ELECTRICAL DISCHARGE MACHINE

Abstract: An electric discharge machine capable of easily identifying and regulating the operational condition of a working fluid cooling apparatus. A working fluid cooling apparatus for an electric discharge machine is provided with an apparatus body positioned on the rear side of an electric discharge machine body, and a panel (21) set on the front side of a control apparatus facing the front side of the electric discharge machine body. This panel is provided thereon with a fluid thermometer (15) and a flow meter (16) which constitute an operation parameter display for the working fluid cooling apparatus, a power source switch (17) constituting an operation parameter regulating operator for the same apparatus, a target temperature setter (18), a target temperature difference setter (19) and an operational mode changeover switch (20).

Description: The present invention relates to an electrical discharge machine. In a wire-cut electrical discharge machine, a machining fluid is supplied from a machining fluid supplying system to the gap between a wire electrode and a workpiece to remove heat and chips produced by electrical discharge machine. Also, the machining fluid is supplied to the workpiece, a workpiece table, and members surrounding the table to prevent temperature fluctuations of these elements, thereby preventing lowering of machining accuracy attributable to temperature fluctuations of those various elements. If the machining fluid supplying system is designed so that the used machining fluid can be circulated for reuse after it is cleaned in a disposer, the machining fluid temperature gradually rises after the start of electrical discharge machining, so that the temperature of the workpiece and the like also rises. If the machining fluid temperature fluctuates in this manner, the machining speed also fluctuates, so that the machining accuracy, including surface roughness, lowers. Conventionally, a device is provided to keep the machining fluid temperature constant, as disclosed for example in JP-U-57-43932. One form of conventional machining fluid cooler, along with the aforesaid machining fluid disposer, is located on the rear side of a housing of the electrical discharge machine. Further, the machining fluid cooler comprises display sections for displaying various operation parameters of the machining fluid cooler, including the machining fluid temperature and the amount of machining fluid supply, and operating sections having various operating elements, including power switches and various switches for adjusting the parameters, these display sections and operating sections being located on the rear side of the machine housing. Accordingly, an operator must take the trouble to get behind the machine housing in turning on the power or identifying or adjusting the various operation parameters of the machining fluid cooler. If the electrical discharge machining is started with any of the various operation parameters off or with the power switches and the like off, moreover, it sometimes may not be able to be noticed. The object of the present invention is to provide an electrical discharge machine in which the operating state of a machining fluid cooler can be easily detected and adjusted. According to the present invention there is provided an electrical discharge machine, comprising: an electrical discharge machine housing; and a machining fluid temperature changer including an operating section for adjusting at least one operation parameter, said operating section of said machining fluid temperature changer being located at a front side of said electrical discharge machine housing, characterised in that: the machining fluid temperature changer is a machining fluid cooler; the machining fluid cooler further includes a display section for displaying at least one other operation parameter and located at said front side of the electrical discharge machine housing, and a machining fluid cooler body independent of said display section and said operating section and located on a rear side of the electrical discharge machine housing; the machining fluid cooler is operable in either a first operation mode in which a machining fluid temperature is controlled to a target value, or a second operation mode in which the temperature difference between the machining fluid temperature and the air temperature is controlled to a target value; said operating section includes a power switch of the machining fluid cooler, a switch for selecting either of said first and second operation modes, a first setter for setting the target temperature for said first operation mode, and a second setter for setting the target temperature difference for said second operation mode; and said target temperature and said target temperature difference constitute said at least one adjustable operation parameter. Since the display section and the operating section of the machining fluid cooler are located on the front side of the electrical discharge machine housing, as described above, the operating state of the machining fluid cooler can be easily determined and adjusted, so that electrical discharge machining can be safely effected under optimum conditions. Brief Description of the Drawings Fig. 1 is a schematic perspective view showing a wire-cut electrical discharge machine according to one embodiment of the present invention; Fig. 2 is a schematic plan view of the electrical discharge machine of Fig. 1; and Fig. 3 is a schematic front view showing display sections and operating sections of a machining fluid cooling device attached to the electrical discharge machine of Fig. 1. Referring to Figs. 1 and 2, a wire-cut electrical discharge machine 1 according to one embodiment of the present invention comprises an electrical discharge machine housing 2, a machining fluid circulating and supplying system mentioned later, and a control device 4 having