Machine tool machining accuracy diagnosis device and machining accuracy management system

Abstract

To quantitatively predict the effects of opening and closing doors and shutters on machining accuracy of a machine tool.SOLUTION: A machining accuracy diagnosis device 20 includes: a diagnostic information acquisition unit 21 that acquires a room temperature inside a factory, a set temperature of an air conditioner, a temperature outside the factory, a wind speed outside the factory, an opening degree of a shutter, and a body temperature of a machine tool as diagnostic information; an opening time setting unit 22 for setting an opening time of the shutter; a machining time setting unit 23 for setting a scheduled start time and a scheduled end time of machining by the machine tool; and a machining accuracy influence amount prediction unit 24 for predicting the amount of influence on machining accuracy due to opening of the shutter based on the acquired diagnostic information, the opening time set for the shutter, and the scheduled start time and scheduled end time for the machining.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a machining accuracy diagnosis device and a machining accuracy management system for predicting the influence on machining accuracy caused by the opening and closing of a door or shutter on a machine tool installed in a factory equipped with an openable and closable door or shutter and preventing poor machining accuracy.

Background Art

[0002] When performing machining using a machine tool, if the room temperature in the factory changes, thermal displacement occurs in the machine tool, and the machining accuracy of the workpiece deteriorates. As a countermeasure against thermal displacement, generally, a measure is taken to use air conditioning (including air conditioning equipment and air conditioning devices) so that the room temperature in the factory does not change significantly. However, if high-precision temperature control is carried out constantly for 24 hours, the energy consumption of the air conditioning increases, and the cost burden also increases. Furthermore, in actual production, it may be difficult to always keep the temperature in the factory constant. For example, in order to carry in and out materials and products, it is necessary to open and close the doors and shutters of the factory. When the doors and shutters are opened, the temperature in the factory changes. As a result, there is a problem that thermal displacement occurs in the machine tool and the machining accuracy of the workpiece deteriorates. As a countermeasure against the above problems, Patent Document 1 discloses a diagnosis method of obtaining the rate of temperature change of a predetermined part of a machine tool and calculating the influence on the accuracy of the machine tool due to thermal displacement based on that. In addition, Patent Document 2 discloses a method of using a double shutter and providing an air curtain controlled to the same temperature as the air conditioning in the factory in the space between the two shutters so that the room temperature in the factory does not change during loading and unloading.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the method of Patent Document 1, although the magnitude of the influence of thermal displacement can be known, if it is determined that the influence is large, measures such as delaying the start of processing or interrupting the processing will be taken, resulting in losses. Further, the method of Patent Document 2 is effective in suppressing temperature changes in the factory, but since it is necessary to make the shutter a double structure, it is difficult to install when the space in the factory is limited.

[0005] Therefore, an object of the present disclosure is to provide a machining accuracy diagnosis device and a machining accuracy management system for a machine tool that can appropriately determine the timing of starting machining on the machine tool or determine a method of opening and closing a door or shutter so as not to adversely affect the machining accuracy of the machine tool by quantitatively predicting in advance the influence of the opening and closing of the door or shutter on the machining accuracy of the machine tool.

