JP3660739B2 - Method for determining the drilling position of the pilot hole - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a pilot hole drilling position determining method for determining an optimum position for forming a pilot hole through which a discharge wire is inserted in order to drill a machining hole in a workpiece by wire electric discharge machining.
[0002]
[Prior art]
Conventionally, for example, when processing a plate of a press die or the like, it is often processed by a machining center. However, in the case of drilling a machining hole having a complicated shape, wire electric discharge machining is performed. When performing wire electric discharge machining, it is necessary to make a pilot hole for inserting the electric discharge wire through the plate in advance.
[0003]
When drilling a machining hole in the plate, if the area of the machining hole is large, it is possible to drill a lower hole with a drill, but if the area of the machining hole is small, the machining hole Since it is difficult to drill a pilot hole in the outline of the hole, a drill hole is drilled outside the outline and the wire is inserted, and a machining hole is formed from the lower hole position along the outline of the machining hole. Is electrodischarge processed into a single stroke and cut off.
According to the above-described wire electric discharge machining, stress is concentrated during press working between the prepared hole and the processed hole. Thus, there is a problem that fatigue is remarkable, and the working efficiency of plate preparation decreases as the number of prepared holes increases. Therefore, the applicant of the present invention disclosed in Japanese Patent Application Laid-Open No. 6-55352 is a pilot hole position determination device that automatically determines whether the position of the pilot hole drilled outside the contour line of the machining hole is appropriate. Proposed.
[0004]
[Problems to be solved by the invention]
However, when the machining hole by wire electric discharge machining is smaller than a certain diameter (several tens of microns), the workpiece has low rigidity, so that it is necessary to slow down the speed at which the drill enters, and the machining time becomes long. Therefore, in order to improve the work efficiency, it is desirable to drill as large a pilot hole as possible within the contour of the machining hole and perform wire electric discharge machining.
[0005]
Therefore, in the past, the diameter of the pilot hole and the position of the drilling hole were determined by trial and error by visual inspection on the CAD drawing. For this reason, depending on the shape of the processed hole, it may be difficult to set the optimum diameter of the pilot hole within the contour line, and it may take a long time to determine the pilot hole position.
[0006]
The object of the present invention is to solve the above-mentioned problems of the prior art, automatically determine the optimum position for forming a pilot hole having a diameter as large as possible for inserting the discharge wire into the contour of the machining hole, It is an object of the present invention to provide a pilot hole drilling position determination method that can shorten the time.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention comprises the following arrangement.
That is, in the pilot hole drilling position determination method for determining the optimum position for forming the pilot hole through which the discharge wire is inserted in order to drill the machining hole in the workpiece by wire electric discharge machining, the plane shape data and size of the workpiece by the input means Basic data including data is input, the basic data is stored in the storage means, and a virtual plane corresponding to the workpiece is logically configured based on the basic data by the control means, and included in the machining hole on the virtual plane. Conversion data converted into a pseudo-machined hole made of a line segment and / or an arc of a specified size is stored in the storage unit, and the contour line of the pseudo-machined hole in the converted data is input separately by the input unit offset vertically inside the radius of only segments of the lower hole diameter, offset radially inward for arc, line segments and / or arcs Based on the formed non-enclosed portion deletes graphic data, and determined by the control means whether it is possible to drill a pilot hole in the lower hole diameter input, maximum possible drilling in outline of the processing hole The center position of the pilot hole of the drill diameter is determined.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a block diagram showing the structure of a pilot hole drilling position determination device, FIG. 2 is a flowchart showing a pilot hole drilling position determination process, FIG. 3 is an explanatory diagram showing a method for offsetting line segments and arcs, and FIG. It is explanatory drawing which shows a figure processing method.
[0009]
First, the configuration of the pilot hole drilling position determination device will be described with reference to the block diagram shown in FIG. The pilot hole drilling position determining device in this embodiment is for determining the center position of the pilot hole when drilling a machining hole by wire electric discharge machining when manufacturing a press die plate.
[0010]
In FIG. 1, reference numeral 1 denotes a CAD system as input means, which is basic design data (plate size, shape, and position, size, shape, etc. on the plate of the working hole on the plate for a press die as a workpiece). ) Is generated and output. As the input means, in addition to the CAD system 1, a keyboard 2, an external storage device, an external computer system connected online, or the like may be used.