a built-in computer. The control device 4 is disposed adjacent to the electrical discharge machine housing 2 so that its front faces in the same direction as the front of the electrical discharge machine housing 2. Under the control of the control device 4, moreover, the electrical discharge machine 1 causes a wire electrode 7 stretched between upper and lower guides 5 and 6 to run along a wire transportation path, and causes electric discharge in the gap between a workpiece 9 on a workpiece table 8 and the wire electrode 7, thereby working the workpiece 9. During the electrical discharge machining, furthermore, a machining fluid is supplied to the electric discharge gap, the workpiece table 8 and its surroundings, and the workpiece 9 through nozzles (not shown) attached individually to the upper and lower guides 5 and 6. Numeral 14 denotes a machining fluid collecting vessel which surrounds the workpiece table 8. The machining fluid circulating and supplying system includes a machining fluid cooler and a machining fluid disposer 10 which, connected to the electrical discharge machine housing 2 by means of a first duct pair 12, is used to clean the used machining fluid. The machining fluid cooler includes a machining fluid cooler body 3 which, connected to the disposer 10 by means of a second duct pair 11, is used to cool the machining fluid and adjust the flow rate of the machining fluid. Further, the machining fluid cooler includes a panel 21 which, along with display sections and operating sections of the control device 4, is located on the front of control device 4, that is, on the front side of the electrical discharge machine housing 2. Display sections and operating sections of the machining fluid cooler are arranged on the panel 21. Namely, the machining fluid cooler body 3 and the display and operating sections are independent of one another. Consequently, the electrical discharge machine 1 is compact as a whole, and does not require a wide installation space, despite the location of the display sections and the operating sections on the front side of the electrical discharge machine housing. The body 3, the display sections, and the operating sections of the machining fluid cooler are connected individually to the control device 4, and machining fluid cooling operation and machining fluid flow rate adjusting operation of the cooler body 3 are controlled in the manner mentioned later by means of the control device 4. As shown in Fig. 3, the display sections of the machining fluid cooler on the panel 21 include a liquid thermometer 15 for indicating the temperature of the machining fluid as a machining fluid state parameter and a flowmeter 16 for indicating the flow rate of the machining fluid as a machining fluid supply state parameter. Further, the operating sections of the machining fluid cooler on the panel 21 has various operating elements, including a power switch 17, a first setter 18 for setting a target temperature for a first operation mode in which the machining fluid temperature is adjusted to a target value, a second setter 19 for setting a target temperature difference for a second operation mode in which the temperature difference between the machining fluid temperature and the air temperature is adjusted to a target value, and a mode selector switch 20 used alternatively to select the first or second operation mode. The target temperature and the target temperature difference, along with the aforesaid machining fluid temperature and machining fluid flow rate, constitute operation parameters for the machining fluid cooler. In Fig. 3, numerals 22, 23 and 24 denote an air thermometer, an alarm buzzer, and a breaker, respectively. The following is a description of the operation of the wire-cut electrical discharge machine with the aforementioned construction. In starting the electrical discharge machining, an operator turns on various power switches for various parts of the electrical discharge machine, including the power switch 17 for the machining fluid cooler, and then selects the operation mode of the machining fluid cooler by operating the mode selector switch 20. If the first operation mode is selected, the operator sets the target temperature in the first setter 18. For high-accuracy electrical discharge machining, it is advisable to set the target temperature in consideration of the air temperature indicated on the air thermometer 22. Since the display section 22 and the operating sections 17, 18 and 20 of the machining fluid cooler are arranged on the front of the control device 4 on the front side of the electrical discharge machine housing, the operator can easily turn on the power switch, select the operation mode, and set the temperature in the aforesaid manner. During the electrical discharge machining, electric discharge is caused in the gap between the workpiece 9 and the wire electrode 7 running along the wire transportation path. Also, the machining fluid from the machining fluid disposer 10 is supplied to the gap between the wire electrode 7 and the workpiece 9, the workpiece table 8 and its surroundings, and the workpiece 9 through one duct of the first duct pair 12 and the nozzles of the upper and lower guides 5 and 6, thereby cooling these elements. The machining fluid, having been used for the cooling, is returned to the machining fluid disposer 10 through the machining fluid collecting vessel 14 and the other duct of the first duct pair 12. After being cleaned in the disposer 10, the machining fluid is supplied to the machining fluid cooler body 3 through one duct of the second duct pair 11, whereupon it is cooled in the cooler body 3. Thereafter, the machining fluid is returned to the machining fluid disposer 10 through the other duct of the second duct pair 11. During the electrical discharge machining, the operator monitors various operating parameters displayed on the display sections of the machining fluid