JP2020204980A - Nc program creation method and deceleration controller of machine tool - Google Patents

Abstract

To easily and quickly generate an NC program for processing a plurality of intersecting holes with a drill without putting calculation loads on a calculation unit of a machine controller attached to an NC machine tool.SOLUTION: The shape of a drill is modeled with an aggregate of a plurality of straight lines, an intersection between a hole formed before a work and the straight line is calculated, based on a result of the calculation, a deceleration start point for decelerating the feed speed of the drill and a deceleration end point for ending the deceleration of the feed speed of the drill after the drill crosses the hole and enters the work again are calculated before the tip of the drill enters an inside of the hole formed before the work, and based on the deceleration start point and the deceleration end point, a second NC program obtained by correcting a first NC program is generated.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for creating an NC program for drilling a plurality of intersecting holes such as a manifold of a hydraulic device and an injection molding die, and a deceleration control device for a machine tool.

For example, the molten high-temperature resin flows into the mold used in injection molding every shot to heat the mold. The appropriate temperature range is determined for the mold, although it depends on the type of resin used. Therefore, the mold is formed with a large number of passages for cooling cooling water, steam, etc., and for circulating a heating medium. Among these passages, there are passages that intersect each other, as shown in FIGS. 15 and 16.

In FIGS. 15 and 16, the work 200 is formed with a first hole 202 formed in the previous step and a second hole 204 formed in the subsequent step. When the tip of the drill T used for machining reaches the space of the first hole 202 when forming the second hole 204, the reaction force or load acting on the feed shaft device that feeds the drill T is sharply reduced. Further, when the tip of the drill T crosses the space of the first hole 202 and reaches the inner surface on the opposite side, the reaction force or the load acting on the feed shaft device increases sharply. This can damage the drill and cause burrs at the intersections of the holes.

Patent Document 1 describes that when it is necessary to modify the machining process or machining conditions, such as when the machined hole is a through hole or the holes interfere with each other, it is most suitable for NC machining on a CAD / CAM system. An NC data automatic creation device that automatically determines a machining process and cutting conditions is described.

Japanese Unexamined Patent Publication No. 7-276185

In the NC data automatic creation device of Patent Document 1, since the hole data of the workpiece which is a three-dimensional solid model is used by CAD / CAM, the calculation load is large and it can be easily mounted on the machine tool or in the vicinity of the machine tool. It is not possible to place a dedicated device in.

The present invention has a technical problem of solving such a problem of the prior art, and from the first NC program for drilling a plurality of intersecting holes, the feed speed of the drill is adjusted when machining the intersecting holes. An NC program creation method and a machine tool that automatically creates a second NC program to decelerate easily and quickly with almost no computational load on the arithmetic unit of the machine control device attached to the NC machine tool. It is an object of the present invention to provide a deceleration control device.

In order to achieve the above object, according to the present invention, the first NC program for drilling a plurality of holes using a drill as a tool and the data of the tool used for machining intersect in the work. In the method of creating an NC program that automatically creates a second NC program that slows down the feed speed of the tool when machining a hole to be drilled, the shape of the drill is modeled with an aggregate of a plurality of straight lines, and the work is prioritized. The intersection of the formed hole and the straight line is calculated, and based on the calculation result, deceleration is started to reduce the feed speed of the drill before the tip of the drill enters the previously formed hole. The point and the deceleration end point at which the deceleration of the feed speed of the drill ends after the drill crosses the hole and re-enters the work are calculated, and based on the deceleration start point and the deceleration end point, the deceleration end point is calculated. Provided is a method of creating an NC program in which a second NC program modified from the first NC program is generated.

Further, according to the present invention, when a drill is used as a tool and a hole intersecting in a work tool is machined based on a first NC program for drilling a plurality of holes and data of a tool used for machining. , Create a second NC program that slows down the feed rate of the tool. In the deceleration control device of a machine tool, store at least the number of straight lines when modeling the shape of a drill with an aggregate of a plurality of straight lines as a parameter. A parameter storage unit, a tool information acquisition unit that acquires tool information including a tool diameter, a tool trajectory acquisition unit that acquires a tool trajectory of the drill of the first NC program from a reading / interpretation unit of an NC device, and the tool. A model generator that generates a tool model represented by an aggregate of straight lines from information and the tool locus and a cylindrical model of a hole, and an intersection position between a tool and a hole are calculated from each straight line of the tool model and the cylindrical model. The first deceleration start position and deceleration end position are calculated from the intersection position calculation unit and the calculated intersection position based on the deceleration start and end position calculation units and the calculated deceleration start position and deceleration end position. A machine tool deceleration control device is provided that includes an NC program generator that modifies the NC program to generate a second NC program.

