JPH04322948A - Spindle zero position setter - Google Patents

Abstract

PURPOSE:To provide a spindle zero position setter that sets a zero position in the spindle direction of relative coordinates of a machine tool for three- dimensional machining by means of numerical control. CONSTITUTION:On the absolute coordinate inherent in a machine tool, a spindle down signal is given to a spindle head 8 fitted with a graving cutter 7a and retracted upward, whereby this spindle head 8 is lowered, while a descent of the spindle head 8 is stopped by giving the spindle down signal to the spindle head 8 at a time when a tip 7a' of the graving cutter 7a has come into contact with a sensor 9 set in a state of contacting with a workpiece, for example, a graving surface 6a of seal material 6, and a coordinate value in the spindle direction at a point, adding height of the sensor 9 in the down direction of a spindle further from this stop point, is set to a zero position of the spindle direction at the relative coordinate. Therefore, since a downward motion of the spindle is surely stopped at a moment the tip of the cutter is reached to the sensor, the zero position in the spindle direction of the relative coordinate is set at high positional accuracy and, what is more, the zero position can be set in a short time.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle origin setting device for setting the relative coordinates of a machine tool that performs three-dimensional machining by numerical control.

0002

[Prior Art] A machine tool that performs three-dimensional machining through numerical control using a computer has machine coordinates that are absolute coordinates unique to the machine tool, and machining is performed on these machine coordinates. In order to efficiently cut a workpiece, workpiece coordinates are often set in a program as relative coordinates according to each workpiece, and machining operations are often performed on these workpiece coordinates.

For example, when setting the workpiece coordinates of a seal engraving machine 31 as shown in FIG. It is done as follows.

First, the main shaft 33 is retracted upward as shown by the solid line in FIG. A gauge 38 having a thickness of tmm is placed on the engraving surface 37a. Next, the main shaft 33 is gradually lowered by manual operation, and it is visually confirmed that the tip 32' of the engraving cutter 32 has reached the surface 38a of the gauge 38, as shown by the dotted line in FIG. At this point, the main shaft 33 is stopped by manual operation. Since the engraving surface 37a of the stamp material 37 is located below this stopping point by the gauge thickness tmm, the workpiece coordinate origin is determined by setting the offset value from the stopping point in the direction of the spindle 33 as tmm, and this workpiece coordinate is used as the reference point. The stamp material 37 is engraved based on a predetermined program.

[0005]

[Problem to be Solved by the Invention] When setting the origin using the above-mentioned gauge, if the descent of the spindle is stopped before the tip of the engraving cutter reaches the gauge surface, the offset value becomes smaller than the thickness t of the gauge. Since the workpiece coordinate origin is set too upward, the engraving on the stamp material may become shallower than originally intended, or the tip of the engraving cutter may not reach the engraving surface of the stamp material. Furthermore, if the timing to stop the descent of the main shaft is missed and the stopping operation is delayed, the engraving cutter may come into contact with the gauge and the tip of the engraving cutter may be damaged. Furthermore, even if the engraving cutter cuts the gauge without being damaged, the offset value will be smaller than the thickness t of the gauge.
The workpiece coordinate origin is set too far downward, resulting in the engraving on the stamp material being deeper than it should be. Furthermore, differences in the angle at which the tip of the engraving cutter is viewed also cause a difference in the stopping point of the tip of the engraving cutter. As described above, setting the origin by visual inspection and manual operation is a task that requires extremely skill, and the set origin differs even among experts, resulting in low positional accuracy of the set origin. In addition,
In order to determine the stopping point, it is necessary to stare at the tip of the very thin engraving cutter, and it is inevitable that the positional accuracy of the set origin will deteriorate due to operator fatigue. As aforementioned,
Conventional origin setting devices have problems in position accuracy.

[0006] Furthermore, the work of setting the origin requires time even for an experienced person, and there are problems in terms of work efficiency.

[0007]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides a spindle origin setting device for setting the relative coordinates of a machine tool that performs three-dimensional machining by numerical control. A shaft body installed vertically in a vise that fixes the workpiece is provided so as to be movable above and to the sides of the processing surface of the workpiece, and is attached to the main shaft in contact with the processing surface of the workpiece. A sensor that detects that the tip of the cutter has contacted, on absolute coordinates, lowers the spindle by giving a spindle lowering signal to the spindle, and at the time it detects that the tip of the cutter has contacted the sensor. A spindle lowering control means for stopping the lowering of the spindle by stopping applying a spindle lowering signal to the spindle, and a spindle direction at a point where the height of the sensor is added to the descending direction of the spindle from the stopping point of the spindle. The present invention provides a main axis origin setting device characterized by comprising a calculation means that calculates a coordinate value on the absolute coordinates as the origin in the main axis direction in the relative coordinates.

