JPS5993256A - Positioning of machine tool - Google Patents

Abstract

PURPOSE:To permit positioning with high accuracy in a short time, preventing a working tool from being broken, by setting a positioning tool which is easily deformed by an external force and restored when the external force is removed, in opposed state to an article to be worked, permitting replacement with the working tool. CONSTITUTION:A positioning tool 62 which is easily deformed by an external force and restored when the external force is removed is installed onto a tool replacement apparatus 58, and a tool 62 is brought close to an article 56 to be worked, at high speed, and when a contact detection apparatus 60 detects contact, said tool 62 is stopped by the instruction of an NC apparatus 24, and each position on the X and Y axes is detected by detectors 22 and 38 respectively, and input into the NC apparatus 24. Then, replacement to a working tool 44 is performed by the tool replacement apparatus 58, and then positioning is performed stepwise from high speed to low speed to a close position, taking account of the size and safety of the tool 44, on the basis of the positioning data by the tool 62 which are memorized in the NC apparatus 24, and then contact positioning is performed at ultralow speed. Therefore, the breakage of the working tool due to the collision with the article to be worked is prevented, and the positioning time can be reduced by a large margin.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for positioning a machine tool, particularly a workpiece fixed on an X-Y cross table.

This invention relates to a method for positioning a machine tool that performs cutting using a tool attached to a spindle according to instructions from the device.

First, the outline and main points of a machine tool to which the method of the present invention is applied will be explained with reference to FIG. In FIG. 1, the X-Y cross table has an X-axis table 12 movable in the X-axis direction stacked on a Y-axis table 10 that moves in the Y-axis direction, and the X-axis table 12 is attached to one ball screw 14. It is driven in the X-axis direction by the rotation of the directly connected X-axis motor 16. This X
The shaft motor 16 is connected to a drive amplifier 18 and a positioning control circuit 20.
The movement of the X-axis motor 16 is detected by a rotation angle detector (rotary encoder) 22 and fed back to the positioning control circuit 20, and the N
The X-axis table 12 is controlled to a desired position by the command ξ from the oscilloscope 24.

The information source of the command pulse is programmed in advance into the perforated tape 26 loaded into the No. device 24. On the other hand, the same applies to the Y-axis table 10, and the Y-axis is rotated by the rotation of the Y-axis motor 32 directly connected to the ball screw 30.
Driven in the axial direction.

Like the X-axis motor 16, the movement of this Y-axis motor 32 is controlled by a drive amplifier 34 and a positioning control circuit 36, and the movement of this Y-axis motor 32 is detected by a rotation angle detector 38 to control the above-mentioned fat determination. By being fed into circuit 36 and the command pulse from NO device β, 24 supplied to the positioning control circuit, Y
The axis table 1o is controlled to a desired position.

A tool 44 is attached to the tip of the main shaft 40 with an insulator 42 interposed therebetween. This main shaft 4o moves up and down, that is, in the Z-axis direction, by rotation of a ball screw 48 driven by a Z-axis motor 46. This two-axis motor 46 is connected to a positioning control circuit 50. The movement is determined by the drive amplifier 52, the rotation angle detector 54, and the No. device 24, thereby controlling the main shaft 4o to a desired position. Then, by combining the horizontal movement of the X-Y cross table in the X-Y axis direction and the vertical movement of the tool 44 in the Z111 direction, the workpiece 56 placed on the X-axis table 12 is cut into a desired shape. do. According to this cutting process, the tool 44 is exchanged with other tools 44a, 44b by a tool changer 58 to perform the desired cutting process.In the machine tool having the above-mentioned configuration, conventionally, the tool 44 and the target are In order to know the relative positional relationship with the workpiece 56, a contact detection device 60 is connected between the tool 44 and the workpiece 56, and a low DC voltage of approximately IOV is applied between the two. The X-Y cross table is moved by the 240 command, and the electric current flows from the contact between the tool 44 and the workpiece 56, i.e., through both, thereby detecting contact from the Ji detection device fli60 to the No device [24]. A signal is supplied to detect the relative position.

Next, the above-mentioned relative position detection or positioning process will be described in detail with reference to FIG. First, the X-axis table 12 is moved in the X-axis direction as shown in FIG.
When transmitted to the o device 24, the no device 24 immediately stops the movement of the X-axis table 12 and resets the X coordinate value to zero at the time of the stop. Next, as shown in FIG. 2(b), the tool 44 and workpiece 56 are similarly connected to the Y axis.
The Y coordinate value is reset to zero at the point of contact with. After positioning the tool 44 at the zero point of the X-Y coordinates as shown in FIG. 2(c), the known X-axis radius of the tool 44 is determined as shown in FIG. 2(d). The X-axis table 12 and the Y-axis table 10 are moved only outside the Y-axis radius. As a result, the center of the tool 44 is positioned at the reference point P of the workpiece 56, so if the angle X-Y coordinate value is reset to zero, the program tape 26 with the workpiece 560 reference point P as the starting point Can be processed.