When creating the first NC program, it is easy to program by simply giving a command to make a hole at a predetermined position at a constant feed rate without worrying about the intersection of the holes. Then, according to the present invention, it is only necessary to calculate the intersection of the cylinder, which is a machined hole, and the straight line that models the drill shape. Therefore, when machining a hole that intersects in the work with a small calculation load. In addition, it is possible to automatically create a second NC program in which the feed rate of the tool is reduced. Therefore, even if the software for performing the arithmetic processing of the present invention is added to the machine control device provided as standard in the machine tool, the second NC program can be created with almost no computational load. Further, the existing machine tool can be easily upgraded by installing the software for carrying out the present invention on a general-purpose personal computer and adding it to the machine control device.

It is a block diagram of the deceleration control device by a preferable embodiment of this invention. It is a flowchart for demonstrating the method of making NC program by the preferable embodiment of this invention. It is a flowchart for demonstrating the method of making NC program by the preferable embodiment of this invention. It is a flowchart for demonstrating the method of making NC program by the preferable embodiment of this invention. It is a perspective view which shows an example of a model tool. It is a perspective view which shows an example of a model hole. It is a perspective view which shows the straight line in the axial direction of a tool along the side surface of a model tool. It is a side view for demonstrating the shape of a model tool. It is a side view for demonstrating another shape of a model tool. It is a schematic diagram for demonstrating the method of calculating the intersection of a straight line of a model tool and a model hole. It is a schematic diagram for demonstrating the method of calculating the intersection of a straight line of a model tool and a model hole. It is a schematic diagram for demonstrating the method of calculating the intersection of a straight line of a model tool and a model hole. It is a schematic diagram for demonstrating the method of calculating the intersection of a straight line of a model tool and a model hole. It is a schematic diagram for demonstrating the method of calculating the intersection of a straight line of a model tool and a model hole. It is a perspective view of the work for demonstrating the intersection hole. (A) is a plan view of FIG. 15, and (b) is a cross-sectional view of FIG.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.
Referring to FIG. 1, the deceleration control device 10 is a new NC program (referred to in the present specification) based on an NC program (referred to as a first NC program in the present specification) supplied to the NC device 100 of the machine tool. A second NC program) is generated. The NC device 100 includes a reading / interpreting unit 102, an interpolation unit 104, and a servo calculation unit 106, similarly to a general NC device. The reading / interpreting unit 102 reads and interprets the first NC program, and outputs a movement command to the interpolation unit 104. The interpolation unit 104 calculates a position command value for each interpolation cycle based on the input movement command, and sends the position command value to the servo calculation unit 106. The servo calculation unit 106 calculates the current value supplied to the servomotor 108 of each feed axis such as the X-axis and the Y-axis based on the position command value, and drives the servomotor 108 of each feed axis.

The deceleration control device 10 includes an input unit 12, a parameter storage unit 14, a tool information acquisition unit 16, a tool locus acquisition unit 18, a model generation unit 20, an intersection position calculation unit 22, a deceleration start / end position calculation unit 24, and an NC program generation unit 26. , A storage unit 28 and a display unit 30 are provided as main components. The parameter storage unit 14, the tool information acquisition unit 16, the tool trajectory acquisition unit 18, the model generation unit 20, the intersection position calculation unit 22, the deceleration start / end position calculation unit 24, the NC program generation unit 26, and the storage unit 28 are the CPUs (center). Computational elements), memory devices such as RAM (random access memory) and ROM (read-only memory), storage devices such as HDD (hard disk drive) and SSD (solid state drive), input / output ports, and mutual It can consist of a computer including a bidirectional bus to connect and related software.

As will be described later, the input unit 12 is an element for the operator to input the parameters necessary for generating the second NC program to the deceleration control device 10, and can be formed from a keyboard, a touch panel, or the like. .. The display unit 30 is a component for displaying the calculation result by the deceleration control device 10, and can be formed from a liquid crystal display or a touch panel. The input unit 12 and the display unit 30 may be formed by a common touch panel.

The parameter storage unit 14 stores the parameters input by the operator through the input unit 12. The parameters input by the operator are the number n of straight lines that define the tool, the shape parameter that represents the shape of the tool tip, the deceleration feed rate, the start point parameter for determining the position to start deceleration, and the release or end of deceleration. An end point parameter for determining the position can be included. These parameters can be stored in relation to the tool number of the tool used. Further, these parameters can be easily input from the parameter setting screen displayed on the input unit 12.

