Carving mold electric discharge machine

Abstract

An engraving electric discharge machine (100) is provided with: a main shaft (1); a machining electrode (5) which is detachably mounted on the main shaft (1) and which machines the workpiece (16) by means of non-contact discharge on the workpiece (16) placed in an insulating machining liquid; an imaging device (3) that is detachably mounted on the main shaft (1) so as to be replaceable with the machining electrode (5), images the workpiece (16) that has been machined by the machining electrode (5), and acquires imaging data indicating the shape of the workpiece (16) that has been machined; a contact detection unit (70) that is connected to the main shaft (1) and detects the contact when the imaging device (3) is in contact with the workpiece (16) when the imaging device (3) is mounted on the main shaft (1); and an NC device (72) for controlling the movement and stop of the main shaft (1), the NC device (72) emergently stopping the movement of the main shaft (1) when the contact detection unit (70) detects the contact. The user inspects the shape and size of the workpiece (16) on the basis of the captured data.

Description

Technical Field

[0001] The present invention relates to an engraving die electric discharge machining machine. Background Art

[0002] Generally, an engraving die electric discharge machining machine is a device that performs engraving die electric discharge machining for transferring the shape of a machining electrode to a workpiece to be machined. In engraving die electric discharge machining, first, the workpiece to be machined is set relative to a machining table provided in a machining tank filled with an insulating machining fluid such as oil or water. Next, in a state where the machining electrode and the workpiece are opposed to each other, the highly precisely machined machining electrode is continuously brought closer to the workpiece, and an electric current is passed through the machining electrode to perform electric discharge. At this time, while maintaining a minute distance of about several tens of μm constant between the workpiece and the machining electrode, the workpiece is machined. The gap between the workpiece and the machining electrode is called a discharge gap. Through the above steps, the workpiece is machined into a three-dimensional shape having the shape of the transferred machining electrode.

[0003] In engraving die electric discharge machining, after machining, the workpiece is removed from the machining table, and it is confirmed whether the shape and dimensional accuracy of the workpiece meet the requirements. In the case where the result of the confirmation does not meet the requirements, additional machining is performed on the workpiece. In the case of performing additional machining, the workpiece is again set on the machining table, and thus it takes time until the start of the re-machining of the workpiece. In addition, if the workpiece is temporarily removed from the machining table, it is very difficult to reproduce the state at that time with high precision and install the workpiece at exactly the same position. In addition, sometimes even if the position of the workpiece can be completely reproduced, if time has passed, positional changes of the machine and the tool will occur, and even if the workpiece is re-machined for dimensional correction, accurate correction cannot be performed.

[0004] Therefore, a method for confirming the shape and dimensions of the workpiece without removing the workpiece from the machining table is required. As such a method, for example, the method described in Patent Document 1 has been proposed. In Patent Document 1, a camera is installed relative to a main shaft on which a tool is mounted and the tool arrangement. The camera moves synchronously with the tool. An image obtained by the camera is subjected to automatic recognition processing by a recognition device, and is thus displayed on a monitor. The user can confirm the shape and dimensions of the workpiece based on the displayed image.

[0005] Patent Document 1: Japanese Patent Laid-Open No. 4-93150 Summary of the Invention

[0006] The NC (Numerical Control) machine tool described in Patent Document 1 is a processing device mainly for grinding, and does not intend to perform processing with the workpiece immersed in the processing fluid.

[0007] On the other hand, in die-sinking electrical discharge machining of a die-sinking electrical discharge machine, since oil fume is generated from the processing fluid, as described in Patent Document 1, if a camera is installed on the spindle, there is a possibility that the lens of the camera will be soiled by the oil fume, or the internal substrate of the camera will deteriorate due to the oil fume and malfunction.

[0008] As described above, when the camera described in Patent Document 1 is not applied to a general machine tool but to a die-sinking electrical discharge machine, there are the following problems: due to the oil fume during die-sinking electrical discharge machining, the lens of the camera will be soiled and unable to take clear images, and the internal substrate of the camera may malfunction.

[0009] The present invention has been made in view of the above circumstances, and its object is to obtain a die-sinking electrical discharge machine that can prevent dirt on the lens of the photographing device and malfunction of the photographing device, and can confirm the shape and size of the workpiece without removing the workpiece from the table.

[0010] In order to solve the above problems and achieve the object, the die-sinking electrical discharge machine according to the present invention is characterized by having: a spindle; a processing electrode that can be detachably loaded on the spindle and discharges through a non-contact needle to the workpiece placed in an insulating processing fluid to process the workpiece; a photographing device that can be detachably loaded on the spindle by replacing with the processing electrode, photographs the workpiece processed by the processing electrode, and obtains photographing data representing the shape of the processed workpiece; a contact detection unit that is connected to the spindle and detects contact when the photographing device is loaded on the spindle and the photographing device contacts the workpiece; and an NC device that controls the movement and stop of the spindle, and the NC device urgently stops the movement of the spindle when the contact detection unit detects contact.

[0011] Effect of the Invention

[0012] The die-sinking electrical discharge machine according to the present invention has the following effects: it can prevent dirt on the lens of the photographing device and malfunction of the photographing device, and can confirm the shape and size of the workpiece without removing the workpiece from the table. Description of the Drawings

[0013] Figure 1 It is a diagram showing the structure of the die-sinking electrical discharge machine according to Embodiment 1.

[0014] Figure 2It is a diagram showing the internal structure of the control box provided in the die sinking electrical discharge machine according to Embodiment 1.

[0015] Figure 3 It is a schematic diagram showing the method of photographing and the method of confirmation of the workpiece in the die sinking electrical discharge machine according to Embodiment 1.

[0016] Figure 4 It is a flowchart showing the processing flow of the NC device and the control box provided in the die sinking electrical discharge machine according to Embodiment 1.

[0017] Figure 5 It is a diagram showing an example of the structure of the ATC provided in the die sinking electrical discharge machine according to Embodiment 1.

[0018] Figure 6 It is a schematic diagram showing the situation where the photographing device and the processing electrode are replaced by the ATC provided in the die sinking electrical discharge machine according to Embodiment 1.

[0019] Figure 7 It is a diagram showing an example of the structure of the connection of the connector provided in the die sinking electrical discharge machine according to Embodiment 1.

[0020] Figure 8 It is a diagram showing the roller bearing structure for preventing falling in the second connector terminal provided in the die sinking electrical discharge machine according to Embodiment 1.

[0021] Figure 9 It is a diagram showing the structure of the contact detection function in the die sinking electrical discharge machine according to Embodiment 1.

[0022] Figure 10 It is a diagram showing the structure of the insulation function in the die sinking electrical discharge machine according to Embodiment 1.

[0023] Figure 11 It is a diagram showing an example of the structure of the processing circuit in the case where the processing circuit provided in the control box according to Embodiment 1 is implemented by a processor and a memory.

[0024] Figure 12 It is a diagram showing an example of the processing circuit in the case where the processing circuit provided in the control box according to Embodiment 1 is constituted by dedicated hardware.

[0025] Figure 13 It is a diagram showing the internal structure of the power supply board provided in the die sinking electrical discharge machine according to Embodiment 1.

