Remaining amount estimation device and remaining amount estimation method

Abstract

A remaining amount estimation device (30) estimates the remaining amount of wire (S) on a wire bobbin (18) on which a wire electrode (16) has been wound and comprises: an acquisition unit (50) that acquires a first rotational position (60) for the wire bobbin (18) and a second rotational position (62) for a delivery roller (20) that delivers the wire electrode (16); and a first estimation computation unit (52) that estimates the remaining amount of wire (S) using the ratio of the rotation amount of the wire bobbin (18) and the delivery roller (20) at each of a start time and an end time of a prescribed time period (T) and the total rotation amount (φ) that the delivery roller (T) has rotated during the prescribed time period (T).

Description

Technical Field

[0001] The present invention relates to a remaining amount estimation device for estimating the remaining amount of a wire electrode wound around a wire bobbin of a wire electrical discharge machining machine, and a remaining amount estimation method executed by the remaining amount estimation device.

Background Art

[0002] A wire electrical discharge machining machine performs electrical discharge machining using a wire electrode. The wire electrode is wound around a wire bobbin in advance. The amount of the wire electrode wound around the wire bobbin is also described as "wire remaining amount" hereinafter.

[0003] The wire remaining amount gradually decreases during the execution of electrical discharge machining. When the wire remaining amount runs out during the execution of electrical discharge machining, the electrical discharge machining is interrupted. A prior art for preventing this interruption is disclosed in Japanese Utility Model Publication No. 02-039824. This prior art relates to a method for calculating the wire remaining amount. This prior art includes calculations using the density of the wire electrode and the winding diameter of the wire electrode. The density is described as the winding ratio in Japanese Utility Model Publication No. 02-039824.

Summary of the Invention

[0004] The above prior art has at least the following problems. In order to implement the above prior art, an operator measures the density and the winding diameter. Here, the operation of measuring both the density and the winding diameter is a burden on the operator.

[0005] An object of the present invention is to solve the above-described problems.

[0006] A first aspect of the present invention is a remaining amount estimation device for estimating the remaining amount of wire on a wire bobbin of a wire electrical discharge machining machine, the device comprising: a wire bobbin; a feed roller for feeding a wire electrode wound around the wire bobbin; a first rotation position detection sensor for detecting a first rotation position of the wire bobbin; and a second rotation position detection sensor for detecting a second rotation position of the feed roller, the device further comprising: an acquisition unit for acquiring the first rotation position and the second rotation position; a first ratio which is a ratio of rotation amounts at the start of a predetermined period between the wire bobbin and the feed roller; a second ratio which is a ratio of rotation amounts at the end of the predetermined period between the wire bobbin and the feed roller; and a first estimation calculation unit for estimating the remaining amount of wire at the end of the predetermined period based on the first ratio, the second ratio, and the total rotation amount of the feed roller during the predetermined period.

[0007] A second aspect of the present invention is a remaining amount estimation method for estimating the remaining amount of wire on a wire bobbin of a wire electrical discharge machining machine, the method comprising: a wire bobbin; a feed roller for feeding a wire electrode wound around the wire bobbin; a first rotation position detection sensor for detecting a first rotation position of the wire bobbin; and a second rotation position detection sensor for detecting a second rotation position of the feed roller, the method further comprising: an acquisition step of acquiring the first rotation position and the second rotation position; a first ratio which is a ratio of rotation amounts at the start of a predetermined period between the wire bobbin and the feed roller; a second ratio which is a ratio of rotation amounts at the end of the predetermined period between the wire bobbin and the feed roller; and an estimation calculation step of estimating the remaining amount of wire at the end of the predetermined period based on the first ratio, the second ratio, and the total rotation amount of the feed roller during the predetermined period.

[0008] According to each aspect of the present invention, the remaining amount of wire can be obtained while reducing the burden on the operator.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

DETAILED DESCRIPTION OF THE INVENTION

[0010] [Embodiment] FIG. 1 is a configuration diagram of a remaining amount estimation system 10 according to the embodiment. Note that the illustration in FIG. 1 includes not only the remaining amount estimation system 10 but also the feed mechanism 14 of the wire electrical discharge machining machine 12.

[0011] The feed mechanism 14 includes a wire bobbin 18, a plurality of delivery rollers 20, and two motors 22.

[0012] The wire bobbin 18 is a rotatable bobbin. Point O in FIG. 1 indicates the rotation axis of the wire bobbin 18 (see also FIG. 5). A wire electrode 16 is wound around the wire bobbin 18. The wire electrode 16 is a wire used for electrical discharge machining. The wire electrode 16 is drawn out from the wire bobbin 18.

[0013] Each of the plurality of delivery rollers 20 is a rotatable roller. The plurality of delivery rollers 20 includes a first roller 201 and a second roller 202. The wire electrode 16 drawn from the wire bobbin 18 is passed over the first roller 201 and the second roller 202 in this order.

[0014] The plurality of delivery rollers 20 further includes an auxiliary roller 203. The auxiliary roller 203 changes the traveling direction of the wire electrode 16. Also, the auxiliary roller 203 reduces the deflection of the wire electrode 16. The number of installed auxiliary rollers 203 is not particularly limited. The installation location of the auxiliary roller 203 is also not particularly limited.

[0015] Each of the two motors 22 is, for example, a servo motor. The two motors 22 include a first motor 221 and a second motor 222. The first motor 221 rotates the first roller 201. The second motor 222 rotates the second roller 202.

[0016] Each of the two motors 22 is controlled by a control device 24. The control device 24 is an electronic device (computer) for controlling the wire electrical discharge machining machine 12. The control device 24 is, for example, a numerical control device (CNC: Computerized Numerical Controller).

[0017] The feed mechanism 14 further includes two wire guides 25. The two wire guides 25 are installed between the first roller 201 and the second roller 202 (see FIG. 1). A workpiece W is installed between the two wire guides 25. As each of the first roller 201 and the second roller 202 rotates, the wire electrode 16 is fed from the wire bobbin 18 toward the workpiece W. The wire electrode 16 that has passed through the workpiece W is sent to a recovery box. Note that the recovery box is not shown.

