JP4722598B2 - Die-sinker EDM - Google Patents

Description

  The present invention relates to a die-sinking electric discharge machining apparatus including a plurality of machining heads. In particular, the present invention relates to a die-sinking electric discharge machining apparatus having two machining heads of the same type of linear motor drive system that can move synchronously.

  In the sculpture electric discharge machining, as disclosed in Patent Document 1, a linear motor is used in comparison with a machining head of a driving system using a combination of a rotary servo motor, a ball screw and a nut (hereinafter referred to as a rotary servo motor driving system). It is known that a machining head of a driving system (hereinafter referred to as a linear motor driving system) is advantageous. However, in order to realize a die-sinking electrical discharge machining apparatus with a linear motor drive type machining head in reality, a structure that can withstand even when reciprocating at high speed and high acceleration by suspending the entire tool electrode. is necessary. Actually, the sculpting electric discharge machining apparatus provided with the linear motor drive type machining head as disclosed in Patent Document 2 has been invented. However, the machining is limited to machining using a small tool electrode such as a rib groove. It was difficult to carry out the processing using the tool electrode. Therefore, an electric discharge machining apparatus having a linear motor driving type machining head having a structure disclosed in Patent Document 3 has been devised, and a general-sized tool having a standard size with a linear motor driving type machining head. Processing using electrodes is now possible.

  However, in a machining head of a linear motor drive system, if the mass of the tool electrode is large, the mover becomes large in order to obtain a thrust commensurate with the tool electrode, and the weight of the entire moving part becomes heavy. Since the gravity acts so as to slide down when moving to, it is necessary to increase the thrust of the linear motor. And there is a problem that the larger the thrust of the linear motor is, the larger the mover becomes and the heavier the moving part becomes. Therefore, like the sculpture electric discharge machine disclosed in Patent Document 4, the machining is performed with a linear motor drive type machining head as much as possible, and a tool electrode having a size that is difficult with the linear motor drive type machining head is used. In the machining to be performed, there is considered a sculpting electric discharge machining apparatus configured to control reciprocation by switching to a rotary servo motor drive system.

  By the way, regardless of the rotary servo motor drive system or the linear motor drive system, the sculpting electric discharge machining apparatus having a plurality of machining heads as disclosed in Patent Document 2 and Patent Document 4 is well known. It has been. For example, Patent Document 5 is known as a sculpting electric discharge machining apparatus provided with a plurality of machining heads having different sizes as in Patent Document 2. Further, for example, as the sculpting electric discharge machining apparatus provided with a plurality of machining heads of the same type, there are the sculpting electric discharge machining apparatuses disclosed in Patent Document 6, Patent Document 7, Patent Document 8, and the like.

JP-A-5-104332 Japanese Patent No. 3427172 Japanese Patent No. 3542508 JP 2000-225527 A US Pat. No. 5,444,204 Japanese Patent Laid-Open No. 62-15015 Japanese Patent Publication No. 63-27938 JP-A-5-228734

  In this way, the linear motor drive type machining head is directly affected by gravity and therefore requires a thrust that matches the mass of the tool electrode. Further, since the influence of positive pressure and negative pressure due to the electric discharge machining liquid must be countered only by the thrust of the linear motor, a thrust that can counter the pressure, in other words, a thrust corresponding to the area of the tool electrode is required. Originally, one of the advantages of the EDM machine equipped with a linear motor drive type machining head is that the tool electrode can be moved at a higher acceleration speed, reversed at high speed, and jumped. It is an indispensable condition for a motor-driven type sculpting electric discharge machining apparatus to have a structure capable of moving the entire moving part with high acceleration and reversing the moving direction at high speed.

  However, providing a large output linear motor suitable for a large general tool electrode (mass and area) may cause the mover to be too large relative to the size of the tool electrode. In addition, if the entire moving part that is too large for the tool electrode is reciprocated in the vertical direction at high speed and high acceleration by the high-power linear motor, the entire machine is required without obtaining the required rigidity. There is a risk that it may be difficult to perform actual processing because the machine accuracy cannot be obtained or a large vibration is generated. In short, there is no merit of adopting a linear motor drive type machining head instead of a rotary servo motor drive type machining head. For this reason, there is a limit to the size of the tool electrode that can be used in the linear motor drive system, and it is difficult to adopt a linear motor drive system machining head in machining that uses a large overall tool electrode. Met.

