NC machine tool machining condition modification support device

Abstract

To provide a machining condition modification support device for NC machine tools that enables even unskilled workers to easily and quickly search for appropriate machining conditions for each process. [Solution] The device 10 that assists in modifying machining conditions in an NC machine tool 30 comprises a data processing unit 22 that calculates at least one piece of load information data during machining of the workpiece W, a storage unit 20 that stores the data calculated by the data processing unit for each process, a process list creation unit 12 that creates a process list including at least one piece of load information data for each process based on the data stored in the storage unit, a tool path image generation unit 14 that generates a tool path image by superimposing the data from the storage unit onto the tool path data in real time, and a linkage unit 16 that links the process list and the tool path image and displays them on a display unit.

Description

Technical Field

[0001] The present invention relates to a machining condition correction support device that inputs machining programs and machining conditions into a numerical control (NC) device and supports the correction of machining conditions in an NC machine tool that sequentially exchanges tools to machine a workpiece.

Background Art

[0002] In a machine tool, when machining a workpiece, inappropriate machining conditions may affect the workpiece quality and tool life due to chatter vibration or overload. In a general production process, trial and error of machining conditions is carried out during initial workpiece machining to find appropriate machining conditions and apply them to mass production machining. This operation of determining machining conditions requires a lot of man-hours, and the experience and skills of the operator are required to explore better conditions. Therefore, in recent years when the turnover of personnel has become an issue, it is required that unskilled operators can easily determine machining conditions in a short time.

[0003] Conventionally, as a machining condition correction support function, there is a function of proposing an appropriate spindle rotation speed from vibration data during actual machining in order to suppress chatter vibration. However, in determining machining conditions for an NC machine tool having an automatic tool changer such as a machining center, it is necessary to correct the conditions of a plurality of tools, and it takes time to correct the conditions of each tool. Also, due to chatter vibration, the quality of the machined surface of the workpiece may deteriorate and cause quality defects. However, when chatter vibration occurs in a part of the machined surface of the workpiece, in the case of a large-sized workpiece, the operator may overlook the presence of a chattered surface. Furthermore, even when a chattered surface is discovered, it has taken time to identify which tool and which machining condition has a problem.

[0004] To solve this problem, for example, Patent Document 1 describes a vibration information display device that instantaneously displays chatter vibration information on a monitor to quickly notify an operator who is away from the machine of machining abnormalities.

Prior Art Documents

[0005] [Patent Document 1] Japanese Patent Publication No. 2016-224695 [Overview of the project] [Problems that the invention aims to solve]

[0006] While the vibration information display device described in Patent Document 1 can inform the operator that a processing abnormality has occurred, it does not allow the operator to know which process is causing the abnormality or which processing part is experiencing it. Therefore, it is not possible to easily modify the processing conditions to resolve the processing abnormality.

[0007] The present invention aims to solve the problems of the prior art described above, and to provide a machining condition modification support device for NC machine tools that enables even unskilled workers to easily and quickly search for appropriate machining conditions for each process. [Means for solving the problem]

[0008] To achieve the above objectives, the present invention provides a device for assisting in modifying machining conditions in an NC machine tool that inputs machining programs and machining conditions into an NC device and processes a workpiece by sequentially changing tools, comprising: a data processing unit that calculates at least one piece of load information during workpiece machining; a storage unit that stores data calculated by the data processing unit for each process during workpiece machining; a process list creation unit that creates a process list including at least one piece of load information for each process based on the data stored in the storage unit during or after workpiece machining; a tool trajectory image generation unit that generates a tool trajectory image by superimposing the data from the storage unit onto the tool trajectory data at any given moment during or after workpiece machining; and a linkage unit that links the process list and the tool trajectory image and displays them on a display unit. [Effects of the Invention]

[0009] Since the process list and the tool path image are linked and displayed on the display unit, the operator can compare and refer to the process list and the tool path image, making it easy for even unskilled operators to modify the machining conditions. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic block diagram showing a preferred embodiment of a machining condition modification support device shown together with an NC machine tool. [Figure 2] This is a schematic diagram of the machining condition modification window, which displays the process list and tool path image. [Figure 3] This is a schematic diagram showing an example of a process list. [Figure 4] This is a schematic diagram showing an example of a tool path image. [Figure 5] This flowchart illustrates the processing in the data processing unit and storage unit that acquire load information and processing conditions. [Figure 6] This flowchart shows an example of a method for modifying machining conditions based on load information obtained from actual workpiece machining. [Figure 7] This flowchart shows an example of a method for modifying machining conditions based on load information obtained from simulated machining of a workpiece using a simulator. [Figure 8] This flowchart shows an example of a method for identifying a problematic machining area from a tool path image and confirming the tool, load information, and machining conditions (feed rate and spindle speed) for machining that area in the process list. [Figure 9] This flowchart shows an example of a method for identifying a problematic machining area from a process list and confirming the tool, load information, and machining conditions (feed rate and spindle rotation speed) used to machine that area. [Modes for carrying out the invention]

[0011] Preferred embodiments of the present invention will be described below with reference to the attached drawings. Referring to Figure 1, an example of a machining condition correction support device 10 and an NC machine tool 30 is illustrated.