[0018] The wire electrode 16 is fed from the wire bobbin 18 toward the workpiece W while relatively moving with respect to the workpiece W. The wire electrode 16 relatively moves based on the machining program 48. The machining program 48 specifies the path of the relative movement of the wire electrode 16. The machining program 48 is input to the control device 24 (see FIG. 2).

[0019] Also, a voltage is applied to the wire electrode 16. Thereby, a discharge occurs between the wire electrode 16 and the workpiece W. The voltage is applied to the wire electrode 16 based on the machining conditions 46. The machining conditions 46 include one or more parameters. The machining conditions 46 are input to the control device 24 (see FIG. 2).

[0020] The workpiece W is machined according to the relative movement of the wire electrode 16 and the discharge between the wire electrode 16 and the workpiece W. However, when the remaining wire amount runs out during the machining of the workpiece W, the wire electrical discharge machining machine 12 stops during the machining. In this case, the operator performs the replenishment work of the wire electrode 16 (the work of replacing the wire bobbin 18) and the reconnection work of the wire electrode 16. However, these operations impose a burden on the operator. Therefore, it is important for the operator to check the remaining wire amount before the execution of machining.

[0021] However, it is not easy for the operator to check the remaining wire amount. For example, when the above prior art is implemented, the operator has to measure both the density and the coil diameter. The operation of measuring both the density and the coil diameter is a great burden on the operator. In particular, it is difficult for the operator to accurately measure the density.

[0022] The remaining amount estimation system 10 will be described based on the above preliminary explanation. The remaining amount estimation system 10 is a system for estimating the remaining wire amount S. The remaining amount estimation system 10 includes a first rotational position detection sensor 26, a second rotational position detection sensor 28, and a remaining amount estimation device 30 (see FIG. 1).

[0023] The first rotational position detection sensor 26 is a sensor for detecting the rotational position of the wire bobbin 18. The first rotational position detection sensor 26 is appropriately installed in the wire electrical discharge machining machine 12. The first rotational position detection sensor 26 outputs a signal corresponding to the rotational position of the wire bobbin 18. In the following description, the signal corresponding to the rotational position of the wire bobbin 18 is also referred to as the first detection signal 32. The first detection signal 32 is input to the remaining amount estimation device 30.

[0024] The second rotational position detection sensor 28 is a sensor for detecting the rotational position of the first roller 201. The second rotational position detection sensor 28 is appropriately installed in the wire electrical discharge machining machine 12. The second rotational position detection sensor 28 outputs a signal corresponding to the rotational position of the first roller 201. In the following description, the signal corresponding to the rotational position of the first roller 201 is also referred to as the second detection signal 34. The second detection signal 34 is input to the remaining amount estimation device 30.

[0025] Note that the second rotational position detection sensor 28 may detect the rotational position of the shaft of the first motor 221.

[0026] FIG. 2 is a configuration diagram of the remaining amount estimation device 30 of FIG. 1.

[0027] The remaining amount estimation device 30 is an electronic device that estimates the wire remaining amount S. The remaining amount estimation device 30 also serves as the control device 24 of the wire electrical discharge machining machine 12. The remaining amount estimation device 30 includes a display unit 36, an operation unit 38, a storage unit 40, and a calculation unit 42 (see FIG. 2).

[0028] The display unit 36 is a display device having a display screen 361. Information is appropriately displayed on the display screen 361. The material of the display unit 36 includes liquid crystal. However, the material of the display unit 36 is not limited to liquid crystal. For example, the material of the display unit 36 may include OEL (Organic Electro-Luminescence).

[0029] The operation unit 38 is an input device that receives information input by an operator. The operator can input information to the remaining amount estimation device 30 via the operation unit 38. The operation unit 38 has, for example, an operation panel, a mouse, a keyboard, and a touch panel. The touch panel is installed on the display screen 361.

[0030] The storage unit 40 has a memory. For example, the storage unit 40 has a RAM (Random Access Memory) and a ROM (Read Only Memory).

[0031] The remaining amount estimation program 44 is stored in the storage unit 40. The remaining amount estimation program 44 is a program for causing the remaining amount estimation device 30 to estimate the wire remaining amount S. Note that the information stored in the storage unit 40 is not limited to the remaining amount estimation program 44. Various information is appropriately stored in the storage unit 40 as needed. For example, the remaining amount estimation device 30 of the present embodiment also serves as the control device 24. In this case, the processing conditions 46 and the processing program 48 may be stored in the storage unit 40.

[0032] The calculation unit 42 has a processor. For example, the calculation unit 42 has a CPU (Central Processing Unit) and a GPU (Graphics Processing Unit). The calculation unit 42 can appropriately refer to the information stored in the storage unit 40.

[0033] The calculation unit 42 has an acquisition unit 50, an estimation calculation unit (first estimation calculation unit) 52, a comparison unit 54, an alarm generation unit 56, and a display control unit 58 (see FIG. 2). The acquisition unit 50, the estimation calculation unit 52, the comparison unit 54, the alarm generation unit 56, and the display control unit 58 are realized by the calculation unit 42 executing the remaining amount estimation program 44.

[0034] The acquisition unit 50 has a first signal analysis unit 501 and a second signal analysis unit 502 (see FIG. 2).

[0035] The first signal analysis unit 501 analyzes the first detection signal 32. As a result, the first signal analysis unit 501 obtains the first rotation position 60. The first rotation position 60 indicates the rotation position of the wire bobbin 18. The first rotation position 60 is stored in the storage unit 40. The first rotation position 60 is referred to by the estimation calculation unit 52.

[0036] The second signal analysis unit 502 analyzes the second detection signal 34. As a result, the second signal analysis unit 502 obtains the second rotation position 62. The second rotation position 62 indicates the rotation position of the first roller 201. The second rotation position 62 is stored in the storage unit 40. The second rotation position 62 is referred to by the estimation calculation unit 52.

