JP2018112870A - Finishing processing controller and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set a tool angle which can avoid uneven wear of a tool and precisely perform fining processing of the entire processed surface without changing the tool angle during feeding the tool in a finishing processing controller for finishing processing of a work piece with a grindstone tool held by a five axes NC machine tool.SOLUTION: The finishing processing controller includes: a processing surface direction calculation part 14 for dividing a processed surface of a work piece into a plurality of processed surfaces and calculating a processing surface direction orthogonal to each processed surface; an angle difference calculation part 15 for calculating a plurality of tool directions in which a grindstone tool 2 can be set, an angle difference between each tool direction and the processing surface direction and a correlation between the angle difference and a grinding length per tool direction; a tool angle setting part 16 for setting a tool angle in a tool direction in which the total grinding length is the shortest in a range of an angle difference defining a non-recommended range of a preset tool tip; and a processing operation part 17 for performing a processing simulation with the set tool angle and creating processing control data.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a finishing process control device and a program, and more particularly, to a finishing process control device and a program capable of setting a tool angle capable of avoiding uneven wear of a tool and finishing the entire processing surface with high accuracy.

For example, when a die having an uneven surface after cutting is used as a workpiece and grinding finish processing is performed on the uneven surface, a spindle head of a machine tool for XYZ orthogonal 3-axis numerical control (referred to as 3-axis NC) has been conventionally used. A ball end grindstone tool is attached to the main shaft, which is rotated at high speed around the main axis.
In the case of a 3-axis NC machine tool, as schematically shown in FIG. 12, the axial direction of the grindstone tool 51 is always directed to a certain direction, for example, the vertical direction.

However, if the axial direction of the grindstone tool 51 is always directed to a certain direction, one point at the tip of the tool will always be in contact with the workpiece W, and only a predetermined portion of the grindstone tool 51 will be worn, and the life of the grindstone tool 51 will be increased. There were problems such as shortening.
Further, when the workpiece shape has large irregularities, there is a problem that an interference site B is generated on the workpiece W as shown in the figure, and the tip of the grindstone tool 51 cannot be applied.

The above-described problems can be solved by using, for example, a 5-axis (XYZ orthogonal 3-axis, rotation axis, tilt axis) NC machine tool as disclosed in Patent Document 1.
That is, since the 5-axis NC machine tool can tilt the tool freely, the tool axis intersects the surface of the part B as shown in FIG. 13 (interfering with the 3-axis NC machine tool). The inclination angle of the grindstone tool 52 may be set so as to do this.

  In the 5-axis NC machine tool disclosed in Patent Document 1, an inclination angle setting data table for setting the inclination angle of the grindstone tool 52 with respect to the work surface of the workpiece W is created as shown in the flow of FIG. A step (step SP1), a step of fetching triaxial NC data for a tool created in advance with respect to the machining surface of the workpiece W (step SP2), and an inclination angle read from the inclination angle setting table into the triaxial NC data And adding the setting data to create the 5-axis NC data (step SP3).

According to the invention disclosed in Patent Document 1, the contact point between the tip of the grindstone tool 52 and the workpiece W can be changed by inclining the grindstone tool 52 based on the 5-axis NC data created along the flow. The occurrence of uneven wear can be suppressed.
Further, by inclining the grindstone tool 52, it is possible to perform processing on the surface to be processed without interfering with the workpiece W.

JP-A-8-229770

By the way, in the machine tool disclosed in Patent Document 1, the optimum tool angle for each machining part is calculated so that the tool angle is appropriately changed during tool feeding during machining.
However, when applied to a large machine tool that uses automobile parts as a workpiece, the angle change is generally 1 ° pitch, so a fine angle change cannot be made, and the angle change during tool feed leads to a machining error. There was a problem.
Therefore, there has been a demand for a method capable of suppressing uneven wear and machining the entire workpiece surface with high accuracy without changing the tool angle during tool feeding.

  The present invention has been made paying attention to the above points, and in a finishing control device for finishing a workpiece with a grindstone tool held by a 5-axis NC machine tool, a tool capable of avoiding uneven wear of the tool. An object of the present invention is to provide a finishing control device and a program capable of accurately finishing the entire surface to be processed without setting a corner and changing the tool angle during tool feeding.