[0011]
Reference numeral 3 denotes a RAM serving as storage means, which stores the previous basic data input from the CAD system 1. Further, based on the basic data, a microprocessor (MPU) as a control means to be described later logically configures a virtual plane corresponding to the plate in the storage area of the RAM 3, and the MPU has a simple shape in the machining hole on the virtual plane. Graphic data converted into a pseudo-machined hole (for example, a line segment and an arc) is generated, and data such as the position, size, and planar shape of the pseudo-machined hole on the virtual plane is stored.
The RAM 3 has a function as a storage area for storing commands and data input from the CAD system 1 and the keyboard 2 as well as a function as a work area of the MPU described later, and is obtained by data processing by the MPU. Information and calculation results are temporarily stored.
As the storage means, an external memory such as a flexible disk or an IC memory card can be used instead of the RAM 3.
[0012]
Reference numeral 4 denotes a ROM which stores in advance an MPU operating system, a control program for a pilot hole drilling position determination device, control data, and the like, which will be described later. Note that the control program, control data, and the like are not stored in the ROM 4, and an external memory such as a flexible disk or an IC memory card can be used.
A graphic display 5 is a part of the output unit. As the output unit, in addition to the graphic display 5, a printer, an external storage device, a control device for a machining center for processing a plate, a control device for a wire electric discharge processing device for processing a plate, and the like can be employed.
[0013]
Reference numeral 6 denotes an MPU as a control means, which is a pseudo-working made of a simple shape having a size contained in a working hole on the virtual plane configured on the RAM 3 based on basic data transmitted from the CAD system 1. Conversion into a pseudo-processed hole made of a hole, for example, a line segment and / or an arc, and conversion data such as the position, size, and planar shape of the pseudo-processed hole on a virtual plane is generated and stored in the RAM 3. Further, according to the control program stored in the ROM 4 based on the size and planar shape of the pseudo machining hole, an area where a pilot hole having a maximum diameter for inserting a discharge wire can be drilled in the contour line of the pseudo machining hole is specified. . Specifically, as will be described later, based on an arbitrary prepared hole diameter inputted from the CAD system 1, the contour line forming the pseudo-processed hole stored in the RAM 3 is formed by being offset inward by the radius of the prepared lower hole diameter. The graphic data to be displayed is displayed on the display 5 and it is determined whether or not a pilot hole having a predetermined pilot hole diameter can be opened. When the graphic satisfies a predetermined condition, a display indicating that the prepared hole can be drilled in the pseudo-processed hole with the set prepared hole diameter is displayed. By setting the diameter of the lower hole as large as possible, it is possible to specify the area at the center position where the lower diameter hole can be drilled within the contour line of the machining hole.
[0014]
Next, the pilot hole drilling position determination method of the pilot hole drilling position determination apparatus will be described with reference to the flowchart shown in FIG.
In FIG. 2, when the pilot hole drilling position determination device is activated (step S1), the MPU 6 reads the control program stored in the ROM 4 and makes preparations such as clearing the RAM 3. First, the MPU 6 reads basic data about a work from the CAD system 1 and stores it in the RAM 3 (step S2). The MPU 6 determines a machining hole to be subjected to wire electric discharge machining from the planar shape and size of the machining hole to be drilled from the basic data (step S3). Then, a specific machining hole is selected based on the size of the machining hole for wire electric discharge machining and the type and size of the tool held by the machining center (step S4).
[0015]
Next, the MPU 6 configures a virtual plane in the RAM 3 based on the basic data, converts the machining hole into a pseudo machining hole composed of a line segment and / or an arc having a simple shape on the virtual plane, and this pseudo machining hole. Conversion data that is data such as the position, size, and planar shape on the virtual plane is generated (step S5). An example of the pseudo-machined hole based on the conversion data is shown by the outline 7 in FIG.
The selection of the simple shape of the pseudo-machined hole may be determined in consideration of the positioning characteristics of the processing machine that processes the workpiece, the memory capacity of the computer system, the arithmetic processing capability, and the like. In any case, the pseudo-machined hole converted into a simple shape such as a polygon is easier to process than the data indicating the shape of the complicated machined hole itself.
