JP2013158862A - Supporting device for machining condition setting of die sinking electric discharge machining - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve machining efficiency of a finished shape which can be worked only by a partial electrode.SOLUTION: A memory device 3 stores a plurality of machining condition values of a kind of machining condition related to average machining current applicable to the minimum dimension of a bottom of a protruding region. An operator operates an operation device 1 to apply data of machining information containing data of a finished form and data of a material of a tool electrode given by an input device 2 as information related to the finished shape. An arithmetic device 5 determines whether or not a machining hole where the protruding region using a graphite-made formed electrode is to be machined based on the data of the finished form and the data of the material of the tool electrode, obtains the machining conditions of the kind of machining condition related to the average machining current applicable to the minimum dimension of the protruding region, and sets a combination of the machining conditions.

Description

  The present invention relates to a machining condition setting support device for setting a combination of machining conditions including a series of machining conditions in a predetermined machining process of electric discharge machining.

  Die-sinking electrical discharge machining is a method in which a tool electrode having a reversal shape of a desired machining shape is disposed opposite to a workpiece with a predetermined machining gap, and a predetermined voltage pulse is applied to the machining gap to repeatedly generate a discharge. This is a machining method in which a material is gradually removed from a workpiece by energy to form a machining hole having a desired machining shape in the workpiece. Therefore, a machining hole having a desired machining shape is formed in the workpiece such that the contour shape of the tool electrode is transferred to the workpiece. A tool electrode having an inverted shape of a desired machining shape is referred to as a total type electrode.

  As the material for the tool electrode of the sculpture electric discharge machining, copper, brass, copper tungsten, graphite, iron, and aluminum are well known. Unless the workpiece material is special or there is a special requirement for the final product, machining efficiency, price, ease of manufacture, and handleability when machining a hole with a machining area that is not extremely small Therefore, copper or graphite is mainly used as the material for the tool electrode.

  By the way, in the cutting process, it is impossible to process a deep hole in which the processing area is small relative to the processing area of the entire processing hole, such as a rib, and a cutting tool cannot be inserted. Therefore, the processing of the projecting deep hole that cannot be processed by cutting is performed exclusively by the sculpting electric discharge machining. Hereinafter, such a protruding hole and a corresponding portion of the total electrode having the inverted shape of the hole are collectively referred to simply as a protruding portion.

  When the material of the tool electrode is copper, warpage occurs when the protruding portion is processed, and therefore it is difficult to manufacture a total electrode having the protruding portion by cutting. Also, since the tool electrode is manufactured as small as the electrode reduction required for the machining gap, it is extremely difficult to form the protruding part on the mold with the required machining shape accuracy, and the total electrode having the protruding part Can not be cast.

  When the material of the tool electrode is graphite, it is possible to manufacture a general electrode having an arbitrary contour shape with high accuracy relatively easily by cutting. However, as shown in Patent Document 1, for example, rough machining is basically performed according to an average machining current value (current density) determined on the basis of the projected area of the tool electrode, in other words, the machining area of the entire machining hole. Since the machining conditions in the process (first cut) are set, when electric discharge machining is performed using a fragile graphite-made total electrode, there is a high possibility that the projecting portion is missing.

  In order not to cause the defect of the protruding portion in the graphite-made electrode, for example, as shown in Patent Document 2, the average processing current value is determined based on the processing area (bottom area) of the protruding portion. It is conceivable to set machining conditions in the rough machining process according to the determined average machining current value. However, since the machining area of the protruding portion is smaller than the machining area of the entire machining hole, the average machining current value is relatively small in the entire machining hole, and it takes too much machining time to be put to practical use.

  Since it is difficult to machine a hole with a projecting part with a copper or graphite type electrode, the shape corresponding to the projecting part is divided into a projecting part and a part excluding the projecting part. A tool electrode having a shape and a tool electrode having a shape corresponding to a portion excluding the protruding portion are separately manufactured and subjected to electric discharge machining. A tool electrode manufactured by dividing the entire machining hole into a plurality of parts with respect to the total electrode is referred to as a partial electrode. When processing with partial electrodes, as shown in Patent Document 3, the processing conditions are set based on the projected area (processing area) of each partial electrode.

