JPH11291048A - Method for setting height of torch and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set a pattern for changing the height of a torch at a piercing point and to minimize a time required for cutting as much as possible accoding to a distance from a finishing point of cutting a member to the piercing point of a following member when the plural members are cut from a matetial to be cut using a plasma cutting torch or the like. SOLUTION: An upwards and downwards moving bracket 4 is made to descent by driving an elevating/lowering motor 2, the tip of a torch 1 is made to contact a material to be worked and the contact is detected by a sensor and is stopped and thereafter, the torch is raised up to the preliminarily set height of piercing. When the cutting of one member is finished, the torch 1 is, at the finishing point, set at a shifting height lower than a ascending limit and higher than the piercing height, further, when shifted to the piercing point of a following member, the torch 1 is directly set at the piercing height respectively in the case that a shifting distance is larger than a dimension as a standard, after the torch 1 is once elevated up to an ascending limit or in the case that the distance is smaller.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for setting the height of a torch when cutting a plurality of members from a material to be cut, when cutting the members.

[0002]

2. Description of the Related Art A plasma cutting torch, a laser cutting torch, or a gas cutting torch is selectively used to select a non-ferrous metal such as a steel plate or a non-ferrous metal such as aluminum or a non-metal such as a plywood or an acrylic plate. Cutting is performed on a cut material. For example, to explain the case of performing die cutting on a steel sheet using a plasma cutting torch, first, a plasma cutting torch is set at a processing start position on a steel sheet, and a hole penetrating the steel sheet in the thickness direction is formed at this position. Piercing is performed, and a series of mold cutting is performed from the hole as a starting point.

[0003] In performing the cutting as described above, in order to sufficiently exert the performance of the torch and maintain the quality,
It is important to keep the height of the torch from the surface of the workpiece substantially constant. However, during cutting, the torch measures the distance from the surface of the material to be cut to the tip of the torch because an ultra-high temperature plasma arc, a laser beam with high energy density, or a high-temperature gas flame is injected from the torch. Is very difficult to control. Therefore, various methods have been proposed and adopted for setting the height of the torch.

A typical device for setting the height of the torch is, as shown in FIG. 7, a plurality of distance detecting sensors 52 arranged around a torch 51 at a predetermined distance from the center. Material 53 detected by the sensor 52
The height from the surface to the sensor 52 is controlled so as to be a predetermined value, so that the height of the torch 51 can be set. That is, the height of the torch 51 is indirectly controlled by controlling the height of the sensor 52. This apparatus also sets the initial height of the torch 51 at the start of processing.

[0005]

In the torch initial height setting apparatus, a plurality of sensors for setting the torch height are arranged around the torch. When the torch is in operation, the sensor is disposed at a position that is separated by a distance that is not affected by plasma arc, laser light, or flame, so that the distance between the torch and the sensor is large. Therefore, for example, when the target processing is die cutting, when the torch is moved to the vicinity of the edge of the material to be cut when performing piercing, some of the sensors are displaced from the end of the material to be cut. Height cannot be set.

[0006] Further, in the material to be cut such as a steel plate, the material to be cut is not a genuine flat plate but often has a slight undulation. Further, the surface near the edge may be curved and sagged downward or sharpened upward. In such a case, there is a problem that a difference occurs between the height from the surface of the material to be cut to the tip of the torch and the height from the surface of the material to be cut to the sensor. In particular, when the torch is a plasma torch or a laser torch, the height from the surface of the material to be cut to the tip of the torch is small due to the specification, and even a slight change in the height greatly affects the piercing performance. Will be.

A plurality of members may be cut from one workpiece. In this case, after the cutting of one member is completed, the torch is moved to the next member at a high speed. At this time, there is a problem of how to control the height of the torch. That is, if the height is controlled in accordance with the signal from the sensor when the torch is moved, the ascending and descending speed of the torch may not be able to follow the moving speed of the torch, and the torch may collide with the workpiece. Occurs. For this reason, it is common to raise the torch to the ascending limit when the torch moves, and to maintain this state. Accordingly, since the torch is lowered from the ascending limit each time the cutting is started and the initial height is set, there is a problem that a work time loss occurs even though the same workpiece is cut. .

An object of the present invention is to cut a plurality of members from a material to be cut, after moving from one member to another member,
When executing piercing, the torch height setting procedure is changed according to the distance between these members to reduce the loss time as much as possible, and the setting to realize this setting method It is to provide a device.

