Machine tool

Abstract

To provide a machine tool having a function for assisting replenishing work of a coolant liquid concentrate or water for dilution.SOLUTION: The machine tool comprises: a device for various machining operations, which is for executing prescribed machining on a workpiece by a tool; a coolant device that repeatedly feeds a used coolant stored in a coolant tank by a coolant pump; and a control device that controls driving of the device for various machining operations and the coolant device. The coolant tank is provided with a level sensor that measures a coolant level indicating the liquid surface height of the coolant and a density sensor that measures the concentration of a coolant liquid concentrate in the coolant. The control device calculates replenishing amounts of a coolant liquid concentrate and water necessary for replenishment and days necessary for replenishment on the basis of the measurement values measured by the level sensor and the concentration sensor, and outputs the results as replenishment information to a notification device for notifying an operator of the information.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a machine tool having a function of assisting in the replenishment of coolant concentrate and water for diluting the coolant used for cooling and cleaning a workpiece during machining. [Background technology]

[0002] In machine tools, coolant is used to reduce processing heat, lubricate, and wash away chips from processing areas. After use, the coolant is returned to the coolant tank and is supplied again into the processing chamber by a coolant pump. When coolant is used repeatedly, the total amount decreases after long periods of operation, and the concentration increases due to evaporation of water caused by processing heat, etc. Therefore, in machine tools, it is necessary to periodically replenish the coolant tank with a specified amount of undiluted coolant or water (tap water) by stirring. Therefore, the coolant in the coolant tank needs to be managed by the operator, and as shown in Patent Document 1 below, the timing of replenishment of the coolant and the amount of replenishment are adjusted to ensure a specified concentration. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-65938 Summary of the Invention [Problem to be solved by the invention]

[0004] In the conventional example of the above-mentioned patent document, the refill control process is executed when the timing is reached. At the timing of refill, the control device automatically calculates the supply amounts of the coolant concentrate and water so as to satisfy the stored refill amount and refill concentration, and the coolant concentrate and water are supplied to the mixing unit using the coolant concentrate supply unit and the water supply unit to generate the refill dilution liquid. However, in this conventional example, the operator must know the consumption amount of the coolant in the coolant tank, the trend of change in the coolant concentration, the size of the coolant tank, the storage amount, the target management concentration, etc. Therefore, the operator must input the refill amount and refill concentration of the refill coolant according to the characteristics of the coolant tank, as well as the timing to refill the refill coolant.

[0005] SUMMARY OF THE PRESENT DISCLOSURE In order to solve the above problems, an object of the present invention is to provide a machine tool having a function for assisting in the refilling of coolant concentrate and water for dilution. [Means for solving the problem]

[0006] The machine tool according to the present invention includes various processing devices for performing predetermined processing on a workpiece with a tool in a processing chamber, a coolant device that repeatedly supplies used coolant that flows from the processing chamber and is stored in a coolant tank to the processing chamber by a coolant pump, and a control device that controls the operation of the various processing devices and the coolant device. The coolant tank is provided with a level sensor that measures the coolant level, which is the liquid level of the coolant, and a concentration sensor that measures the concentration of the coolant concentrate in the coolant, and the control device calculates the amounts of coolant concentrate and water required for replenishment and the number of days for which replenishment is required based on the measurements taken by the level sensor and the concentration sensor, and outputs the results as replenishment information to an alarm device that notifies an operator. Effect of the Invention

[0007] According to the above-mentioned configuration, workpieces are processed in the processing chamber by driving various processing devices, and the coolant used at that time is stored in the coolant tank and repeatedly sent to the processing part by the coolant device. Since the coolant in the coolant tank not only decreases in volume but also increases in concentration after a certain period of use, the coolant level, which is the liquid height of the coolant, is measured by the level sensor, and the concentration of the coolant concentrate is measured by the concentration sensor. Based on the measured values, the control device calculates the amount of coolant concentrate and water required for replenishment and the number of days for which replenishment is required, and outputs the results as replenishment information to an alarm device that notifies the operator. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a side view of an internal structure showing one embodiment of a machine tool. [Diagram 2] FIG. 2 is a perspective view showing a coolant tank. [Diagram 3] FIG. 2 is a simplified circuit diagram of a coolant device. [Figure 4] FIG. 2 is a block diagram showing a control system of the machine tool. [Diagram 5] 11 is a display output on the screen of an operation display device in accordance with a coolant replenishment calculation program. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] An embodiment of a machine tool according to the present invention will be described below with reference to the drawings. Fig. 1 is a side view of the internal structure showing one embodiment of the machine tool. This machine tool 1 is an NC lathe, and is mounted on a movable bed 14 equipped with wheels, and is configured to be movable in the front-rear direction (Z-axis direction) along rails 13 laid on the upper surface of a base 4. Various machining devices such as a spindle unit 5 are mounted on the movable bed 14, and the drive and control of the various machining devices is performed by a control device 6 mounted on the rear of the machine body.