[0026] Figure 14 It is a diagram showing the internal structure of the numerical control device (NC device) provided in the die sinking electrical discharge machine according to Embodiment 1.

[0027] Figure 15 This is a diagram showing the wiring structure when a processing electrode is loaded in the die engraving electric discharge machine according to Embodiment 1.

[0028] Figure 16 This is a diagram showing the wiring structure when a photographing device and a control box are loaded in the die engraving electric discharge machine according to Embodiment 1. Detailed Embodiment

[0029] Hereinafter, the die engraving electric discharge machine according to the embodiment of the present invention will be described in detail with reference to the drawings.

[0030] Embodiment 1.

[0031] (Structural Elements)

[0032] Figure 1 This is a diagram showing the structure of the die engraving electric discharge machine according to Embodiment 1. The die engraving electric discharge machine 100 includes a main shaft 1, an electrode chuck 2, a photographing device 3, a control box 4, a processing electrode 5, a contact detection circuit 7, an ATC (Automatic Tool Changer) 9, a power supply board 10, and a table 21. The power supply board 10 has a contact detection unit 70.

[0033] As Figure 1 shown, an electrode chuck 2 is provided on the main shaft 1 of the die engraving electric discharge machine 100. The electrode chuck 2 is a mounting member for loading the photographing device 3 or the processing electrode 5 on the main shaft 1. The photographing device 3 or the processing electrode 5 can be detachably fixed to the main shaft 1 through the electrode chuck 2. The photographing device 3 and the processing electrode 5 are not loaded on the main shaft 1 at the same time, and always one of them is loaded on the main shaft 1. In Figure 1 the example, a state where the photographing device 3 is loaded on the electrode chuck 2 is shown.

[0034] The photographing device 3 is provided with a lens 3a at its lower end. The lens 3a is disposed opposite to the workpiece 16. The photographing device 3 is powered through the control box 4. The photographing device 3 and the control box 4 are connected through a power supply line 41 for supplying power and a signal line 45 for transmitting photographing data. After the die engraving electric discharge machining of the workpiece 16 is performed on the die engraving electric discharge machine 100, the photographing device 3 photographs the workpiece 16. Moreover, the photographing device 3 transmits the photographing data obtained through this photographing to the control box 4 through the signal line 45. The power supply to the photographing device 3 is performed from the power supply 30 through the control box 4. The power supply 30 is, for example, an external power supply such as a socket. The power supply 30 is composed of an AC power supply such as a commercial power supply, for example, but may also be a DC power supply such as a storage battery. The photographing device 3 is composed of a camera, for example.

[0035] The control box 4 is connected to the power supply 30 via the power cord 40. The control box 4 supplies power from the power supply 30 to the imaging device 3. In addition, the control box 4 performs image processing on the imaging data received from the imaging device 3 to generate image data 15. The image data 15 is input to a PC (Personal Computer) 8 via the signal line 42. The user displays the image data 15 on the screen of the PC 8 and confirms the shape, size, etc. of the workpiece 16 based on the image data 15. As described above, by sequentially forwarding the image data 15 from the control box 4 to the PC 8, the user can use the PC 8 to confirm the processing state of the workpiece 16 in real time during the imaging of the imaging device 3. In addition, the control box 4 is connected to the ground 11 via the ground wire 43.

[0036] Figure 2 It is a diagram showing the internal structure of the control box provided in the die sinking electrical discharge machine according to the first embodiment. As Figure 2 shown, the control box 4 has a power supply unit 4a, an image processing unit 4b, a storage unit 4c, and an arithmetic unit 4d. The power supply unit 4a uses the power from the power supply 30 to supply power to the imaging device 3. The image processing unit 4b performs image processing on the imaging data acquired by the imaging device 3 to generate image data 15. The storage unit 4c stores the operation program of the control box 4 and stores various data such as the operation results of the control box 4. The arithmetic unit 4d performs various operations for confirming the shape and size of the workpiece 16. Figure 2 This is an example of the control box 4 and is not limited thereto. The control box 4 does not necessarily have Figure 2 all of the parts shown, and in addition, it may have Figure 2 other structures other than the parts shown. And, Figure 2 a part or all of the parts of the control box 4 may be constituted by a cloud server. In addition, the control box 4 may be constituted by a server. In this case, the control box 4 may be provided near the die sinking electrical discharge machine 100, but may also be provided remotely. When the control box 4 is provided remotely, the control box 4 and the die sinking electrical discharge machine 100 can be connected via a network such as the Internet. In addition, in Figure 1 the example, the control box 4 and the power supply board 10 are separately constituted, but are not limited to Figure 1 the example. That is, the control box 4 may be mounted inside the power supply board 10 or may be provided outside the power supply board 10.

[0037] Return to Figure 1Description. The machining electrode 5 is loaded onto the spindle 1 via the electrode chuck 2. The machining electrode 5 is precisely machined into a shape that is the reverse of the completed shape of the workpiece 16. The machining electrode 5 is made of, for example, copper, graphite, etc. and has electrical conductivity. Additionally, the machining electrode 5 can also be made of other materials such as tungsten that have electrical conductivity only in a state at a temperature higher than a certain temperature. The machining electrode 5 machines the workpiece 16 by discharging without contacting the workpiece 16 placed in the insulating machining fluid.

[0038] The die sinking electrical discharge machining will be described in more detail. First, the workpiece 16 is set in the machining tank filled with the machining fluid. Next, the machining electrode 5 is continuously brought closer to the workpiece 16, and current is passed through the machining electrode 5 to perform discharging. As a result, the workpiece 16 is machined into a three-dimensional shape that is the reverse of the shape of the machining electrode 5. The shape of the workpiece 16 after machining is sometimes referred to as the product shape. In addition, the machining electrode 5 and the imaging device 3 can be automatically replaced relative to the spindle 1 through program operation without manual operation by using the ATC 9.

[0039] The machining fluid used in die sinking electrical discharge machining is composed of an insulating liquid such as water or oil. When the workpiece 16 and the machining electrode 5 are made into an insulating state by the machining fluid, if the workpiece 16 and the machining electrode 5 approach each other, insulation breakdown will occur between the workpiece 16 and the machining electrode 5. Insulation breakdown refers to the following phenomenon: when the electric field applied to the insulator exceeds the threshold value, the resistance drops sharply, and a large current will flow. Due to insulation breakdown, pulsed current instantaneously flows in, thereby generating a high-density discharge state of an arc column, and the surface of the workpiece 16 locally becomes a high temperature of about 6000 - 7000 °C. As a result, the workpiece 16 made of metal will melt. By performing the processes of insulation breakdown and melting for each machining area of the workpiece 16, the workpiece 16 is machined until it finally becomes the product shape.