Means for Solving the Problems

[0006] In order to achieve the above object, a first configuration of the present disclosure is a machining accuracy diagnosis device for diagnosing the machining accuracy of a machine tool installed inside a factory equipped with an openable and closable door or shutter, the room temperature inside the factory, the set temperature of a temperature adjustment device that controls the room temperature inside the factory or the temperature of the machine tool, the temperature outside the factory 、 the degree of opening of the door or the shutter, respectively diagnostic information acquisition means for acquiring as diagnostic information, opening time setting means for setting the opening time of the door or the shutter, processing time setting means for setting a scheduled machining start time and a scheduled machining end time by the machine tool, Based on the obtained diagnostic information, the set opening time of the door or the shutter, and the set scheduled machining start time and scheduled machining end time, there is provided machining accuracy influence amount prediction means for predicting the amount of influence on the machining accuracy due to the opening of the door or the shutter. Another aspect of the first configuration is that, in the above configuration, the diagnostic information acquisition means as the diagnostic information acquires the body temperature of the machine tool further and the machining accuracy influence amount prediction means predicts the temperature change of the room temperature in the factory or the body temperature of the machine tool based on the set temperature of the temperature adjustment device or the temperature outside the factory, predicts the thermal displacement of the machine tool based on the predicted temperature change, and determines the amount of change in the thermal displacement during the machining time from the scheduled machining start time to the scheduled machining end time as the amount of influence on the machining accuracy. Another aspect of the first configuration is that, in the above configuration, the machining accuracy influence amount prediction means inputs the set temperature of the temperature adjustment device when the door or the shutter is closed, and inputs the temperature outside the factory when the door or the shutter is open to predict the temperature change of the room temperature in the factory or the body temperature of the machine tool. Another aspect of the first configuration is that, in the above configuration, there is provided accuracy change allowable value setting means for setting an allowable value for the change in the accuracy of the machine tool and based on a comparison between the amount of influence on the machining accuracy predicted by the machining accuracy influence amount prediction means and the allowable value for the accuracy change, there is provided openable time calculation means for obtaining the openable time of the door or the shutter. Another aspect of the first configuration is that, in the above configuration, there is provided openable time display means for displaying the openable time of the door or the shutter obtained by the openable time calculation means. Another aspect of the first configuration is that, in the above configuration, there is provided accuracy change allowable value setting means for setting an allowable value for the change in accuracy during the machining time set by the machining time setting means A machining startable time calculation means for obtaining a machining startable time that satisfies a condition that an amount of influence on the machining accuracy predicted by the machining accuracy influence amount prediction means is smaller than an allowable value of the accuracy change. Another aspect of the first configuration is characterized in that, in the above configuration, it includes a machining startable time display means for displaying the machining startable time.

[0007] To achieve the above object, a second configuration of the present disclosure is a system for managing the machining accuracy of a machine tool installed inside a factory equipped with an openable door or shutter, A machining accuracy diagnostic device for a machine tool of the first configuration including the openable time calculation means, A shutter control means for controlling the opening and closing of the door or the shutter based on the openable time of the door or the shutter. To achieve the above object, a second configuration of the present disclosure is a system for managing the machining accuracy of a machine tool installed inside a factory equipped with an openable door or shutter, A machining accuracy diagnostic device for a machine tool of the first configuration including the machining startable time calculation means, A machine tool control means for stopping machining or in-machine measurement before the machining startable time and starting machining or in-machine measurement after the machining startable time to control the machine tool.

Advantages of the Invention

[0008] According to the present disclosure, the influence of the room temperature change caused by the opening and closing of the door or shutter on the machining accuracy of the machine tool can be quantitatively predicted. Therefore, it is possible to appropriately determine the timing of starting machining on the machine tool or to determine a method of opening and closing the door or shutter so as not to adversely affect the machining accuracy of the machine tool. According to another aspect of the first configuration, in addition to the above effects, the machining accuracy influence amount prediction means predicts the change in the room temperature in the factory and the temperature change of the machine body of the machine tool due to the opening and closing of the door or shutter by calculation using a physical model, predicts the thermal displacement of the machine tool based on this, and determines the amount of change in the predicted thermal displacement within the machining time, so that the influence on the actual workpiece accuracy can be accurately estimated. According to another aspect of the first configuration, in addition to the above effects, by changing the method of predicting the room temperature change according to the opening and closing state of the door or shutter, the room temperature change in the factory can be accurately predicted. According to another aspect of the first configuration, in addition to the above effects, it is possible to know the openable time of the door or shutter that satisfies the condition that the predicted influence amount on the machining accuracy is equal to or less than the allowable value of the accuracy change. This is effective when the machining schedule is determined in advance and it is necessary to open the door or shutter for loading and unloading before the start of machining. According to another aspect of the first configuration, in addition to the above effects, by displaying the openable time of the door or shutter and notifying the operator of the openable time, the opening and closing of the door or shutter can be performed in consideration of the influence on the machining accuracy. This can prevent the problem that an operator who is not involved in machining and does not know the machining schedule or required accuracy opens the door or shutter for a long time without knowing it, resulting in deterioration of the machining accuracy. According to another aspect of the first configuration, in addition to the above effects, the time until the influence of the room temperature change due to the opening of the door or shutter subsides and the influence amount on the machining accuracy becomes equal to or less than the allowable value is predicted and presented as the machining startable time, so that the machining schedule can be established in consideration of the influence on the machining accuracy. This method is an effective method when the time for opening the door or shutter for loading and unloading is determined in advance. According to another aspect of the first configuration, in addition to the above effects, by displaying the machining startable time and notifying it to the operator, it is possible to prevent the machining from starting in a state where the accuracy change of the machine tool is large and the machining accuracy becomes poor. According to the second configuration, in addition to the above effects, by controlling the opening and closing of the door or shutter based on the calculated openable time, loading and unloading can be performed at a timing with little influence on the machining accuracy. According to the second configuration, in addition to the above effects, by controlling to perform the stop and start of processing or in-machine measurement based on the calculated startable processing time, the processing or in-machine measurement can be performed with high accuracy.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. FIG. 1 shows a factory 1 to which a machining accuracy diagnosis device 20 which is an example of the first configuration of the present disclosure and a machining accuracy management system S which is an example of the second configuration are applied. In the factory 1, machine tools 2, 2 are installed. As shown in this figure, there may be not one but a plurality of machine tools 2 of different types. A control device 3 of the machine tool 2 is attached to each machine tool 2, and information regarding the machine tool 2 can be displayed on a display unit 3a. Further, in the factory 1, an air conditioner 4 (including air conditioning equipment and individual air conditioning devices) for controlling the temperature in the factory 1, a shutter 5 for opening and closing an opening when loading and unloading materials and products, a shutter driving device 6 for operating the shutter 5 to open and close, and a shutter opening and closing device 7 for controlling the shutter driving device 6 are provided. The opening and closing of the opening may be a door instead of the shutter 5.