[0037] The estimation calculation unit 52 includes a ratio calculation unit 521 and a remaining amount calculation unit 522 (see FIG. 2).

[0038] The ratio calculation unit 521 calculates a first ratio α. The first ratio α indicates the ratio of the rotation amount of the first roller 201 to the rotation amount of the wire bobbin 18. The first ratio α is calculated based on the first rotation position 60 and the second rotation position 62. However, the first ratio α is the ratio at the start of a predetermined period T. The predetermined period T is the period during which the wire electrode 16 is sent out from the wire bobbin 18. The range of the predetermined period T is arbitrarily specified by the operator. However, the remaining amount estimation device 30 may automatically set the range of the predetermined period T.

[0039] The first ratio α is expressed by the following formula (1). The values indicated by each character in formula (1) are as follows. That is, "α: first ratio". "θ 18 : the rotation amount of the wire bobbin 18 at the start of the predetermined period T". "θ 20 : the rotation amount of the first roller 201 at the start of the predetermined period T".

[0040]

Number

[0041] The first ratio α is referred to by the remaining amount calculation unit 522.

[0042] FIG. 10 is an explanatory diagram of a predetermined period T. A time flow including the predetermined period T is illustrated in FIG. 10.

[0043] The denominator (rotation amount θ 18 ) in Equation (1) is not zero. Therefore, the "start time" of the predetermined period T has a time width (TWA, TWA', or TWA'') by which the first rotation position 60 changes. In this case, the rotation amount θ 18 indicates the change amount of the first rotation position 60 within the time width TWA, the time width TWA', or the time width TWA''. Also, the rotation amount θ 20 indicates the change amount of the second rotation position 62 within the time width TWA, the time width TWA', or the time width TWA''.

[0044] The start point of the time width TWA in FIG. 10 coincides with the start point of the predetermined period T. The end point of the time width TWA is a time point after the start point of the predetermined period T.

[0045] The start point of the time width TWA' in FIG. 10 is a time point before the start point of the predetermined period T. The end point of the time width TWA' coincides with the start point of the predetermined period T.

[0046] The start point of the time width TWA'' in FIG. 10 is a time point before the start point of the predetermined period T. The end point of the time width TWA'' is a time point after the start point of the predetermined period T.

[0047] Note that when the acquisition unit 50 acquires the first rotation position 60 and the second rotation position 62 within the time width TWA' or the time width TWA'', the wire delivery starts before the start point of the predetermined period T.

[0048] Also, the ratio calculation unit 521 calculates a second ratio β. The second ratio β indicates the ratio of the rotation amount of the first roller 201 to the rotation amount of the wire bobbin 18. The second ratio β is calculated based on the first rotation position 60 and the second rotation position 62. However, the second ratio β is the ratio at the end of the predetermined period T.

[0049] The second ratio β is expressed by the following mathematical formula (2). The values indicated by each character in the mathematical formula (2) are as follows. That is, “β: the second ratio”. “θ’ 18 : the rotation amount of the wire bobbin 18 at the end of the predetermined period T”, “θ’ 20 : the rotation amount of the first roller 201 at the end of the predetermined period T”.

[0050] [Number]

[0051] The denominator (rotation amount θ’ 18 ) in the mathematical formula (2) is not zero. Therefore, the “end” of the predetermined period T has a time width (TWB, TWB’, or TWB’’) by which the first rotation position 60 changes (see FIG. 10). In this case, the rotation amount θ’ 18 indicates the change amount of the first rotation position 60 within the time width TWB, the time width TWB’, or the time width TWB’’. Also, the rotation amount θ’ 20 indicates the change amount of the second rotation position 62 within the time width TWB, the time width TWB’, or the time width TWB’’.

[0052] The start point of the time width TWB in FIG. 10 is a time point before the end point of the predetermined period T. The end point of the time width TWB coincides with the end point of the predetermined period T.

[0053] The start point of the time width TWB’ in FIG. 10 coincides with the end point of the predetermined period T. The end point of the time width TWB’ is a time point after the end point of the predetermined period T.

[0054] The start point of the time width TWB’’ in FIG. 10 is a time point before the end point of the predetermined period T. The end point of the time width TWB’’ is a time point after the end point of the predetermined period T.

[0055] Note that when the acquisition unit 50 acquires the first rotation position 60 and the second rotation position 62 within the time width TWB’ or the time width TWB’’, the wire feeding continues even after the end point of the predetermined period T.

[0056] When the feeding mechanism 14 feeds the wire electrode 16, the following mathematical formula (3) holds. The values represented by each character in the mathematical formula (3) are as follows. That is, "Q: roller radius (half of the roller diameter)" (see Fig. 1). "θ 20 : rotation amount of the first roller 201". "R: winding radius of the wire electrode 16 wound around the wire bobbin 18 (half of the winding diameter)" (see Fig. 1). "θ 18 : rotation amount of the wire bobbin 18".

[0057]

Number

[0058] The roller radius Q is constant. In this case, the rotation amount θ 20 for feeding a fixed amount of the wire electrode 16 is also constant. On the other hand, the winding radius R becomes shorter as the remaining wire amount S decreases. Therefore, the rotation amount θ 18 for feeding a fixed amount of the wire electrode 16 gradually increases based on the mathematical formula (3).

[0059] From the above, the following relationships hold. That is, the rotation amount θ 20 in the mathematical formula (1) and the rotation amount θ' 20 in the mathematical formula (2) are equal (θ 20 = θ' 20 ). Also, between the rotation amount θ 18 in the mathematical formula (1) and the rotation amount θ' 18 in the mathematical formula (2), the rotation amount θ' 18 is larger (θ 18 < θ' 18 ). Therefore, the second ratio β is smaller than the first ratio α.

[0060] The second ratio β is referred to by the remaining amount calculation unit 522.

[0061] The remaining amount calculation unit 522 calculates the wire remaining amount S based on the following mathematical formula (4). The values indicated by each character in the mathematical formula (4) are as follows. That is, "S: wire remaining amount". "α: first ratio". "β: second ratio". "Q: roller radius". "L: body radius of the wire bobbin 18 (half of the body diameter)" (see FIG. 1 or FIG. 5). "φ: total rotation amount of the first roller 201". "π: pi".