  In order to solve the above-mentioned problems, a finishing control device according to the present invention grinds a work surface of a workpiece by rotating a tip-shaped spherical grindstone tool mounted on a 5-axis numerical calculation machine tool around its axis. A finishing processing control device for finishing the workpiece, wherein the processing surface of the workpiece is divided into a plurality of processing surfaces, and a processing surface direction orthogonal to the surface is calculated for each processing surface. A direction calculation unit, a plurality of tool directions that can be set by the grindstone tool, an angle difference between each tool direction and the machining surface direction, and a correlation between the angle difference and the grinding length is calculated for each tool direction. An angle difference calculation unit, a tool angle setting unit that sets a tool direction with the shortest total grinding length as a tool angle in a range of angle differences that defines a preset non-recommended range of the tool tip, and the set tool Machining simulation by angle It was carried out, characterized in further comprising a machining operation unit that creates a machining control data.

  In addition, a control unit that determines whether or not there is a non-machined surface in the workpiece is provided, and when the control unit determines that there is a non-machined surface, the machining surface direction calculation unit performs machining that is orthogonal to the surface with respect to the non-machined surface. A surface direction is calculated, and the angle difference calculation unit calculates a plurality of tool directions that can be set by the grindstone tool, and an angle difference between each tool direction and the machining surface direction, and the angle difference is calculated for each tool direction. The tool angle setting unit calculates the correlation with the grinding length, and sets the tool direction that has the shortest total grinding length as the tool angle within a range of angle differences that defines a preset deprecated range of the tool tip. The machining operation unit preferably performs machining simulation using the tool angle set by the tool angle setting unit to create second machining control data.

Further, the angle difference calculation unit calculates an angle difference between the tool direction and the machining surface direction when the tool direction is the Z-axis direction among the three XYZ orthogonal axes, and the correlation between the angle difference and the grinding length. It is preferable that the tool direction is changed by a predetermined angle in the XZ-axis direction and the YZ-axis direction, and the correlation between the angle difference and the grinding length is calculated for each tool direction.
The non-recommended range of the tool tip is preferably a region including a tip apex located on the rotation axis of the grindstone tool.

According to such an apparatus configuration, it is possible to grind the work surface of the workpiece as wide as possible with one tool angle set so that the tool tip portion where the tool is hard to wear is in contact with the workpiece. As for the machined surface, by machining with a different tool angle set so that the tool tip where the tool is hard to wear is in contact with the workpiece, all the work surfaces are precisely finished while suppressing uneven wear of the tool. be able to.
That is, the entire processing surface can be processed with high accuracy without changing the tool angle during tool feeding.

  Further, in order to solve the above-described problems, the finishing machining control program according to the present invention rotates a tip-shaped spherical grindstone tool mounted on a 5-axis numerical calculation machine tool around its axis to work a workpiece surface. Is a finishing process control program for performing a finishing process on the workpiece, wherein the computer divides the work surface of the work into a plurality of work surfaces, and each work surface is perpendicular to the surface. Calculating a plurality of tool directions that can be set by the grindstone tool, and calculating an angle difference between each tool direction and the machining surface direction, and calculating a correlation between the angle difference and the grinding length for each tool direction. And a step of setting a tool direction having the shortest total grinding length as a tool angle in a range of angle differences that define a preset non-recommended range of the tool tip, and the set tool angle. Perform engineering simulations, characterized in that to execute the steps of creating a machining control data.

  In addition, after performing the machining simulation with the set tool angle and creating machining control data, the computer determines whether there is an unmachined surface, and if there is an unmachined surface, the unmachined surface Calculating a machining surface direction orthogonal to the surface, a plurality of tool directions that can be set by the grinding wheel tool, calculating an angular difference between each tool direction and the machining surface direction, and calculating the angular difference for each tool direction. A step of calculating a correlation between the grinding length, a step of setting a tool direction with the shortest total grinding length as a tool angle in a range of angle differences that define a preset non-recommended range of the tool tip, It is desirable to perform a machining simulation with the set tool angle and create the second machining control data.