[0011] Each part of the machine tool 2 is provided with a machine body temperature sensor 8. In the factory 1, a plurality of room temperature sensors 9, 9... are installed. Outside the shutter 5 of the factory 1, an outside air temperature sensor 10 is installed. Further, outside the shutter 5, an anemometer 11 is attached so that the state of the wind outside the factory 1 can be measured. In this example, as the temperature adjustment device, an air conditioner 4 that controls the room temperature of the entire factory 1 is installed. However, instead of the air conditioner, a temperature adjustment device that directly controls the temperature of the machine tool 2 may be used. This temperature adjustment device may be, for example, a device that seals the periphery of the machine tool 2 and air-conditions the inside, or a device that provides an oil jacket on the machine body of the machine tool 2 and flows a temperature-controlled coolant.

[0012] The machining accuracy management system S of the machine tool 2 includes a machining accuracy diagnosis device 20, a control device 3 that inputs and outputs information with the machining accuracy diagnosis device 20, and a shutter opening and closing device 7. The set temperature information of the air conditioner 4, the detected temperatures of the temperature sensors 8 to 10, the wind speed outside the factory 1 of the anemometer 11, and the information on the opening degree of the shutter 5 of the shutter drive device 6 are input to the machining accuracy diagnosis device 20. Based on the input information, the machining accuracy diagnosis device 20 predicts the amount of influence on the machining accuracy of the machine tool 2 due to the opening of the shutter 5, and determines the opening time of the shutter 5 and the machining startable time when the machining accuracy is stable. The determined result is output to the control device 3 and the shutter opening and closing device 7. However, the machining accuracy diagnosis device 20 may be built into the control device 3 or the shutter opening and closing device 7, or may be built into another information device network-connected to the control device 3 or the shutter opening and closing device 7. Therefore, the machining accuracy diagnosis device 20 may be outside the factory 1.

[0013] As shown in FIG. 2, the machining accuracy diagnosis device 20 includes a diagnosis information acquisition unit 21, an opening time setting unit 22, a machining time setting unit 23, a machining accuracy influence amount prediction unit 24, an accuracy change allowable value setting unit 25, an arithmetic unit 26, and a display unit 27. The diagnostic information acquisition unit 21 receives, as diagnostic information, the set temperature information of the air conditioner 4, the detected temperatures of the temperature sensors 8 to 10, the wind speed outside Factory 1 of the anemometer 11, and the information on the opening degree of the shutter 5 of the shutter drive device 6. The diagnostic information acquisition unit 21 is an example of the diagnostic information acquisition means of the present disclosure. The opening time setting unit 22 can arbitrarily set the opening time of the shutter 5 during the loading of materials or the unloading of products, etc., by an input means (not shown). The opening time setting unit 22 is an example of the opening time setting means of the present disclosure. The processing time setting unit 23 can set the scheduled processing start time and the scheduled processing end time of the machine tool 2 by an input means (not shown). The processing time setting unit 23 is an example of the processing time setting means of the present disclosure.