JP 2009-279735 A (paragraph 0081) JP 2003-291032 A (paragraph 0079) No. 2009-101688 (paragraph 0017)

  Since the design of the partial electrode requires a high level of knowledge, the work burden in designing and manufacturing the tool electrode is greater, and extra work time is required. In addition, when machining a machining hole with a protruding portion using a partial electrode, since the portion excluding the protruding portion is processed in advance, one or more protruding portions are sequentially processed one by one. Compared to machining at once using a general-purpose electrode, the time required for the entire machining process, including the time required for tool electrode replacement and the relative positioning of the tool electrode and workpiece, is considerably longer. ing.

  The main object of the present invention is to provide an improved machining condition setting support device capable of easily setting a combination of machining conditions suitable for sculpting electric discharge machining using a general electrode having a projecting portion made of graphite. Advantages of the present invention are specifically shown in the description of the embodiments.

  In order to solve the above-described problem, the machining condition setting support device of the present invention can be applied to a plurality of types of machining conditions in a specific sculpting electric discharge machining device by a specific sculpting electric discharge machining device. Machining of machining condition types related to average machining current that saves machining condition value data that integrates machining condition values and adapts to the minimum dimension of the bottom surface of the protruding part where the machining area is small relative to the machining area of the entire machining hole A storage device (3) in which a plurality of condition values are stored, an input device (2) for inputting machining information data including machining shape data and tool electrode material data given as machining shape information, and a machining shape. The average machining power applied to the minimum dimension obtained by acquiring the minimum dimension when indicating that the machining of the drilled hole exists and indicating that the tool electrode material is graphite. Are obtained from the storage device (3), and the machining condition values of other types of machining conditions are sequentially obtained based on the machining condition values of the types of machining conditions related to the average machining current value. And an arithmetic unit (5) for setting and setting a combination of machining conditions including a series of a plurality of types of machining conditions in a predetermined machining process.

  According to the machining condition setting support device of the present invention, it is determined that the machining mode is to machine a machining hole in which there is a projecting portion where a cutting tool does not enter using a total electrode of graphite, Based on the minimum size of the bottom surface, obtain the machining condition value of a specific type of machining condition that can obtain the largest possible machining current value within the range where the defect of the protruding part does not occur, and set the combination of machining conditions Can do.

  Therefore, it is possible to easily set a combination of machining conditions suitable for electric discharge machining of a machining hole in which the protruding portion exists only by inputting the minimum dimension of the bottom surface of the protruding portion by the operator. As a result, the electric discharge machining of the machining hole in which the projecting portion such as a rib that can only be machined by the partial electrode exists can be electric discharge machining using the graphite-made total electrode, and the machining efficiency is improved.

It is a block diagram which shows the outline | summary of the processing condition setting assistance apparatus of this invention. It is a flowchart which shows the process which sets a process condition. It is the perspective view and top view which show the total type electrode which has a some protrusion part.

  FIG. 1 shows a preferred embodiment of the machining condition setting support device of the present invention. The machining condition setting support device shown in FIG. 1 is provided in a computer numerical control device (CNC) of a sculpting electric discharge machining device. The machining condition setting support device can be provided in a personal computer having a computer-aided manufacturing system (CAM) that supports creation of an NC program in sculpting electric discharge machining.

  The machining condition setting support device includes an operation device 1, an input device 2, a storage device 3, a display device 4, and a calculation device 5. The machining condition setting system for operating the machining condition setting support device is one of many functions of the computer numerical control device. Therefore, the machining condition setting support device of the embodiment shares each device included in the numerical control device.

  The operating device 1 is means for operating the machining condition setting support device. In particular, the controller device 1 is a means for an operator to give data necessary for setting the machining conditions to the machining condition setting system. The machining condition setting system indicates a program that substantially operates the machining condition setting support device. The operation device 1 is specifically an operation panel of a numerical control device. When the processing condition setting system is included in the computer-aided manufacturing system, the operation device 1 includes a mouse and a keyboard of a personal computer.

  The input device 2 is means for taking in data necessary for setting machining conditions from the outside to the inside of the machining condition setting support device. In particular, the input device 2 is means for inputting machining information data including machining mode data and tool electrode material data. The input device 2 includes, for example, a port for inputting / outputting data from a storage device provided outside the machining condition setting support device, various magnetic disk drives for reading data from the storage medium, and a communication line adapter for inputting data through a communication line An interface circuit for inputting data through the operation device 1 is also included.