[0062] [Number]

[0063] Note that the roller radius Q and the body radius L are stored in advance in the storage unit 40. The total rotation amount φ is the total amount of the rotation amount of the first roller 201 in a predetermined period T. Therefore, the total rotation amount φ is obtained based on the second rotation position 62.

[0064] The wire remaining amount S indicates an estimated value of the remaining amount of the wire electrode 16 wound around the wire bobbin 18 at the end of the predetermined period T. The wire remaining amount S is referred to by the comparison unit 54.

[0065] The comparison unit 54 compares the wire remaining amount S with the wire estimated amount S'. The wire estimated amount S' is an estimated amount of the wire remaining amount S required for electrical discharge machining. The wire estimated amount S' is calculated based on, for example, the machining program 48. Note that the wire estimated amount S' may be calculated based not only on the machining program 48 but also on the machining conditions 46.

[0066] Further, the comparison unit 54 determines whether the wire remaining amount S is less than the wire estimated amount S'. The determination is made based on the comparison result. When the wire remaining amount S is less than the wire estimated amount S', the comparison unit 54 calls the alarm generation unit 56.

[0067] The alarm generation unit 56 generates an alarm. The alarm is generated according to the comparison result. The alarm is generated in the form of a message that can be displayed on the display unit 36. This message indicates, for example, that the remaining wire amount S is less than the estimated wire amount S'. The generated alarm is referred to by the display control unit 58.

[0068] The display control unit 58 controls the display unit 36. The display control unit 58 causes the estimated remaining wire amount S to be displayed on the display screen 361. Thereby, the operator knows the remaining wire amount S. In addition, the display control unit 58 also causes the message generated by the alarm generation unit 56 to be displayed on the display screen 361. Thereby, the operator knows that the remaining wire amount S is less than the estimated wire amount S'.

[0069] Note that the information that the display control unit 58 causes to be displayed on the display screen 361 is not limited to only the remaining wire amount S and the message. For example, the display control unit 58 may also cause the comparison result performed by the comparison unit 54 to be displayed on the display screen 361.

[0070] The remaining amount estimation device 30 calculates the remaining wire amount S without using the density and the winding diameter (winding radius R). Therefore, it is not necessary for the operator to measure the density and the winding diameter (winding radius R). Thus, the remaining amount estimation device 30 reduces the burden on the operator. The description of the remaining amount estimation device 30 is as above.

[0071] FIG. 3 is a flowchart illustrating the flow of the remaining amount estimation method according to the embodiment.

[0072] The remaining amount estimation method is a method for estimating the remaining wire amount S. The remaining amount estimation method is executed by the remaining amount estimation device 30. The remaining amount estimation method includes an acquisition step 82, an estimation calculation step 84, a comparison step 86, an alarm generation step 88, and a display step 90 (see FIG. 3).

[0073] The remaining amount estimation device 30 executes an acquisition step 82. The acquisition step 82 includes a start determination step 821, a first acquisition step 822, an end determination step 823, and a second acquisition step 824 (see FIG. 3).

[0074] In the start determination step 821, the acquisition unit 50 determines whether or not a predetermined period T has started. When the start of the predetermined period T occurs (start determination step 821: YES), the acquisition unit 50 executes the first acquisition step 822.

[0075] In the first acquisition step 822, the acquisition unit 50 acquires a first rotation position 60 and a second rotation position 62. The first rotation position 60 acquired here indicates the rotation position of the wire bobbin 18 at the start of the predetermined period T. Also, the second rotation position 62 acquired here indicates the rotation position of the first roller 201 at the end of the predetermined period T.

[0076] In the end determination step 823, the acquisition unit 50 determines whether or not the predetermined period T has ended. When the end of the predetermined period T occurs (end determination step 823: YES), the acquisition unit 50 executes the second acquisition step 824.

[0077] In the second acquisition step 824, the acquisition unit 50 acquires a first rotation position 60 and a second rotation position 62. The first rotation position 60 acquired here indicates the rotation position of the wire bobbin 18 at the end of the predetermined period T. Also, the second rotation position 62 acquired here indicates the rotation position of the first roller 201 at the end of the predetermined period T. The remaining amount estimation device 30 executes an estimation calculation step 84 after the acquisition step 82.

[0078] The estimation calculation step 84 includes a ratio calculation step 841 and a remaining amount estimation step 842 (see FIG. 3).

[0079] In the ratio calculation step 841, the ratio calculation unit 521 calculates the first ratio α and the second ratio β. Note that the first ratio α may be calculated before the end of the predetermined period T. Therefore, the remaining amount estimation device 30 may start the ratio calculation step 841 after the first acquisition step 822. In this case, the ratio calculation step 841 may be executed in parallel with the end determination step 823 or the second acquisition step 824.

[0080] In the remaining amount estimation step 842, the remaining amount calculation unit 522 calculates the wire remaining amount S. The remaining amount estimation device 30 executes the comparison step 86 after the estimation calculation step 84.

[0081] In the comparison step 86, the comparison unit 54 compares the estimation result of the wire remaining amount S with the wire estimated amount S'. When the estimated wire remaining amount S is less than the wire estimated amount S' (86: YES), the remaining amount estimation device 30 executes the alarm generation step 88. When the wire remaining amount S is greater than or equal to the wire estimated amount S' (86: NO), the remaining amount estimation device 30 executes the display step 90.

[0082] In the alarm generation step 88, the alarm generation unit 56 generates an alarm. The alarm is in the form of a message. This message indicates, for example, that the wire remaining amount S is insufficient. The remaining amount estimation device 30 executes the display step 90 after the alarm generation step 88.

[0083] In the display step 90, the display control unit 58 causes the wire remaining amount S to be displayed on the display screen 361. Also, when the alarm generation step 88 has been completed in advance, the display control unit 58 also causes the generated alarm to be displayed on the display screen 361.