[0040] The imaging device 3 has: a housing (not shown); an imaging device cover 6 loaded in a manner to cover the housing; a lens 3a; and an electrical unit 3b (refer to Figure 9 ). The housing constitutes the outer contour of the imaging device 3. The electrical unit 3b includes an internal substrate that realizes various functions of the imaging device 3. The imaging device cover 6 has electrical conductivity. The imaging device cover 6 has, for example, a cylindrical shape as Figure 1 shown. The lower end portion of the imaging device cover 6 is open. The lens 3a provided at the lower end portion of the imaging device 3 protrudes toward the outside from the opening of the imaging device cover 6. When the imaging device 3 is loaded onto the spindle 1, a state where the lens 3a and the workpiece 16 face each other is formed. The imaging device cover 6 is connected to the contact detection circuit 7 of the die sinking electrical discharge machining machine 100.

[0041] The contact detection circuit 7 has a first contact detection line 7a and a second contact detection line 7b. The first contact detection line 7a connects a platform 21 provided in a processing groove (not shown) and a contact detection unit 70. The second contact detection line 7b connects the photographing device cover 6 and the contact detection unit 70. When the photographing device cover 6 comes into contact with the workpiece 16, an electrical circuit is formed through the contact detection circuit 7, the photographing device cover 6, the workpiece 16, the platform 21, and the contact detection unit 70. Based on the conduction state of this electrical circuit, that is, when the contact detection unit 70 detects that current flows through this electrical circuit, it detects that the photographing device cover 6 and the workpiece 16 are in contact. When the contact detection unit 70 detects this contact, the spindle control unit 72a (refer to Figure 14 ) in the numerically controlled device (hereinafter referred to as the NC device) 72 provided on the power supply board 10 instantaneously stops the spindle 1. Thereby, damage to the photographing device 3 and the workpiece 16 can be minimized. In addition, the lower end of the photographing device cover 6 is preferably at the same height position as the lens 3a of the photographing device 3, or extends to a position lower than the lens 3a. In addition, in the description of the first embodiment, for the sake of simplicity, the "contact between the photographing device cover 6 of the photographing device 3 and the workpiece 16" is sometimes referred to as the "contact between the photographing device 3 and the workpiece 16".

[0042] The die sinking electric discharge machine 100 is provided with an ATC 9 that replaces the machining electrode 5 and the photographing device 3 relative to the spindle 1. The ATC 9 replaces the machining electrode 5 and the photographing device 3 relative to the spindle 1 in response to a signal input from the outside. The signal input from the outside is, for example, an instruction from the ATC control unit 72b in the NC device 72 provided on the power supply board 10. When the NC device 72 determines that the machining of the workpiece 16 is completed, it outputs an instruction to the ATC 9 to remove the machining electrode 5 from the spindle 1 and load the photographing device 3 onto the spindle 1 instead of the machining electrode 5. In addition, when the NC device 72 receives an instruction to re-machine the workpiece 16 from the PC 8, it outputs an instruction to the ATC 9 to remove the photographing device 3 from the spindle 1 and load the machining electrode 5 onto the spindle 1 instead of the photographing device 3. Based on these instructions from the NC device 72, the ATC 9 automatically disassembles and assembles the machining electrode 5 or the photographing device 3 relative to the spindle 1. The machining electrode 5 or the photographing device 3 removed from the spindle 1 is returned to the magazine 9a of the ATC 9. The ATC 9 is sometimes referred to as an automatic tool changer.

[0043] As Figure 1As shown, a first connector terminal 12 for connector connection is provided in the photographing device 3. In addition, a second connector terminal 13 for connector connection is provided on the main shaft 1. By connecting the first connector terminal 12 of the photographing device 3 to the second connector terminal 13 of the main shaft 1, a wired connection between the photographing device 3 and the control box 4, and a wired connection between the photographing device cover 6 and the contact detection unit 70 can be achieved. In addition, the main body of the first connector terminal 12 may not be installed on the photographing device 3 but on the photographing device cover 6. On the other hand, the first connector terminal 12 is not provided on the machining electrode 5.

[0044] In the power supply board 10, as Figure 1 shown, a contact detection unit 70 is provided inside. Here, Figure 13 is a diagram showing the internal structure of the power supply board provided in the die sinking electric discharge machine according to the first embodiment. If described in more detail Figure 13 , a contact detection unit 70, a power supply unit 71, and an NC device 72 are provided in the power supply board 10. The contact detection unit 70 detects the contact between the photographing device cover 6 and the workpiece 16, and also detects the contact between the machining electrode 5 and the workpiece 16. When the contact detection unit 70 detects any of these contacts, it outputs a contact detection signal to the NC device 72. If the NC device 72 receives the contact detection signal, it instantaneously causes the main shaft 1 to stop urgently via the main shaft control unit 72a (refer to Figure 14 ). Thereby, damage to the photographing device 3, the machining electrode 5, and the workpiece 16 can be minimized. Figure 13 The power supply unit 71 shown uses the power from the power supply 30 to supply power to the ATC 9, the machining electrode 5, and the drive device 50. Figure 13 The NC device 72 shown controls the main shaft 1, the ATC 9, and the machining electrode 5 to perform machining control of the workpiece 16. Figure 14 is a diagram showing the internal structure of the numerical control device (NC device) provided in the die sinking electric discharge machine according to the first embodiment. As Figure 14 shown, a main shaft control unit 72a, an ATC control unit 72b, and a machining control unit 72c are provided in the NC device 72. The main shaft control unit 72a controls the movement and stop actions of the main shaft 1, and also performs an emergency stop in case of an emergency of the main shaft 1. The ATC control unit 72b controls the operation of the ATC 9 to cause the ATC 9 to replace the machining electrode 5 and the photographing device 3. The machining control unit 72c outputs a power supply command to the power supply unit 71 inside the power supply board 10, thereby supplying power to the machining electrode 5. In addition, the machining control unit 72c also controls the value of the machining voltage in the machining electrode 5. As Figure 1 shown, the power supply board 10 is connected to the power supply 30. In addition, the power supply board 10 is connected to the ground 11 via the ground wire 44.

[0045] Return Figure 1 The description of Figure 1 . The platform 21 is disposed in a processing groove (not shown). The platform 21 has a flat plate shape as shown in Figure 1 shown. The shape of the platform 21 may be rectangular or circular when viewed from above. The upper surface of the platform 21 is set to be horizontal, for example. As shown in Figure 1 shown, the workpiece 16 is placed on the upper surface of the platform 21. The platform 21 is connected to the contact detection unit 70 via the first contact detection line 7a. The platform 21 has conductivity. The platform 21 is sometimes referred to as a processing machine platform.

[0046] A PC 8 is connected to the die sinking electric discharge machine 100. The PC 8 may be one of the structural elements of the die sinking electric discharge machine 100 or may be disposed outside the die sinking electric discharge machine 100. The PC 8 has a display device such as a monitor. In addition, the PC 8 has a user interface that receives various inputs through the operation of the user. The user interface is, for example, a keyboard and a mouse. The PC 8 outputs instructions to the NC unit 72 according to inputs from the user and the like.