Further, calculating a plurality of tool directions that can be set by the grindstone tool, an angle difference between each tool direction and the machining surface direction, and calculating a correlation between the angle difference and the grinding length for each tool direction, Calculating the angle difference between the tool direction and the machining surface direction when the tool direction is the Z-axis direction among the three XYZ orthogonal axes, and calculating the correlation between the angle difference and the grinding length; It is desirable to include a step of changing by a predetermined angle in the XZ-axis direction and the YZ-axis direction and calculating a correlation between the angle difference and the grinding length for each tool direction.
The non-recommended range of the tool tip is preferably a region including a tip apex located on the rotation axis of the grindstone tool.

By executing such a program on a computer, it is possible to grind the workpiece surface as wide as possible on the workpiece with one tool angle set so that the tool tip where the tool is less likely to wear is in contact with the workpiece. The remaining unmachined surface is machined with a different tool angle set so that the tool tip where the tool is less likely to wear is in contact with the workpiece. It can be finished.
That is, the entire processing surface can be processed with high accuracy without changing the tool angle during tool feeding.

  According to the present invention, in a finishing control device for finishing a workpiece with a grindstone tool held by a 5-axis NC machine tool, a tool angle capable of avoiding uneven wear of the tool is set, and the tool angle during tool feeding is set. The entire surface to be processed can be finished with high accuracy without changing.

FIG. 1 is a side view of a tool used in a finishing control device according to the present invention. FIG. 2 is an enlarged cross-sectional view of the tip of the grindstone tool of FIG. FIG. 3 is a side view showing an image of machining a non-machined surface of a workpiece with the grindstone tool of FIG. 1. FIG. 4 is a functional block diagram of the finishing control device according to the present invention. FIG. 5 is a flowchart showing a procedure for creating machining control data. FIG. 6 is a perspective view showing an example of a workpiece. FIG. 7 is a side view showing rotation and tilting operations of the machine tool holding the tool of FIG. FIG. 8 is a graph showing the grinding length for each angle difference at a certain tool angle. FIG. 9 is a graph showing the grinding length for each angle difference at another tool angle. FIG. 10 is a cross-sectional view of the tool tip for explaining the NG range. FIG. 11A is a side view showing a state in which a workpiece is machined by an inclined tool, and FIG. 11B is a side view showing a state in which the inclined tool interferes with the workpiece. FIG. 12 is a side view showing the operation of the tool by the conventional 3-axis NC machining. FIG. 13 is a side view showing the operation of the tool by the conventional 5-axis NC machining. FIG. 14 is a flowchart showing a procedure for setting the inclination of the tool of FIG.

  Embodiments of a finishing control device according to the present invention will be described below with reference to the drawings. FIG. 1 is a side view of a tool used in a finishing control device according to the present invention. Specifically, a state in which the grindstone tool 2 is attached to the machine tool 1 by numerical control (NC) of five axes (three axes of XYZ, the rotation axis R, and the tilt axis K) is shown.

  The tip portion 2a of the grindstone tool 2 is formed in a hemispherical shape having a diameter of 30 mm, for example, and the surface thereof has a nickel layer 4 formed on a base material 3 such as chromium molybdenum steel as shown in FIG. A diamond grindstone 5 having an average particle diameter of 0.25 mm is scattered. In addition, as a material of a grindstone, high hardness is required in order to perform high precision processing. In particular, by using the diamond grindstone 5, the wear resistance on the tool side becomes higher.

  The above-described grindstone tool 2 is mounted on the machine tool 1 and contacts the work surface of the workpiece W while rotating around its axis with a predetermined inclination angle as shown in FIG. Is what you do.

FIG. 4 is a functional block diagram of the finishing control device according to the present invention.
The finishing process control device 10 shown in FIG. 4 includes a control unit 11 that controls the operation of the entire apparatus, a tool data acquisition unit that acquires data of the grindstone tool 2 and data of the machine tool 1 for performing 5-axis NC machining. 12 and a work data acquisition unit 13 that acquires shape data and the like of a work to be ground.

  Further, an angle at which the machining direction calculation unit 14 that calculates the direction of the work surface of the workpiece and the angle difference between the work surface and the direction of the grindstone tool (referred to as the tool direction) is calculated, and the grinding length is aggregated for each angle difference. A difference calculation unit 15, a tool angle setting unit 16 that sets a tool angle used for machining based on a result of aggregation by the angle difference calculation unit 15, and a machining calculation unit that performs machining simulation on the workpiece and creates optimum machining control data 17.