[0084] When the remaining amount estimation method of FIG. 3 is executed, it is not necessary for the operator to measure both the density and the winding radius R. Therefore, the burden on the operator is reduced. The description of the remaining amount estimation method of FIG. 3 is as above.

[0085] [Modification Example] Modifications according to the above-described embodiments will be described below. However, descriptions overlapping with the above-described embodiments will be omitted as much as possible in the following description. The reference signs of the components described in the above-described embodiments are adopted from the above-described embodiments unless otherwise specified.

[0086] (Modification 1) FIG. 4 is a configuration diagram of the remaining amount estimation device 30(301) according to Modification 1.

[0087] The remaining amount estimation device 301 includes the components of the remaining amount estimation device 30 in the embodiment (see FIG. 2). However, in FIG. 4, the illustration of some components is omitted.

[0088] The remaining amount estimation device 301 further includes a density calculation unit 68, a memory control unit 70, and a second estimation calculation unit 72. The density calculation unit 68, the memory control unit 70, and the second estimation calculation unit 72 are realized by the calculation unit 42 executing the remaining amount estimation program 44. In this regard, the remaining amount estimation program 44 is appropriately changed.

[0089] FIG. 5 is an explanatory diagram of the wire bobbin 18 around which the wire electrode 16 is wound. In FIG. 5, the wire electrode 16 and the wire bobbin 18 are shown in cross section. The virtual straight line O is the rotation axis of the wire bobbin 18.

[0090] The density calculation unit 68 calculates the density A based on the following formula (5). The values indicated by each character in formula (5) are as follows. That is, "A: density", "α: first ratio", "β: second ratio", "D: wire diameter of the wire electrode 16" (see FIG. 5), "H: inner width of the wire bobbin 18" (see FIG. 5), "Q: roller radius", and "φ: total rotation amount of the first roller 201".

[0091] [Number]

[0092] The memory control unit 70 associates the density A, the wire diameter D, the inner width H, and the barrel radius L with each other. Thereby, the memory control unit 70 creates a reference table 74.

[0093] FIG. 6 is a configuration example of the reference table 74 stored in the memory unit 40.

[0094] The reference table 74 has a column of the identifier (name or number) of the wire bobbin 18, a column of the density A, a column of the wire diameter D, a column of the inner width H, and a column of the barrel radius L. The information arranged horizontally in each row corresponds to each other. For example, the reference table 74 includes "identifier: bobbin 1" of a certain wire bobbin 18 (see FIG. 6). The density A of the wire electrode 16 wound around the wire bobbin 18 with "identifier: bobbin 1" is "AA". The wire diameter D of the wire electrode 16 is "DA". Also, the inner width H of the wire bobbin 18 with "identifier: bobbin 1" is "HA". The barrel radius L of the wire bobbin 18 with "identifier: bobbin 1" is "LA".

[0095] In many cases, the wire electrode 16 is designed based on a predetermined standard regarding the wire electrode 16. Therefore, the operator can easily identify the wire diameter D based on the standard of the wire electrode 16. Also, in many cases, the wire bobbin 18 is designed based on a predetermined standard regarding the wire bobbin 18. Therefore, the operator can easily identify each of the inner width H of the wire bobbin 18 and the barrel radius L of the wire bobbin 18 based on the standard of the wire bobbin 18.

[0096] The memory control unit 70 stores the reference table 74 in the memory unit 40. The reference table 74 is referred to by the second estimation calculation unit 72.

[0097] The second estimation calculation unit 72 estimates the wire remaining amount S based on the following mathematical formula (6). The values indicated by each character in the mathematical formula (6) are as follows. That is, "S: wire remaining amount", "R: winding radius", "A: density", "H: inner width", "L: barrel radius", and "D: wire diameter". Note that the density A, the wire diameter D, the inner width H, and the barrel radius L correspond to each other in the reference table 74. The winding radius R is measured in advance by the operator.

[0098]

Number

[0099] The reference table 74 includes identifiers corresponding to the density A, the wire diameter D, the inner width H, and the barrel radius L. Therefore, the operator can easily specify the density A, the wire diameter D, the inner width H, and the barrel radius L by specifying the identifier.

[0100] FIG. 7 is a flowchart illustrating the flow of the remaining amount estimation method according to Modification 1. Note that the "estimation calculation step" in FIG. 3 is described as the "first estimation calculation step" in FIG. 7.

[0101] The remaining amount estimation method in FIG. 7 includes an acquisition step 82, a first estimation calculation step 84, a comparison step 86, an alarm generation step 88, and a display step 90. In this regard, the remaining amount estimation method in FIG. 7 is common to the remaining amount estimation method in FIG. 3. However, the remaining amount estimation method in FIG. 7 further includes a selection step 92, a density calculation step 94, a storage step 96, and a second estimation calculation step 98. In this regard, the remaining amount estimation method in FIG. 7 is different from the remaining amount estimation method in FIG. 3.

[0102] The remaining amount estimation device 301 first executes the selection step 92. In the selection step 92, the operation unit 38 receives an input operation. In the selection step 92, the operator selects the first estimation calculation step 84 or the second estimation calculation step 98.

[0103] When the operator selects the first estimation calculation step 84, the remaining amount estimation device 301 executes the acquisition step 82. The descriptions of each of the acquisition step 82 and the first estimation calculation step 84 are omitted in this modified example. The remaining amount estimation device 301 executes a density calculation step 94 after the first estimation calculation step 84.

[0104] In the density calculation step 94, the density calculation unit 68 calculates the density A. The density A is calculated based on Equation (5). Here, the density calculation unit 68 diverts the first ratio α, the second ratio β, and the total rotation amount φ used in the most recent first estimation calculation step 84. The remaining amount estimation device 301 executes a storage step 96 after the density calculation step 94.

[0105] In the storage step 96, the storage control unit 70 stores the density A in the storage unit 40. Here, the density A is associated with the wire diameter D, the inner width H, and the body radius L. The remaining amount estimation device 301 appropriately executes the comparison step 86 to the display step 90 after the storage step 96 (see FIG. 7).