[0047] (Shooting method of the shooting device 3)

[0048] Figure 3 is a schematic diagram showing a method of shooting and confirming a workpiece in the die sinking electric discharge machine according to Embodiment 1. The shooting data of the workpiece 16 is shown in the upper part of Figure 3 . In the shooting data in the upper part of Figure 3 , the entire workpiece 16 is shot. Figure 3 In the left part of the lower part of

[0049] , a partial image 60 of the workpiece 16 when the position of the main shaft 1 coincides with the first measurement point A described later is shown, and in the right part of the lower part, a partial image 61 of the workpiece 16 when the position of the main shaft 1 coincides with the second measurement point B described later is shown. The images 60 and 61 are, for example, an example of the images displayed on the screen of the PC 8 based on the image data 15. First, the case of confirming the shape of the workpiece 16 will be described. The shooting device 3 can clearly shoot the fine shape of the surface of the workpiece 16 with sub-micron accuracy. The shooting data representing the shape of each part of the workpiece 16 obtained by the shooting device 3 is forwarded to the control box 4 in real time. The control box 4 performs image processing on the shooting data by the image processing unit 4b, thereby transforming the shooting data into the image data 15. The image data 15 is forwarded from the control box 4 to the PC 8. Thus, the user can sequentially confirm the shape and size of the workpiece 16 by displaying the image data 15 on the screen of the PC 8.

[0050] In addition, since the imaging device 3 is mounted on the main shaft 1, the imaging device 3 can also be moved along with the movement of the main shaft 1. Therefore, by moving the imaging device 3 in the height direction to increase the distance between the workpiece 16 and the imaging device 3, wide-range imaging of the workpiece 16 can be performed. Conversely, by moving the imaging device 3 in the height direction to decrease the distance between the workpiece 16 and the imaging device 3, local fine-part imaging of the workpiece 16 can be performed. As described above, since the movement of the imaging device 3 can be performed, arbitrary imaging, including wide-range imaging and narrow-range imaging of the workpiece 16, can be performed, and the focus adjustment area of the imaging device 3 becomes large. Also, the imaging device 3 can move in the Figure 1 X direction together with the main shaft 1. Therefore, in the workpiece 16, the positions of the first measurement point A and the second measurement point B are determined in advance, and the main shaft 1 is sequentially moved to the first measurement point A and the second measurement point B, and local imaging data can also be obtained at the positions of the respective measurement points.

[0051] Next, the case of measuring the dimensions of the workpiece 16 will be described. As described above, the main shaft 1 can move in the X direction by, for example, the drive device 50. The X direction is, for example, the horizontal direction. The drive device 50 is composed of, for example, a motor. The operation of the drive device 50 is controlled by the main shaft control unit 72a of the NC device 72. Power supply to the drive device 50 is performed by the power supply unit 71 in the power supply board 10 using electric power from the power supply 30 via the power line 46. The power line 46 is arranged to pass through the main shaft 1 as described later in Figure 15 and Figure 16 shown, and connects the drive device 50 and the power supply unit 71. The drive device 50 is provided inside or outside the main shaft 1. Here, the case where the main shaft 1 moves in the height direction and the horizontal direction by the drive device 50 is described as an example, but the structure for moving the main shaft 1 can also be other structures. For the following description, here, the left end edge of the workpiece 16 is referred to as the first edge 16a, and the right end edge of the workpiece 16 is referred to as the second edge 16b. In addition, a preset point on the first edge 16a is referred to as the first measurement point A, and a preset point on the second edge 16b is referred to as the second measurement point B.

[0052] First, the main shaft control unit 72a of the NC device 72 moves the main shaft 1 so as to align with the first edge 16a or the first measurement point A of the workpiece 16. Moreover, when the position of the imaging device 3 mounted on the main shaft 1 coincides with the position of the first edge 16a or the first measurement point A, the control box 4 records the current machine coordinates of the main shaft 1, that is, the position of the main shaft 1 and Figure 3 the coordinates (x a , y a)Stored in the storage unit 4c. In addition, the "coordinates when the position of the main shaft 1 coincides with the first measurement point A" are sometimes simply referred to as the "coordinates of the first measurement point A" or the "first coordinates".

[0053] Next, the main shaft control unit 72a of the NC device 72 moves the main shaft 1 so as to align with the second edge 16b or the second measurement point B of the workpiece 16. Moreover, when the position of the imaging device 3 mounted on the main shaft 1 coincides with the position of the second edge 16b or the second measurement point B, the control box 4 records the current machine coordinates of the main shaft 1, that is, the coordinates when the position of the main shaft 1 coincides with Figure 3 the second measurement point B (x b , y b ) and stores them in the storage unit 4c. In addition, the "coordinates when the position of the main shaft 1 coincides with the second measurement point B" are sometimes simply referred to as the "coordinates of the second measurement point B" or the "second coordinates".

[0054] Based on the coordinates (x a , y a ) of the first measurement point A and the coordinates (x b , y b ) of the second measurement point B stored in the storage unit 4c, the arithmetic unit 4d of the control box 4 calculates the distance between the first edge 16a and the second edge 16b and the distance between the first measurement point A and the second measurement point B. These distances can be calculated, for example, by the following formula (1).

[0055] The distance of AB = { (x a - x b ) 2 + (y a - y b ) 2} 1 / 2 ··· (1)

[0056] As described above, the control box 4 can calculate the distance between two desired edges or the distance between two desired measurement points. In addition, here, an example of the arithmetic unit 4d of the control box 4 calculating these distances is described, but it is not limited to this case. These distances can also be calculated by the PC 8, for example.

[0057] The user uses the PC 8 to compare the shape and size of each part of the workpiece 16 with the design data based on the distance between two edges or the distance between two measurement points, and confirm whether the workpiece 16 is machined into the final product shape with high precision, or whether the dimensional accuracy meets the pre-set conditions, etc. In addition, when the result of the confirmation is that the workpiece 16 is not machined into the final product shape with high precision, the user replaces the imaging device 3 and the machining electrode 5 and performs die sinking EDM on the workpiece 16 again.

[0058] Figure 4 is a flowchart showing the processing flow of the NC device and the control box provided in the die sinking EDM machine according to Embodiment 1. In Figure 4 it shows the processing flow of obtaining the distance between the first measurement point A and the second measurement point B among the processes of the NC device 72 and the control box 4. By repeating the Figure 4 process flow for each machining area of the workpiece 16, the shape and size of the entire workpiece 16 can be confirmed. In addition, by comparing the dimensions with the design data, it is possible to confirm whether the dimensional accuracy meets the conditions. Next, the Figure 4 process flow will be described.

[0059] In step S1, the spindle control unit 72a of the NC device 72 moves the spindle 1 toward the first measurement point A.

[0060] In step S2, when the position of the spindle 1 coincides with the first measurement point A, the control box 4 stores the coordinates of the spindle 1, that is, the coordinates of the first measurement point A (x a , y a ) as the first coordinate in the storage unit 4c.

[0061] In step S3, the spindle control unit 72a of the NC device 72 moves the spindle 1 toward the second measurement point B.

[0062] In step S4, when the position of the spindle 1 coincides with the second measurement point B, the control box 4 stores the coordinates of the spindle 1, that is, the coordinates of the second measurement point B (x a , y a ) as the second coordinate in the storage unit 4c.

[0063] In step S5, the arithmetic unit 4d of the control box 4 calculates the distance between the first measurement point A and the second measurement point B based on the first coordinate and the second coordinate.