[0012] As an example, the NC machine tool 30 includes a bed 32 as a base fixed to the factory floor, a column 34 mounted on the upper surface of the bed 32 at the rear end (right side in Figure 1) so as to be able to reciprocate in the left-right direction or in the X-axis direction (direction perpendicular to the plane of the paper in Figure 1), a Y-slider 36 mounted on the front of the column 34 so as to be able to move in the up-down direction or in the Y-axis direction, a spindle head 38 mounted on the Y-slider 36, and a table 42 mounted on the upper surface of the front part (left side in Figure 1) of the bed 32 so as to be able to move in the front-back direction or in the Z-axis direction (left-right direction in Figure 1).

[0013] A workpiece W is fixed to the upper surface of the table 42. In the example shown in Figure 1, the workpiece W is fixed to the table 42 via a workpiece holder 42a, such as an angle bracket. The NC machine tool 30 also includes a control panel (not shown) for an operator to operate the NC machine tool 30. The spindle 40 is rotatably supported on the spindle head 38 about a horizontal axis of rotation O extending in the Z-axis direction. The spindle head 38 includes a spindle motor 50 that rotationally drives the spindle 40. The spindle motor 50 is preferably formed by a built-in motor disposed within a housing (not shown) of the spindle head 38.

[0014] A rotary encoder 62 for measuring the rotational speed of the spindle 40 is attached to the rear end of the spindle 40. A tool T for machining the workpiece W fixed to the table 42 is attached to the tip of the spindle 40. The spindle 40 is equipped with a displacement sensor (not shown) for measuring cutting force. An acceleration sensor 54 for measuring vibrations occurring in the spindle 40 is attached to the spindle head 38.

[0015] The operation panel includes a display panel for displaying various operating conditions and machining conditions of the NC machine tool 30. The display panel can be formed by a touch panel that enables the operator to touch the screen with a finger or a touch pen to select the touched part or make an input corresponding to the touched part. The operation panel can also include a key input section. By operating the key input section, predetermined numbers and characters can be input into the NC device 52.

[0016] The NC machine tool 30 can further include a tool magazine (not shown) for storing a plurality of tools used for machining, an automatic tool changer (not shown) for exchanging tools between the tool magazine and the spindle 40, a coolant supply device (not shown) for supplying coolant to the machining area of the NC machine tool 30, and other peripheral devices, and a machine control device (not shown) for controlling the peripheral devices. In this embodiment, the NC machine tool 30 constitutes a horizontal machining center, but the NC machine tool 30 may be a vertical machining center that rotates the spindle around a vertical axis. It may also be other NC machine tools that perform turning, grinding, etc.

[0017] The column 34 is provided so as to be reciprocally movable along a pair of X-axis guide rails (not shown) extending in the X-axis direction on the upper front surface of the table 42. On the bed 32, as an X-axis feed device for reciprocally driving the column 34 along the X-axis guide rails, a ball screw (not shown) extending in the X-axis direction and an X-axis motor 44 connected to one end of the ball screw are provided, and a nut (not shown) engaging with the ball screw is attached to the column 34. An X scale 56 for measuring the coordinate position of the column 34 in the X-axis direction is also attached to the bed 32.

[0018] The Y-slider 36 is provided so as to be reciprocally movable along a pair of Y-axis guide rails extending in the Y-axis direction on the front surface of the column 34. The column 34 is provided with a ball screw (not shown) extending in the Y-axis direction and a Y-axis motor 46 connected to one end of the ball screw as a Y-axis feed device for reciprocally driving the Y-slider 36 along the Y-axis guide rails. A nut (not shown) engaging with the ball screw is attached to the Y-slider 36. The column 34 is also provided with a Y-scale 58 for measuring the coordinate position of the Y-slider 36 in the Y-axis direction.

[0019] The table 42 is provided so as to be reciprocally movable along a pair of Z-axis guide rails (not shown) extending in the horizontal Z-axis direction (the left-right direction in FIG. 1) on the upper surface of the bed 32. The bed 32 is provided with a ball screw (not shown) extending in the Z-axis direction and a Z-axis motor 48 connected to one end of the ball screw as a Z-axis feed device for reciprocally driving the table 42 along the Z-axis guide rails. A nut (not shown) engaging with the ball screw is attached to the table 42. The bed 32 is also provided with a Z-scale 60 for measuring the coordinate position of the table 42 in the Z-axis direction.