  The storage device 3 is means for storing data necessary for setting processing conditions. The storage device 3 is a means for storing a plurality of processing condition values of processing conditions of a type related to the average processing current adapted to the minimum dimension of the bottom surface of the protruding portion having a small processing area with respect to the processing area of the entire processing hole. is there. In the embodiment, the minimum dimension of the bottom surface of the projecting part in the machining hole and the minimum dimension of the tip surface of the projecting part of the tool electrode are treated synonymously although there is a difference in the electrode reduction amount.

  In the following, a large number of data of each machining condition value of a specific type of machining condition related to the average machining current applicable to every unit minimum dimension, for example, every 0.1 mm, is simply put together and data of machining condition values corresponding to the minimum dimension. That's it. However, the storage device 3 does not limit the method of storing the machining condition value corresponding to the minimum dimension, and each machining condition value corresponding to the unit minimum dimension is stored in a data table format (table format) or specified. Or can be stored in the form of an arithmetic expression.

  The storage device 3 includes a main storage device such as a memory that temporarily stores data and an auxiliary storage device such as a hard disk drive that stores data for a long period of time. Further, it includes a storage device such as a USB memory that can be accessed in the same way as an auxiliary storage device through a specific input port without a drive (drive device) interposed.

  The display device 4 stores data of a plurality of screens of the machining condition setting system, data necessary for setting the machining conditions given by the input device 2, and is stored in the storage device 3 and selectively requested to be displayed. It is a means to display the data of the processing condition value extracted from. The display device 4 includes a monitor having a liquid crystal display and a display circuit that converts original data into data for display and outputs the data to the monitor.

  The arithmetic device 5 is means for executing a machining condition setting system (program) when setting machining conditions. The operation of the arithmetic device 5 in the machining condition setting support device of the embodiment will be described in detail later. Specifically, the arithmetic device 5 is a central processing unit (CPU). The arithmetic device 5 includes a command device for a numerical control device.

  FIG. 2 shows a process for setting processing conditions in a certain processing step. In particular, FIG. 2 shows a process for setting processing conditions in the roughing process. FIG. 3 shows an example of a tool electrode having a plurality of protruding portions. The lower view of FIG. 3 is a plan view of the tool electrode shown in the upper view as seen from below. Below, including the operation of each device of the machining condition setting support device of the embodiment shown in FIG. 1, the machining conditions for electric discharge machining of the machining hole in which the projecting portion exists with a graphite-type electrode is set. How to do it.

  The operator operates the operation device 1 and inputs data necessary for setting the machining conditions by the input device 2 to the machining condition setting support device (S1). Data necessary for setting the machining conditions is machining information data and machining condition value data. However, since the machining condition value data is stored in the storage device 3 in advance, it is not necessary for the operator to supply the machining condition value data to the machining condition setting support device every time the machining condition is set.

  The processing information data includes information on the processing shape, information on the processing result, and information that restricts processing. The information regarding the machining shape is, for example, the projected area (machining area) of the tool electrode, the machining mode, the machining dimension, the machining depth, and the minimum side electrode reduction amount (offset). The information regarding the processing result is, for example, processing surface roughness, processing shape accuracy, and electrode consumption ratio. Information that restricts machining is, for example, the material of the tool electrode and the workpiece.

  The processing form data given as information on the processing shape is determined by looking at sample images of a plurality of processing forms on a screen where an operator requests input of the processing form displayed on the display of the monitor of the display device 4. Select and enter. The data of the processing form is not limited to data that directly shows the feature of the processing shape such as a cylindrical shape or a conical shape, but indirectly the feature of the processing shape such as rib processing, gate processing, and core pin processing. Contains data to show.

  The machining condition value data refers to data obtained by accumulating a large number of machining condition values that can be applied in a specific electric discharge machining apparatus for each of a plurality of types of machining conditions in the specific electric discharge machining apparatus. The processing condition value data is stored in advance in the storage device 3 as data indicating a correlation between specific types of processing conditions or a correlation between specific types of processing conditions and specific types of processing information. Alternatively, the machining condition value data can be stored in the storage device 3 as a machining condition database storing a plurality of combinations of machining conditions, which are a series of a plurality of types of machining conditions in a predetermined machining step.

  In the processing condition setting support device of the embodiment, when the arithmetic device 5 displays a list of images of a plurality of forms on the display device 4 and the operator selects an image of a specific processing form on the touch panel of the operation device 1, the input device 2 gives the arithmetic device 5 data indicating a specific processing mode. When an operator selects and inputs an identification number assigned in advance for each tool electrode material from an input field provided on an input screen displayed on the display device 4, the input device 2 performs an operation. The device 5 is provided with electrode material data indicating the material of a specific tool electrode.