[0064] (Automatic replacement of the imaging device 3 by the ATC 9)

[0065] Figure 5FIG. 0 is a diagram showing an example of the structure of the ATC provided in the engraving die electric discharge machine according to Embodiment 1. Figure 6 FIG. 2 is a schematic view showing a case where the photographing device and the processing electrode are replaced by the ATC provided in the engraving die electric discharge machine according to Embodiment 1.

[0066] As Figure 5 shown, the ATC 9 has a cassette 9a, a rotating shaft 9b, a support portion 9c, and a guide portion 9d. The cassette 9a stores the unused processing electrodes 5 and the photographing device 3. As Figure 5 shown, the processing electrodes 5 and the photographing device 3 are stored in a suspended manner in the cassette 9a. The rotating shaft 9b connects the cassette 9a and the support portion 9c. The rotating shaft 9b can rotate in the direction indicated by the arrow C. The central axis of the rotating shaft 9b extends, for example, in the vertical direction or the plumb direction. The direction indicated by the arrow C is the circumferential direction centered on the position of the central axis of the rotating shaft 9b. In synchronization with the rotation of the rotating shaft 9b in the direction of the arrow C, the cassette 9a also rotates in the direction of the arrow C. The support portion 9c supports the cassette 9a via the rotating shaft 9b. The support portion 9c is guided by the guide portion 9d and can move in the direction of the arrow D. The guide portion 9d is a rod-shaped member extending in the direction of the arrow D. By the movement of the support portion 9c and the rotation of the rotating shaft 9b, the processing electrodes 5 and the photographing device 3 are automatically moved to the position of the loading spindle 1. In addition, the direction of the arrow D may be the same as the Figure 1 X direction or different.

[0067] Normally, the processing electrode 5 is loaded on the spindle 1 of the engraving die electric discharge machine 100 via the electrode chuck 2. By using the ATC 9, the processing electrode 5 can be automatically disassembled and assembled with respect to the electrode chuck 2 by the program operation of the NC device 72. In addition, the processing electrode 5 removed from the spindle 1 of the engraving die electric discharge machine 100 returns to the cassette 9a of the ATC 9. By using the automatic processing electrode replacement mechanism realized by the ATC 9, the photographing device 3 can also be automatically disassembled and assembled on the spindle 1 of the engraving die electric discharge machine 100.

[0068] In Figure 6 , Figure 6 (a) shows a state where the photographing device 3 is loaded on the spindle 1, Figure 6 (b) shows a state where the processing electrode 5 is loaded on the spindle 1. As Figure 6 (a) shows, the photographing device 3 is connected to the spindle 1 by a connector. The first connector terminal 12 and the second connector terminal 13 are connected, whereby the connector connection is established. As described above, in Embodiment 1, in order to connect the photographing device 3 to the spindle 1, no cables or the like are used.

[0069] On the other hand, the camera of the existing processing device such as Patent Document 1 is connected to the recognition device or the arithmetic device by a cable. Assuming that the camera of the existing processing device such as Patent Document 1 can be automatically disassembled and assembled by the ATC 9, there is the following problem when the camera is moved in and out of the cassette of the ATC 9, that is, the cable of the camera may be wound around the main shaft 1, immersed in the processing fluid, or broken.

[0070] In Embodiment 1, since the photographing device 3 is connected to the main shaft 1 by a connector, the problems caused by the cable as described above do not occur. Hereinafter, the connector connection will be described.

[0071] (Connector connection of the photographing device 3)

[0072] Figure 7 FIG. is an example of a structure of a connector connection provided in the die sinking electric discharge machine according to Embodiment 1. Figure 16 FIG. is a diagram showing a wiring structure when the photographing device and the control box are loaded in the die sinking electric discharge machine according to Embodiment 1. In addition, Figure 16 in order to make the description easier to understand, a part of the wiring that is not necessary is omitted in the description. As Figure 1 , Figure 7 and Figure 16 shown, a first connector terminal 12 is provided in the photographing device 3, and a second connector terminal 13 is provided in the main shaft 1. The first connector terminal 12 is a male type, and the second connector terminal 13 is a female type. By inserting the first connector terminal 12 into the recess of the female second connector terminal 13, the first connector terminal 12 and the second connector terminal 13 are electrically connected, and the connector connection is established. In addition, the first connector terminal 12 may be a female type, and the second connector terminal 13 may be a male type.

[0073] As Figure 7 and Figure 16 shown, a second contact detection line 7b, a power line 41, and a signal line 45 pass through the inside of the first connector terminal 12 and the second connector terminal 13. When the photographing device 3 is loaded on the main shaft 1, the second contact detection line 7b connects the photographing device cover 6 and the contact detection unit 70. The power line 41 supplies power from the power supply 30 to the photographing device 3 via the control box 4. The signal line 45 sends the photographed data obtained by the photographing device 3 to the control box 4.

[0074] Therefore, when the photographing device 3 is loaded on the main shaft 1, the photographing device 3 and the control box 4 can be connected and the photographing device cover 6 and the contact detection unit 70 can be connected by the connector connection.

[0075] In Embodiment 1, as described above, the wired connection between the imaging device 3 and the control box 4 is implemented by connecting through a connector in a manner that is automatically established. In Embodiment 1, according to the control of the NC device 72, through program operation, while the imaging device 3 is loaded onto the electrode chuck 2 provided on the main shaft 1, the connector connection is also automatically performed. Therefore, when replacing the machining electrode 5 and the imaging device 3, the operation load on the user can be reduced. In addition, in the case of automatically performing the connector connection, for example, the first connector terminal 12 is supported by a component having high rigidity. This component is, as shown in Figure 1 shown, a component that is provided between the first connector terminal 12 and the imaging device 3 and holds the first connector terminal 12, and has an L-shaped form, for example, when viewed from above. Alternatively, the first connector terminal 12 and the second connector terminal 13 are each supported by a component having high rigidity. Thereby, the posture of the first connector terminal 12 is maintained and held in a state of extending in the vertical direction. Therefore, even if the user does not perform an operation, as the imaging device 3 moves, the first connector terminal 12 is automatically loaded into the second connector terminal 13. In addition, as another method of automatically performing the connector connection, a robot can be used. In this case, a jig such as a robot arm for holding and transporting the first connector terminal 12 is provided in the ATC 9. Moreover, the first connector terminal 12 is held by this jig, transported to the second connector terminal 13, and the first connector terminal 12 is inserted into the second connector terminal 13 for connection.

[0076] Figure 8 FIG. is a diagram showing a roller bearing structure for preventing dropping in the second connector terminal provided in the die-sinking electric discharge machine according to Embodiment 1. As shown in Figure 7 and Figure 8 shown, a roller 17 is provided in the second connector terminal 13 on the main shaft 1 side. The roller 17 has a circular shape when viewed from the side. The roller 17 is a cylindrical component or a spherical component. In addition, as shown in Figure 7 shown, a recess 18 for receiving the roller 17 is provided in the first connector terminal 12 on the imaging device 3 side. The recess 18 is formed by a concave portion and, as shown in Figure 7 shown, is formed to be recessed from the surface of the first connector terminal 12 toward the inside. The recess 18 has a complementary shape with respect to the roller 17. The recess 18 functions as a roller bearing for the roller 17. When the first connector terminal 12 is loaded into the second connector terminal 13, the roller 17 abuts against the inner wall of the recess 18, thereby being hooked and preventing the first connector terminal 12 from falling off the second connector terminal 13.