  In view of the above-described problems, the present invention provides a sculpture discharge that enables electric discharge machining using a large-sized general-purpose tool electrode that has been limited by a sculpture electric discharge machining apparatus including a machining head of a linear motor drive system. An object is to provide a processing apparatus. Advantages in the specific configuration of the present invention will be described in detail in the description of the embodiments.

Further, an electric discharge machining apparatus according to the present invention is an electric discharge machining apparatus having a plurality of machining heads, and includes a gantry (7) that reciprocates in a horizontal uniaxial direction (Y-axis direction), and a gantry ( 7) The top beam (73) of 7) is provided so as to be symmetrically disposed on both side surfaces of the top beam (73), and is uniaxial in the horizontal direction (X-axis direction) perpendicular to the horizontal uniaxial direction (Y-axis direction). The two processing heads (1) and (2) of the same type that reciprocate in parallel with each other, and the movable bodies provided in the processing heads (1) and (2) reciprocate in the vertical direction (Z-axis direction). The linear motors (11) and (12) to be moved, and the linear motors (11) and (12) are controlled to move the respective moving bodies synchronously, and one tool electrode (commonly attached to each moving body) ( And a control device (4) for moving 3) relative to the workpiece. Yeah.

  Since the EDM apparatus according to the present invention is provided with an attachment member that attaches one tool electrode in common to two machining heads of the same type of linear motor drive system that move synchronously. Electrical discharge machining can be performed using a tool electrode having a mass twice the maximum mass that can be suspended by the base machining head. As a result, for example, machining of large liquid crystal display molds and automobile dashboard molds has been impossible with a sculpting electric discharge machine equipped with a linear motor drive type machining head. Electric discharge machining using a large-sized tool electrode can be performed, and electric discharge machining that fully utilizes the advantages of the EDM apparatus equipped with a linear motor drive type machining head is possible.

  Further, the mover of the linear motor does not become too large with respect to the size of the tool electrode. Accordingly, the height of the entire machine is not particularly high, and the structure supporting the machining head is less likely to be distorted or vibrated, so that the structure does not become extremely large. Therefore, the required rigidity can be ensured in a smaller space, machine accuracy can be maintained, and a large workpiece can be processed.

  The EDM apparatus according to the present invention includes two machining heads of the same type, a linear motor that reciprocates a moving body of the machining head in the vertical direction, and controls the linear motor to synchronize the moving bodies. Since the machining head does not become too large with respect to the size of the tool electrode, the gantry type for moving the top beam is provided. Easy to adopt structure. In addition, the gantry-type structure reduces the amount of complex displacement even if a large-sized tool electrode is suspended, compared to a so-called C-frame type EDM, so that the required mechanical accuracy is reduced. can get. As a result, excellent machining accuracy can be obtained even in machining using a large tool electrode.

  Since the EDM apparatus according to the present invention has a configuration in which two machining heads of the same type of linear motor drive system are synchronously controlled to relatively move one tool electrode, the transmission mechanism of the shaft feeder Therefore, the influence of a slight positional error that occurs with time due to the synchronization deviation of the two machining heads, which cannot be avoided, can be minimized. Therefore, one tool electrode can be moved by two machining heads without any practical problem. Further, since the machining head is driven by a linear motor, even if the stationary positions of the moving bodies of the two machining heads are slightly deviated from each other, the shaft feed mechanism does not fail, and the moving body of the machining head is selectively selected by the control device. Can be moved independently. Therefore, tool electrode alignment such as tilt correction can be performed without providing any special means. As a result, it becomes easier to attach a large tool electrode, and workability is improved.