Conventionally, as mentioned above, the relative position of the tool and workpiece is detected by electrical contact between the two, so unless the speed at which they make contact is extremely slow, the tool will not be machined due to over-run. There was a risk that the tool would be damaged by colliding with something. In particular, when outputting 4η with high precision at a value of 10 μm or less, the inertia of a normal machine is 1 to 2
This method has the disadvantage that it is necessary to send the X-Y crosstable at an extremely low speed of about π/min, 2 and that a long detection time is required.

The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to position a workpiece relative to a tool with high precision and in a short time without the risk of damaging the tool. Our goal is to provide a positioning method for machine tools.

To achieve the above object, the present invention provides a machine tool that cuts a workpiece fixed on an X-Y cross table using a machining tool attached to a spindle according to instructions from a No. The trap deforms and the external force disappears
A positioning tool that returns to its original shape is provided to face the workpiece in place of the processing tool, and the positioning tool is initially opposed to the workpiece, and both are moved at relatively high speeds. The machining tool is moved and contact positioning is performed to obtain positioning data, and then the machining tool is phantomed to the workpiece, and based on the positioning data, both the machining tool and the workpiece are moved from high speed to low speed repeatedly until they are extremely close together. The edge is moved reciprocally at a step speed, and the two are moved reciprocally at a very low speed until they come into contact to determine the position 1t4'.

Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

In order to carry out the method of the present invention, the tool changing device 58 of the machine tool shown in FIG.

Hereinafter, the positioning process according to the method of the present invention will be explained in detail with reference to FIG. In FIG. 3, (a) is the positioning tool 6
2 is a high speed F with respect to the workpiece 56.

(b) is a diagram showing a state in which the positioning tool 62 is approaching.
(C) is a diagram showing the moment when the positioning tool 6 comes into contact with the workpiece 56, and the table movement is stopped by the No. device 24 command after receiving the contact detection signal from the contact detection device 60, and the positioning tool 6
2 shows the table being deformed due to overrun, (d) shows the table returning in the opposite direction at low speed FL, and (e) shows the positioning tool 62 and workpiece 56. is in a non-contact state, the positioning tool returns to its original shape, and the movement of the table is stopped by a command from the No. device 24 which has received a non-contact detection signal from the contact detection device 60. Yes, the current value of the table is stored in the No device 24 in this state (e).

He did the above 1liII work on the X and Y axes,
As shown in FIG.
Based on the current values of the table in the state shown in FIG. 3(e) stored in 4, taking into account the sizes of the positioning tool 62 and the machining tool 44, and taking safety into account,
The machining tool 44 is positioned very close to the workpiece 56 at stepwise speeds from high speed FH to low speed FL, and then, as shown in FIG.
By performing welding positioning at L, the center of the processing tool 44 can be positioned at the reference point P of the workpiece 560 (see the valley in FIG. 2(d)).

In the above embodiment, positioning in the X-Y axes has been described, but the same effects as in the above embodiment can be achieved even when detecting the 411 pair positions of the tool and the workpiece in the Z-axis direction.

As described above, according to the present invention, the rope is easily deformed by external force, and the rope returns to its original shape. The processing tool is replaced with the processing tool, and using the above positioning data, both the processing tool and the workpiece are moved relatively close to each other at multiple speeds from slow to slow to position them, and then both are moved. Since the relative position is detected by moving at a relatively low speed, there is no risk of the machining tool colliding with the workpiece and breaking it, and the time required for overall positioning can be significantly shortened and the The effect of being able to perform positioning with precision is obtained.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of the entire machine tool to which the positioning method of the present invention is applied; Fig. 2 is an explanation of the conventional positioning process; It is a figure. In each figure, the turning parts have the same numbers, 10 is the Y-axis table, 12 is the X-axis table, 24 is the No. device, 40 is the main spindle, 44 is the processing tool, and 56 is the plate. The workpiece, 60 is a contact detection device, and 621 is a determination tool. Agent Patent attorney Kuzumachi II - (1 other person) Figure 2 Figure 3

Claims (1)

[Claims] (1) In a machine tool that cuts a workpiece fixed on an X, Y cross table using a machining tool attached to the spindle according to the instructions of a No. device, it is easily deformed by external force. A positioning tool that returns to its original shape is provided to face the workpiece in place of the processing tool, and initially the positioning tool is placed opposite the workpiece, and both are moved at a relatively high speed. to perform contact positioning to obtain positioning data, then place the machining tool to face the workpiece, and based on the positioning data, move both the machining tool and the workpiece extremely close (from high to low speed). A method for positioning a machine tool, characterized in that the machine tool is positioned by relatively moving the two at a multi-step speed and moving the two at a relatively low speed until they come into contact.