[0020] The X-axis motor 44, Y-axis motor 46, Z-axis motor 48, X-scale 56, Y-scale 58, Z-scale 60, spindle motor 50 and rotary encoder 62 are connected to the NC device 52. The X-axis motor 44, Y-axis motor 46, Z-axis motor 48 and spindle motor 50 are controlled according to a machining program input to the NC device 52 based on the measured values of the X-scale 56, Y-scale 58, Z-scale 60 and rotary encoder 62. Thus, the NC machine tool 30 processes the workpiece W by relatively moving the tool T at the tip of the spindle 40 and the workpiece W on the table 42 while rotating the spindle 40 according to the machining program supplied to the NC device 52.

[0021] The machining condition modification support device 10 comprises a process list creation unit 12, a tool trajectory image generation unit 14, a linkage unit 16, a machining condition modification unit 18, a storage unit 20, a data processing unit 22, a display unit 24, and a machining condition input unit 26 as its main components. The process list creation unit 12, the tool trajectory image generation unit 14, the linkage unit 16, the machining condition modification unit 18, and the storage unit 20 can be composed of a computer and related software including a CPU (Central Processing Unit), memory devices such as RAM (Random Access Memory) and ROM (Read-Only Memory), storage devices such as HDD (Hard Disk Drive) and SSD (Solid State Drive), an RTC (Real-Time Clock) consisting of an integrated circuit with a clock function, input / output ports, and a bidirectional bus that interconnects these. The process list creation unit 12, the tool trajectory image generation unit 14, the linkage unit 16, the machining condition modification unit 18, and the storage unit 20 may be configured in software as part of the NC device 52 or machine control device of the NC machine tool 30 shown in Figure 1.

[0022] The display unit 24 can be formed, for example, by the display panel of the control panel of the NC machine tool 30. The machining condition input unit 26 can be formed, for example, by the touch panel, key input unit, etc. that make up the display panel of the control panel of the NC machine tool 30. If the machining condition modification support device 10 is configured with a personal computer (not shown) or a portable terminal such as a tablet (not shown) that is independent of the NC machine tool 30, the display unit 24 and the machining condition input unit 26 can be formed with the display device and keyboard of the personal computer and the touch panel of the portable terminal.

[0023] The data processing unit 22 is connected to the X-axis motor 44, Y-axis motor 46, Z-axis motor 48, spindle motor 50, acceleration sensor 54, X-scale 56, Y-scale 58, Z-scale 60, spindle motor 50, and rotary encoder 62. It processes the outputs from the X-axis motor 44, Y-axis motor 46, Z-axis motor 48, spindle motor 50, acceleration sensor 54, displacement sensor for cutting force measurement (not shown), X-scale 56, Y-scale 58, Z-scale 60, spindle motor 50, and rotary encoder 62 and outputs them to the storage unit 20 as load information. The load information may include at least one of the following: cutting force acting on the tool T, load (torque) applied to the spindle 40, vibration value due to machining (amplitude of vibration including the rotational speed component of the spindle 40), regenerative chatter vibration value, workpiece removal rate, and presence or absence of machining abnormalities.

[0024] The cutting force acting on the tool T can be calculated from the current values ​​supplied to the X-axis motor 44, Y-axis motor 46, and Z-axis motor 48, or from the values ​​detected by the displacement sensor built into the spindle 40. Alternatively, it can be calculated from the displacement sensor built into the spindle 40. The load applied to the spindle 40 can be calculated from the current values ​​supplied to the spindle motor 50. The vibration value due to machining and the regenerative chatter vibration value can be calculated based on the measurement values ​​of the acceleration sensor 54. The workpiece removal rate is the machining volume of the workpiece W per unit time, and can be calculated as the product of the tool's cutting width, cutting depth, and feed rate. Furthermore, the data processing unit 22 can determine that machining is abnormal when the spindle load, cutting force, vibration value, and regenerative chatter vibration value exceed predetermined thresholds, and output a signal indicating machining abnormality to the storage unit 20. The thresholds can be set according to the machining program, workpiece, or tool type, for example, based on normal machining.

[0025] Furthermore, the data processing unit 22 calculates the feed rate and spindle rotation speed as machining conditions. Based on the measured values ​​of the X scale 56, Y scale 58, and Z scale 60, it calculates the feed rate of the tool T relative to the workpiece W and outputs it to the storage unit 20. Based on the measured value of the rotary encoder 62, the data processing unit 22 calculates the rotation speed of the spindle 40 and outputs it to the storage unit 20.

[0026] Referring to Figure 5, a flowchart is shown illustrating the processing in the data processing unit 22 and the storage unit 20. The data processing unit 22 first records the start and end points of each process (step S10). For example, each process can be defined as one process for each tool change. The indicators representing the start and end points of a process can be data that represents the progress of machining, such as the time the tool change was performed, the scan count, the cutting distance, or the line number of the machining program.