Hereinafter, the operation of each part of the deceleration control device 10 will be described in more detail with reference to the flowcharts of FIGS. 2 to 4.
First, when the deceleration control device 10 is activated, 1, 0, 0 are input to the flags i, j, and m, respectively (step S10), and the parameters input by the operator are read from the parameter storage unit 14 into the model generation unit 20. (Step S12).

When the NC program is supplied to the NC device 100, the deceleration control device 10 reads the first NC program block by block from the reading / interpreting unit 102 (step S14). The tool information acquisition unit 16 acquires tool information, particularly the tool diameter, based on the first NC program read and interpreted by the reading and interpreting unit 102 of the NC device 100 (step S16). Since the tool used for machining is usually indicated by the tool number or the tool pot number of the tool magazine storing a large number of tools in the NC program, the tool information acquisition unit 16 separately obtains the tool diameter and other tool information. It can be stored in advance in association with the tool number, or can be accessed by another server (not shown) to acquire tool information of the tool used for machining. The tool information acquired by the tool information acquisition unit 16 is output to the model generation unit 20.

The tool locus acquisition unit 18 acquires tool locus information regarding the machining start point, machining end point, and direction of the tool to be used based on the first NC program read and interpreted by the reading and interpreting unit 102 of the NC device 100. The acquired tool locus is output to the storage unit 28 as hole information, and is stored in association with (m + 1) (step S18).

Next, in step S20, it is determined whether or not the flag m is 0. When m = 0 (Yes in step S20), it means that no hole has been machined in the work before this machining. In this case, since the hole intersecting with other holes is not formed by this processing, the first NC program is not modified (step S22), the flag m is added with 1 and the process returns to step S14, and the first NC is performed. The next block of the program is loaded.

If No in step S20, that is, if a hole has been machined in the workpiece before the current machining, the model generation section 20 is based on the parameters from the parameter storage section 14 and the tool information from the tool information acquisition section 16. This time, the tool (FIG. 5) to be used for machining is modeled (step S26). In FIG. 5, the model tool M _T, which is a modeled tool, has a cylindrical main body M _{T 1} and a conical tip M _{T 2} provided at one end of the main body M _{T 1} .

Model generator 20 also, depending on the number n of straight lines that define the tool read from the parameter storage unit 14, as shown in FIG. 7, the axis of the tool along the side surface of the main body portion M _T1 models tool M _T A straight line _Li (i = 2 ... n) in the direction is set, and the tool is approximated by the straight line Li _i . In FIG. 7, the number of straight lines is n = 4, but the number of straight lines n is not limited to this and can be an integer of 2 or more. When the number n of straight lines is 2 or more, linear L _i are set at equal intervals around the central axis line of the tool.

The model generation unit 20 further generates a tip portion _MT2 based on the shape parameter read from the parameter storage unit 14, and sets a straight line _Ti (i = 2 ... n). For example, in the case of a normal drill, the shape parameters are the axial length L _T of the tip portion M _{T 2} of the conical shape and the angle θ of the generatrix of the cone with respect to the central axis O of the tool, as shown in FIG. Can include. Even if the tip portion M _T2 has a prefix conical shape (gun drill) as shown in FIG. 9, the shape of the tip portion M _{T 2} can be defined by the length L _T and the angle θ. When L _T = 0 or θ = 0, the model tool M _T has only the cylindrical main body M _{T 1} having a flat tip.

Next, the model generation unit 20 reads the hole information associated with the flag m among the information related to the holes (described as hole traces) formed by the conventional processing stored in the storage unit 28 (described as hole traces). Step S28), modeling the hole marks (FIG. 6) (step S30). In FIG. 6, the model hole _MH, which is the modeled hole trace, is composed of a columnar hole body. The model hole M _H has a central axis O _H , a start surface S _S, and an end surface S _E.

Next, as will be described later, the intersection of each straight line L _i and T _i and the model hole M _H is calculated (step S32). Next, in step S34, it is determined whether or not the calculation of the intersection with the model hole _MH has been completed for all the straight lines L _i and T _i . If No at step S34, that is, for all linear L _i and T _i, if the calculation of the intersection of the model holes M _H has not been completed, 1 is added to i (step S36), returns to step S32 , The intersection is calculated for the next straight lines L _{i + 1} and T _{i + 1} .

In step S34, if Yes, the words, if the calculation of the intersection of the model holes M _H for all linear L _i and T _i are finished, deceleration start position and the deceleration end position is read from the parameter storage unit 14 The deceleration start point and deceleration end point are calculated based on (step S38). The deceleration start point is a position shifted from the calculated intersection to the front by the distance of the start point parameter, and the deceleration end point is a position shifted from the calculated intersection to the back by the distance of the end point parameter. The start point parameter and the end point parameter represent the marginal distance or the safe distance from the calculated intersection. Normally, the start point parameter is set shorter than the end point parameter. The reason is that deceleration starts when the tip of the drill approaches the calculated intersection, and deceleration ends when the calculated intersection passes from the tip (cone) of the drill to the main body (cylindrical), that is, the drill This is because it is necessary to move the deceleration end point to the back by the length L _T of the tip portion.

Next, in step S40, it is determined whether or not the deceleration start point and the deceleration end point have been obtained for all the hole traces. In the case of Yes in step S40, the deceleration start point and the deceleration end point calculated by the deceleration start / end position calculation unit 24 are output to the NC program generation unit 26. In the NC program generation unit 26, the deceleration start position, deceleration feed speed, and deceleration end position of the tool of the block of the first NC program are corrected based on the deceleration start point and the deceleration end point (step S44). It is output to the NC device 100 as a second NC program.

Then, in step S46, the flags i and j are reset, 1 is added to the flag m, the flowchart returns to step S14, and the next block of the first NC program is read.

When the above-mentioned calculation of the deceleration start point and the deceleration end point is not completed for all the hole traces (when No in step S40), 1 is added to the flag j (step S42), and the flowchart returns to step S28. Information related to the next hole trace is read into the model generation unit 20.

Next, with reference to FIG. 4, how to find the intersection of the straight line L _i and the model hole M _H will be described. As described above, in the model generation unit 20, a straight line _Li (i = 2 ... n) in the axial direction of the tool along the side surface of the main body portion M _T1 of the model tool M _T is set according to the number n of straight lines. (Step S50). Next, as shown in FIG. 10, in the intersection position calculation unit 22, one straight line _Li and a model hole M _H are set on the X, Y, and Z coordinate axes (step S52). Intersection calculating unit 22, as shown in FIG. 11, as the center axis O _H of the cylinder is coincident with the Z-axis, is rotated and translated to model holes M _H, linear L _i be rotational and translational under the same conditions moving (step S54), as shown by a broken line in FIG. 11, to erase the portion of the straight line L _i other than the high range of the model holes M _H (range in the Z axis direction).

The intersection position calculation unit 22 then projects the model hole _MH and the straight line L _i on the XY plane, as shown in FIG. 12, and in the XY plane, the intersection point I _P1 (X) between the circle C and the straight line L _i ′. ₁ , Y ₁ ) and I _P2 (X ₂ , Y ₂ ) are calculated (step S56). At this time, if the intersections I _P1 and I _P2 do not exist (No in step S58), the flowchart moves to step S34, and has the calculation of the intersection with the model hole M _H completed for all the straight lines L _i ? Whether or not it is determined.

If the intersection point I _P1, I _P2 is present (Yes in step S58), the intersection point _{I P1 (X 1, Y 1} ), based on the _{I P2 (X 2, Y 2} ), the intersection I _P1, I _P2 The Z coordinate is calculated (step S60). Next, with respect to I _P1 (X ₁ , Y ₁ , Z ₁ ) and I _P2 (X ₂ , Y ₂ , Z ₂ ), the rotation and translation movement in the opposite direction to the rotation and translation movement performed in step S54 are performed. , The intersection of the model hole M _H and the straight line L _i is calculated (step S62). The calculation result, the number of intersections, the modified second NC program, and the like can be displayed on the display unit 30.

The intersection of the straight line T _i and the model hole M _H can be obtained in the same manner. The calculation of the intersection of a straight line and a circle in the two-dimensional coordinates of step S56, the rotation of the coordinates of steps S54 and S62, and the calculation of translational conversion are the three-dimensional solid model of the conventional drill and the three-dimensional solid model of the hole shape. It is a much lighter task for the computer than the calculation of the intersection position with.

Using FIGS. 15 and 16, the first NC program (before conversion) and the second NC program (after conversion) in the case of drilling the second hole 204 after processing the first hole 202 according to the embodiment of the present invention. ) Will be explained. The origin A of the NC program when drilling the second hole 204 is set at one corner of the work 200 as shown in the figure, and the X-axis, Y-axis, and Z-axis are defined. The first NC program of the part where the second hole 204 is machined is created as follows.

G17Z100.0
X-12.5Y10.0
Z50.0
G01Z0.0F40
G00Z100.0
This first NC program positions the reference position of the tool tip (usually the center of the boundary surface between the tip and the main body) at the coordinates (-12.5, 10, 100) and rotates the tool. First, move to Z = 50 (processed surface of the work). It means that the tool feed speed is 40 mm / min, the cutting feed is 50 mm to the position of Z = 0 (the hole 204 penetrates), and then the speed returns to the original coordinate Z = 100.

When the first NC program is converted to generate the second NC program, the result is as follows.
G17Z100.0
X-12.5Y10.0
Z50.0
G01Z35.0F40
G01Z15.0F15
G01Z0.0F40
G00Z100.0
This is the same as the first NC program in that the part that moves the tool from the coordinates (-12.5, 10, 100) to Z = 50. After that, it moves to Z = 35 (deceleration start position in front of the first hole 202) at a feed rate of 40 mm / min, and then moves to Z = 15 (deceleration end position) with the feed rate reduced to 15 mm / min. It moves (completely intersects the first hole 202), then restores the feed rate to 40 mm / min and moves to the position of Z = 0 to penetrate the hole 204. After that, it means that the original coordinates Z = 100 are returned in fast forward.
In this example, it is understood that "G01Z0.0F40" is decomposed into three steps of "G01Z35.0F40", "G01Z15.0F15" and "G01Z0.0F40", and the Z coordinate is decelerated between 35-15. Yeah.

In the above-described embodiment, the deceleration control device 10 sequentially outputs the second NC program by pre-reading the first NC program during the actual machining in the machine tool. The invention is not limited to this, and before supplying the first NC program to the NC device 100, the first NC program is collectively modified over the entire first NC program to generate a second NC program. You may do it.

10 Deceleration control device 12 Input unit 14 Parameter storage unit 16 Tool information acquisition unit 18 Tool locus acquisition unit 20 Model generation unit 22 Crossing position calculation unit 24 Deceleration start / end position calculation unit 26 NC program generation unit 28 Storage unit 30 Display unit 100 NC device

Claims (3)

Based on the first NC program that uses a drill as a tool to machine multiple holes and the data of the tool used for machining, the tool feed speed is reduced when drilling intersecting holes in the workpiece. In the method of creating an NC program for creating a second NC program,
Model the shape of the drill with a collection of multiple straight lines
Calculate the intersection position of the hole formed before the work and the straight line,
Based on the calculation result, before the tip of the drill enters the previously formed hole, the deceleration start point for decelerating the feed rate of the drill and the drill cross the hole to form a work. After re-entering, the deceleration end point at which the deceleration of the feed speed of the drill ends is calculated.
A method for creating an NC program, which comprises generating a second NC program modified from the first NC program based on the deceleration start point and the deceleration end point. The calculation of the intersection position between the hole previously formed in the work and the straight line is performed by converting the intersection of the straight line representing the modeled drill with the cylindrical model of the previously formed hole. The method for creating an NC program according to claim 1, wherein the calculation is performed as the intersection of a straight line and a circle projected from the axial direction of the cylinder model, and the calculation result is inversely converted to obtain the intersection position of the hole and the straight line. .. Based on the first NC program that uses a drill as a tool to drill multiple holes and the data of the tool used for machining, the feed speed of the tool is reduced when drilling intersecting holes in the workpiece. In the deceleration control device of the machine tool that creates the second NC program
A parameter storage unit that stores at least the number of straight lines as parameters when modeling the shape of a drill with a collection of multiple straight lines,
Tool information acquisition unit that acquires tool information including tool diameter,
A tool locus acquisition unit that acquires the tool locus of the drill of the first NC program from the reading / interpretation unit of the NC device, and a tool locus acquisition unit.
A model generator that generates a tool model represented by an aggregate of straight lines from the tool information and the tool locus, and a cylindrical model of a hole.
An intersection position calculation unit that calculates the intersection position between the tool and the hole from each straight line of the tool model and the cylinder model.
From the calculated intersection position, the deceleration start and deceleration start and deceleration end position calculation units that calculate the deceleration start position and deceleration end position, and
An NC program generator that modifies the first NC program and generates a second NC program based on the calculated deceleration start position and deceleration end position.
A machine tool deceleration control device characterized by being equipped with.

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