[0008]

[Operation] When setting the origin of the spindle using the spindle origin setting device of the present invention, the spindle is moved on the machining surface of the workpiece and to the sides on the shaft that is erected in the vise that fixes the workpiece. The processing is performed with the sensor provided in contact with the processing surface of the workpiece. First, on the absolute coordinates unique to the machine tool, the spindle with the cutter attached and retracted upward is gradually lowered by applying a spindle lowering signal, and the cutter comes into contact with the sensor on the processing surface of the workpiece. As a result, the application of the spindle lowering signal to the spindle is stopped, and the lowering of the spindle is stopped. Next, a coordinate value on the absolute coordinates in the main axis direction at a point obtained by adding the height of the sensor to the downward direction of the main axis from this stopping point is set as the origin in the main axis direction in the relative coordinates by calculation. In this way, the origin can be set in relative coordinates with positional accuracy equivalent to the movement accuracy of moving the main shaft in the vertical direction.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, specific embodiments of the spindle origin setting device according to the present invention will be described with reference to the drawings.

FIG. 1 shows a numerically controlled seal engraving machine 1 equipped with a spindle origin setting device according to the present invention. In this stamp engraving machine 1, a stamp material 6 is clamped by a chuck 5 of a vise 4 fixed on a table 3 which is located on a base 2 and moves back and forth and left and right, and a main shaft drive motor rotates at the tip for rough cutting and finishing. A spindle head 8 to which two engraving cutters 7a and 7b of different thicknesses are attached moves up and down, and characters are engraved on the stamp material 6 by a combination of movements in these three directions. Further, as shown in FIG. 2, a sensor 9 is provided on the shaft 16 erected on the vice 4 to detect when the tips of the engraving cutters 7a, 7b come into contact with each other. This sensor 9 is located on the engraving surface 6a of the stamp material 6 (work coordinate setting position) as shown by the solid line in FIG. 2 when setting the workpiece coordinates, and during engraving work as shown by the dotted line in FIG. Rotate the stamp material 6
Evacuate to the side evacuation position. Note that this sensor 9 is moved by manual operation.

The above-mentioned vertical movement of the spindle head 8 and left/right movement of the table 3 are performed by a spindle head vertical drive motor 10 connected to the spindle head 8, etc., and a table vertical movement, as shown in FIG. drive motor 11,
The movement in each direction is performed by the table horizontal drive motor 12, and the CPU 13 sends signals based on a predetermined program to the spindle head vertical drive motor 10, table vertical drive motor 11, and table horizontal drive motor 12 via the input/output port 14. Controlled by giving. Furthermore, whether or not the engraving cutters 7a, 7b are in contact with the sensor 9, in other words, the engraving cutters 7a, 7b and the sensor 9 are checked.
A sensor state signal indicating whether or not the power is on is provided to the CPU 13 via the input/output port 14.

Further, when setting the work coordinate origin of the spindle, the spindle head 8 is connected to the CP via the input/output port 14.
The spindle head 8 is lowered by applying a spindle lowering signal from U13 to the spindle head vertical drive motor 10, and the lowering of the spindle head 8 is stopped by stopping the application of the spindle lowering signal in accordance with the content of the sensor status signal.

By the way, as shown in FIG. 4, the machine coordinates, which are the absolute coordinates unique to this seal engraving machine 1, are
Y, Z), the vertical and horizontal direction in which table 3 moves is X
, Y, and the main axis direction according to the present invention is represented as Z. The origin in machine coordinates is (0, 0, 0)
Therefore, when the spindle head 8 is at the origin, in other words, at the top end as shown in FIG. 4, the coordinate value Z representing the spindle head position is "0". On such machine coordinates, relative coordinates of workpiece coordinates (X1', Y1', Z1') and (X
2', Y2', Z2') are set, and the origin of these workpiece coordinates is the coordinate value (X01', Y01') in the machine coordinate.
, Z01') and (X02', Y02', Z02')
It is expressed as Note that in the coordinate system of this example, 1
mm is set to 100 coordinate units.

Next, a method for setting the workpiece coordinate origin using the spindle origin setting device according to the present invention will be described.
This will be explained using an example. First, the spindle head 8 is retracted to the uppermost position, which is the origin in the machine coordinates, as shown by the solid line in FIG. The sandwiched stamp material 6 is positioned directly below the engraving cutter 7a. Next, the sensor 9 that was in the retracted position is rotated and moved to the workpiece coordinate setting position on the engraving surface 6a of the stamp material 6, and
After confirming that a is in contact with the sensor 9, the preparation work for setting the workpiece coordinates is completed.

Next, the CPU 13 is activated by a predetermined program.
gives a spindle lowering signal to the spindle head vertical drive motor 10 via the input/output port 14 to gradually lower the spindle head 8, and a sensor status signal is input from the sensor 9 to the CPU 13 via the input/output port 14. . The tip 7 of the engraving cutter 7a is shown by the dotted line in FIG.
When a' reaches the surface 9a of the sensor 9, it is determined by the sensor status signal that the engraving cutter 7a and the sensor 9 are energized, and the spindle head vertical drive motor 10
Application of the spindle lowering signal to the spindle head 8 is stopped, and the spindle head 8 is stopped. The coordinate value at the point where the thickness tmm of the sensor is added from this stopping point is calculated, and this calculated coordinate value is set in the memory 15 of the CPU 13 as the origin Z01' on the workpiece coordinate, and is moved from the workpiece coordinate origin in the main axis direction. The stamp material 6 is engraved based on a predetermined program by setting the offset value to tmm (coordinate value: t×100).

