KR20000024604A - Automatic setting of a machine and work origin point of numerically controlled Z axis in proximity way - Google Patents

Abstract

PURPOSE: An apparatus for automatically setting mechanical zero point of z-shaft is provided to automatically set zero point of z shaft simply without any manipulation of users by including two sensors and value control software. CONSTITUTION: An apparatus for automatically setting mechanical zero point of z-shaft includes a sensor(2a) mounted on a bottom surface of a pole supporting z shaft for automatically sensing an end of a workpiece attached to z shaft without any contact, an optical or proximity sensor(1) mounted on a position of a machine attached to z shaft for automatically sensing a predetermined distance on a machining table, and a controller(1-1) having a control software, so that z shaft is lowered when the sensor(1) senses an upper surface of a machining table, the lowering pulse value is stored when the sensor(2a) senses the end of the workpiece and the control software sets a zero point by offsetting previously stored height of the sensor(2a) with the input value.

Description

Automatic setting of a machine and work origin point of numerically controlled Z axis in proximity way}

In simple CNC machine tools, Cartesian coordinate robots or computer-controlled engravers, if the tool is equipped with a numerically controlled Z-axis, the tool must be replaced or turned on to start work. Zero point should be set for each Z axis. That is, the position of the mechanical origin coincides with the coordinate calculation reference point in the controller. At this time, limit switch is installed at one end of X, Y axis and contact or non-contact sensor or switch is installed at other end of axis to set zero point based on this point. X, Y are zero because the length of axis is always constant. It is common and common for the configuration process to be automatic. On the other hand, since a tool having a fixed length is attached to the Z axis, the total length of the Z axis is not constant depending on the tool. Therefore, in setting the zero point of the Z axis, the zero point of the Z axis is set when the end of the tool descends and comes into contact with the machining table by manual operation while watching the tool tip with the naked eye, or it is set by recognizing it as a contact sensor. The machining origin of the shaft is generally set by manually inputting the height of the workpiece to the controller or visually checking the descent of the tool and approaching the workpiece.

However, this method has the following problems.

First, the manual operation and the contact type by visual confirmation are difficult because it is necessary to stop the operation by setting the zero point at the point where the tip of the tool is in contact with the upper surface of the work table while performing the descent operation of the Z axis. Productivity falls.

Second, the above method is inferior in accuracy due to an error in capturing a contact point.

Third, the workpiece is fixed to the table, and the operation is cumbersome and the productivity decreases because the Z axis is to be visually lowered and the contact is visually discriminated until the tip of the tool contacts the upper surface of the workpiece.

Fourth, in the case of inputting the height of the workpiece into the controller for setting the processing origin of the workpiece, there is a need to additionally input the height of the workpiece into the controller every time after the fixing work of the workpiece is completed. If the attachment for fastening enters, additional work is required to re-measure the height of the workpiece.

The present invention solves the above-mentioned problems, the object of the present invention is to enable the zero-axis of the Z axis easily and automatically without any intervention by the operator before starting the first operation after changing the tool or power.

Another object of the present invention is to automatically fix the work piece to the worktable without the cumbersome operation for the operator to grasp the Z-axis machining point, so that the productivity of the worker can be increased and the error that can occur in manual setting can be eliminated. .

Another object of the present invention is to easily apply to the existing processing machine by simply utilizing the existing numerical control software and attaching only two sensors to achieve a non-contact automatic setting at a minimum cost.

Figure 1 is a sensor and a signal connection line and a control device constituting the automatic setting device according to the present invention

2 is a diagram showing the positions of two sensors constituting the present invention;

3 is a view showing that the sensor detects the processed upper surface of the workpiece when the workpiece is fixed to the machining table;

4 is a performance diagram for setting zero point

5 is a performance diagram for setting the machining origin

The present invention automatically sets the mechanical zero and the machining origin of the Z axis in a non-contact machine in a machine of a numerically controlled Z axis. First, in FIG. 2, the tool is placed at a specific position for setting the zero point of the Z axis on the upper surface of the machining table (FIGS. Attach an optical sensor or a non-contact proximity sensor (sensor 2A, Fig. 2-2) to detect the tip, or face the machining table to a pillar supporting the Z axis (Fig. 2-5). Attach an optical sensor or non-contact proximity sensor (sensor 2B, Figure 2-3) to detect the tool tip on the Z axis. On the Z-axis, an optical sensor or a proximity sensor (sensor 1, Fig. 2-1) can be attached to the tool to detect the presence of an object in a specific direction and distance. And by configuring the signal of both sensors to the signal line (Fig. 1-6) connecting to the Z-axis controller (controller: Fig. 1-1), it is a control software of the controller (controller), it is possible to automatically set the zero point of the Z axis without special equipment There is a characteristic.

The process of setting the mechanical zero and machining origin of the Z axis according to the present invention is as follows. For convenience of explanation, the case of the sensor 2A (Fig. 2-2) attached to the processing table is taken as an example. However, the same logic applies to sensor 2B (Fig. 2-5) in the column.