[0016]
When the conversion data is generated on the virtual plane, an arbitrary diameter of the pilot hole is set from the input means such as the CAD system 1 or the keyboard 2 (step S6). It is preferable to set the lower hole diameter as large as possible in consideration of work efficiency. Since the offset amount of the contour line 7 is ½ of the lower hole diameter, ½ of the value input as the lower hole diameter is automatically set.
[0017]
Next, it is determined whether or not the lower hole can be opened within the contour line 7 of the pseudo-processed hole as conversion data based on the lower hole diameter (step S7). Specifically, the figure formed by offsetting the contour line 7 forming the pseudo-processed hole to the inside by the radius of the set pilot hole diameter is displayed on the display 5, and the pilot hole with the set pilot hole diameter is displayed. It is determined whether or not the contour line 7 can be opened.
[0018]
A method for offsetting the contour line 7 of the pseudo-machined hole will be described with reference to FIGS. The offset amount is R, the shape before the offset is indicated by a solid line, and the shape after the offset is indicated by a broken line.
First, as shown in FIG. 3B, when the contour line 7 is a line segment, the offset direction is a direction perpendicular to the line segment, and is offset by R toward the inside of the pseudo-processed hole.
Further, as shown in FIG. 3C, when the contour line 7 is an arc, the offset direction is offset by R toward the radial direction, and portions other than the figure surrounded by the line segment and / or arc are deleted. It shall be.
[0019]
Further, as shown in FIG. 3D, this is a case where the contour line 7 is composed of a line segment and an arc, and when the radius of the arc is equal to or less than the offset amount R, the offset of the arc is omitted. Further, as shown in FIG. 3 (e), when the intersection 8 between the line segments constituting the contour line 7 forms an obtuse angle that is convex inward, or when the arcs 8 are adjacent to each other, The offset is made assuming that there is an arc whose radius is the offset amount R at the center.
Further, as shown in FIG. 3F, when the figure after the offset has two intersections 8 and 8 'due to the adjacent line segment and arc, the other intersection 8 after the offset is left and another figure is left. The graphic part forming the intersection 8 'is deleted.
[0020]
Next, as shown in FIG. 4A, a graphic in which the directions of the start and end points of the line segment or arc constituting the graphic after the offset are reversed is deleted. For example, in FIG. 4A, if the figure before offset is assumed to be a counterclockwise figure, among figures A, B, and C forming a closed loop, figures A and C are left-handed loops, and are left as figure B. Is a clockwise loop and the figure is inverted, so delete it.
[0021]
Further, as shown in FIG. 4B, line segments connecting intersections a, b, c, d of the figure before offset and intersections a ′, b ′, c ′, d ′ of the figure after offset are connected. If the intersection 9 is present, the line segment or arc of the movement destination that forms the intersection 9 is deleted from the offset graphic part. For example, in FIG. 4B, when the intersection of the graphic before the offset and the intersection of the graphic after the offset are connected, each line segment has the intersection 9, so all the destination line segments forming the intersection 9 are deleted. As a result, the offset cannot be offset with the set offset amount R, that is, the pilot hole cannot be opened with the radius R.
[0022]
In accordance with the above determination method, it is determined whether the pilot hole can be opened with the pilot hole diameter set within the contour line of the pseudo-processed hole as conversion data. If the pilot hole cannot be opened, the next pilot hole diameter R is set. Then, the determination is made by the determination method shown in step S6. The lower hole diameter R is desirably set to a value as large as possible in order to shorten the machining time, and the value of the lower hole diameter R is set so that the maximum diameter of the lower hole is opened within the contour line of the pseudo-machined hole. . When it is determined that the pilot hole is to be opened, the center position where the pilot hole is opened with the preset pilot hole diameter R is determined as the figure formed within the contour line of the pseudo-processed hole (step S8). . The center position for drilling the pilot hole may be anywhere in the figure.
[0023]
The center position where the maximum diameter of the lower hole diameter actually determined by the control procedure shown in the flowchart can be drilled is indicated by a broken line in the outline 10 of FIG. In addition, it is preferable to set the value of the said lower hole diameter so that it may become small in steps from a large thing, in order to ensure the largest possible diameter.
[0024]
According to the pilot hole drilling position determination method, the center position where the pilot hole with the maximum diameter can be drilled can be determined and displayed within the contour line of the pseudo-machined hole as a figure, so that the work time for determining the pilot hole diameter and the drilling position is determined. It is greatly shortened and the drilling time for the pilot hole is shortened.