  In addition, a configuration in which two machining heads of the same type are arranged symmetrically on both side surfaces of the top beam of one gantry balances when one tool electrode is supported by two machining heads. It is easy to bend, distort, and vibrate more easily. As a result, more stable machine accuracy can be obtained and excellent machining accuracy can be obtained.

  In addition, when the machining head is configured to be movable in one horizontal axis and the gantry and machining head are moved and controlled by the control device, the table is fixed and the workpiece cannot be moved. The amount of work piece and electric discharge machining fluid does not affect the accuracy, and excellent machining accuracy can be obtained. Further, since the processing tank does not move, the space can be made relatively smaller than the size of the workpiece. Then, by moving the machining head in the horizontal one-axis direction with a linear motor, it is possible to minimize the influence of a slight positional error that occurs with time due to a synchronization shift that cannot be avoided as a whole. Therefore, one tool electrode can be moved in synchronization with two machining heads without any practical problem.

  Furthermore, the linear motor drive type machining head is configured to move in the horizontal 1-axis direction (X-axis) by the linear motor drive type, so that the shaft feed mechanism can be transmitted even if the stationary positions of the two machining heads are slightly displaced. There is no obstacle such as damage to the mechanism, and the processing head can be selectively moved independently by the control device. Therefore, tool electrode alignment such as leveling and tilt correction can be performed without providing any special means. As a result, it becomes easier to attach a large tool electrode, and workability is improved.

  FIG. 1 to FIG. 3 show the configuration of the machine of a preferred embodiment of the sculpting electric discharge machining apparatus of the present invention. A machining fluid supply device including a storage tank that stores the electrical discharge machining fluid is not shown. Of the two machining heads shown in FIG. 2, the machining head on the right side of the drawing is shown with the upper side cover removed. FIG. 4 shows a block configuration of a preferred control device. Hereinafter, the electric discharge machining apparatus of the present invention will be described in detail with reference to FIGS. 1 to 4.

  The sculpture electric discharge machining apparatus of the present invention includes two machining heads, a first machining head 1 and a second machining head 2 of the same linear motor driving system that move synchronously. The first machining head 1 and the second machining head 2 have detachable attachment members 10 and 20 for attaching one tool electrode in common to the lower end of the moving body. The attachment member 10 and the attachment member 20 are face plates, and one large tool electrode can be attached and fixed by two face plates, and the tool electrodes can be attached separately. As shown in FIG. 3, the attachment member 10 and the attachment member 20 are configured to attach the tool electrode 3 to one large attachment member 30 provided to bridge between the first machining head 1 and the second machining head 2. can do.

  The first machining head 1 and the second machining head 2 are controlled to move synchronously by the control device 4 including the computer numerical control device 41 and the motor control device 42 shown in FIG. One tool electrode commonly attached to the attachment member 30 is moved relative to the workpiece. The main axis (main control axis) of the electric discharge machining apparatus according to the embodiment is the vertical direction and the Z axis in numerical control. The moving bodies of the first machining head 1 and the second machining head 2 are reciprocated in the vertical direction by the linear motor 11 and the linear motor 21. The linear motor 11 and the linear motor 21 are driven and controlled by control currents Zia and Zib that are output based on the command signal Zr of the computer numerical control device 41, so that the first machining head 1 and the second machining head 2 The moving body of the base machining head is moved in synchronization with the Z-axis direction. Therefore, in the numerical control program, one command value (Zr) is programmed in the Z-axis direction.

  When machining is performed by attaching one tool electrode in common to the first machining head 1 and the second machining head 2, there is one main shaft, and a quill which is a moving body of the first machining head during electric discharge machining. 12 and the quill 22 which is the moving body of the first machining head 2 are not allowed to move apart. Therefore, the meaning that the two machining heads realized by the electric discharge machining apparatus of the present invention move in synchronization is the same in the same direction based on the same command signal Zr of the control device 4. It means that it is controlled to move at the same distance with the acceleration and speed. At this time, since the electric discharge machining apparatus of the present invention has two machining heads of the same type, it is relatively easy to control movement of the two machining heads in synchronization. However, even if the same type of machining head is manufactured using exactly the same parts and is strictly controlled in the same process, each type has its own characteristics. The difference in performance occurs. For this reason, even if the two machining heads are controlled to move synchronously based on the same command signal Zr, a slight but inevitable synchronization shift may occur.