[0106] When the operator selects the second estimation calculation step 98 in the selection step 92, the remaining amount estimation device 301 executes the second estimation calculation step 98. In the second estimation calculation step 98, the second estimation calculation unit 72 estimates the wire remaining amount S. The wire remaining amount S is calculated based on Equation (6).

[0107] When the second estimation calculation step 98 is executed, the acquisition step 82 is not executed. Therefore, when the second estimation calculation step 98 is executed, wire feeding over a predetermined period T is unnecessary. After the second estimation calculation step 98, the comparison step 86 to the display step 90 are appropriately executed (see FIG. 7).

[0108] When the second estimation calculation step 98 is executed, the operator measures the winding radius R in advance. However, the operator does not need to measure the density A. Therefore, the burden on the operator is reduced.

[0109] The remaining amount estimation device 301 may automatically select the second estimation calculation step 98 in the selection step 92. In this case, the operator instructs the remaining amount estimation device 301 in advance to automatically select the second estimation calculation step 98 in the selection step 92. Further, the operator designates in advance the density A to be referred to by the second estimation calculation unit 72, the wire diameter D, the inner width H, and the barrel radius L.

[0110] Further, the remaining amount estimation device 301 may execute a density calculation step 94 before the first estimation calculation step 84. In that case, the first ratio α, the second ratio β, and the total rotation amount φ may be calculated in the density calculation step 94. Also, in that case, the first ratio α, the second ratio β, and the total rotation amount φ may be diverted in the first estimation calculation step 84.

[0111] (Modification Example 2) The flow following the acquisition step 82 to the storage step 96 in FIG. 7 may be executed for the wire bobbin 18 for which the density A has been calculated in the past. Here, for example, each of the first detection signal 32 and the second detection signal 34 may include an error (noise). Due to this error, the density A calculated in the past and the density A calculated most recently may show different values from each other. In this case, a plurality of densities A related to the same wire bobbin 18 are stored in the storage unit 40. However, only one value of the density A to be substituted into the mathematical formula (6) is used. Based on the above premises, in this modification example, a remaining amount estimation device 30 (302) that can calculate the wire remaining amount S even when a plurality of densities A have been calculated for the same wire bobbin 18 is described.

[0112] FIG. 8 is a configuration diagram of the remaining amount estimation device 302 according to Modification Example 2.

[0113] The remaining amount estimation device 302 includes the components of the remaining amount estimation device 301 (see FIG. 4). Further, the remaining amount estimation device 302 further includes an average calculation unit 76. The average calculation unit 76 is realized by the calculation unit 42 executing the remaining amount estimation program 44. In this regard, the remaining amount estimation program 44 is appropriately changed.

[0114] The average calculation unit 76 calculates the average value of a plurality of densities A. Here, for the plurality of densities A, the corresponding wire diameters D are the same as each other. Also, for the plurality of densities A, the dimensions (inner width H, body radius L) of the corresponding wire bobbins 18 are also the same as each other.

[0115] The second estimation calculation unit 72 substitutes the average value of the plurality of densities A into the formula (6) instead of the density A. Thereby, even when a plurality of densities A have been calculated for the same wire bobbin 18, the wire remaining amount S is estimated. Also, by using the average value of the plurality of densities A for the estimation of the wire remaining amount S, the influence of the aforementioned error on the estimation result of the wire remaining amount S is reduced.

[0116] Note that the average calculation unit 76 may calculate the moving average value of the plurality of densities A instead of the average value of the plurality of densities A. In this case, the second estimation calculation unit 72 substitutes the moving average value of the plurality of densities A into the formula (6) instead of the density A.

[0117] (Modification Example 3) In this modification example, a remaining amount estimation device 30 (303) that notifies an operator located at a location away from the remaining amount estimation device 30 of the wire remaining amount S is described.

[0118] FIG. 9 is a configuration diagram of a remaining amount estimation system 10 (101) according to Modification Example 3.

[0119] The remaining amount estimation system 101 includes a first rotation position detection sensor 26, a second rotation position detection sensor 28, a remaining amount estimation device 303, and an external device 78. Explanation of each of the first rotation position detection sensor 26 and the second rotation position detection sensor 28 is omitted in this modification example.

[0120] The external device 78 is an electronic device (terminal) capable of communicating with the remaining amount estimation device 303. The external device 78 has a display screen 781. The external device 78 can be installed at a location away from the remaining amount estimation device 303. The external device 78 may be a portable terminal that can be carried by an operator.

[0121] The remaining amount estimation device 303 includes the components of the remaining amount estimation device 30 of the embodiment (see FIG. 2). However, in FIG. 9, illustration of some components is omitted.

[0122] The remaining amount estimation device 303 further includes a communication control unit 80. The communication control unit 80 is realized by the arithmetic unit 42 executing the remaining amount estimation program 44. In this regard, the remaining amount estimation program 44 is appropriately changed.

[0123] The communication control unit 80 controls communication with the external device 78. In particular, the communication control unit 80 transmits the estimated wire remaining amount S to the external device 78. The external device 78 displays the received wire remaining amount S on the display screen 781. Thereby, an operator who is not near the remaining amount estimation device 303 can check the wire remaining amount S.

[0124] Note that the communication control unit 80 may transmit the comparison result between the estimation result and the wire estimated amount S' to the external device 78. Also, the communication control unit 80 may transmit an alarm to the external device 78.

[0125] Also, the remaining amount estimation system 101 may have a plurality of external devices 78.

[0126] (Modification Example 4) The dimensions (inner width H, body radius L) of the wire bobbin 18 may be specified by the operator via the operation unit 38. For example, in many cases, the wire bobbin 18 is designed based on the standards regarding the wire bobbin 18. However, there are also wire bobbins 18 having dimensions not based on the standards. In this case, the operator measures the dimensions of the wire bobbin 18. Also, the operator inputs the measurement result into the remaining amount estimation device 30 via the operation unit 38.

[0127] Note that there are also wire electrodes 16 not based on the standards regarding the wire electrode 16. When the operator uses such a wire electrode 16, the wire diameter D may be specified via the operation unit 38.