Further, since the pilot hole with the maximum diameter can be selected and opened within the contour line of the pseudo machining hole, the drilling time of the machining hole is shortened, and the work time required for the electric discharge machining for the workpiece as a whole can be shortened. it can.
In addition, since the data such as the size of the machined hole of the workpiece is converted into a pseudo machined hole made of a simple shape such as a line segment and / or arc on the virtual plane, the amount of data handled is greatly reduced. Thus, the load on the computer can be reduced and the processing speed can be increased.
[0025]
The preferred embodiments of the present invention have been described above in various ways. However, the present invention is not limited to the above-described embodiments. For example, the machining holes are formed on line segments and / or arcs on a virtual plane. The data was converted into a pseudo-machined hole made of a simple shape and the drilling position of the pilot hole was determined. However, the converted graphic data is not limited to line segments and arcs, but is converted to graphic data including general curves such as ellipses. Of course, many modifications can be made without departing from the spirit of the invention.
[0026]
【The invention's effect】
As described above, in the present invention, on the virtual plane formed on the basis of the basic data of the workpiece, the pseudo-processed hole graphic data composed of a simple shape having a size included in the processed hole is generated and inputted arbitrarily. Based on the graphic data formed by offsetting the contour line of the simulated hole by the radius of the pilot hole diameter, the center position where the pilot hole can be drilled can be automatically determined and displayed as a graphic. And the work time for deciding the drilling position is greatly shortened, and the pilot hole drilling work time can be shortened. Further, since the pilot hole with the maximum diameter can be selected and opened within the contour line of the pseudo machining hole, the drilling time of the machining hole is shortened, and the work time required for the electric discharge machining for the workpiece as a whole can be shortened. it can.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a pilot hole drilling position determination device.
FIG. 2 is a flowchart showing a pilot hole drilling position determination process.
FIG. 3 is an explanatory diagram showing a line segment and arc offset method;
FIG. 4 is an explanatory diagram showing a graphic processing method after offset.
[Explanation of symbols]
1 CAD system 2 Keyboard 3 RAM
4 ROM
5 Graphic display 6 MPU
7, 10 Contour lines 8, 8 ', 9, a, b, c, d, a', b, 'c', d '

Claims (5)

In a pilot hole drilling position determination method for determining an optimum position for forming a pilot hole through which a discharge wire is inserted in order to drill a machining hole in a workpiece by wire electric discharge machining,
Basic data including the plane shape data and size data of the workpiece is input by the input means, the basic data is stored in the storage means, and the virtual plane corresponding to the workpiece is logically configured based on the basic data by the control means. , Conversion data converted into a pseudo machining hole made of a line segment and / or an arc included in the machining hole on the virtual plane is stored in the storage means, and the contour line of the pseudo machining hole in the conversion data Is offset inward in the vertical direction for a line segment by the radius of an arbitrary pilot hole diameter separately input by the input means , offset inward in the radial direction for an arc, and other than the portion surrounded by the line segment and / or arc based on the graphic data is formed by removing, as judged by the control means whether it is possible to drill a pilot hole in the lower hole diameter input, drilled in the outline of the processing hole Lower hole drilling position determination method characterized by determining the center position of the lower hole of the ability maximum drill diameter. When the radius of the arc is equal to or less than the offset amount, the offset of the arc is omitted, and when the intersection of the line segments forms an obtuse angle that protrudes inside the contour line, and when the intersection of the arcs is adjacent 2. The pilot hole drilling position determining method according to claim 1, wherein the offset is performed assuming that there is an arc having a radius as an offset amount centering on each intersection. When the graphic data after the offset has two intersections due to an adjacent line segment and an arc, the line segment data forming the other intersection is deleted except for the one near the intersection before the offset. A method for determining a pilot hole drilling position according to claim 1 or 2. 2. The graphic data constituting the closed loop is deleted when the direction of the closed loop constituting the graphic data after the offset is reversed from the direction of the closed loop constituting the graphic data before the offset. A method for determining a pilot hole drilling position according to claim 2. In the figure data after the offset, when the line segment connecting the intersection of the figure before the offset and the intersection of the figure after the offset intersects, the figure data between the intersection after the offset is deleted. The method for determining a pilot hole drilling position according to any one of claims 1 to 4.

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