  Data of machining information given to the machining condition setting system is temporarily stored in the storage device 3. Based on the machining information given to the machining condition setting system, the arithmetic device 5 determines whether or not the machining hole is a machining hole in which a projecting portion using a graphite-made total electrode is present (S2).

  It can be determined from data on the processing form and data on the material of the tool electrode whether or not the processing hole is a processing hole in which a projecting portion is formed by the graphite-made total electrode. For example, a predetermined identifier is additionally registered in the processing form data, which is a processing shape in which the protruding portion exists, among the plurality of processing form data.

  For example, when the operator selects and inputs “rib processing” registered in advance as a processing form having a protruding portion as a processing form, and selects and inputs graphite (Gr) as the material of the tool electrode, The arithmetic unit 5 determines that the processing hole is to be processed with a projecting portion formed by the graphite-made total electrode. However, the operator can cancel the result determined by the arithmetic device 5.

  In the machining condition setting support device according to the embodiment, the input device 2 is configured to be able to input the minimum dimension of the bottom surface of the protruding portion. When the arithmetic unit 5 determines that the machining hole has a projecting portion that uses a graphite-made electrode, a screen requesting the input of the minimum size of the bottom surface of the projecting portion is displayed on the monitor of the display device 4 (S3). The minimum dimension of the bottom surface of the protruding portion is, for example, a short side length when the shape of the bottom surface of the protruding portion is a square, and a short diameter (diameter) when the shape is a circle. In the case of the tool electrode shown in FIG. 3, it is the width L of the bottom surface of the rib that is the protruding portion.

  When the solid data (three-dimensional shape data) of the model created by the computer-aided design device (CAD) is given to the machining condition setting system, the arithmetic unit 5 determines whether there is a protruding portion in the machining hole from the solid data. The minimum size of the bottom surface of the protruding portion is obtained from the solid data, and is displayed in a specific input field on the input screen displayed on the display device 4 so that the operator can determine the minimum size of the bottom surface of the protruding portion. Prompt for dimensions.

  Specifically, in the processing condition setting support device of the embodiment, the arithmetic device 5 determines whether or not there is a protruding portion in the entire processing hole based on the processing shape that is determined from the solid data. For example, by identifying the depth and width of the protruding portion that can be extracted from the machining shape and the preset depth and width, respectively, it is identified that there is a protruding portion that does not contain a cutting tool. Can do. Also, it is determined whether or not there is a protruding portion by combining several criteria such as the ratio of the width and depth of the protruding portion or the ratio of the processing area of the entire processing hole and the processing area of the protruding portion. be able to.

  The operator inputs the minimum dimension of the bottom surface of the protruding portion according to the instruction displayed on the input screen of the display device 4 (S4). When processing information data is obtained from solid data, the operator agrees with the minimum dimension displayed in the input field and calculates the minimum dimension data in the same way as when entering numbers directly. Send to 5. In a broad sense, it can be said that the data of the minimum dimension of the bottom surface of the protruding portion given to the machining condition setting system is one piece of machining information. When the operator does not input the minimum dimension, or when a value of 0 or less is input, the processing by the total-type electrode having the protruding portion is canceled.

  The computing device 5 sets the machining condition value corresponding to the minimum dimension stored in the storage device 3 to the machining condition value of the type related to the average machining current that is adapted to the inputted minimum dimension of the bottom surface of the protruding portion. The data is extracted from the data and displayed on the display device 4 (S5). Specifically, the types of machining conditions related to the average machining current are, for example, data on the peak current value, on time (pulse width), and off time (rest time) of the discharge current pulse.

  The processing condition value data corresponding to the minimum dimension stored in the storage device 3 in the processing condition setting support device according to the embodiment is substantially within a range in which the defect of the protruding portion verified in advance by the test processing does not occur. This is a safe value of the machining conditions that can obtain as large an average machining current as possible. In the processing condition value data corresponding to the minimum dimension, new data obtained by actual processing can be added and recorded at the request of the operator.

  In the machining condition support setting device of the embodiment, the average machining current value is determined from the minimum dimension of the bottom surface of the protruding portion. If the average machining current value is determined by the bottom area of the protruding portion, the average machining current value becomes too small. Also, it is difficult to clarify the stable relationship that can obtain the safe value of the limit between the maximum dimension of the bottom surface of the protruding part and the average machining current value, and select the machining condition value that makes the average machining current value too large There is a risk that it will be, and safety is low. According to the machining condition support setting device of the embodiment, it is possible to set machining conditions that are safer and have excellent machining efficiency.