When the zeroing process starts, the zeroing of X and Y is automatically performed. And Z-axis is moved to the coordinate where Z-axis can set zero point based on the zero point of X, Y-axis. Then, if the control software detects whether the machining table is detected on the sensor 1 (Fig. 1-7) attached to the Z axis as in the process of Fig. 4-3 (Fig. 4-3), the Z axis is lowered. Since the pulse value cannot be counted correctly, the control software of the controller (controller) in Fig. 1-1 sends a pulse to the drive (Fig. 1-2) to drive the motor (Fig. 1-3) and the machine attached to the Z axis. (Spindle motor, etc., Figs. 1-4) are raised to the line where the machining table is not detected. Then, the falling pulse count is set to "0", and then the Z axis is lowered in the same manner (Fig. 4-4). The sensing distance of sensor 1 (Fig. 1-7) is sufficiently longer than the length of the tool (Fig. 1-9) and the height of the sensor (Fig. 1-8). Is detected. Therefore, when the detection signal comes to the sensor 1 (FIG. 1-7), the controller (FIG. 1-1) continues to descend the Z axis while counting and storing the pulse which lowers the Z axis. When the end of the tool (Fig. 1-9) is detected by the sensor 2A (Fig. 1-8), the Z axis stops descending immediately and converts the falling pulse value into distance and saves it (Fig. 4-8). . This distance becomes the distance between the tool tip and the sensor 2A (Fig. 1-8) at the time when the machining table (Fig. 1-5) is detected by the sensor 1 (Fig. 1-7). Since the height of the sensor 2A (Fig. 1-8) previously input is stored in the control software, the mechanical zero of the Z-axis is set to zero by offsetting the input value (Fig. 4-10). In addition, the distance between the tool tip (Fig. 1-9) and the upper surface of the machining table (Fig. 4-8) is also calculated at the time when sensor 1 (Fig. 1-7) detects the machining table (Fig. 1-5). This distance is stored by the control software and used to automatically set the machining origin of the workpiece afterwards.

When the workpiece (Fig. 3-1) is fixed to the machining table (Fig. 3-2) in Fig. 3, the control software enables the sensor 1 (Fig. 3-3) to detect the Z axis as a coordinate for setting the machining origin of the workpiece. Move to this location (Fig. 5-2). Then, when the workpiece is detected by the sensor 1 (Fig. 3-3), the Z axis is gradually raised (Fig. 5-3). When the detection signal disappears in the sensor 1 (Fig. 3-3), the Z-axis is gradually lowered again (Fig. 5-5) and stopped at the time when the sensor 1 (Fig. 3-3) is detected. At the Z-axis position at that time, offsetting the distance of the already stored value (Fig. 4-8) sets the machining origin of the Z-axis relative to the workpiece.

In addition, even if the height of the workpiece is not constant and the Z-axis machining origin should be set at different coordinates of the Z-axis, the control software moves the focus of the sensor 1 (Fig. 3-3) to the coordinates of the different Z-axis. The Z-axis is lowered until the surface of the workpiece is sensed on the sensor 1 (Fig. 3-3), and at the moment when the sensor 1 (Fig. 3-3) is sensed, it is offset to the value memorized in the same manner as above. Set.

As described so far, according to the present invention, in setting the zero point of the Z-axis that is controlled numerically and the machining origin (reference point) of the workpiece, two sensors having characteristics are provided and the characteristics of numerical control are utilized. Simply set the zero point of the Z axis, the height of the workpiece and the machining origin non-contact.

This saves the time and effort required to set a new zero point on the Z axis as the tool lengths are different each time the tool is changed, and to set the machining point each time a workpiece with a different height is fixed to the machining table. The trouble of inputting by measuring the height of a workpiece | work or a workpiece | work performed for this purpose or a workpiece | work is mentioned.

Also, unlike the current method of mounting the device at a high cost to implement the automatic setting, it can be implemented by the simple change of the numerical control software and the installation of two sensors, so the convenience of the automatic setting is easily maintained. It can be realized.

Claims (2)

In the Cartesian robot, simple CNC machine tool, computer-controlled engraver, etc., the device automatically sets the mechanical zero point for the numerically controlled Z axis and automatically sets the machining origin of the Z axis for the workpiece. Using the sensor, one is installed on a specific area of the machining table or on the bottom of the pillar supporting the Z axis, so that the tip of the tool attached to the Z axis is detected without contact, and the other is the position of the machine attached to the Z axis. Non-contact automatic control of the Z-axis numerically controlled so as to set the origin of the Z-axis while counting the falling pulse for feeding the Z-axis between the sections detected by both sensors by detecting the upper surface of the machining table at a constant distance Home position setting device. According to claim 1, wherein the control software of the Z-axis receives the detection signal from the sensor attached to the Z-axis in the process of performing the mechanical zero setting of the Z-axis, and is attached to the processing table specific area or the bottom of the pillar supporting the Z-axis The falling pulse value until the end of the tool receives a sensed signal from the sensor, and the value equal to the height of the sensor attached to the machining table or column, is taken as an offset value, and the sensor attached to the Z axis Non-contact machining origin automatic setting device for numerical control Z-axis, characterized in that the machining origin is set immediately when the upper surface is detected.