[0077] As shown in Figure 8As shown, a spring 19 is connected to the roller 17. One end of the spring 19 engages with the roller 17, and the other end of the spring 19 engages with the second connector terminal 13. In normal times, as Figure 8 shown, the spring 19 does not contract, and a part of the roller 17 flies out from the inner wall of the second connector terminal 13 toward the space inside the second connector terminal 13. On the other hand, when the imaging device 3 is loaded onto the main shaft 1 via the electrode chuck 2, the roller 17 is pressed by the insertion pressure of the first connector terminal 12, and the spring 19 contracts. As a result, the entire roller 17 is completely housed inside the second connector terminal 13. Thereby, the first connector terminal 12 can be inserted into the second connector terminal 13. Moreover, if the insertion of the first connector terminal 12 into the second connector terminal 13 is completed, due to the elastic force of the spring 19, the contraction of the spring 19 returns to its original state, the roller 17 is inserted into the recess 18, and the first connector terminal 12 is fixed to the second connector terminal 13. As described above, once the roller 17 is inserted into the recess 18, the roller 17 engages with the recess 18, so that the first connector terminal 12 can be prevented from falling off the second connector terminal 13.

[0078] (Wiring structure when a machining electrode is loaded)

[0079] Figure 15 is a diagram showing a wiring structure when a machining electrode is loaded in the die sinking electric discharge machine according to Embodiment 1. In addition, in Figure 15 , for easy understanding of the description, the illustration of a part of the wiring that is not required is omitted in the description. As Figure 6 (b) and Figure 15 shown, when connecting the machining electrode 5, connector connection is not used. The power supply to the machining electrode 5 is performed by the power supply unit 71 of the power supply board 10 via the machining control unit 72c of the NC device 72. Specifically, the NC device 72 uses the machining control unit 72c, as Figure 13 shown, to output a power command to the power supply unit 71 instructing the power supply to the machining electrode 5. Thereby, the power supply unit 71 supplies power to the machining electrode 5 via the power line 47. The power line 47 is configured to pass through the inside of the main shaft 1, as Figure 15 shown, and connect the machining electrode 5 and the power supply unit 71. The power supply to the drive device 50 is performed by the power supply unit 71 via the power line 46 using the power of the power supply 30. In addition, when the machining electrode 5 is loaded on the main shaft 1, the second contact detection line 7b connects the machining electrode 5 and the contact detection unit 70.

[0080] (Contact detection function)

[0081] Figure 9This is a diagram showing the structure of the contact detection function in the die sinking electric discharge machine according to Embodiment 1. In Figure 9 it, a contact detection circuit for detecting the contact between the camera device cover 6 of the camera device 3 and the workpiece 16 is shown.

[0082] In order to obtain an image with sub-micron accuracy, the camera device 3 needs to approach the workpiece 16. Generally, in existing die sinking electric discharge machines, a contact detection function for detecting the contact between the machining electrode 5 and the workpiece 16 is provided. However, in existing die sinking electric discharge machines, a contact detection function for detecting the contact between the camera device 3 and the workpiece 16 is not provided. Therefore, when the camera device 3 and the workpiece 16 come into contact, in fact, both the camera device 3 and the workpiece 16 may be damaged.

[0083] Therefore, in Embodiment 1, the contact detection circuit 7 specific to the die sinking electric discharge machine 100 for the machining electrode 5 and the workpiece 16 is also applied to the camera device 3. For this purpose, in Embodiment 1, the camera device cover 6 that can be electrically connected to the camera device 3 is installed. Thus, as is known from Figure 9 when the workpiece 16 and the camera device cover 6 come into contact, an electrical circuit is formed through the camera device cover 6, the workpiece 16, the table 21, the first contact detection line 7a, the contact detection unit 70, and the second contact detection line 7b. The contact detection unit 70 detects the contact between the workpiece 16 and the camera device cover 6 by detecting the flow of current in this electrical circuit. Moreover, when the contact detection unit 70 detects this contact, it instantaneously outputs a contact detection signal to the NC device 72. If the NC device 72 receives the contact detection signal, it outputs an instruction to immediately stop the operation of the spindle 1 from the spindle control unit 72a to the drive device 50 that drives the spindle 1.

[0084] The operation when the machining electrode 5 and the workpiece 16 come into contact is the same. That is, when the workpiece 16 and the machining electrode 5 come into contact, an electrical circuit is formed through the machining electrode 5, the workpiece 16, the table 21, the first contact detection line 7a, the contact detection unit 70, and the second contact detection line 7b. The contact detection unit 70 detects the contact between the workpiece 16 and the machining electrode 5 by detecting the flow of current through this electrical circuit. Moreover, when the contact detection unit 70 detects the contact, it instantaneously outputs a contact detection signal to the NC device 72. If the NC device 72 receives the contact detection signal, it outputs an instruction to immediately stop the operation of the spindle 1 from the spindle control unit 72a to the drive device 50 that drives the spindle 1.

[0085] As described above, in the first embodiment, the contact detection circuit 7 composed of the first contact detection line 7a and the second contact detection line 7b is provided. Therefore, it is possible to detect not only the contact between the machining electrode 5 and the workpiece 16, but also the contact between the imaging device 3 and the workpiece 16. Thus, when the imaging device 3 contacts the workpiece 16, the contact detection unit 70 in the power supply board 10 can immediately detect this contact and cause the main shaft 1 to stop urgently via the NC device 72. Thereby, the damage to the imaging device 3 and the workpiece 16 can be minimized.

[0086] (Connection of the connector of the imaging device cover 6)

[0087] The imaging device cover 6 and the contact detection unit 70 need to be wired-connected in the same manner as the imaging device 3. The wired connection between the imaging device cover 6 and the contact detection unit 70 is preferably automatically detachable and attachable through program operation. Therefore, in the first embodiment, as described above, through Figure 7 the connector connection shown, the wired connection between the imaging device cover 6 and the contact detection unit 70 is implemented.

[0088] (Insulation function)

[0089] Figure 10 It is a diagram showing the structure of the insulation function in the die-sinking electric discharge machine according to the first embodiment. In Figure 10 it shows the insulation function of insulating the contact detection unit 70 in the power supply board 10 of the die-sinking electric discharge machine 100 from the control box 4. In the first embodiment, by providing the insulation function, it is possible to prevent misdetection of contact between the imaging device 3 and the workpiece 16 when the imaging device 3 is loaded on the main shaft 1, thereby preventing the situation where the main shaft 1 is always in a stopped state.