[0027] The data processing unit 22 accesses the X-axis motor 44, Y-axis motor 46, Z-axis motor 48, spindle motor 50, acceleration sensor 54, displacement sensor for measuring cutting force, X scale 56, Y scale 58, Z scale 60, spindle motor 50, and rotary encoder 62 at predetermined time intervals from the start point to the end point of each process, and extracts the output of each as data (step S12). At the end of the process or after completion, the data processing unit 22 calculates load information and machining conditions (feed rate and spindle rotation speed) and outputs them to the storage unit 20 (step S14). The load information includes the maximum value of each of the cutting force acting on the tool T, the load applied to the spindle 40, the vibration value due to machining, the regeneration chatter vibration value, and the workpiece removal rate in each process. In addition to the maximum value, the load information may also include the average value and cumulative value.

[0028] The storage unit 20 stores the load information, feed rate, and spindle rotation speed received from the data processing unit 22, associating them with indicators that show the start and end points of the process (for example, the time when tool changes were performed). The load information, feed rate, and spindle rotation speed are stored in the storage unit 20 as time-series data arranged in the order of the process.

[0029] The operation of the machining condition modification support device 10 for the NC machine tool 30 according to this embodiment will be described below. Referring to Figure 2, the machining condition modification window 100 displayed on the display unit 24 is shown. The machining condition modification window 100 includes several function buttons 102 to 110, including a machining condition modification button 106. When the operator taps the machining condition modification button 106, the machining condition modification window 100 is displayed. The machining condition modification window 100 includes a process list window 200 and a tool path window 300.

[0030] When the operator taps the machining condition modification button 106 displayed on the display unit 24 and selects the machining performance data or simulation data for the machining program whose machining conditions they wish to modify, the linkage unit 16 outputs a command to create a process list to the process list creation unit 12 and a command to generate a tool path image to the tool path image generation unit 14.

[0031] Upon receiving a process list creation command from the linkage unit 16, the process list creation unit 12 accesses the storage unit 20 and creates a process list as shown in Figures 2 and 3 as an example, by retrieving the machining program number, tool information, machining conditions, load information, spindle rotation speed, and feed rate, associating them with indicators that show the start and end points of the process (for example, the time when the tool change was performed). The process list can be created in real time during machining and stored in the storage unit 20, or it can be created from time-series data stored in the storage unit 20.

[0032] Referring to Figure 3, the process list window 200 displays a process list consisting of a table containing multiple columns and rows. An example process list shown includes a process column 202, a tool column 204, a cutting time column 206, an air cut time column 208, a spindle load column 210, a vibration value column 212, a chatter vibration column 214, a spindle rotation speed column 216, and a feed rate column 218. The process list may also include checkboxes 201 for each row to the left of the process column 202.

[0033] The process list may include columns other than those shown in Figure 2. Furthermore, the process list does not need to include all columns 202-218 shown in Figures 2 and 3. For example, the process list may omit one or more columns other than process column 202, spindle load column 210, vibration value column 212, and chatter vibration column 214, specifically the tool column 204, cutting time column 206, air cut time column 208, spindle rotation speed column 216, and feed rate column 218. The tool column 204, cutting time column 206, air cut time column 208, spindle rotation speed column 216, and feed rate column 218 may, if necessary, include buttons (not shown) that allow the operator to selectively display them.

[0034] The fields in process column 202 display the machining program number or tool number. In the example in Figure 2, field 202a of process column 202 displays the main program number O1001, field 202b displays the subprogram number O2001, which indicates one subprogram, subprogram, or subroutine of main program number O1001, field 202c displays the tool number T2001 / 1 assigned to one tool used in the machining program of subprogram number O2001, field 202d displays the tool number T2002 / 2 assigned to another tool used in the machining program of subprogram number O2001, and field 202e displays the tool number assigned to yet another tool used in the machining program of subprogram number O2001. The assigned tool number T2003 / 3 is displayed in field 202f, the tool number T2004 / 4 is displayed in field 202g, the tool number T2005 / 5 is displayed in field 202g, the tool number T2005 / 5 is displayed in field 202h, the subprogram number O3001 is displayed, indicating another subprogram, subordinate program or subroutine included in main program number O1001, and the tool number T3001 / 6 is displayed in field 202i, which is assigned to one tool used in the machining program of subprogram number O3001.

[0035] In the example shown in Figures 2 and 3, the process column 202 indicates that the higher-level process indicated by program number O1001 includes two lower-level processes corresponding to program numbers O2001 and O3001, the lower-level process corresponding to program number O2001 includes five further lower-level processes executed by tools corresponding to tool numbers T2002 / 1, T2002 / 2, T2002 / 3, T2002 / 4, and T2002 / 5, and the process corresponding to program number O3001 includes one further lower-level process executed by a tool corresponding to tool number T3001 / 6. In other words, in the present invention, the process list is a table that defines a process for each tool or for each tool change and summarizes the machining data for each process.

[0036] The tool column 204 displays the type of tool corresponding to the tool number displayed in the process column 202. In the examples in Figures 2 and 3, the fields 202a, 202b, and 202h of the process column, which correspond to fields 204a, 204b, and 204h of the tool column 204, display the main program number or subprogram number, so fields 204a, 204b, and 204h of the tool column 204 are left blank. Fields 204c, 204e, and 204g of the tool column 204 display BEM (ball end mill) as the tool type corresponding to tool numbers T2001 / 1, T2003 / 3, and T2005 / 5 in the corresponding fields 202c, 202e, and 202g of the process column 202, while fields 204d, 204f, and 204i of the tool column 204 display FEM (flat end mill) as the tool type corresponding to tool numbers T2002 / 2, T2004 / 4, and T3001 / 6. The tool column 204 may also display tool types other than ball end mills and flat end mills, such as drills, face mills, and rotary grinding wheels.

[0037] The cutting time is displayed in the field of the cutting time column 206. In the example in Figures 2 and 3, the total time for which cutting feed commands were given to the tools corresponding to tool numbers T2001 / 1, T2002 / 2, T2003 / 3, T2004 / 4, T2005 / 5, and T3001 / 6 is displayed as the cutting time. The cutting time for subprogram O2001 is the sum of the cutting times for the tools corresponding to tool numbers T2001 / 1, T2002 / 2, T2003 / 3, T2004 / 4, and T2005 / 5 used in that subprogram. The cutting time for subprogram O3001 is the cutting time for the tool corresponding to tool number T3001 / 6 used in that subprogram. The cutting time for main program O1001 is the sum of the cutting times for subprogram O2001 and subprogram O3001.

[0038] The cutting time may be calculated and displayed using the following formula, either as the time required to execute the main program or subprogram, or as the time the tool corresponding to the tool number is used for cutting, that is, the time the tool is actually engaged with the workpiece W. Tc = Lm / Vf Here, Tc: Cutting time (min) Lm: Processing length (mm) Vf: Feed rate (mm / min) That is the case.

[0039] In the examples in Figures 2 and 3, the cutting times for the processes using tools corresponding to tool numbers T2001 / 1, T2002 / 2, T2003 / 3, T2004 / 4, and T2005 / 5 are 7 minutes 15 seconds, 7 minutes 45 seconds, 6 minutes 50 seconds, 2 minutes 0 seconds, and 2 minutes 10 seconds, respectively. Therefore, the cutting time for the machining process corresponding to subprogram O2001 is 26 minutes 00 seconds. The cutting time for the process using tool number T3001 / 6 is 2 minutes 30 seconds, therefore, the cutting time for the machining process corresponding to subprogram O3001 is 2 minutes 30 seconds. The total cutting time for main program O1001 is shown to be 28 minutes 30 seconds.

[0040] The spindle load column 210 displays the maximum load acting on the spindle 40 for each process. The load acting on the spindle 40 is defined by the current value (A) supplied to the spindle motor 50 or the torque (Nm) generated by the spindle motor 50. In the example shown in Figures 2 and 3, a warning mark (▲) is displayed indicating that the spindle load has exceeded a predetermined allowable value, reaching 105% (a percentage of the motor's rated torque as 100%) in the process using the tool corresponding to tool number T3003 / 3. The warning mark (▲) is displayed based on an indicator of machining abnormality in the load information stored in the memory unit 20.

[0041] The vibration value column 212 displays the maximum output of the acceleration sensor 54 attached to the spindle 40 for each process. In the example shown in Figures 2 and 3, in the processes using tools corresponding to tool numbers T2002 / 2 and T2003 / 3, the vibration values ​​of the spindle 40 are 5.0G (gravitational acceleration) and 9.0G, respectively, and a warning mark ▲ is displayed indicating that the predetermined allowable value has been exceeded. The warning mark ▲ is displayed based on an index indicating a machining abnormality in the load information stored in the memory unit 20.

[0042] The chatter vibration column 214 displays the maximum value of regenerative chatter vibration calculated based on the output of the acceleration sensor 54 attached to the spindle 40 for each process. Here, regenerative chatter vibration (self-excited chatter vibration) is a vibration component caused by the deflection of the tool T due to the load acting on the tool T during cutting, and does not include forced chatter vibration, which is a mechanical vibration that occurs intermittently when the vibration of the NC machine tool 30 body is amplified by the vibration characteristics of the NC machine tool 30. In the example shown in Figures 2 and 3, in the process using the tool corresponding to tool number T3003 / 3, the maximum value of regenerative chatter vibration is 70, and a warning mark ▲ is displayed indicating that it has exceeded the predetermined allowable value. The warning mark ▲ is displayed based on an index indicating machining abnormality in the load information stored in the memory unit 20. The magnitude of the tool chatter vibration value is a dimensionless value obtained using a unique method, and a larger number indicates a larger vibration.

[0043] The spindle speed column 216 displays the spindle speed (rpm) for each process. The feed rate column 218 displays the relative speed (mm / min) of the tool T relative to the workpiece W. The stable spindle speed column 208 displays the stable rotational speed calculated by formula (1) described later.

[0044] Upon receiving a tool path generation command from the linkage unit 16, the tool path image generation unit 14 accesses the storage unit 20 to obtain tool number, load information, spindle rotation speed, feed rate, and machine coordinate information, thereby generating a tool path image in the tool path window 300, as shown as an example in Figures 2 and 4.

[0045] The tool path window 300 displays the tool paths corresponding to each tool in the process list shown in the process list window 200, along with the shape of the workpiece W after machining. In Figure 4, tool path 302 shows the tool path corresponding to tool number T2001 / 1 (convex frustoconical shape), tool path 304 shows the tool path corresponding to tool number T2002 / 2 (convex rectangular parallelepiped shape), tool path 306 shows the tool path corresponding to tool number T2003 / 3 (convex square pyramidal shape), tool path 308 shows the tool path corresponding to tool number T2004 / 4 (convex cylindrical shape), tool path 310 shows the tool path corresponding to tool number T2005 / 5 (convex hemispherical shape), and tool path 312 shows the tool path corresponding to tool number T3001 / 6 (concave cylindrical shape).

[0046] The tool path window 300 further includes a load information selection field 314. As an example shown in Figures 2 and 4, the load information selection field 314 in the tool path window 300 is in the form of a drop-down list. By expanding the drop-down list in the load information selection field 314, one of the load information corresponding to the load information displayed in the first row of the process list—in the example in Figure 3—can be selected: spindle load, spindle vibration value, and tool chatter vibration value. While the load information selection field 314 is in the form of a drop-down list in this example, it may also be in another format, such as a table displaying the load information in a list.

[0047] Tool paths 302-312 can be color-coded according to the selected load information value. Additionally, a color bar 316 corresponding to the load information value can be displayed within the tool path window 300. For example, in the example in Figure 4, the spindle vibration value is selected as the load information, and the spindle vibration value can be color-coded as green, yellow, orange, red, and purple for values ​​of 0-2.0, 2.0-4.0, 4.0-6.0, 6.0-8.0, and 8.0-10.0, respectively. The area near the corner of the contour line path marked with an "x" in tool path 304 corresponds to a spindle vibration value (maximum output of acceleration sensor 54) of 5.0 when machining with the tool corresponding to tool number T2002 / 2, and is shown in orange in Figure 4. The area near the corner of the contour line path marked with an "x" in tool path 306 corresponds to a spindle vibration value (maximum output of acceleration sensor 54) of 9.0 when machining with the tool corresponding to tool number T2003 / 3, and is shown in purple in Figure 4. The parts of tool paths 302 to 312 other than those marked with an "x" have small spindle vibrations and are shown in green and yellow. Generally, in corners where the tool feed direction changes discontinuously, the spindle vibration increases, and is often shown in orange, red, and purple.

[0048] Since the process list and tool paths are linked by indicators showing the start and end points of the process (e.g., the time when tool changes were performed), as shown in Figure 2, by displaying them in a single window (machining condition modification window 100), when the operator taps a checkbox 201 or row displaying a tool number in the process list window 200, the linkage unit 16 outputs a highlighting command to the tool path image generation unit 14, which then highlights the corresponding tool path in the tool path window 300. In particular, when the operator taps a checkbox 201 or row displaying a tool number with a warning mark ▲, the linkage unit 16 highlights the problematic tool path that exceeds the tolerance limit in the tool path window 300. Highlighting can be achieved by blinking or highlighting the display color. Additionally, the checkbox 201 can be used to show or hide tool paths for emphasis.

[0049] Conversely, when the operator taps near the × mark on a tool path of a color assigned to load information with a high value in the tool path window 300, such as tool path 304 or tool path 306 in Figure 4, the linkage unit 16 outputs a highlighting command to the process list creation unit 12, causing the row of the corresponding tool number T2001 / 2 or T2001 / 3 to be highlighted. Highlighting is achieved by blinking the corresponding row, changing the display color, highlighting, displaying a check mark in checkbox 201, or hiding rows other than the corresponding row. In this embodiment, the process list creation unit 12 and the tool path image generation unit 14 cooperate through the linkage unit 16 to display the process list and tool path image in a single machining condition modification window 100.

[0050] Next, we will explain how to modify the processing conditions. Referring to Figure 6, first, the NC machine tool 30 actually processes the workpiece W (step S20), and during the actual processing, the data processing unit 22 reads the output values ​​from the X-axis motor 44, Y-axis motor 46, Z-axis motor 48, spindle motor 50, acceleration sensor 54, X-scale 56, Y-scale 58, Z-scale 60, spindle motor 50 and rotary encoder 62 as processing data at predetermined time intervals (step S22). Next, when the operator taps the processing condition modification button 106, the processing condition modification window 100 is displayed on the display unit 24, and the process list and tool path image are displayed in the processing condition modification window 100 (step S24). The tool path image can be generated by reading the moment-by-moment coordinate position of the tip of the tool T using the X-scale 56, Y-scale 58, and Z-scale 60, and sequentially connecting them with polylines.

[0051] The operator identifies problematic processes by referring to the process list and tool path images in the machining condition modification window 100, particularly the warning marks in the process list and the tool paths displayed in colors assigned to high-value measurement information in the tool path images (step S26). In this process, even if the operator has little experience or knowledge, they can easily find problematic processes by performing coordinated operations such as tapping the tool number with a ▲ warning mark in the process list to highlight the corresponding tool path, or tapping the tool path displayed in colors assigned to high-value measurement information in the tool path image to highlight the corresponding process in the process list. This is significantly easier than the conventional method of visually inspecting the machined surface of the workpiece.

[0052] The operator, having identified the problematic process, determines whether or not the machining conditions need to be modified (step S28). If the operator determines that no modification to the machining conditions is necessary (no in step S28), for example, if no warning mark (▲) is displayed in the process list, or if the tool path colors in the tool path image are all colors assigned to low measurement information, the flowchart ends.

[0053] If a warning mark (▲) is displayed in the process list, or if a tool path of a color assigned to high-value measurement information is displayed in the tool path image, and the operator determines that the machining conditions need to be modified (if the answer is Yes in step S28), the operator inputs the modified machining conditions from the machining condition input unit 26 in Figure 1 to the NC device 52.

[0054] For example, if the chatter vibration value of the tool is higher than a predetermined threshold value which is an allowable value, the rotational speed of the spindle 40 can be changed to a stable rotational speed. Also, if the spindle load is higher than a predetermined threshold value which is an allowable value, the feed rate can be reduced, or the depth of cut of the cutting edge of the tool T into the workpiece can be reduced.

[0055] The stable spindle rotation speed can be automatically calculated by the machining condition modification unit 18. The machining condition modification unit 18 obtains the regenerated chatter vibration frequency from the memory unit 20, accesses the process list creation unit 12 to obtain the number of cutting edges of the tool that is causing the regenerated chatter vibration, and calculates the stable spindle rotation speed based on the regenerated chatter vibration frequency and the number of cutting edges using the following formula.

[0056] Stable rotational speed = (60 × regenerative chatter frequency / number of tool teeth × (k value + 1)) ... (1) Note that k is an integer value greater than or equal to 0. The stable rotational speed can be calculated by substituting k = 0, 1, 2, 3, 4... in order into equation (1).

[0057] Multiple calculated stable spindle speeds can be displayed on the display unit 24. The operator views the stable spindle speeds displayed on the display unit 24, selects a stable spindle speed close to the current spindle speed, and inputs it into the NC device 52 from the machining condition input unit 26 to modify the spindle speed as a machining condition. Alternatively, when the stable spindle speed is displayed on the display unit 24, a dialog box (not shown) prompting the operator to modify the spindle speed may be opened simultaneously, and the operator can tap a button in the dialog box to input the stable spindle speed directly from the machining condition modification unit 18 to the NC device 52.

[0058] After the correction, the flowchart returns to step S20, processes the workpiece W again, and executes steps S22 to S28 again to determine if the machining conditions need to be modified. Steps S10 to S30 can be repeatedly executed until it is determined in step S28 that there is no need to modify the machining conditions (the result in No in step S28).

[0059] In the embodiments described above, load information, feed rate, and spindle rotation speed were explained to be obtained by the NC machine tool 30 while actually machining the workpiece W. However, the present invention is not limited thereto, and load information, feed rate, and spindle rotation speed may be obtained based on simulation results using a simulator (not shown). In other words, in Figure 1, the NC machine tool 30, NC device 52, and data processing unit 22 can be replaced by a simulator such as a personal computer.

[0060] In the flowchart of Figure 6, load information and machining conditions (feed rate and spindle speed) are obtained based on measurement results from actually machining the workpiece W. However, as mentioned above, they may also be obtained by performing simulated machining using a simulator. Referring to Figure 7, a flowchart of the method for modifying machining conditions when load information and machining conditions (feed rate and spindle speed) are obtained using a simulator is shown.

[0061] The machining program and the 3D shape data of the workpiece W before machining are loaded into the simulator (step S40). The simulator then performs a simulated machining operation according to the loaded machining program to generate load information and machining conditions (feed rate and spindle rotation speed) as machining simulation data (step S42). Next, when the operator taps the machining condition modification button 106, the machining condition modification window 100 is displayed on the display unit 24 based on the load information and machining conditions (feed rate and spindle rotation speed) generated as machining simulation data, and the process list and tool path image are displayed within the machining condition modification window 100 (step S44). Steps S46 to S50 are the same as steps S26 to S30 in Figure 6, so their explanation is omitted.

[0062] As described above, in the present invention, the process list and the tool path image are displayed in conjunction with each other within the machining condition modification window 100, making it easy to identify the process where a problem is occurring. Referring to the flowchart shown in Figure 8, a method for identifying the machining area where a problem is occurring from the tool path image and confirming the tool, load information, and machining conditions (feed rate and spindle rotation speed) for machining that area will be explained.

[0063] When the operator discovers an abnormality such as a machined surface defect or precision defect in a specific part of a workpiece that has been actually machined or a workpiece generated by simulated machining using a simulator (step S60), the operator opens the machining condition modification window 100, checks whether there is an abnormality in the load information of the corresponding part in the tool path image where the abnormality is occurring, and taps that part (step S62). As a result, the linkage unit 16 instructs the process list creation unit 12 to highlight the process corresponding to the part selected by the operator (step S64). The operator can identify the cause of the problem by checking the tool number, machining conditions, and load information of the highlighted process (step S66).

[0064] Conversely, it is also possible to identify the process causing the problem from the process list and confirm the corresponding area on the tool path image. Referring to the flowchart shown in Figure 9, when the operator discovers an abnormality such as a machined surface defect or accuracy defect in a specific area of ​​a workpiece that has been actually machined or a workpiece generated by simulated machining using a simulator, or when the operator wants to further improve the machining conditions (step S70), the operator opens the machining condition modification window 100 and taps the problematic process or a process that can be improved from the process list (step S72). As a result, the linkage unit 16 instructs the tool path image generation unit 14 to highlight the tool path corresponding to the process selected by the operator (step S74). By referring to the highlighted tool path, the operator can identify the machining conditions that are causing the problem. [Explanation of symbols]

[0065] 10 Machining condition modification support device 12. Process List Creation Department 14 Tool path image generation section 16. Liaison Department 18 Machining condition correction section 20 Memory section 22 Data Processing Unit 24 Display section 26 Processing Condition Input Section 30 NC machine tools 52 NC device 100 Machining Condition Modification Window 200 Process List Window 300 Toolpath Window

Claims

1. In a device that assists in modifying machining conditions in an NC machine tool, which inputs machining programs and machining conditions into an NC device and processes a workpiece by sequentially changing tools, A data processing unit that calculates at least one piece of load information during workpiece machining, During workpiece processing, a storage unit stores the data calculated by the data processing unit for each process, A process list creation unit creates a process list that includes at least one piece of load information for each process, based on the data stored in the storage unit during or after the processing of the workpiece. A tool path image generation unit generates a tool path image by superimposing the data from the storage unit onto the tool path data at each moment during or after machining of the workpiece. A linking unit that links the process list and the tool path image and displays them on the display unit, A machining condition modification support device for an NC machine tool, characterized by being equipped with the following features.

2. The NC machine tool machining condition modification support device according to claim 1, wherein the data processing unit measures and calculates at least one data of load information while the NC machine tool is machining a workpiece.

3. The NC machine tool machining condition modification support device according to claim 1, wherein the data processing unit performs a machining simulation of the workpiece of the NC machine tool and calculates at least one data of load information at that time.

4. The NC machine tool machining condition modification support device according to any one of claims 1 to 3, wherein the data processing unit calculates spindle load or vibration value as load information, and the process list creation unit creates a process list including at least one data point for each process, which is the maximum value of the spindle load and whether or not there is regenerative chatter vibration.

5. The machining condition modification support device for an NC machine tool according to claim 1, wherein the coordinating unit, when a tool number is selected from the process list, causes the tool trajectory image generation unit to highlight the corresponding portion in the tool trajectory image processed with the tool.

6. The machining condition modification support device for an NC machine tool according to claim 1, further comprising a machining condition modification unit that calculates a stable spindle rotation speed to suppress regenerative chatter vibration based on the vibration frequency and the number of cutting edges of the tool, and displays the stable spindle rotation speed on the display unit.

7. The machining condition modification support device for an NC machine tool according to claim 1, further comprising a machining condition modification unit that calculates a stable spindle rotation speed to suppress regenerative chatter vibration based on the vibration frequency and the number of teeth of the tool, and outputs the stable spindle rotation speed to the NC device.

Images