[0010] The spindle unit 5 has a spindle chuck 11 attached to a rotatable spindle, and rotates the gripped workpiece W by a spindle motor. The machine tool 1 is provided with a turret unit 7 that selects one of a plurality of tools corresponding to the workpiece machining. The turret unit 7 has a tool rest 12 to which a plurality of tools are attached, and selects and positions the tool to be used for machining by rotating and indexing. The drive units that move the tool to the machining position of the workpiece W are a Z-axis drive unit 8 that moves the tool in the Z-axis direction, which is the front-rear direction of the machine body, and an X-axis drive unit 9 that moves the tool in the X-axis direction, which is the up-down direction of the machine body.

[0011] In the machine tool 1, the workpiece W is gripped in the spindle chuck 11 by delivery to and from an automatic workpiece transporter (not shown), and rotation is imparted by driving the spindle unit 5. In the turret unit 7, a tool to be used for machining the workpiece W is selected by rotation indexing. Then, the tool is moved together with the turret unit 7 in the machining axis direction by driving the Z-axis drive unit 8 and the X-axis drive unit 9, and a predetermined machining is performed on the workpiece W. After machining of the workpiece W, the machined workpiece W is replaced with a new workpiece W in the spindle chuck 11, and the automatic machining of the workpiece W is repeated.

[0012] In the machine tool 1, a coolant tank 15 is provided below the machining chamber 10 where machining is performed, and chips and the like generated during machining of the workpiece W are washed away with coolant and stored in the coolant tank 15. FIG. 2 is a perspective view showing the coolant tank 15. A chip conveyor 18 is built into the coolant tank 15, and an inlet 19 is formed at the bottom of the machining chamber 10. Chips generated during machining are washed away with the coolant supplied into the machining chamber 10, enter the inlet 19 together with the coolant, and are stored in a storage tank of the chip conveyor 18. Then, by driving the chip conveyor 18, only the chips are carried out of the machine and discharged and collected in an external collection box.

[0013] The machine tool 1 is provided with a coolant device so that the coolant can be used repeatedly. In the coolant device, a coolant pump 16 pumps up the coolant stored in a coolant tank 15 and sends it back to the machining chamber 10. For example, the storage tank of the chip conveyor 18 has a drop port blocked by a punched metal having fine holes, and the coolant that flows out from there is stored in the coolant tank 15. The used coolant is filtered and repeatedly supplied to the machining chamber 10 again.

[0014] Fig. 3 is a simplified circuit diagram of the coolant device. In the coolant device 2, a cylindrical strainer 17 is provided on the suction port side of a coolant pump 16, and a coolant pipe 28 is connected to the secondary side. Specifically, as shown in Fig. 2, a pump chamber 22 surrounded by a side wall 22 is formed at a corner of a coolant tank 15, and a coolant pump 16 equipped with a strainer 17 is installed therein. A suction window 23 with a mesh plate fitted therein is formed in the side wall 22, and the coolant in the coolant tank 15 is drawn into a pump chamber 21 by driving the coolant pump 16, and then sucked up.

[0015] 3, the coolant pipe 28 connected to the coolant pump 16 extends to the machining chamber 10 side, and is branched along the way to form a cleaning-side flow path 281 and a machining section-side flow path 282. The cleaning-side flow path 281 is a flow path that supplies coolant to carry away chips and the like that accumulate at the bottom of the machining chamber 10 to the inlet 19, and the machining section-side flow path 282 is a flow path for spraying coolant that lubricates and cools the machining point of the workpiece W and also washes away the chips. The machining section-side flow path 282 is formed to the machining point of the workpiece W so as to pass through the tool rest 12 of the turret device 7.

[0016] The coolant device 2 of this embodiment is further provided with a level sensor 25 that measures the coolant level, which is the liquid height of the coolant in the coolant tank 15, and a concentration sensor 26 that measures the concentration of the undiluted coolant in the coolant in the coolant tank 15, and is connected to the control device 6. This is configured to calculate the amount of undiluted coolant and water (tap water) to be replenished according to the measured values ​​of the level sensor 25 and the concentration sensor 26, and the control device 6 stores a coolant replenishment calculation program in addition to machining programs related to various types of machining.

[0017] 4 is a block diagram showing the control system of the machine tool 1. The control device 6 of the machine tool 1 is mainly a computer equipped with storage devices such as a ROM 42, a RAM 43, and a non-volatile memory 44 in addition to a CPU 41, and is connected to the coolant unit 2, the spindle unit 5, the turret unit 7, the Z-axis drive unit 8, the X-axis drive unit 9, and the like via an I / O 45. The control device 6 is also connected to the level sensor 25 and the concentration sensor 26 of the coolant unit 2. The control device 6 controls the drive of the pump motor 27 of the coolant pump 16, and the drive motors of the coolant unit 2, the spindle unit 5, and the like are also connected via driver circuits 47.

[0018] A touch panel type operation and display device 3 capable of displaying work information, an operation screen, etc., and allowing the operator to input settings, is attached to the front of the machine tool 1, and is connected to the control device 8 via an I / O 45. FIG. 5 is a diagram showing the screen of the operation and display device 3, and in particular the screen displaying the time to replenish the coolant concentrate and water, outputted according to a coolant replenishment calculation program. The coolant replenishment calculation program is designed to notify the operator of the amount of coolant concentrate and water required for replenishment and information regarding the number of days for which replenishment is required, based on the volume and concentration of coolant stored in the coolant tank 15, as replenishment information.

[0019] Screen 30 of operation display device 3 shown in Fig. 5 has function selection buttons provided below monitor screen 51. When coolant management button 52 is selected there and graph button 53 is pressed, management data related to the coolant in coolant tank 15 is displayed as a graph as shown in the figure. The displayed coolant management data is the liquid level (coolant level) in coolant tank 15 measured by level sensor 25 and the coolant concentration measured by concentration sensor 26. As can be seen from this graph, in machine tool 1, the coolant level decreases over the course of operating time, and the total amount of coolant in coolant tank 15 decreases, while the coolant concentration increases.

[0020] In the coolant replenishment calculation program, an average value of the decrease in the coolant level and an average value of the increase in the coolant concentration are calculated based on one day's operation of the machine tool 1, and replenishment information of the replenishment amount and replenishment date for the coolant stock solution and water is calculated from these average values. The average values ​​of the decrease in the coolant level and the increase in the coolant concentration are calculated, for example, from values ​​measured over a five-day period starting from the day after replenishment.

[0021] In the coolant refilling operation, an appropriate amount of undiluted coolant and water are mixed and refilled into the coolant tank 15. Thus, the coolant level and coolant concentration of the coolant in the coolant tank 15 are returned to a constant state, and this state can be confirmed from the measurements of the level sensor 25 and the concentration sensor 26. When the measurements of either or both of the coolant level and the coolant concentration return to a constant value, it is determined that the refilling operation is complete, the coolant refill calculation program is reset, and a new refilling process is executed. However, a reset button may be provided on the screen 30 of the operation display device 3, and the operator may press the button to reset the coolant after the coolant refilling operation is completed.

[0022] In a new refill process after the reset, the coolant level and the coolant concentration in the coolant tank 15 are measured in the same manner, and the daily average values ​​of the amount of change in level detected by the level sensor 25 and the amount of change in concentration detected by the concentration sensor 26 over a five-day period are calculated again. Note that, although this average value is set for five days, the number of days covered can be changed as appropriate, and it is also possible to use a value set by the machine tool or a value set based on the machining content of the workpiece without calculating an average value.

[0023] Next, in the coolant replenishment calculation program, replenishment information is obtained from the measured values ​​of the level sensor 25 and the concentration sensor 26 based on the obtained average value as follows. In the machine tool 1 of this embodiment, the capacity of the coolant tank 15 is 4.00 L and the corresponding measurement range of the level sensor is 400 mm for ease of understanding of the calculations described below. Then, the thresholds for determining that replenishment of the coolant in this coolant tank 15 is required are set to a case where the level has decreased to 50 mm and the coolant concentration has increased to 80%.

[0024] In machine tool 1, the coolant level and coolant concentration in coolant tank 15 are measured and stored by level sensor 25 and concentration sensor 26 at least once during operation each day, for example at 5 pm on that day, and average values ​​are calculated based on the values. That is, an average value X of a daily decrease measured by level sensor 25 and an average value Y of a daily increase measured by concentration sensor 26 for a predetermined number of days are calculated. Then, it is assumed that the reference value of the coolant level measured by level sensor 25 and the reference value of the coolant concentration measured by concentration sensor 26, which are actually measured on an arbitrary day (reference day) for predicting the replenishment date, are x mm and y %, respectively.

[0025] From the above values, the number of days m until the coolant level reaches the lower limit (50 mm) and the number of days n until the coolant concentration reaches the upper limit (80%) can be calculated using the following equations (1) and (2). 50 = x - mX, m = (x - 50) / X ···(1) 80 = y + nY, n = (80 - y) / Y ···(2)

[0026] In this way, the number of days m and n until replenishment is required can be obtained, but the two numbers of days do not necessarily match. Therefore, based on the number of days m when the Courant level reaches the lower limit value and the number of days n when the Courant concentration reaches the upper limit value, the replenishment amounts of the Courant stock solution and water are calculated according to the condition of the one that reaches first (the smaller numerical value).

[0027] First, the case where the Courant level reaches the lower limit value of 50 mm first (m < n) will be explained. Here, the Courant concentration on the m-th day after the calculated reference day when the Courant level reaches the lower limit value, that is, the replenishment day, is obtained as (y + mY)%. Therefore, it is expected that in the Courant in the Courant tank 15 on the replenishment day after m days, the Courant level becomes 50 mm and the Courant concentration becomes (y + mY)%. And by this replenishment operation, the Courant level is returned from 50 mm to 400 mm (the capacity of the Courant is 4.00 L), and the Courant concentration is returned from (y + mY)% to 50%. In the Courant replenishment calculation program, the replenishment amounts of the Courant stock solution and water for this purpose are calculated as follows.

[0028] Among the 50 mm of Courant remaining in the Courant tank 15 on the replenishment day after m days, the amount corresponding to the Courant stock solution is 50(y + mY) / 100 [mm]. And when this is converted to volume (L), in 0.5 L of Courant, the amount corresponding to the Courant stock solution is 0.5(y + mY) / 100 [L]. Therefore, to return the Courant concentration to 200 mm (2.00 L) which is 50% of the level 400 mm (capacity 4.00 L), the replenishment amount of the Courant stock solution is 2.00 - (y + mY) / 200 [L], and the replenishment amount of water is 1.50 + (y + mY) / 200 [L].

[0029] Next, a case where the coolant concentration reaches the upper limit of 80% first (m>n) will be described. Here, the coolant level n days after the calculated reference date when the coolant concentration reaches the upper limit, i.e., on the refill date, is calculated as (x-nX) mm. Therefore, it is expected that the coolant concentration in the coolant tank 15 on the refill date n days later will be 80% mm and the coolant level will be (x-nX) mm. Then, this situation is changed to a refill operation, where the coolant concentration is returned from 80% to 50%, and the coolant level is returned from (x-nX) mm to 400 mm (coolant capacity 4.00 L). In the coolant refill calculation program, the refill amounts of coolant concentrate and water for this purpose are calculated as follows:

[0030] Of the coolant remaining in the coolant tank 15 on the refill date n days later, the amount equivalent to the coolant concentrate is (x-nX)·80 / 100[mm]. If this is converted to volume (L), the amount equivalent to the coolant concentrate in the coolant with a volume of (x-nX)·0.001[L] is (x-nX)·8 / 1000[L]. Therefore, to return the coolant concentration to 200mm (2.00L), which is 50% of the level of 400mm (volume 4.00L), the refill amount of the coolant concentrate is 2.00-8(x-nX) / 1000[L], and the refill amount of water is 2.00-2(x-nX) / 1000[L].

[0031] The results calculated as above are displayed on display unit 55 on monitor screen 51 in Fig. 5 as the refill date, on display unit 56 as the water refill amount, and on display unit 57 as the coolant (undiluted) refill amount. The refill date on display unit 55 is displayed according to the calendar as the reference date on which the reference values ​​of xmm and y% were measured plus the number of days m or number of days n on which the refill condition will be reached first. The refill amounts on displays 56 and 57 are displayed as values ​​calculated based on the number of days m or number of days n as described above.

