JPS61214946A - Return to original point - Google Patents

Abstract

PURPOSE:To cut labor cost, etc. by transferring a machine in the counter- original-point direction and allowing said machine to pass through the original point again when the machine stops, passing through a limit switch installed before the vicinity of the original point, and then carrying-out the return to the original point again, thus eliminating the manual operation. CONSTITUTION:When a machine reaches a limit switch LS during the shift in the direction of return to the original point by the ordinary operation such as JOG, MDI, return to the original point, etc., said limit switch LS is turned-ON, and said turned-ON state is input into a memory. After the memory is turned-ON, the machine which comes to the switch LS begins the shift towards the counter-original point through JOG. When ON/OFF operation is carried-out in the OFF-state where the machine passes through the switch LS, again, the return operation to the original point is carried-out from the position, and the ON-memory inside memory is reset, and the ON-state is continued until the switch LS is turned-ON again. Further, if the ON-state is not generated when the difference (alpha) between the present position and the position in JOG exceeds a certain value, JOG is suspended.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an automatic origin return method for an NC-controlled machine tool.

<Prior Art> In an NC-controlled machine tool, a return-to-origin operation is normally performed, and in this case, the return-to-origin operation is performed between the origin and a limit switch provided near the origin.

In the conventional method of returning to the home position, the limit switch near the home position is manually activated, that is, the switch is turned on.
The manual method involves moving the machine to the OFF position and then performing the home return operation.A limit switch for determining the direction of home return is provided in addition to the vicinity of the home position, and the limit switch for direction determination is turned on (on the limit switch) when performing home return. If the limit switch for direction determination is turned off (moves in the other direction on the limit switch), it will automatically move in the opposite direction to the origin using KJOG, and when this limit switch is turned off, One of the automatic methods was to perform a return to origin.

<Problems to be Solved by the Invention> However, in the above method, the former requires manual operation by the operator, and the latter requires additional limit switches for direction determination. The problem was that it didn't.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method for returning to the origin in which a control circuit is functionalized so that the return to origin is performed between the origin and a limit switch in the vicinity of the origin without manual operation by an operator or the addition of a limit switch for direction determination. shall be.

Means for Solving the Problems〉 The present invention achieves the above object by providing a limit switch at a position near the home of an NC-controlled machine tool, and when the machine stops exceeding this limit switch, the machine is moved away from the home. direction and cross the limit switch again,
After this, the machine returns to the origin again, and is characterized in that the machine is stopped when the movement in the direction opposite to the origin exceeds a certain amount.

<Example> The present invention will now be described in detail with reference to FIGS. 1 and 2. In FIGS. 1 and 2, information regarding the limit switch near the origin is input to the control circuit.

Here, normal operations (JOG, MDI.

While moving in the direction of returning to the origin (return to origin, etc.), when the upper button of the limit switch LS reaches the mechanical position, turn it on and input this on state into the memory.

If the machine returns to the home position during normal operation, the memory is turned on and the limit switch LS is reached (crossed) (shaded area in Figure 1), and the machine then starts moving in the opposite direction to the home position using JOG. do. Thereafter, when the limit switch LS is crossed again and the (off-)on-off operation is performed in the 9 state, the home return operation is performed from that position. in this case,
The ON memory in the memory is reset by the (off-)on-off operation of the limit switch L8, that is, when the limit switch LS is moved in a normal operation in the direction opposite to the origin. The pick and memory are turned on once the limit switch LS is turned on by movement toward the origin, and remains on until the limit switch L8 is turned on again by movement toward the origin.

The amount of movement or movement speed and movement time in the direction opposite to the origin are kept constant, and when JOG movement is completed or JO
Current position and JO before G movement (start of movement in the direction opposite to the origin)
If the difference in position during G (distance α between 1al and all in Figure 2) exceeds a certain value and the limit switch LS is still not turned on, there is an error in the limit switch LS itself or in the memory that is in the on state. The determination is made and the next JOG is started or the currently running JOG is stopped.

<Effects of the Invention> As explained above, according to the present invention, when a return to the origin is performed between the origin and the vicinity of the origin, the limit switch in the vicinity of the origin is automatically moved in the direction opposite to the origin at JOG speed. Off-) After turning on and off, the return to the origin is automatically performed, and in order to prevent continued movement in the direction opposite to the origin due to a failure of a limit switch near the origin, etc. Even if the amount exceeds a certain set value, if the limit switch near the origin is not turned on, the JOG movement is stopped, making manual JOG by one worker easier.
The G operation also has the same effect as when the LS for direction determination is provided with I and S 4fkL for direction determination, and it is possible to reduce costs. In particular, by making it software, it is easy to set the setting values, and it is possible to reduce not only the board costs but also the personnel costs.

[Brief explanation of the drawing]

1 and 2 are for explaining the method according to the embodiment of the present invention. FIG. 1 is an explanatory diagram of the return-to-origin operation and the first ON operation of the limit switch, and FIG. FIG. 6 is an explanatory diagram regarding movement in the direction opposite to the origin, the amount of movement thereof, and the second turning-on operation of the limit switch. In the figure, LS is a limit switch near the origin.

Claims (1)

[Claims] A limit switch is provided in front of the NC-controlled machine tool near the origin, and when the machine crosses this limit switch and stops, the machine moves in the opposite direction to the origin, crosses the limit switch again, and then returns to the origin again. On the other hand, the method for returning to the origin is such that the machine is stopped when the movement in the direction opposite to the origin exceeds a certain amount.