FIG. 6 is a flowchart illustrating the operation of the spindle head 8 regarding the above-mentioned workpiece coordinate origin setting based on the flow of the program, and each step is explained in detail as follows. be.

A: Move the spindle head 8 to the uppermost position, in other words, to the machine coordinate origin. When the spindle head 8 is at the machine coordinate origin, the spindle head coordinate value Z is "0". B: CPU from the seal engraving machine 1 via the input/output port 14
A sensor status signal is input to 13. C: Check the sensor status signal, and if the tip 7a' of the engraving cutter 7a is not in contact with the sensor 9, proceed to step D, and if the tip 7a' of the engraving cutter 7a is in contact with the sensor 9 and is energized. If so, proceed to step F. D: A spindle lowering signal is output from the CPU 13 to the seal engraving machine 1 via the input/output port 14, and the spindle head 8 is lowered by an amount equivalent to one unit, 0.01 mm in this embodiment. E: The spindle head coordinate value Z is increased by 1 unit and the process returns to step B. F: A coordinate value obtained by adding the value obtained by converting the thickness of the sensor to a coordinate value to the spindle head coordinate value Z is set as the workpiece coordinate origin Z01', and the series of processes ends. In this way, the origin of the engraving cutter 7a in the main axis direction in the workpiece coordinates is set.

Next, for the other engraving cutter 7b, the origin Z02' in the main axis direction in the work coordinates is set in the same manner as described above, and the 2nd point for the stamp material 6 is set.
One workpiece coordinate is set. If the origin setting device for the spindle as described above is used, the descent of the spindle will be reliably stopped the moment the tip of the engraving cutter reaches the sensor, so the accuracy of the vertical movement of the spindle (in this example, 0. 01mm)
The origin is automatically set, and the set workpiece coordinates have extremely high positional accuracy. Further, the time required for setting the origin may be short.

In this embodiment, the sensor 9 was moved between the workpiece coordinate setting position and the retreat position by manual operation, but the sensor 9 may be equipped with, for example, a drive motor to
The sensor 9 may be moved by giving a predetermined signal to the drive motor from U13. In this case, by adding content related to the movement of the sensor 9 to the above-mentioned program, the workpiece coordinate origin can be completely set automatically by simply setting the stamp material 6 in the vise 4.

[0020]

[Effects of the Invention] According to the spindle origin setting device of the present invention,
Not only can you set the origin of workpiece coordinates with high positional accuracy, but you can also automatically move the spindle up and down according to the program, which prevents you from lowering the spindle too far and damaging the cutter tip, which was done by visual inspection in the past. do not have. Furthermore, the time required to set the origin is dramatically reduced, improving work efficiency.

[Brief explanation of drawings]

FIG. 1 is an external perspective view of a seal engraving machine equipped with a spindle origin setting device of the present invention.

FIG. 2 is an enlarged view of the main parts of the seal engraving machine.

FIG. 3 is an electrical circuit diagram of the sensor and a block diagram showing the main shaft and table drive section.

FIG. 4 is a drawing showing machine coordinates of a seal engraving machine.

FIG. 5 is an explanatory diagram for explaining an origin setting method using the spindle origin setting device of the present invention.

FIG. 6 is a flowchart of a program for setting the origin using the spindle origin setting device of the present invention.

FIG. 7 is an explanatory diagram for explaining a conventional spindle origin setting device.

[Explanation of symbols]

1, 31 Seal engraving machine 2 Base 3, 34 table 4, 35 Vice 5, 36 Chuck 6, 37 Stamp material 6a, 37a　　Engraving surface 7a, 7b, 32 Engraving cutter 7a’ Engraving cutter tip 8 Spindle head 9 Sensor 9a Sensor surface 10 Main shaft vertical drive motor 11 Table vertical movement motor 12 Table lateral movement motor 13 CPU 14 Input/output port 15 Memory 16 Shaft body 33 Main shaft 38 gauge 38a Gauge surface

Claims (1)

[Claims] Claim 1: In a spindle origin setting device that sets the relative coordinates of a machine tool that performs three-dimensional machining by numerical control, a shaft body that is erected in a vise that fixes a workpiece is used to control the machining of the workpiece. A sensor that is movable on the surface and laterally and detects when the tip of the cutter attached to the main shaft comes into contact with the processing surface of the workpiece; The main shaft is lowered by applying a main shaft lowering signal to the main shaft, and when it is detected that the tip of the cutter contacts the sensor, the lowering of the main shaft is stopped by stopping the application of the main shaft lowering signal to the main shaft. The origin point in the spindle direction in the relative coordinates is calculated by calculating the coordinate value on the absolute coordinates in the spindle direction at the point where the height of the sensor is added to the descending direction of the spindle from the stop point of the spindle and the spindle descent control means. What is claimed is: 1. A spindle origin setting device, characterized in that it is equipped with a calculation means that calculates the following: