank 20, and a valve 28F.

[0099] In addition to the circulation path 28A, valve 28B and reagent container 28C, the adjustment mechanism 28 may also include a supply section 28D, a connecting path 28E and valve 28F.

[0100] (Variation Example 3)

[0101] The processing system 10 is not limited to the embodiments described above. For example, the adjustment mechanism 28 can also adjust the resistivity value of the sludge stored in the sludge tank 18. Alternatively, the reagent container 28C can be replaced with an ion exchange resin that reduces the resistivity value of the processing fluid. In addition, a reagent that reduces the resistivity value can be impregnated in the filter 24.

[0102] Alternatively, the determination unit 58 may only determine whether the resistivity value of the processing fluid has increased. In this case, if the determination unit 58 determines that the resistivity value has increased, the mechanism control unit 60 causes the adjustment mechanism 28 to begin adjusting the resistivity value of the processing fluid. Furthermore, the second sensor 64 may not be provided.

[0103] [Effects]

[0104] Through experiments conducted by the inventors, it was confirmed that when the resistivity of the processing fluid is relatively high, the lifespan of the filter 24 is shortened. As described above, when the determination unit 58 determines that the resistivity value detected by the first sensor 62 has increased, the mechanism control unit 60 causes the adjustment mechanism 28 to adjust the resistivity value of the processing fluid. This reduces the resistivity value of the processing fluid, thereby extending the lifespan of the filter 24. Furthermore, based on the resistivity value detected by the first sensor 62, the degree of adjustment of the processing fluid's resistivity by the adjustment mechanism 28 can be determined.

[0105] Furthermore, if the determination unit 58 determines that both the resistivity value detected by the first sensor 62 and the pressure value detected by the second sensor 64 are increasing, the mechanism control unit 60 can also cause the adjustment mechanism 28 to adjust the resistivity value of the processing fluid. In this case, the lifespan of the filter 24 can be strictly monitored using two indicators related to the lifespan of the filter 24 (resistivity value and pressure value).

[0106] The lifespan of a filter used in machining machines for processing aluminum-based metal workpieces is 10% to 25% of the lifespan of a filter used in machining machines for processing ferrous-based metal workpieces. Therefore, when the metal workpiece is made of aluminum-based material, it is particularly useful to reduce the resistivity of the liquid by adjusting mechanism 28.

[0107] Regarding the above-described embodiments, the following notes are further disclosed.

[0108] (Note 1)

[0109] This disclosure discloses a liquid filtration device (14) comprising: a sludge tank (18) for storing sludge, the sludge being a liquid containing metal shavings generated during the processing of a metal workpiece; a filter (24) for filtering the sludge; and a clear liquid tank (20) for storing the liquid that has passed through the filter, i.e., clear liquid. The liquid filtration device further comprises: an adjustment mechanism (28) for adjusting the resistivity value of the liquid; a first sensor (62) for detecting the resistivity value of the liquid; a determination unit (58) for determining, based on the resistivity value detected by the first sensor, whether the resistivity value has increased; and a mechanism control unit (60) for causing the adjustment mechanism to adjust the resistivity value of the liquid if it is determined that the resistivity value has increased.

[0110] (Note 2)

[0111] According to the liquid filtration device described in Appendix 1, the adjusting mechanism reduces the resistivity value of the liquid.

[0112] (Note 3)

[0113] According to the liquid filtration device described in Appendix 2, the adjusting mechanism supplies the liquid with a reagent or tap water that reduces the resistivity value, or causes the liquid to pass through a container containing a reagent that reduces the resistivity value.

[0114] (Note 4)

[0115] According to any one of the appendices 1 to 3, the liquid filtration device further comprises: a notification control unit (70) that controls a notification unit (72) to issue a warning when it is determined that the resistivity value has increased.

[0116] (Note 5)

[0117] According to any one of the appendices 1 to 4, in the liquid filtration device, if the current resistivity value (R1) exceeds the past resistivity value (R2) detected before a predetermined period, the determination unit determines that the resistivity value has increased.

[0118] (Note 6)

[0119] According to any one of Appendices 1 to 4, the liquid filtration apparatus includes: an average value calculation unit (66) that calculates a first average value (AV1) and a second average value (AV2), wherein the first average value (AV1) is the average value of the resistivity detected during a first period (PD1), the second average value (PD1) is the average value of the resistivity detected during a second period (PD2), the start time of the second period is before the start time of the first period, the length of the second period is greater than or equal to the length of the first period, and the determination unit determines that the resistivity value has increased when the first average value exceeds the second average value.

[0120] (Note 7)

[0121] According to the liquid filtration apparatus described in Appendix 6, the second period includes at least a portion of the first period.

[0122] (Postscript 8)

[0123] According to the liquid filtration device described in Appendix 6, the start time of the first period is equal to the end time of the second period.

[0124] (Note 9)

[0125] According to any one of Appendices 1 to 4, the liquid filtration device includes: a cumulative value calculation unit (68) that calculates a first cumulative value (IG1) and a second cumulative value (IG2), wherein the first cumulative value (IG1) is the cumulative value of the resistivity detected in a first period, the second cumulative value (IG2) is the cumulative value of the resistivity detected in a second period, the end time of the second period is before the end time of the first period, the length of the second period is greater than or equal to the length of the first period, and the determination unit determines that the resistivity value has increased when the first cumulative value exceeds the second cumulative value.

[0126] (Postscript 10)

[0127] According to the liquid filtration apparatus described in Appendix 9, the second period includes a portion of the first period.

[0128] (Postscript 11)

[0129] According to the liquid filtration device described in Appendix 9, the start time of the first period is equal to the end time of the second period.

[0130] (Postscript 12)

[0131] According to any one of Appendix 1 to 11, the liquid filtration device includes: a second sensor (64) that detects the pressure value applied to the filter, and when it is determined that both the resistivity value and the pressure value are increasing, the mechanism control unit causes the adjustment mechanism to adjust the resistivity value of the liquid.

[0132] (Postscript 13)

[0133] According to any one of the appendices 1 to 12, the liquid filtration device is made of aluminum-based material.

[0134] (Postscript 14)

[0135] This disclosure is a processing system (10) comprising a liquid filtration device as described in any one of Appendices 1 to 13 and a processing machine (12) for processing the metal workpiece.

[0136] This disclosure has been described in detail, but it is not limited to the various embodiments described above. Various additions, substitutions, modifications, and partial deletions can be made to these embodiments without departing from the spirit of this disclosure, or from the spirit of this disclosure derived from the content described under the claimed scope and its equivalents. Furthermore, these embodiments can also be implemented in combination. For example, in the embodiments described above, the order of each action and the order of each process are shown as an example and are not limited thereto. Similarly, the use of numerical values ​​or mathematical formulas in the description of the embodiments described above is also relevant.

[0137] Explanation of reference numerals in the attached figures

[0138] 10 machining systems

[0139] 12 machining centers

[0140] 14 Liquid Filtration Device

[0141] 16 control devices

[0142] 18 wastewater tanks

[0143] 20 Clear Liquid Tanks

[0144] 24 filters

[0145] 28 Adjustment Institutions

[0146] 54 Record Control Department

[0147] 56 Acquired Department

[0148] 58 Judgment Department

[0149] 60 Institutional Control Department

[0150] 62 First Sensor

[0151] 64 Second Sensor

[0152] 66 Average Calculation Department

[0153] 68 Cumulative Value Calculation Department

[0154] 70 Notification Control Department

[0155] 72 Notification Department.

Claims

1. A liquid filtration apparatus comprising: a sludge tank for storing sludge, said sludge being a liquid containing metal shavings generated during the processing of a metal workpiece; a filter for filtering said sludge; and a clear liquid tank for storing said liquid having passed through said filter, i.e., clear liquid. Its features are, The liquid filtration device includes: An adjustment mechanism that adjusts the resistivity value of the liquid; A first sensor detects the resistivity value of the liquid; The determination unit determines whether the resistivity value has increased based on the resistivity value detected by the first sensor. as well as The mechanism control unit, upon determining that the resistivity value has increased, causes the adjustment mechanism to adjust the resistivity value of the liquid.

2. The liquid filtration device according to claim 1, characterized in that, The adjustment mechanism reduces the resistivity of the liquid.

3. The liquid filtration device according to claim 2, characterized in that, The adjustment mechanism supplies the liquid with a reagent or tap water that reduces the resistivity value, or causes the liquid to pass through a container containing a reagent that reduces the resistivity value.

4. The liquid filtration apparatus according to any one of claims 1 to 3, characterized in that, The liquid filtration device includes a notification control unit that issues a warning when it is determined that the resistivity value has increased.

5. The liquid filtration apparatus according to any one of claims 1 to 4, characterized in that, If the current resistivity value exceeds the past resistivity value detected before a predetermined period, the determination unit determines that the resistivity value has increased.

6. The liquid filtration apparatus according to any one of claims 1 to 4, characterized in that, The liquid filtration device includes an average value calculation unit that calculates a first average value and a second average value, wherein the first average value is the average of the resistivity values ​​detected during a first period, and the second average value is the average of the resistivity values ​​detected during a second period. The start time of the second period is before the start time of the first period. The length of the second period is greater than or equal to the length of the first period. If the first average value exceeds the second average value, the determination unit determines that the resistivity value has increased.

7. The liquid filtration device according to claim 6, characterized in that, The second period includes at least a portion of the first period.

8. The liquid filtration device according to claim 6, characterized in that, The start time of the first period is equal to the end time of the second period.

9. The liquid filtration apparatus according to any one of claims 1 to 4, characterized in that, The liquid filtration device includes a cumulative value calculation unit that calculates a first cumulative value and a second cumulative value, wherein the first cumulative value is the cumulative value of the resistivity detected during a first period, and the second cumulative value is the cumulative value of the resistivity detected during a second period. The end time of the second period is before the end time of the first period. The length of the second period is greater than or equal to the length of the first period. If the first cumulative value exceeds the second cumulative value, the determination unit determines that the resistivity value has increased.

10. The liquid filtration device according to claim 9, characterized in that, The second period includes a portion of the first period.

11. The liquid filtration device according to claim 9, characterized in that, The start time of the first period is equal to the end time of the second period.

12. The liquid filtration apparatus according to any one of claims 1 to 11, characterized in that, The liquid filtration device includes: a second sensor that detects the pressure applied to the filter. If it is determined that both the resistivity value and the pressure value are increasing, the mechanism control unit causes the adjustment mechanism to adjust the resistivity value of the liquid.

13. The liquid filtration apparatus according to any one of claims 1 to 12, characterized in that, The metal workpiece is made of aluminum-based material.

14. A processing system, characterized in that, have: The liquid filtration device according to any one of claims 1 to 13; and A processing machine for processing the metal workpiece.

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