Each function of the finishing process control device 10 is formed by a computer unit (a CPU, a storage device, a computer program recorded in the storage device) (not shown), and functions by executing the computer program in the CPU (computer). To do. More specifically, the finishing process control device 10 is incorporated in a CAM (computer-aided manufacturing) system, and the process control data generated by the machining operation unit 17 is incorporated in an NC program for machining.
That is, in the finishing control device 10 according to the present invention, the processing control data is created, and in the actual finishing operation, the machining control data is set based on the NC program for processing. The machine tool 1 performs processing on the workpiece W.

Next, a procedure for creating the machining control data will be described along the flow of FIG.
First, in the finishing process control device 10, the tool data acquisition unit 12 acquires data related to the grindstone tool 2 to be used (step S1 in FIG. 5). Specifically, data of the grindstone tool 2 (tip shape, diameter, etc.) and data of the machine tool 1 for performing 5-axis NC machining (tiltable angle, angle change pitch, tool rotation speed, etc.) are acquired.
Further, the work data acquisition unit 13 acquires 3D shape data (work data after cutting) related to the work W shown in FIG. 6 as an example (step S2 in FIG. 5). Note that the shape target value of the workpiece W is recorded in advance in a storage device (not shown) of the finishing process control device 10.

After the tool data and the work data are acquired, when the operator instructs the creation of the machining control data via a keyboard or the like (not shown), the machining surface direction calculation unit 14 reads the work data from the work data acquisition unit 13, For each processed surface obtained by dividing the entire processed surface by a predetermined unit area (for example, 1 mm ² ), a direction perpendicular to the surface (hereinafter referred to as a processed surface direction) is calculated as indicated by an arrow in the drawing (step in FIG. 5). S3).

  Next, the angle difference calculation unit 15 calculates the angle difference with each machining surface direction when the tool direction is the Z-axis direction, and totals the grinding length when each machining surface is ground for each angle difference ( The correlation between the angle difference and the grinding length is obtained) (step S4 in FIG. 5). The Z-axis direction is the vertical axis direction in FIG. The grinding length is the length of grinding until the target value is reached.

Further, the angle difference calculating unit 15 changes the tool direction by a predetermined angle in the XZ-axis direction and the YZ-axis direction, calculates the angle difference between the tool direction and each machining surface direction, and calculates the angle for each tool direction. The correlation between the difference and the grinding length is tabulated (step S5 in FIG. 5).
As shown in FIG. 7, the change pitch of the angle in the XZ-axis direction and the Y-Z-axis direction of the machine tool 1 having the rotation axis R and the tilt axis K is a rotatable angle of the rotation axis R (for example, − 350 °, −340 °,... -20 °, −10 °, 0 °, 10 °, 20 °,..., 340 °, 350 °) and the tiltable angle of the tilt axis K (for example, − 60 °, −50 °,..., −20 °, −10 °, 0 °, 10 °, 20 °,..., 50 °, 60 °) (for example, 36 × 12 ways) The angle difference is obtained for the tool direction by each combination.

Thus, the angle difference calculation unit 15 totals the grinding length for each angle difference when the tool direction is changed in the Z-axis direction (that is, the tool 2 is in an upright state along the Z-axis direction). The grinding length when the tool direction is inclined in the XZ axis direction and the YZ axis direction is totaled for each tool direction for each angle difference.
For example, in the case of the tool direction (1, 0, 1), the grinding length is shown for each angle difference as shown in the graph of FIG.
In the case of the tool direction (0, 1, 1), the grinding length is indicated for each angle difference as shown in the graph of FIG.

Next, the tool angle setting unit 16 has an angle difference (for example, within 30 °) when a non-recommended range (referred to as an NG range) that has a low grinding effect and is prone to uneven wear is in contact with the workpiece W. In the range), the tool direction at which the total grinding length is the shortest is set as the tool angle.
Then, the machining calculation unit 17 performs machining simulation using the tool 2 fixed to the tool angle, and creates machining control data including tool angle control data and machined workpiece shape data (FIG. 5). Step S6).
In other words, in this step S5, machining control data is generated that can reduce the uneven wear of the tool tip and grind the widest possible area of the workpiece W with one tool angle.