[0014] Based on the diagnostic information acquired by the diagnostic information acquisition unit 21 and the opening time of the shutter 5 set by the opening time setting unit 22, the processing accuracy influence amount prediction unit 24 predicts the temperature change of the body temperature of the machine tool 2, and based on the predicted temperature change and the scheduled processing start time and the scheduled processing end time set by the processing time setting unit 23, predicts the thermal displacement of the machine tool 2, and obtains the change in accuracy due to the thermal displacement as the influence amount on the processing accuracy. The processing accuracy influence amount prediction unit 24 is an example of the processing accuracy influence amount prediction means of the present disclosure. The allowable value setting unit 25 for accuracy change can arbitrarily set the allowable value of the accuracy change during the processing of the machine tool 2 by an input means (not shown). The allowable value setting unit 25 for accuracy change is an example of the allowable value setting means for accuracy change of the present disclosure. Based on the influence amount on the processing accuracy obtained by the processing accuracy influence amount prediction unit 24 and the allowable value set by the allowable value setting unit 25 for accuracy change, the calculation unit 26 obtains the shutter opening possible time with a small influence on the body temperature change and the processing start possible time. The calculation unit 26 is an example of the opening possible time calculation means and the processing start possible time calculation means of the present disclosure. The display unit 27 displays the diagnostic results such as the calculation results of the calculation unit 26.

[0015] When opening the shutter 5, if the temperature difference between the inside and outside of the factory 1 is small, even if the shutter 5 is opened, the impact on the processing accuracy is small. However, if the temperature difference is large, the room temperature will change significantly when opened, resulting in a large impact on the processing accuracy. At this time, when the shutter 5 is opened and closed, the room temperature inside the factory 1 changes greatly for a while, so the impact on the processing accuracy becomes large. However, if enough time passes, the room temperature change inside the factory 1 will become gentle, and the impact on the processing accuracy will also become small. By setting the processing start time as the time when the predicted impact on the processing accuracy is expected to be smaller than the allowable value, the processing schedule can be determined so that poor processing accuracy does not occur. Also, the impact on the processing accuracy varies depending on the length of the opening and closing time of the shutter 5. In some cases, if the opening and closing is done in a very short time, the impact on the processing accuracy can be small. Therefore, by predicting the impact on the processing accuracy and indicating the available opening time, it is possible to plan the loading and unloading so that there is no impact on the processing accuracy.

[0016] Hereinafter, a method in which the processing accuracy diagnostic device 20 predicts the accuracy change of the machine tool 2, determines the processing schedule so that poor processing accuracy does not occur, and obtains the shutter opening available time will be described using the flowchart of FIG. 3 and the graph of the temperature change in FIG. 4. Step A1: The diagnostic information acquisition unit 21 acquires diagnostic information. As diagnostic information, the current room temperature inside the factory 1, the current outside air temperature of the factory 1, the current outside wind speed of the factory 1, the set temperature of the air conditioner 4, the opening degree of the shutter 5, and the current body temperature of the machine tool 2 are acquired. Step A2: The processing time setting unit 23 sets the planned processing start time and the planned processing end time. Step A3: The accuracy change allowable value setting unit 25 sets the allowable value of the accuracy change during the processing time. In steps A2 and A3, as information related to processing, set a processing schedule and an allowable value for accuracy change. For example, regarding the type of workpiece to be processed and the processing program prepared according to the processing stage such as rough machining and finish machining, set their required processing time and required processing accuracy, and set the scheduled processing start time. In this embodiment, assume that processing with a required processing time of 4 hours and a required processing accuracy of 10 μm is to be performed. If the scheduled processing start time is set to 14:00, the allowable value for the accuracy change of the machine tool 2 between 14:00 and 18:00 (scheduled processing end time) is 10 μm.