[0128] (Modification Example 5) The form of the alarm is not limited to the message form. For example, the alarm may include an icon. Also, the alarm may include sound (e.g., an error sound).

[0129] (Modification Example 6) A torque motor may be connected to the wire bobbin 18. The torque motor is a motor for adjusting the rotational torque of the wire bobbin 18.

[0130] The first rotation position detection sensor 26 may detect the rotational position of the shaft of the torque motor. In this case, the rotational position of the shaft of the torque motor is treated as the first rotation position 60.

[0131] (Modification Example 7) Each of the first ratio α and the second ratio β may be the ratio of the rotation amount of the second roller 202 to the rotation amount of the wire bobbin 18. In this case, the second detection signal 34 is output in response to the rotation of the second roller 202. Also, in this case, the total rotation amount φ may be the total rotation amount of the second roller 202 during a predetermined period T.

[0132] (Modification Example 8) The remaining amount estimation device 30 and the control device 24 of the wire electrical discharge machining machine 12 may be separate electronic devices from each other.

[0133] In that case, the remaining amount estimation device 30 and the control device 24 may communicate with each other. Thereby, the remaining amount estimation device 30 can request the control device 24 to execute wire feeding for a predetermined period T, for example, in order to execute the acquisition step 82.

[0134] Note that the present invention is not limited to the above-described embodiments and modification examples, and various configurations can be adopted without departing from the gist of the present invention.

[0135] [Invention Obtained from Embodiment] The inventions that can be grasped from the above embodiments and modification examples are described below.

[0136] <First Invention> A remaining amount estimation device (30, 301, 302, 303) for estimating the remaining amount (S) of wire on a wire bobbin of a wire electrical discharge machining machine (12) comprising a wire bobbin (18), a delivery roller (20) for delivering a wire electrode (16) wound around the wire bobbin, a first rotational position detection sensor (26) for detecting a first rotational position (60) of the wire bobbin, and a second rotational position detection sensor (28) for detecting a second rotational position (62) of the delivery roller, the remaining amount estimation device comprising: an acquisition unit (50) for acquiring the first rotational position and the second rotational position; a first ratio (α) which is a ratio of rotational amounts at the start of a predetermined period (T) between the wire bobbin and the delivery roller; a second ratio (β) which is a ratio of rotational amounts at the end of the predetermined period between the wire bobbin and the delivery roller; and a first estimation calculation unit (52) for estimating the remaining amount of wire at the end of the predetermined period based on the total rotational amount (φ) by which the delivery roller has rotated during the predetermined period, the first ratio, and the second ratio.

[0137] Thereby, the remaining amount (S) of wire can be obtained while reducing the burden on the operator.

[0138] The first estimation calculation unit may estimate the remaining amount of wire at the end of the predetermined period (T) based on the total rotational amount, the first ratio, the second ratio, the body radius (L) of the wire bobbin, and the roller radius (Q) of the delivery roller.

[0139] The first estimation calculation unit may estimate the remaining amount of wire based on Equation (4).

[0140] The remaining amount estimation device may further include a density calculation unit (68) that calculates the density (A) of the wire electrode wound around the wire bobbin based on the total rotation amount, the first ratio, the second ratio, the wire diameter (D) of the wire electrode, and the dimensions of the wire bobbin; a storage control unit (70) that associates the density, the wire diameter, and the dimensions of the wire bobbin and stores them in the storage unit (40); and a second estimation calculation unit (72) that estimates the remaining amount of the wire based on the winding radius (R) of the wire electrode wound around the wire bobbin, the density, the wire diameter, and the dimensions of the wire bobbin. Thereby, the density (A) can be easily calculated. Also, the remaining amount of the wire (S) is saved.

[0141] The second estimation calculation unit may estimate the density based on Equation (5).

[0142] When a plurality of the densities in which each of the corresponding wire diameter and the dimensions of the corresponding wire bobbin are the same are stored in the storage unit, the remaining amount estimation device may further include an average calculation unit (76) that calculates an average value of the plurality of densities or a moving average value of the plurality of densities, and the second estimation calculation unit may estimate the remaining amount of the wire using the average value or the moving average value as the density. Thereby, even when a plurality of densities (A) have been calculated for the same wire bobbin (18), the remaining amount of the wire (S) is estimated.

[0143] The remaining amount estimation device may further include an operation unit (38) that allows an operator to specify at least one of the wire diameter and the dimensions of the wire bobbin. Thereby, for example, even when the dimensions of the wire bobbin (18) do not conform to a predetermined standard, the remaining amount estimation device (30) estimates the remaining amount of the wire (S).

[0144] The remaining amount estimation device may further include a display control unit (58) that causes the display unit (36) to display the remaining amount of the wire. Thereby, the operator can confirm the remaining amount of the wire (S).

[0145] The remaining amount estimation device (303) may further include a communication control unit (80) that transmits the remaining wire amount to an external device (78). Thereby, an operator located at a location away from the remaining amount estimation device can check the remaining wire amount (S).

[0146] The remaining amount estimation device may further include an alarm generation unit (56) that generates an alarm according to a comparison result between the estimated wire amount (S’) of the wire electrode required for electrical discharge machining and the remaining wire amount. Thereby, for example, the operator is informed that the remaining wire amount (S) is insufficient.

[0147] The remaining amount estimation device may be provided in a control device (24) that controls the wire electrical discharge machine.

[0148] <Second Invention> A method for estimating the remaining wire amount (S) of a wire bobbin (18) of a wire electrical discharge machine (12) including a wire bobbin, a delivery roller (20) that delivers a wire electrode (16) wound around the wire bobbin, a first rotational position detection sensor (26) that detects a first rotational position (60) of the wire bobbin, and a second rotational position detection sensor (28) that detects a second rotational position (62) of the delivery roller, the method including: an acquisition step (82) of acquiring the first rotational position and the second rotational position; a first ratio (α) that is a ratio of rotational amounts at the start of a predetermined period (T) between the wire bobbin and the delivery roller; a second ratio (β) that is a ratio of rotational amounts at the end of the predetermined period between the wire bobbin and the delivery roller; and an estimation calculation step (84) of estimating the remaining wire amount at the end of the predetermined period based on the first ratio, the second ratio, and a total rotational amount (φ) by which the delivery roller has rotated during the predetermined period.