The NG range (for example, an angle difference of 30 ° or less) is a preset range. As an example of the tool direction in which the total grinding length in the NG range is the shortest, the tool shown in the graph of FIG. The direction (1, 0, 1) can be mentioned.
On the other hand, as an example of the tool direction in which the total grinding length in the NG range becomes longer, the tool direction (0, 1, 1) shown in the graph of FIG. 9 can be given.

  Here, the NG range will be described in more detail. As shown in the sectional view of the tool tip 2a in FIG. 10, the region including the tool tip vertex P defined by a predetermined arc angle centered on the hemispherical center C is NG. It is a range. This NG range is largely related to the peripheral speed of the hemispherical tool tip. That is, the tool tip vertex P has a peripheral speed of 0 m / min, and the peripheral speed increases as the arc angle around the hemispherical center C increases. If machining is performed at a portion where the peripheral speed is low, such as the tool tip apex P, the number of times one grindstone (diamond grindstone 5 in FIG. 2) hits the surface to be machined increases and wear tends to occur.

The limit angle that defines this NG range is limθ, the tool diameter is φ, the spindle speed of the grindstone tool 2 is R (1 / min), and the grinding speed (peripheral speed) at which wear easily occurs is 600 m / min or less. Then, the relational expression shown in Expression (1) is defined.
π · φ · sinθlim · R = 600 (1)
Based on equation (1), θlim is defined as in equation (2).
θlim = sin ⁻¹ {600 / π · φ · R} (2)

  According to the machining control data formed in step S6 of FIG. 5, it is possible to machine most or all of the workpiece surface by setting one tool angle. , It is determined whether there is an unmachined surface that could not be machined with the tool angle set in the machining control data, and if there is an unmachined surface, the machined surface direction of the unmachined surface is calculated. The processing from step S2 to step S4 is continued.

For example, as shown in FIG. 11 (a), when the grindstone tool 2 is inclined at a predetermined angle, the tip 2a is almost always applied to the workpiece surface of the workpiece W for grinding. Can do. However, in the state of the same tool angle, the tool 2 may interfere with the work surface Wa of the workpiece W as shown in FIG.
When such an unprocessed surface Wa (indicated by cross-hatching in FIG. 6) exists, the control unit 11 calculates a processed surface direction only for the surface, and performs the processing from step S4 to step S6. Do.

  Then, the tool angle setting unit 16 has a tool direction (for example, (−1, 1) in which the total grinding length is the shortest in the angle difference (for example, a range within 30 °) when the NG range of the grindstone tool 2 hits the workpiece W. , 0) direction) is set as the tool angle, and the machining calculation unit 17 performs machining simulation at the tool angle and creates second machining control data.

Then, in step S7, the control unit 11 determines whether there is an unprocessed surface that could not be processed with the tool angle set in the second processing control data, and if there is no unprocessed surface, End the process.
Or when there exists an unprocessed surface, it returns to step S4 again and it processes (it repeats step S4 to step S7 until there is no unprocessed surface).

As described above, according to the embodiment of the present invention, the work surface of the work W as wide as possible is ground by one tool angle set so that the tool tip portion where the tool is hard to wear is in contact with the work. The remaining unmachined surface that can be machined is processed with a different tool angle that is set so that the tool tip where the tool is less likely to wear is in contact with the workpiece. The surface can be finished with high accuracy.
That is, the entire processing surface can be processed with high accuracy without changing the tool angle during tool feeding.

In the above-described embodiment, the tip 2a of the grindstone tool 2 is hemispherical, but it may be a ball end tip 2a that is more nearly spherical.
Moreover, although the grindstone of the grindstone tool 2 is the diamond grindstone 5, it can be applied not only to the diamond grindstone 5 but also to a grindstone tool using a grindstone formed of other materials.