[0017] Step A4: The shutter opening time setting unit 22 sets a certain shutter opening time. After setting the shutter opening time, the processing accuracy influence amount prediction unit 24 performs the processing after step A5. When the shutter opening time is predetermined and the possible processing start time is obtained, this processing is only performed once. At this time, the shutter opening time can be set by input from a screen or the like, or the opening / closing status can be acquired from the shutter opening / closing device 7 and set automatically. When the processing schedule is determined and the possible opening time of the shutter 5 is obtained, the processing in steps A5 to A10 is repeated by assuming various shutter opening times. The shutter opening times for calculation are determined in advance, for example, "in the range of 0 to 1200 seconds, with an interval of 30 seconds".

[0018] Step A5: Predict the room temperature change (temperature change) in the factory 1 when the shutter 5 is opened and after the shutter 5 is closed. When the shutter 5 is opened, as shown in the following formulas 1 and 2, the room temperature θ in the factory 1 in approaches the outside air temperature θ of the factory 1. out

[0019]

Number

Number

[0020] Also, after closing the shutter 5 again, as shown in the following Equation 3, the room temperature in Factory 1 approaches the set temperature θ of the air conditioner 4. c It approaches.

[0021]

Equation

[0022] This Equation 3, similar to the case of Equation 1, is an equation for the step response of a first-order lag, and the room temperature change followability is represented by the values of the time constants T open and T f The value of the time constant T open representing the delay in the room temperature change in Factory 1 with respect to the outside air temperature when the shutter is opened is likely to change depending on the size of the space in Factory 1, the size of the opening of the shutter 5, the presence or absence of wind outside Factory 1, etc. Among the above, the area of the opening of the shutter 5 changes depending on the degree of opening of the shutter 5, and the wind outside Factory 1 also changes moment by moment. Therefore, by acquiring information on the opening degree of the shutter 5 and the wind outside Factory 1 and obtaining the time constant T open as a function of them, a more accurate estimation according to the situation becomes possible. Equation 2 is an example of this, and the constants are determined and used based on calculations and measurement data. Other forms of equations may be used as the function for obtaining the time constant. Also, the value of the time constant T f representing the delay in the room temperature change in Factory 1 with respect to the air conditioner 4 changes depending on the size of the space in Factory 1, the output of the air conditioner 4, the operating state of the machines in Factory 1, etc. If this value is identified in advance, the room temperature change after turning on the air conditioner 4 can be predicted. This embodiment predicts the room temperature change using Equations 1 to 3, but other equations may be used for prediction based on measurement results, etc.

[0023] Step A6: Predict the change in the body temperature of the machine tool 2 when the room temperature change predicted in Step A5 occurs, and based on this, predict the thermal displacement of the machine tool 2. When the room temperature of the environment where the machine tool 2 is placed changes, the body temperature also changes with a delay. The change in the body temperature at this time can be represented by a first-order lag response with the room temperature change as the input. This response is obtained by sequential calculation using a difference equation such as Equation 4 below.

[0024]

Equation

[0025] For each machine tool 2 and each temperature measurement location, perform the calculation of Equation 4 to estimate the change in the body temperature of each part when the room temperature change predicted by Equations 1 to 3 occurs. Furthermore, predict the accuracy change due to the thermal displacement of the machine tool 2 from the estimated change in the body temperature of the machine tool 2. The accuracy change due to the thermal displacement can be expressed as a function of the body temperature as shown in Equation 5 below. Hereinafter, this function is referred to as the accuracy change function of the machine tool 2. What kind of function the accuracy change function is shall be determined in advance based on experiments or analyses.

[0026]

Equation

[0027] In this embodiment, the machine tool 2 is provided with the body temperature sensor 8, and the change in the body temperature is predicted using the current temperature information. However, it is not always necessary to install the body temperature sensor 8 for predicting the accuracy change of the machine tool 2. Also, it is possible to use variables other than the body temperature, such as the variation in the room temperature around the machine, as variables of the accuracy change function of the machine tool 2.

[0028] Step A7: Here, predict the thermal displacement during workpiece machining when changing the workpiece machining start time. The thermal displacement ΔX during workpiece machining can be obtained by the following Equation 6 w can be obtained.