  Therefore, if one tool electrode is moved in the main axis direction with two machining heads of the same type of rotary servo motor driving system that are controlled to move synchronously, the two machining heads will be out of synchronization. Even if there is a slight difference in the position in the main axis direction over time, in other words, if there is a difference in the speed or acceleration of the two moving bodies at a certain point during the movement, the ball screw and nut will bite, A member such as a ball of a part is abnormally worn, and the transmission mechanism of the shaft feeder is damaged and cannot be processed. Even if the processing can be continued, the mechanical accuracy is not guaranteed because the entire processing head is distorted or the like, resulting in an unacceptable decrease in the processing accuracy. Since the EDM apparatus of the present invention uses two machining heads of the same type as a linear motor drive system, since there is no transmission mechanism, even if there is an unavoidable synchronization shift between the two machining heads, it can be absorbed. One tool electrode can be moved in synchronism with two machining heads without any practical problem.

  The control device 4 shown in FIG. 4 includes a linear motor 11 that moves the quill 12 that is the moving body of the first machining head 1 and a linear motor 21 that moves the quill 22 that is the moving body of the second machining head 2. Each has a motor control device 42 that outputs control currents Zia and Zib. Accordingly, the electric discharge machining apparatus according to the embodiment can correct a difference due to the individuality of two machining heads of the same type by control, so that a temporal position error caused by a synchronization shift can be further reduced. Further, the control device 4 measures the positions of the quill 12 and the quill 22 with a linear scale (not shown), and if there is an error between the detected positions Za and Zb, an intermediate value (Za + Zb) / 2. Is provided with a position detector 43 that outputs the current position Zd. Therefore, the electric discharge machining apparatus according to the embodiment can quickly correct the difference due to the individuality of the two machining heads of the same type within a smaller range, so that the time position error caused by the synchronization shift can be further reduced. This is advantageous in reducing the size.

  The numerical control device 41 of the control device 4 is configured to perform at least simultaneous three-axis control. The numerical control device 41 can move the motor for moving each moving body in the horizontal one-axis direction (Y-axis direction) and the horizontal one-axis direction (X-axis direction) orthogonal to the horizontal one axis in synchronization with the main shaft. The command signals Xr and Yr for each axis are output in synchronization with the command signal Zr for the main shaft. The control device 4 shown in FIG. 4 includes a motor control device 44 that controls a motor in the X-axis direction and a motor control device 45 that controls a motor in the Y-axis direction.

  In the electric discharge machining apparatus according to the embodiment described above, the control device 4 can selectively move the movable bodies of the first machining head 1 and the second machining head 2 independently. . Therefore, for example, the tilt of the tool electrode can be corrected by moving the moving body of the first machining head 1 in the vertical direction while the moving body of the second machining head 2 is stopped. Further, for example, a tool electrode having a relatively small size that can be suspended by either one of the first processing head 1 and the second processing head 2 or separately by one processing head is attached. By doing so, it is possible to enjoy the advantages of a conventional electric discharge machining apparatus having a plurality of machining heads. At this time, in the EDM apparatus of the embodiment, the tool electrode can be attached to the attachment member (face plate) 10 or the attachment member 20, but the attachment member 10 (20) is removed and the attachment member is built in. The tool electrode can be attached to the (chuck) 13 or the attachment member 23 via an electrode holder.

  When one of the first machining head 1 and the second machining head 2 is moved and controlled to perform one machining, there is one main control axis (main axis). Therefore, the control device 4 can be easily switched and used. In the case of the configuration of the control device 4 shown in FIG. 4, for example, when electric discharge machining is performed with the first machining head 1, the command signal Zr is not output to the motor control device 42 of the second machining head 2. . At this time, the detection signal from the position detector 43 is set to Za = Zd. When the first machining head 1 and the second machining head 2 are independently controlled to move simultaneously and two electric discharge machinings are performed simultaneously, the number of spindles becomes two. Accordingly, two numerical control devices are provided when two machining heads can be independently moved and controlled simultaneously.

  The power supply device 5 for machining supplies power to the tool electrode and the workpiece through an inter-electrode wire (not shown). The first machining head 1 and the second machining head 2 are each configured to be able to supply power to the tool electrode. When the first machining head 1 and the second machining head 2 are controlled to move independently at the same time and two electric discharge machinings are performed simultaneously, two power supply devices are provided.

  As shown in FIG. 1 and FIG. 2, the electric discharge machining apparatus according to the embodiment includes a gantry 7 that reciprocates in the horizontal one-axis direction (Y-axis direction) provided in the bed 6. In the present invention, the gantry type refers to a structure in which a structure provided across a table moves in a horizontal axis direction and a machining head is provided on the structure. Therefore, it is not necessary to move the table on which the workpiece is placed in a so-called general gate-type structure in which the structure does not move, so that the installation area with respect to the size of the workpiece is not required. Can be made relatively small. The gantry 7 in the profile electric discharge machining apparatus according to the embodiment has two portal columns (columns) of a first column 71 and a second column 72 that are arranged to face each other with the table 8 that does not move and the machining tank 9 interposed therebetween. And a top beam 73 installed between the first support column 71 and the second support column 72.

  The machining head is provided on the top beam of the same type gantry so as to be movable in one horizontal axis direction (X-axis direction) orthogonal to the Y-axis direction in which the gantry moves. Accordingly, the first machining head and the second machining head reciprocate on the top beam in parallel with each other in the X-axis direction. Therefore, the electric discharge machining apparatus according to the embodiment is configured such that the machining tank filled with the electric discharge machining liquid and the table on which the workpiece is placed do not move, and thus can place a workpiece that is heavier and larger. Moreover, the installation area with respect to the size of the workpiece can be further reduced.

  1 and FIG. 2 shows a sculpture electric discharge machining apparatus in which two machining heads of the same type, that is, a first machining head 1 and a second machining head 2 are provided on both side surfaces of a top beam 73 of one gantry 7. They are arranged symmetrically. Therefore, it is easy to balance when one tool electrode is supported by two machining heads, and bending, distortion, and vibration are less likely to occur. Further, since there is one gantry, there is an advantage that the problem of interference between gantry does not occur and the moving area of the gantry can be enlarged. Further, when the movement control of the two machining heads 1 and 2 is performed in synchronization, it is not necessary to perform movement control by synchronizing a plurality of gantry with respect to the horizontal one-axis direction (Y-axis direction) in which the gantry 7 moves. The control system can be configured relatively easily.

  As shown in FIG. 2, in the sculpting electric discharge machining apparatus of the embodiment, two machining heads 1 (2) of the same type have quills 12 (22), which are respective moving bodies, linear motors 11 (21). Secondary side mover 111 (211). Magnet plates 112 (212) of the secondary mover 111 (211) are arranged on both side surfaces of the quill 12 (22), and are arranged at positions facing the magnet plates 112 of the quill 12 (22) with a predetermined interval. A primary stator 114 (214) of the linear motor 11 (21), which is a quill base to which the exciting coil unit 113 (213) is attached, is provided. Further, the above-mentioned sculpting electric discharge machining apparatus is configured such that the air cylinder 14 (24) is provided so that the counter balance weight acts on the same axis as the movement axis of the quill 12 (22). The configuration of the machining head has the same operational effects as the configuration of the sculpting electric discharge machining apparatus shown in Patent Document 2 and the like already described. For the advantages, the description of Patent Document 2 is referred to.

  Further, the electric discharge machining apparatus according to the embodiment includes two linear motors 61 and 62 that reciprocate the gantry 7 in the horizontal uniaxial direction (Y-axis direction), and the first machining head 1 orthogonal to the Y-axis direction. A linear motor 74 that reciprocates in the horizontal one-axis direction (X-axis direction) and a linear motor 75 that reciprocates the second machining head 2 in the X-axis direction parallel to the machining head 1. Each of the gantry 7, the machining head 1 and the machining head 2 is guided by a linear motion guide.