[0149] Thereby, the remaining wire amount (S) can be obtained while reducing the burden on the operator.

Explanation of Reference Numerals

[0150] 12…Wire electrical discharge machine 16…Wire electrode 18…Wire bobbin 20…Delivery roller 24…Control device 26…First rotation position detection sensor 28…Second rotation position detection sensor 30, 301, 302, 303…Remaining amount estimation device 36…Display unit 38…Operation unit 40…Memory unit 50…Acquisition unit 52…Estimation calculation unit (First estimation calculation unit) 56…Alarm generation unit 58…Display control unit 60…First rotation position 62…Second rotation position 68…Density calculation unit 70…Memory control unit 72…Second estimation calculation unit 76…Average calculation unit 78…External device 80…Communication control unit

Claims

1. A wire bobbin (18), a delivery roller (20) for delivering a wire electrode (16) wound around the wire bobbin, a first rotational position detection sensor (26) for detecting a first rotational position (60) of the wire bobbin, a second rotational position detection sensor (28) for detecting a second rotational position (62) of the delivery roller, and a remaining amount estimation device (30, 301, 302, 303) for estimating a remaining amount (S) of the wire on the wire bobbin of a wire electrical discharge machining machine (12) comprising: an acquisition unit (50) for acquiring the first rotational position and the second rotational position; a first estimation calculation unit (52) for estimating the remaining amount of the wire at the end of the predetermined period (T) based on a first ratio (α) which is a ratio of rotational amounts at the start of the predetermined period of the wire bobbin and the delivery roller, a second ratio (β) which is a ratio of rotational amounts at the end of the predetermined period of the wire bobbin and the delivery roller, and a total rotational amount (φ) by which the delivery roller has rotated during the predetermined period; A remaining amount estimation device comprising the above.

2. The remaining amount estimation device according to Claim 1, wherein the first estimation calculation unit estimates the remaining amount of the wire at the end of the predetermined period based on the total rotational amount, the first ratio, the second ratio, a body radius (L) of the wire bobbin, and a roller radius (Q) of the delivery roller.

3. The remaining amount estimation device according to Claim 2, wherein the first estimation calculation unit estimates the remaining amount of the wire based on the following formula (1). (However, S: remaining amount of wire, α: first ratio, β: second ratio, Q: roller radius, L: body radius of wire bobbin, φ: total rotational amount of delivery roller, π: pi) 【Number 1】

4. The remaining amount estimation device (301, 302, 303) according to any one of Claims 1 to 3, a density calculation unit (68) for calculating a density (A) of the wire electrode wound around the wire bobbin based on the total rotational amount, the first ratio, the second ratio, a wire diameter (D) of the wire electrode, and dimensions of the wire bobbin; a storage control unit (70) for associating and storing the density, the wire diameter, and the dimensions of the wire bobbin in a storage unit (40); and a second estimation calculation unit (72) for estimating the remaining amount of the wire based on a winding radius (R) of the wire electrode wound around the wire bobbin, the density, the wire diameter, and the dimensions of the wire bobbin. A remaining amount estimation device further comprising...

5. The remaining amount estimation device according to claim 4, wherein the second estimation calculation unit estimates the density based on the following mathematical formula (2). (However, A: density of the wire electrode wound around the wire bobbin, α: first ratio, β: second ratio, D: wire diameter, H: inner width of the wire bobbin, Q: roller radius, φ: total rotation amount of the feed roller) 【Number 2】

6. The remaining amount estimation device (302, 303) according to claim 4 or 5, wherein when a plurality of the densities, each of which is the same as the corresponding wire diameter and the corresponding dimension of the wire bobbin, are stored in the storage unit, an average calculation unit (76) that calculates an average value of the plurality of the densities or a moving average value of the plurality of the densities is further provided, and the second estimation calculation unit estimates the remaining wire amount using the average value or the moving average value as the density.

7. The remaining amount estimation device according to any one of claims 4 to 6, further comprising an operation unit (38) by which an operator can specify at least one of the wire diameter and the dimension of the wire bobbin.

8. The remaining amount estimation device according to any one of claims 1 to 7, further comprising a display control unit (58) that causes the remaining wire amount to be displayed on a display unit (36).

9. The remaining amount estimation device (303) according to any one of claims 1 to 8, further comprising a communication control unit (80) that transmits the remaining wire amount to an external device (78).

10. The remaining amount estimation device according to any one of claims 1 to 9, further comprising an alarm generation unit (56) that generates an alarm according to a comparison result between the estimated wire amount (S') of the wire electrode required for electrical discharge machining and the remaining wire amount.

11. The remaining amount estimation device according to any one of claims 1 to 10, wherein the remaining amount estimation device is provided in a control device (24) that controls the wire electrical discharge machine.

12. A wire bobbin (18), a feed roller (20) that feeds the wire electrode (16) wound around the wire bobbin, a first rotation position detection sensor (26) that detects a first rotation position (60) of the wire bobbin, a second rotation position detection sensor (28) that detects a second rotation position (62) of the feed roller A remaining amount estimation method for estimating a remaining amount (S) of a wire on the wire bobbin of a wire electrical discharge machining machine (12) comprising: an acquisition step (82) of acquiring the first rotation position and the second rotation position; an estimation calculation step (84) of estimating the remaining amount of the wire at the end of the predetermined period based on a first ratio (α) which is a ratio of rotation amounts at the start of a predetermined period (T) between the wire bobbin and the feed roller, a second ratio (β) which is a ratio of rotation amounts at the end of the predetermined period between the wire bobbin and the feed roller, and a total rotation amount (φ) by which the feed roller has rotated during the predetermined period; A remaining amount estimation method including the above.

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