[0029]

Equation

[0030] Since the time required for workpiece processing is constant, if the workpiece processing start time t w,start is shifted later, the workpiece processing end time t w,end will also be shifted later. While changing t w,start and t w,end , the thermal displacement ΔX w during workpiece processing is obtained. The relationship between the processing start time and the accuracy change during workpiece processing is obtained, for example, as shown in FIG. 5. In this example, the workpiece processing time is assumed to be 4 hours. It can be seen that as time elapses from the opening and closing of the shutter 5, the value of the thermal displacement during workpiece processing decreases.

[0031] Step A8: Record the workpiece processing start time when the thermal displacement during workpiece processing predicted in Step A7 is equal to or less than the allowable value of the accuracy change. Thereby, for a certain shutter opening time, the required time (accuracy stabilization time) until the thermal displacement during workpiece processing becomes equal to or less than the allowable value of the accuracy change can be obtained. Step A9: Determine whether the calculation has been completed for all preset shutter opening times. Step A10: When the calculation has not been completed for all preset shutter opening times, set another shutter opening time and perform the calculations of Steps A5 to A8 again. Step A11: When the calculation has been completed for all preset shutter opening times, create a table of the relationship between the shutter opening time and the accuracy stabilization time. Step A12: The arithmetic unit 26 determines the shutter openable time or the processing startable time based on the table.

[0032] Based on the above flow, examples of obtaining the shutter releaseable time are shown in FIGS. 4 to 6. In this example, it is assumed that the shutter 5 is opened at 10:00 am to carry in materials and processing is performed starting from the afternoon. By calculating how much time is required until the temperature change of the machine stabilizes according to the length of time the shutter 5 is opened, the processing accuracy can be ensured. In this simulation, for the sake of clarity of the results, the set temperature θ of the air conditioner 4 shown by the dashed-dotted line in FIG. 4 c is constant at 20°C, and the air temperature θ of the factory 1 shown by the dotted line out is assumed to be constant at 10°C. Also, in this example, the accuracy change function ΔX of the machine tool 2 m is calculated by the following Equation 7 assuming that it is proportional to the difference between the actual body temperature at a certain location and the reference temperature (20°C).

[0033]

Equation

[0034] FIG. 4 shows the predicted results of the room temperature change in Factory 1 and the body temperature change of the machine tool 2 when it is assumed that the shutter 5 is opened for 15 minutes. In FIG. 4, the time constant T open when the shutter is opened is 5 minutes, and the time constant T f when the shutter 5 is closed is calculated as 60 minutes. When the shutter 5 is opened, cold outside air flows into Factory 1, so as shown by the two-dot chain line, the room temperature θ of Factory 1 in rapidly decreases in a short time. After the shutter 5 is closed, it gradually returns to the set temperature θ c due to the effect of the air conditioner 4. At this time, the body temperature θ of the machine tool 2 m,1 also changes as shown by the solid line, but changes slowly with a delay with respect to the room temperature change. Therefore, when the shutter 5 is opened for a long time, the body temperature changes greatly, but if it is opened for a very short time, the influence on the body temperature change is small.

[0035] From the predicted temperature change of the machine body as shown in Fig. 4, when it is assumed that the shutter 5 is opened for 15 minutes according to Equation 6, the accuracy change function is obtained as shown in Fig. 5. Further, based on the time change of the accuracy change function, the thermal displacement ΔX during the workpiece machining with respect to the machining start time w is obtained as shown by the broken line. Here, it is assumed that the machining time of the workpiece is 4 hours. For example, the value of the broken line at 13:00 is about 15 μm, which means that the change in thermal displacement (the difference between the maximum value and the minimum value) when machining is performed from 13:00 to 17:00 is 15 μm. Also, from this graph, it can be seen that when the allowable value of the accuracy change is 10 μm, machining can be started after 14:14. In this way, the machining startable time that satisfies the condition that the accuracy change of the machine tool during workpiece machining is smaller than the allowable value is obtained. By displaying the obtained machining startable time on the display unit 3a of the control device 3 of the machine tool 2 to alert the user, poor machining accuracy can be prevented. This display unit 3a is an example of the machining startable time display means of the present disclosure. Alternatively, by controlling the machine tool 2 so that the control device 3 stops machining or in-machine measurement before the machining startable time and starts machining or in-machine measurement after the machining startable time, poor machining accuracy can be prevented. This control device 3 is an example of the machine tool control means of the present disclosure.

[0036] Also, when calculating the machining startable time for various shutter release times, a table as shown in FIG. 6 is obtained. Looking at this table, for example, when it is desired to start machining at 14:00, it can be seen that the shutter release time must be within 12 minutes. Also, if the shutter release time is 5 minutes or less, it can be seen that the influence on the change in the body temperature is small and the allowable accuracy change (the allowable value of the accuracy change) is not exceeded. By displaying this information on the display unit 7a of the shutter opening / closing device 7 or the like, the shutter 5 can be opened and closed in consideration of the influence on the workpiece machining accuracy. Also, a method such as displaying the shutter releasable time obtained from the machining start time and the allowable value of the accuracy change on the display unit 7a or the display unit 27 of the machining accuracy diagnostic device 20 and sounding an alarm buzzer when that time approaches can be considered. These display units 7a and 27 are examples of the releasable time display means of the present disclosure.

[0037] Alternatively, the shutter opening / closing device 7 may control the opening and closing of the shutter 5 based on the shutter releasable time. The shutter opening / closing device 7 is an example of the shutter control means of the present disclosure. Also, a method of automatically performing loading and unloading at a timing with little influence on the workpiece machining accuracy using an AGV (Automated Guided Vehicle) or the like can be considered. With such an accuracy management system, it is possible to prevent problems such as an adverse effect on the machining accuracy occurring because an operator not involved in the machining opens and closes the shutter 5 without knowing. In Equation 7, the accuracy change function was obtained assuming it is simply proportional to the body temperature at a certain location, but the equation of the accuracy change function can be arbitrarily set. For example, as the accuracy change function, equations such as the variation in the room temperature or body temperature at a plurality of locations and the differential value of the temperature change can be considered.

[0038] In this way, the machining accuracy diagnosis device 20 and the machining accuracy management system S of the above-described embodiment include a diagnostic information acquisition unit 21 that acquires, as diagnostic information, the room temperature inside the factory 1, the set temperature of the air conditioner 4, the outside air temperature outside the factory 1, the wind speed outside the factory 1, the opening degree of the shutter 5, and the body temperature of the machine tool 2; an opening time setting unit 22 that sets the opening time of the shutter 5; a machining time setting unit 23 that sets the scheduled machining start time and the scheduled machining end time by the machine tool 2; and a machining accuracy influence amount prediction unit 24 that predicts the influence amount on the machining accuracy due to the opening of the shutter 5 based on the acquired diagnostic information, the set opening time of the shutter 5, and the set scheduled machining start time and scheduled machining end time. According to this configuration, it is possible to quantitatively predict the influence of the room temperature change caused by the opening and closing of the shutter 5 on the machining accuracy of the machine tool 2. Therefore, it is possible to appropriately determine the timing of starting machining by the machine tool 2 or to determine a method of opening and closing the shutter 5 so as not to adversely affect the machining accuracy of the machine tool 2.

[0039] In the above-described embodiment, based on the equations shown in Equations 1 to 5, which are based on a physical model, the influence amount on the machining accuracy is calculated by calculating the room temperature change, the body temperature change of the machine tool, and the thermal displacement of the machine tool in this order. However, when obtaining the influence amount on the machining accuracy, it is not always necessary to perform calculations based on theoretical equations. For example, it is also possible to create a model that calculates the influence amount on the machining accuracy using input such as machining time and temperature information by using a machine learning method. Therefore, as the diagnostic information to be acquired, it is not limited to all of the room temperature inside the factory, the set temperature of the air conditioner, the outside air temperature outside the factory, the wind speed outside the factory, the opening degree of the shutter, and the body temperature of the machine tool as in the above-described embodiment, and it is also possible to acquire at least one of these and predict the influence amount on the machining accuracy.