[0032] Therefore, by operating the coolant management button 52 on the operation display device 3 to display the monitor screen 51, the operator can check the refill amounts of the coolant concentrate and water required for refilling and the refill date from the number of days for which the refill is required from the displays 55, 56, and 57 therein. Therefore, it is possible to perform other work without paying particular attention to the situation inside the coolant tank 15 until the refill date several days or weeks in the future. For example, the coolant refill calculation program is provided with an alarm function such as displaying a refill notification on the operation display device 3 or a notification including a voice guide when the machine tool 1 is started from three days before the calculated refill date. Therefore, even if the operator forgets the scheduled refill, the refill work can be performed reliably.

[0033] In addition, in this embodiment, the refill amount and the refill date of the coolant stock solution and water are automatically calculated, so that the worker does not need to perform the measurement himself, and does not need to calculate the refill amount of the coolant stock solution and water or the number of days until the refill date from the measured value. This significantly reduces the burden on the worker regarding the refill of the coolant, and also prevents the worker from making calculation errors. As shown in FIG. 5, the monitor screen 51 displays a graph based on the actual measured values ​​of the coolant level and the coolant concentration, but it can also display a table of numerical values. In this way, the worker can grasp the status of the coolant approaching the refill date. At this time, a graph up to the refill date may be created, including the average values ​​X and Y of the coolant level and the coolant concentration.

[0034] Incidentally, in the coolant replenishment calculation program, by resetting after replenishment of coolant, the results up to that point are deleted, and a new replenishment calculation is performed as described above. In this case, although an example in which a five-day average value is calculated has been described in the above embodiment, it is also possible to obtain a new average value from the replenishment date (reference date) to that day each time the operator presses the coolant management button 52, recalculate each replenishment amount and replenishment date, and overwrite the results. This makes it possible to more accurately respond to the level and concentration of coolant that change depending on the machining status and environment of the machine tool 1.

[0035] Although one embodiment of the present invention has been described above, the present invention is not limited to this embodiment, and various modifications are possible without departing from the spirit of the present invention. For example, in the above embodiment, the numerical values ​​of the capacity and level of the coolant tank 15, and the numerical values ​​of the level and concentration requiring replenishment are numerical values ​​for explanatory purposes and do not correspond to the actual situation. Furthermore, the configuration of the machine tool and the coolant tank provided therein are not limited to those of the above embodiment. Furthermore, in the above embodiment, the time when replenishment is required is shown as the replenishment date on a calendar, but the number of days until the replenishment date may be displayed as a countdown. [Explanation of symbols]

[0036] 1...machine tool 2...coolant unit 3...operation display unit 5...spindle unit 6...control unit 7...turret unit 8...Z-axis drive unit 9...X-axis drive unit 10machining chamber 15...coolant tank 25...level sensor 26...concentration sensor 30...screen 51...monitor screen 52...coolant management button 53...graph button 55,56,57...display unit

Claims

1. Various processing devices for performing predetermined processing on the workpiece using tools in the processing chamber; a coolant device that repeatedly supplies used coolant flowing from the machining chamber and stored in a coolant tank to the machining chamber by a coolant pump; A control device for controlling the operation of the various processing devices and the coolant device; having The coolant tank is provided with a level sensor that measures the coolant level, which is the liquid level of the coolant, and a concentration sensor that measures the concentration of the coolant concentrate in the coolant, and the control device calculates the amount of coolant concentrate and water required for replenishment and the number of days for which replenishment is required based on the measurements taken by the level sensor and the concentration sensor, and outputs the results as replenishment information to an alarm device that notifies an operator.

2. The control device includes: Calculating an average value of the amount of decrease in the coolant level and an average value of the amount of increase in the coolant concentration over a predetermined period from the measured values; Based on the average value, the measurement value measured on an arbitrary day for predicting the replenishment date, and a threshold value set as a value at which the coolant needs to be replenished, The machine tool according to claim 1 , further comprising: a calculation unit for calculating the number of days until the coolant level and the coolant concentration reach the threshold value based on the arbitrary day; and a calculation unit for calculating the amounts of coolant concentrate and water required for replenishment.

3. The machine tool according to claim 2 , wherein the control device calculates the amounts of coolant concentrate and water required for replenishment based on the shorter number of days until the coolant level or the coolant concentration reaches the threshold value.

4. The machine tool according to claim 1, wherein the control device determines from the measurement values ​​of one or both of the level sensor and the concentration sensor that the coolant in the coolant tank has been returned to a certain coolant level and coolant concentration by the coolant replenishment operation, resets the replenishment amounts of the coolant concentrate and water and the number of days until replenishment is required, and performs the calculation process again.

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