DESCRIPTION OF SYMBOLS 1 Machine tool 2 Grinding wheel tool 2a Tool tip 3 Base material 4 Nickel layer 5 Diamond grinding wheel 10 Finishing processing control device 11 Control part 12 Tool data acquisition part 13 Work data acquisition part 14 Work surface direction calculation part 15 Angle difference calculation part 16 Tool angle Setting part 17 Machining operation part W Workpiece

Claims (8)

A finishing control device for grinding a work surface of a work by rotating a tip spherical grindstone tool mounted on a 5-axis numerical operation machine tool around its axis, and finishing the work,
A work surface direction calculation unit that divides a work surface of the workpiece into a plurality of work surfaces and calculates a work surface direction orthogonal to the surface for each work surface;
A plurality of tool directions that can be set by the grindstone tool, an angle difference calculation unit that calculates an angle difference between each tool direction and the machining surface direction, and calculates a correlation between the angle difference and the grinding length for each tool direction; ,
A tool angle setting unit for setting the tool direction to the tool direction with the shortest total grinding length in the range of the angle difference that defines the preset deprecated range of the tool tip;
A machining calculation unit that performs machining simulation with the set tool angle and creates machining control data; and
A finishing process control device comprising: A control unit for determining the presence or absence of an unprocessed surface in the workpiece;
When the control unit determines that there is an unprocessed surface,
The machining surface direction calculation unit calculates a machining surface direction orthogonal to the surface for the unmachined surface,
The angle difference calculation unit calculates a plurality of tool directions that can be set by the grindstone tool, an angle difference between each tool direction and the machining surface direction, and correlates the angle difference and the grinding length for each tool direction. Calculate
The tool angle setting unit sets a tool angle that has the shortest total grinding length as a tool angle within a range of angle differences that defines a preset non-recommended range of the tool tip,
The finishing process control device according to claim 1, wherein the process calculation unit performs a process simulation using the tool angle set by the tool angle setting unit and generates second process control data. The angle difference calculator is
Calculate the angle difference between the tool direction and the machining surface direction when the tool direction is the Z-axis direction among the three XYZ orthogonal axes, and calculate the correlation between the angle difference and the grinding length,
The tool direction is changed by a predetermined angle in the XZ axis direction and the YZ axis direction, and a correlation between the angle difference and the grinding length is calculated for each tool direction. Finishing processing control device described in 1.   The finishing control device according to any one of claims 1 to 3, wherein the non-recommended range of the tool tip is a region including a tip apex located on a rotation axis of the grindstone tool. A finishing control program for grinding a work surface of a workpiece by rotating a tip-shaped spherical grindstone tool mounted on a 5-axis numerical operation machine tool around its axis, and finishing the workpiece,
On the computer,
Dividing the work surface of the workpiece into a plurality of work surfaces, and calculating a work surface direction orthogonal to the surface for each work surface;
A plurality of tool directions that can be set by the grindstone tool, calculating an angular difference between each tool direction and the machining surface direction, and calculating a correlation between the angular difference and the grinding length for each tool direction;
A step of setting a tool direction with the shortest total grinding length as a tool angle in a range of angle difference that defines a preset non-recommended range of the tool tip;
Performing a machining simulation with the set tool angle and creating machining control data;
A finishing machining control program characterized in that After performing a machining simulation with the set tool angle and creating machining control data,
On the computer,
Determining whether there is an unprocessed surface;
If there is an unprocessed surface, calculating a processed surface direction orthogonal to the surface for the unprocessed surface; and
A plurality of tool directions that can be set by the grindstone tool, calculating an angular difference between each tool direction and the machining surface direction, and calculating a correlation between the angular difference and the grinding length for each tool direction;
A step of setting a tool direction with the shortest total grinding length as a tool angle in a range of angle difference that defines a preset non-recommended range of the tool tip;
Performing a machining simulation with the set tool angle and creating second machining control data;
The finishing machining control program according to claim 5, wherein the finishing machining control program is executed. A step of calculating a plurality of tool directions that can be set by the grindstone tool, an angle difference between each tool direction and the machining surface direction, and calculating a correlation between the angle difference and the grinding length for each tool direction,
Calculating the angle difference between the tool direction and the machining surface direction when the tool direction is the XYZ orthogonal three axes, and calculating the correlation between the angle difference and the grinding length;
Changing the tool direction by a predetermined angle in the XZ axis direction and the YZ axis direction, and calculating a correlation between the angle difference and the grinding length for each tool direction;
The finishing machining control program according to claim 5 or 6, characterized by comprising:   8. The finishing machining control program according to claim 5, wherein the non-recommended range of the tool tip is a region including a tip apex located on a rotation axis of the grindstone tool.

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