cooler and indicative of the operating state of the machining fluid cooler (machining fluid temperature and machining fluid flow rate indicated on the liquid thermometer 15 and the flowmeter 16, in this case). If any of the operating parameters greatly changes, the target temperature set in the first setter 18 is reset, or switches (not shown) for the adjustment of control parameters (e.g., control gain) for the machining fluid cooler operation, arranged on the front of the control device 4, are operated. Since the display sections 15 and 16, the operating section 18, etc. of the machining fluid cooler are located on the front of the control device 4, the operator can easily monitor and adjust the operation parameters. The control device 4 controls the machining fluid cooling operation, machining fluid flow rate adjusting operation, etc. of the cooler body 3 in accordance with the operation control parameters adjusted by the aforesaid operation. If any of the various operation parameters of the machining fluid cooler, including the machining fluid temperature and the machining fluid flow rate, changes extraordinarily, an alarm is given from the buzzer 23. Since the buzzer 23 is located on the front of the control device 4, the alarm can never be missed. In running the machining fluid cooler in the second operation mode, the mode selector switch 20 is operated. In this case, the operator sets the target temperature difference for the second operation mode in the second setter 19. The control device 4 controls the machining fluid cooling operation and the machining fluid flow rate adjusting operation of the cooler body 3 so that the difference between the machining fluid temperature and the air temperature is equivalent to the target temperature difference. In other respects, substantially the same processes as in the first operation mode are followed, so that a description of these processes is omitted. The present invention is not limited to the embodiment described above, and various modifications may be effected therein. In the above embodiment, for example, the display sections and the operating sections of the machining fluid cooler are located on the front of the control device 4. Alternatively, however, they may be arranged in any other suitable positions on the front side of the electrical discharge machine housing where the operator usually stands attendant. Although the present invention is applied to the wire-cut electrical discharge machine in the above embodiment, moreover, it may be also applied to electrical discharge machines of any other types. Although the operation of the machining fluid cooler body is controlled by means of the control device 4, furthermore, the machining fluid cooler body may be provided with a control unit for exclusive use. Further, the alarm buzzer may be replaced with any other alarm device, such as a lamp.

Claims: An electrical discharge machine, comprising: an electrical discharge machine housing (2); and a machining fluid temperature changer (3) including an operating section for adjusting at least one operation parameter, said operating section of said machining fluid temperature changer (3) being located at a front side of said electrical discharge machine housing (2), characterised in that: the machining fluid temperature changer (3) is a machining fluid cooler; the machining fluid cooler (3) further includes a display section for displaying at least one other operation parameter and located at said front side of the electrical discharge machine housing (2), and a machining fluid cooler body independent of said display section and said operating section and located on a rear side of the electrical discharge machine housing (2); the machining fluid cooler (3) is operable in either a first operation mode in which a machining fluid temperature is controlled to a target value, or a second operation mode in which the temperature difference between the machining fluid temperature and the air temperature is controlled to a target value; said operating section includes a power switch (17) of the machining fluid cooler (3), a switch (30) for selecting either of said first and second operation modes, a first setter (18) for setting the target temperature for said first operation mode, and a second setter (19) for setting the target temperature difference for said second operation mode; and said target temperature and said target temperature difference constitute said at least one adjustable operation parameter. An electrical discharge machine according to claim 1, which further comprises a control device (4) disposed so that the front thereof faces in the same direction as the front of said electrical discharge machine housing (2) and adapted to control an operation of various parts of said electrical discharge machine, and wherein said display section and said operating section of said machining fluid cooler (3) are located on the front of said control device (4). An electrical discharge machine according to claim 1 or 2, wherein said display section of said machining fluid cooler (3) is operable to display a machining fluid state parameter and a machining fluid supply state parameter, both said state parameters constituting said at least one other operation parameter. An electrical discharge machine according to claim 3, wherein said display section of said machining fluid cooler (3) includes a liquid thermometer (15) for indicating a machining fluid temperature and a flowmeter (16) for indicating a machining fluid flow rate as said at least one other operation parameter. An electrical discharge machine according to any preceding claim, wherein said electrical discharge machine is a wire-cut electrical discharge machine.

Inventors: TAKASHIMA HIDENORI ROOM HAITSU, TAKASHIMA, HIDENORI ROOM 202, HAITSUHINOYA
Applicants: FANUC LTD, FANUC LTD.
Application year: 1989
Main classification: B23H7
IPC codes: B23H11, B23H7