[0090] Depending on the model of the imaging device 3, the ground of the electrical unit 3b of the imaging device 3 is sometimes connected to a housing (not shown) of the imaging device 3. In this case, at the moment when the imaging device 3 is loaded onto the main shaft 1, via the electrode chuck 2, an electrical circuit is formed by the imaging device 3, the control box 4, the contact detection unit 70, and the main shaft 1. If the workpiece 16 comes into contact with the imaging device 3, the contact detection unit 70 will always detect a false contact. At this time, in the die sinking electric discharge machine 100, the main shaft 1 remains in an emergency stop state, and the movement of the main shaft 1 is interlocked. To avoid this situation, in Embodiment 1, in the imaging device 3, a ground 20 is provided at a position not in contact with the housing, and the electrical unit 3b of the imaging device 3 is connected to the ground 20. That is, the ground 20 is not in electrical contact with the housing of the imaging device 3 or the imaging device cover 6. As described above, in Embodiment 1, by providing the ground 20, insulation can be achieved between the contact detection unit 70 connected to the imaging device cover 6 and the control box 4 connected to the electrical unit 3b of the imaging device 3. The ground 20 is sometimes referred to as an insulating unit. Thus, in Embodiment 1, when the imaging device 3 is installed on the main shaft 1, it is possible to prevent the contact detection unit 70 from falsely detecting that the workpiece 16 is in contact with the imaging device 3.

[0091] (Hardware Structure)

[0092] Here, the hardware structure of the control box 4 will be described.

[0093] In the control box 4 according to Embodiment 1, the power supply unit 4a, the image processing unit 4b, and the arithmetic unit 4d are implemented by a processing circuit. The processing circuit can be a processor and a memory that execute a program stored in the memory, or dedicated hardware. The processing circuit is also referred to as a control circuit.

[0094] Figure 11 FIG. is an example of the structure of the processing circuit when the processing circuit included in the control box according to Embodiment 1 is implemented by a processor and a memory.

[0095] Figure 11The processing circuit 90 shown is a control circuit, which has a processor 91 and a memory 92. When the processing circuit 90 is composed of the processor 91 and the memory 92, each function of the processing circuit 90 is implemented by software, firmware, or a combination of software and firmware. The software or firmware is described as a program and stored in the memory 92. In the processing circuit 90, the processor 91 reads and executes the program stored in the memory 92, thereby implementing each function. That is, the processing circuit 90 has a memory 92, and this memory 92 is used to store the program by which the processing of the control box 4 is finally executed. This program can be said to be a program for causing the control box 4 to execute each function implemented by the processing circuit 90. This program can be provided by a storage medium storing the program, or can be provided by other units such as a communication medium.

[0096] The above program can be said to be, for example, a program for causing the control box 4 to execute Figure 4 the processes of steps S2, S4, and S5. That is, the above program can be said to be a program for causing the control box 4 to execute the step of storing the first coordinate, the step of storing the second coordinate, and the step of calculating the distance between the first measurement point A and the second measurement point B based on the first coordinate and the second coordinate.

[0097] Here, the processor 91 is, for example, a CPU (Central Processing Unit), a processing device, an arithmetic device, a microprocessor, a microcomputer, or a DSP (Digital Signal Processor), etc. In addition, the memory 92 is, for example, a non-volatile or volatile semiconductor memory such as a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable ROM), an EEPROM (registered trademark) (Electrically EPROM), a magnetic disk, a floppy disk, an optical disk, a compact disc, a mini disc, or a DVD (Digital Versatile Disc), etc.

[0098] Figure 12 is a diagram showing an example of a processing circuit in the case where the processing circuit included in the control box according to Embodiment 1 is configured by dedicated hardware. Figure 12The processing circuit 93 shown, for example, is a single circuit, a composite circuit, a programmed processor, a parallel-programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination thereof. Regarding the processing circuit 93, a part thereof can be implemented by dedicated hardware, and a part thereof can be implemented by software or firmware. As described above, the processing circuit 93 can implement the above-mentioned various functions by dedicated hardware, software, firmware, or a combination thereof.

[0099] The PC 8 is also composed of, in the same manner as the control box 4, Figure 11 the processing circuit 90 shown or Figure 12 the processing circuit 93 shown. Similarly, the spindle control unit 72a, the ATC control unit 72b, and the machining control unit 72c of the NC device 72 are also composed of, for example, Figure 11 the processing circuit 90 shown or Figure 12 the processing circuit 93 shown. In these cases, the processing circuit 90 and the processing circuit 93 have the same structure as that of the control box 4, and thus the description thereof is omitted here.

[0100] (Effect)

[0101] As described above, in the first embodiment, since the imaging device 3 that can be mounted on the spindle 1 is provided, it is possible to confirm the surface shape and dimensions of the processed workpiece 16 without removing the workpiece 16 from the platform 21. Therefore, even when additional machining of the workpiece 16 is required as a result of the confirmation, the workload of changeover adjustment for reloading the workpiece 16 onto the platform 21 can be reduced. In addition, the occurrence of minute positional deviations caused by reloading the workpiece 16 can be prevented. Moreover, since the imaging device 3 is mounted on the spindle 1, the imaging device 3 can be moved together with the spindle 1. Therefore, it is possible to perform imaging of a desired range from a wide range to a narrow range for the workpiece 16, and the focus adjustment area of the imaging device 3 can be expanded.

[0102] In addition, in Embodiment 1, inside the imaging device 3, a ground 20 is provided at a position that does not contact the housing of the imaging device 3 and the imaging device cover 6. As described above, by connecting the electrical part 3b of the imaging device 3 to a ground 20 different from the ground 11, the contact detection part 70 in the control box 4 and the power supply board 10 is insulated. Therefore, when the imaging device 3 is mounted on the main shaft 1, it is possible to avoid forming an electrical circuit through the imaging device 3, the control box 4, the contact detection part 70, and the main shaft 1. As a result, when the imaging device 3 is mounted on the main shaft 1, it is possible to prevent the contact detection part 70 from erroneously detecting that the workpiece 16 and the imaging device 3 are in contact. As a result, it is possible to avoid the situation where the movement of the main shaft 1 is interlocked by the erroneous detection and the main shaft 1 cannot move. Therefore, after the imaging device 3 is mounted on the main shaft 1, the imaging device 3 and the main shaft 1 can be moved freely together.

[0103] Moreover, in Embodiment 1, the imaging device 3 has an imaging device cover 6 that is conductive. For example, due to a user's operation error or a malfunction of the program, the imaging device 3 and the workpiece 16 may come into contact. In Embodiment 1, by providing the conductive imaging device cover 6, even when the workpiece 16 and the imaging device 3 are in contact, based on the conduction state of an electrical circuit formed by the imaging device cover 6, the workpiece 16, and the contact detection part 70, the contact detection part 70 can immediately detect this contact. In addition, based on the detection result of the contact detection part 70, the NC device 72 instantaneously stops the movement of the main shaft 1, so that damage to the imaging device 3 and the workpiece 16 can be minimized.

[0104] In addition, in Embodiment 1, by using the ATC 9, the machining electrode 5 and the imaging device 3 can be automatically mounted and removed relative to the main shaft 1. The removed machining electrode 5 and imaging device 3 are stored in the magazine 9a of the ATC 9. The magazine 9a is provided separately from the machining tank, so that it is possible to prevent the oil fumes generated from the machining fluid from adhering to the machining electrode 5 and the imaging device 3 stored in the magazine 9a. As a result, it is possible to prevent fouling of the lens 3a of the imaging device 3 caused by the oil fumes and deterioration of the internal substrate of the electrical part 3b of the imaging device 3 caused by the oil fumes.