  When the processing conditions of the types related to the average processing current, specifically, the peak current value, the on time, and the off time are determined, the arithmetic device 5 is based on the determined processing condition values of the various types of processing conditions. Then, suitable machining condition values for other types of machining conditions are retrieved and extracted from the machining condition value data stored in the storage device 3, and the respective machining condition values for the other types of machining conditions are determined in order (S6). ).

  The machining conditions in other types of EDM for machining types related to the average machining current are, for example, electrical machining such as servo reference voltage (average machining voltage), polarity, no-load voltage (power supply voltage) Machining conditions related to movement such as conditions, jump speed, jump time, swing amount, machining conditions related to specific control such as waveform control of discharge current pulse or voltage pulse, machining environment such as presence / absence of machining liquid jet and method Includes processing conditions. In the case of sculpting electric discharge machining using a graphite-made electrode, an oil-based electric discharge machining fluid is used in principle.

  When the operator approves a combination of machining conditions composed of a series of a plurality of types of machining conditions in a predetermined machining process displayed as candidates on the display device 4, the arithmetic unit 5 uses the machining condition combination of machining conditions. A processing condition number is assigned as an aggregate, and each type of processing condition is stored and set in the storage device 3 (S7). At the same time, the machining condition number is recorded in the NC program (S8).

  When the shape of the machined hole is a machined shape with no protruding part (S2), the machining conditions of the type of machining conditions related to the average machining current in the rough machining process based on the machined area (projected area) of the whole machined hole A value is determined (S9). And in the finishing process where the average machining current value is relatively small, the average machining current value in the final finishing process in which the machining conditions are determined based on the rough machining process in which the machining conditions have already been set and the desired machining surface roughness Based on the above, the combination of machining conditions is sequentially set so that the average machining current value becomes smaller stepwise (S10).

  Combinations of machining conditions for each machining process stored with a machining condition number in the storage device 3 can be displayed as a list in a table format called a machining condition column on the display device 4 in accordance with an operator's command as necessary. . The operator operates the operation device 1 and gives a numerical value to the machining condition setting system through the input device 2, whereby each machining condition value (specific parameter value) of each type of machining condition displayed on the display device 4. Can be corrected.

  According to the processing condition setting support device of the present invention described above, the partial electrode is formed by a combination of processing conditions with high processing efficiency so that no defect of the protruding portion is generated by using the total electrode having the protruding portion made of graphite. Thus, it is possible to easily perform electric discharge machining of a machined hole having a narrow and deep hole in which a cutting tool such as a rib that has been machined in does not enter.

  The machining condition setting support device of the present invention has already been given some specific examples. However, the machining condition setting support device of the embodiment described above is within the scope of the technical idea of the present invention. Application is possible without being limited to the configuration.

  The present invention is utilized in the technical field of metal processing. In particular, the present invention improves productivity in the manufacture of products having deep holes or grooves that do not receive cutting tools such as ribs. The present invention contributes to the development of mold processing or component processing technology.

1 Operation Device 2 Input Device 3 Storage Device 4 Display Device 5 Arithmetic Device

Claims (1)

  Data of machining condition values in which a large number of machining condition values that can be applied in the specific die-sinking electric discharge machining apparatus are stored for each of a plurality of types of machining conditions in the specific die-sinking electric discharge machining apparatus and a machining hole A storage device storing a plurality of machining condition values of machining conditions related to the average machining current adapted to the minimum dimension of the bottom surface of the protruding portion having a small machining area relative to the entire machining area, and given as information on the machining shape An input device for inputting machining information data including machining mode data and tool electrode material data, and indicates that the machining mode is machining of a machining hole in which the protruding portion exists, and the material of the tool electrode is graphite. The machining condition value of the type of machining condition related to the average machining current that is applied to the acquired minimum dimension and indicates the minimum dimension when indicating that A processing condition value of another type of processing condition is sequentially determined based on a processing condition value of a type of processing condition obtained from the storage device and related to the average processing current value, and a series of a plurality of types in a predetermined processing step A processing condition setting support apparatus, comprising: an arithmetic device that sets a combination of processing conditions including processing conditions.

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