Explanation of Reference Numerals

[0040] 1 ·· Factory, 2 ·· Machine tool, 3 ·· Control device, 3a ·· Display unit, 4 ·· Air conditioner, 5 ·· Shutter, 6 ·· Shutter drive device, 7 ·· Shutter opening / closing device, 7a ·· Display unit, 8 ·· Body temperature sensor, 9 ·· Room temperature sensor, 10 ·· Outside air temperature sensor, 11 ·· Anemometer, 20 ·· Machining accuracy diagnosis device, 21 ·· Diagnostic information acquisition unit, 22 ·· Opening time setting unit, 23 ·· Processing time setting unit, 24 ·· Machining accuracy influence amount prediction unit, 25 ·· Allowable accuracy change value setting unit, 26 ·· Arithmetic unit, 27 ·· Display unit, S ·· Machining accuracy management system.

Claims

1. A machining accuracy diagnosis device for diagnosing the machining accuracy of a machine tool installed inside a factory equipped with an openable and closable door or shutter, comprising: diagnostic information acquisition means for acquiring, as diagnostic information, the room temperature inside the factory, the set temperature of a temperature adjustment device for controlling the room temperature inside the factory or the temperature of the machine tool, the temperature outside the factory, and the degree of opening of the door or the shutter; opening time setting means for setting the opening time of the door or the shutter; machining time setting means for setting a planned machining start time and a planned machining end time by the machine tool; machining accuracy influence amount prediction means for predicting the amount of influence on the machining accuracy due to the opening of the door or the shutter based on the acquired diagnostic information, the set opening time of the door or the shutter, and the set planned machining start time and planned machining end time; A machining accuracy diagnosis device for a machine tool, characterized by comprising the above.

2. The diagnostic information acquisition means further acquires the body temperature of the machine tool as the diagnostic information, The machining accuracy influence amount prediction means predicts the temperature change of the room temperature inside the factory or the body temperature of the machine tool based on the set temperature of the temperature adjustment device or the temperature outside the factory, predicts the thermal displacement of the machine tool based on the predicted temperature change, and obtains the amount of change in the thermal displacement during the machining time from the planned machining start time to the planned machining end time as the amount of influence on the machining accuracy. The machining accuracy diagnosis device for a machine tool according to claim 1, characterized by this.

3. The machining accuracy influence amount prediction means predicts the temperature change of the room temperature inside the factory or the body temperature of the machine tool by inputting the set temperature of the temperature adjustment device when the door or the shutter is closed and inputting the temperature outside the factory when the door or the shutter is open. The machining accuracy diagnosis device for a machine tool according to claim 2, characterized by this.

4. accuracy change allowable value setting means for setting an allowable value for the accuracy change of the machine tool; Based on the comparison between the amount of influence on the machining accuracy predicted by the machining accuracy influence amount prediction means and the allowable value of the accuracy change, there is provided an openable time calculation means for obtaining the openable time of the door or the shutter. The machining accuracy diagnosis device for a machine tool according to any one of claims 1 to 3, characterized by this.

5. The machining accuracy diagnosis apparatus for a machine tool according to claim 4, further comprising openable time display means for displaying the openable time of the door or the shutter obtained by the openable time calculating means.

6. accuracy change tolerance value setting means for setting a tolerance value for accuracy change during the machining time set by the machining time setting means; machining startable time calculating means for obtaining a machining startable time that satisfies a condition that an amount of influence on the machining accuracy predicted by the machining accuracy influence amount predicting means is smaller than the tolerance value of the accuracy change, the machining accuracy diagnosis apparatus for a machine tool according to any one of claims 1 to 3.

7. The machining accuracy diagnosis apparatus for a machine tool according to claim 6, further comprising machining startable time display means for displaying the machining startable time.

8. A system for managing the machining accuracy of a machine tool installed inside a factory equipped with an openable and closable door or shutter, the machining accuracy diagnosis apparatus for a machine tool according to claim 4; shutter control means for controlling the opening and closing of the door or the shutter based on the openable time of the door or the shutter; A machining accuracy management system for a machine tool, characterized by comprising the same.

9. A system for managing the machining accuracy of a machine tool installed inside a factory equipped with an openable and closable door or shutter, the machining accuracy diagnosis apparatus for a machine tool according to claim 6 or 7; machine tool control means for controlling the machine tool to stop machining or in-machine measurement before the machining startable time and start machining or in-machine measurement after the machining startable time; A machining accuracy management system for a machine tool, characterized by comprising the same.

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