[0105] In Embodiment 1, the connection between the photographing device 3 and the control box 4 and the connection between the photographing device cover 6 and the contact detection unit 70 are made by connecting them with a connector composed of the first connector terminal 12 and the second connector terminal 13. Suppose the photographing device 3 and the control box 4 or the photographing device cover 6 and the contact detection unit 70 are connected by a wired connection using a cable or the like. In this case, when the photographing device 3 is attached to and detached from the main shaft 1, it is possible that the cable gets caught on the main shaft 1 or the ATC 9 or becomes entangled, and the cable is stretched and breaks. Also, the cable may be immersed in the machining fluid. In Embodiment 1, since a connector connection is used, these problems caused by the cable do not occur.

[0106] The photographing data of the workpiece 16 is acquired by the photographing device 3, whereby the control box 4 can acquire the coordinates of the first measurement point A and the second measurement point B in the workpiece 16. Therefore, it is possible to easily measure the dimensions of each part of the workpiece 16. The user can confirm the image data 15 of the workpiece 16 in real time using the PC 8, so it is possible to check whether the shape and dimensions of the workpiece 16 are correct values with high precision.

[0107] When the camera described in the above Patent Document 1 is not applied to a general NC machine tool but to the die sinking electric discharge machine shown in Embodiment 1, the following problems occur.

[0108] (1) Due to the oil fume during die sinking electric discharge machining, the lens of the camera gets dirty and a clear image cannot be taken.

[0109] (2) Due to the oil fume during die sinking electric discharge machining, the internal substrate of the camera deteriorates and the internal substrate may malfunction.

[0110] (3) For example, even if the structure is such that the camera can be removed, since the connection between the camera and the NC machine tool is a wired connection, it is difficult to handle the cable when replacing the camera. As a result, the cable may break.

[0111] (4) When there is no emergency stop function when the camera is not in contact, the camera and the workpiece continue to be in contact and the camera or the workpiece may be damaged.

[0112] (5) For example, even if there is an emergency stop function when the camera is in contact, when the ground of the internal substrate of the camera is connected to the frame of the camera, at the moment when the camera is loaded on the main shaft, the main shaft becomes in an emergency stop state. As a result, the main shaft is fixed, the camera cannot be moved, the workpiece cannot be photographed within the desired range, and the focus adjustment area of the camera also becomes narrow.

[0113] In contrast, in the engraving die sinking EDM 100 according to the first embodiment, as described above, all of these problems (1) to (5) can be solved.

[0114] The structures shown in the above embodiments represent an example, and can also be combined with other known technologies, and various modification examples described in the embodiments can also be combined. Within the scope not departing from the gist, a part of the structure can also be omitted or changed.

[0115] Description of reference numerals

[0116] 1 spindle, 2 electrode chuck, 3 imaging device, 3a lens, 3b electrical unit, 4 control box, 4a power supply unit, 4b image processing unit, 4c storage unit, 4d arithmetic unit, 5 machining electrode, 6 imaging device cover, 7 contact detection circuit, 7a first contact detection line, 7b second contact detection line, 8 PC, 9 ATC, 9a cartridge, 9b rotating shaft, 9c support portion, 9d guide portion, 10 power supply board, 11, 20 ground, 12 first connector terminal, 13 second connector terminal, 15 image data, 16 workpiece, 16a first edge, 16b second edge, 17 roller, 18 recess, 19 spring, 21 platform, 30 power supply, 40, 41, 46, 47 power line, 42, 45 signal line, 43, 44 ground line, 50 drive device, 60, 61 image, 70 contact detection portion, 71 power supply portion, 72 numerical control device (NC device), 72a spindle control portion, 72b ATC control portion, 72c machining control portion, 90, 93 processing circuit, 91 processor, 92 memory, 100 engraving die sinking EDM, A first measurement point, B second measurement point, C, D arrow.

Claims

1. A die sinking electrical discharge machine, characterized in that, it has: a main shaft; a processing electrode that can be detachably loaded on the main shaft, and discharges through non-contact against a workpiece placed in an insulating processing fluid, thereby processing the workpiece; a photographing device that can be detachably loaded on the main shaft by being replaced with the processing electrode, photographs the workpiece processed by the processing electrode, and obtains photographing data representing the shape of the processed workpiece; a contact detection unit that is connected to the main shaft and, when the photographing device is loaded on the main shaft, detects the contact when the photographing device and the workpiece are in contact; and an NC device that controls the movement and stop of the main shaft, wherein the NC device urgently stops the movement of the main shaft when the contact detection unit detects the contact.

2. The die sinking electrical discharge machine according to claim 1, characterized in that, it has a control box that supplies power to the photographing device via the main shaft using the power from an external power source, and receives the photographing data obtained by the photographing device via the main shaft, performs image processing on the photographing data to generate image data, when the photographing device is loaded on the main shaft, insulates the contact detection unit and the control box so that an electrical circuit is not formed through the photographing device, the control box, the contact detection unit, and the main shaft.

3. The die sinking electrical discharge machine according to claim 1 or 2, characterized in that, the photographing device has a photographing device cover that is loaded in a manner to cover the photographing device, is connected to the contact detection unit, and has conductivity, the contact detection unit, when the photographing device is loaded on the main shaft, detects the presence or absence of contact between the photographing device and the workpiece based on the conduction state of an electrical circuit formed by the photographing device cover, the workpiece, and the contact detection unit.

4. The die sinking electrical discharge machine according to claim 3, characterized in that, it has a control box that supplies power to the photographing device via the main shaft using the power from an external power source, and receives the photographing data obtained by the photographing device via the main shaft, performs image processing on the photographing data to generate image data, it has: a first connector terminal provided on the photographing device; and a second connector terminal provided on the main shaft that enables the connector connection to be established when connected to the first connector terminal, the connection between the photographing device and the control box and the connection between the photographing device cover and the contact detection unit are carried out through the connector connection.

5. The die sinking electrical discharge machine according to any one of claims 1 to 4, characterized in that, it has an automatic tool changer that, in response to a signal input from the outside, replaces the processing electrode and the photographing device for the main shaft.

6. The die sinking electrical discharge machine according to any one of claims 1 to 5, characterized in that, There is a control box that supplies power to the imaging device via the main shaft using the power from an external power source, and receives the imaging data obtained by the imaging device via the main shaft, performs image processing on the imaging data to generate image data. When the imaging device captures an image of the workpiece. When the main shaft is moved so that the NC device aligns with a preset first measurement point on the workpiece, the control box stores the coordinates of the main shaft when the position of the main shaft coincides with the first measurement point as the first coordinates. When the main shaft is moved so that the NC device aligns with a preset second measurement point on the workpiece, the control box stores the coordinates of the main shaft when the position of the main shaft coincides with the second measurement point as the second coordinates. The control box calculates the distance between the first measurement point and the second measurement point based on the first coordinates and the second coordinates.

Images