As shown in FIG. 1, the primary side mover (excitation coil) 611 of the linear motor 61 is attached to the bottom portion of the first support 71 of the gantry 7, and the secondary side stator (magnet plate) 612 is a bed. 6 is provided. Similarly, as shown in FIG. 2, the primary side mover 621 of the linear motor 62 is attached to the bottom portion of the second column 72 of the gantry 7, and the secondary side stator (not shown) is a bed. 6 is provided. The primary side mover (excitation coil) 741 of the linear motor 74 is attached to a slider 76 provided on the back of the first machining head 1, and the secondary side stator (magnet plate) 742 is the top of the gantry 7. It is provided along the side surface of the beam 73. The primary side mover (excitation coil) 751 of the linear motor 75 is attached to a slider 77 provided at the back of the second machining head 2. The secondary side stator (magnet plate) 752 of the linear motor 75 is provided along the side surface of the top beam 73 of the gantry 7, and the side surface is opposite to the side surface on which the secondary side stator 742 of the linear motor 74 is provided. Hit the side face.

  As shown in FIG. 4, each linear motor 61, 62, 74, 75 is controlled by the control device 4. 1 is configured to move both the first machining head 1 and the second machining head 2 in the horizontal one-axis direction (X-axis direction), the main axis (Z-axis direction). In the same manner as described above, a current position Xd, which is an intermediate value between the position Xa of the first machining head 1 and the position Xb of the second machining head 2 measured by a position detector 46 on a linear scale (not shown), is obtained. The control device 44 is configured to output control currents Xia and Xib to the linear motors 74 and 75, respectively.

  The gantry 7 is configured such that one moving body is moved by two linear motors. Therefore, the two linear motors 61 and 62 that move the gantry 7 are feedback-controlled at the current position Yd of the gantry 7 detected by one linear scale.

  The configuration of the sculpting electric discharge machining apparatus according to the above-described embodiment can be appropriately modified and applied without departing from the technical idea of the present invention. Moreover, the apparatus and member which comprise the profile electric discharge machining apparatus of embodiment can be combined with another apparatus and member, or can be replaced with the member which has the same function and property.

  The present invention can be applied to a sculpting electric discharge machining apparatus having a linear motor drive type machining head. The present invention broadens the range of tool electrodes that can be subjected to electric discharge machining by an electric discharge machining apparatus equipped with a linear motor drive type machining head, and contributes to the development of the electric discharge machining apparatus.

1 is a perspective view showing an overall configuration of an electric discharge machining apparatus according to an embodiment of the present invention. It is a right view of the die-sinking electric discharge machining apparatus of embodiment of this invention. It is a right view which shows a part of right side of the sculpture electric discharge machine of embodiment of this invention, and shows the state which attached one big tool electrode. It is a block diagram which shows the structure of the control apparatus of the die-sinking electric discharge machining apparatus of embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st processing head 2 2nd processing head 4 Control apparatus 5 Power supply device 6 Bed 7 Gantry 8 Table 9 Processing tank 10,20 Mounting member (face plate)
11, 21 Linear motor 61, 62 Linear motor 71 First strut 72 Second strut 73 Top beam 74 Linear motor 76, 77 Slider

Claims (1)

In a sculpting electric discharge machining apparatus having a plurality of machining heads, a gantry that reciprocates in a horizontal axis direction and a top beam of one gantry are arranged symmetrically on both side surfaces of the top beam. Two processing heads of the same type that reciprocally move parallel to each other in a horizontal uniaxial direction perpendicular to the horizontal uniaxial direction, a linear motor that reciprocates each moving body provided in each processing head in a vertical direction, and A control device that controls each linear motor to move each movable body synchronously and relatively moves one tool electrode attached to each movable body relative to the workpiece; Engraving EDM.

Images