[0009]

According to the present invention, there is provided a method for setting a height of a torch according to the present invention, wherein when cutting a plurality of members from a material to be cut, the cutting of each member is started when the cutting of each member is started. An initial height setting method of a torch for setting an initial height from a surface of a material to a tip of a torch. When cutting a first member, the torch is lowered from an ascending limit height and a surface of a material to be cut is cut. After the piercing is completed, the torch is lowered to a predetermined cutting height to perform cutting while the piercing is being performed by raising the piercing height to a preset piercing height, and then cutting the second and subsequent members. At the end point of cutting of the already cut member, the torch is raised to a position lower than the ascending limit of the torch and higher than the piercing height so that the torch is moved toward the target member. Move to the piercing point, and if the moving distance from the cutting end point of the already cut member to the piercing point of the target member is smaller than the preset distance, release the torch at the piercing point of the target member. While performing the piercing by lowering to the preset piercing height, or after the piercing is completed, the torch is lowered to the predetermined cutting height to perform cutting, and the target member is cut from the cutting end point of the already cut member. If the moving distance to the piercing point is larger than the preset distance, the torch is raised to the ascending limit of the torch at the piercing point for the target member, and the torch is lowered from the ascending limit height. After contacting the surface of the material to be cut, the piercing is completed while raising the piercing height to a preset piercing height or performing piercing. And it is characterized in that for cutting lowers the torch to a predetermined cutting height.

According to the torch height setting method, when a plurality of members are cut from the same material to be cut, when the cutting of each member is completed, the torch is moved to a position lower than the upper limit and higher than the piercing height ( (Moving height), and then move to the piercing point of the member to be cut next, and at the piercing point of the member where the moving distance is larger than the preset distance, raise the torch once to the ascending limit. , Descend from the ascending limit and contact the surface of the material to be cut,
Thereafter, the height is raised to a predetermined piercing height. Further, at the piercing point of the member whose moving distance is closer than the preset distance, the torch is lowered directly from the moving height to the piercing height so that the torch at the piercing point for the new member is obtained. And the loss time can be reduced as much as possible.

That is, even if the surface of the workpiece has undulation, the difference in undulation generated over a short distance is not large. Therefore, when the distance between the members to be cut continuously is small, even if the torch is directly lowered from the moving height to the piercing height at the piercing point, the error with respect to the normal piercing height is not large. No performance can be achieved almost as specified. However, when the distance between the members to be cut continuously is large, it is completely unknown what value the difference in the level of the undulation occurs.In this case, the torch is raised to the ascending limit at the piercing point, and furthermore, By lowering the torch and bringing the torch into contact with the surface of the material to be cut, the torch is raised to the piercing height, whereby regular piercing performance can be exhibited.

Further, in the setting device according to the present invention, when cutting a plurality of members from a material to be cut, the setting device sets an initial height from the surface of the material to be cut to the tip of the torch when starting cutting of each member. And torch elevating means for elevating the torch, detecting means for detecting that the tip of the torch has contacted the surface of the material to be cut, and inputting information on a plurality of members to be cut from the material to be cut, and An input device for inputting information of a piercing point and a cutting end point in the member, and when the torch reaches a piercing point for the first member, the torch elevating means is driven to lower the torch at the ascending limit. When the detecting means detects that the tip of the torch has come into contact with the surface of the material to be cut, it stops driving the torch elevating means to stop the torch descent and restarts the torch elevating means. To move the torch to a preset piercing height, and to lower the torch to a preset cutting height while piercing or after piercing, and to cut the second and subsequent members. ,
At the cutting end point of the already cut member, the torch lifting / lowering means is driven to raise the torch to a position lower than the ascending limit of the torch and higher than the piercing height. When the moving distance of the member to the piercing point is smaller than the preset distance, the torch elevating means is driven at the piercing point of the target member to lower the torch to the preset piercing height, While piercing or after piercing, control to lower the torch to a predetermined cutting height, and the moving distance from the cutting end point of the already cut member to the piercing point of the target member is longer than a preset distance. Is larger, the torch raising / lowering means torch is raised to the ascending limit of the torch at the piercing point with respect to the target member. Is controlled to lower the torch to a predetermined cutting height while piercing or after piercing, after lowering the torch from the ascending limit height and contacting the surface of the material to be cut, raising the piercing height to a preset piercing height. And control means for performing the control.

In the above setting device, the torch can be made to approach the surface of the material to be cut by lowering the torch by the torch raising / lowering means. The detection means detects that the torch has come into contact with the surface of the material to be cut, and controls the elevating means to raise the torch to a preset height based on the detection signal. The initial height from the surface of the material can be set.

When a plurality of members are cut from the same material to be cut, when moving between members in advance from an input device, a distance value which is a reference when setting the height of the torch should be input and cut. By inputting the member information, the control device transmits a drive signal for setting the height of the torch when moving to the next member every time the cutting of one member is completed, to the torch elevating means. Thereby, the height of the torch at the time of performing a series of cutting can be set.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the torch initial height setting device will be described below with reference to the drawings, and a setting method will be described. FIG. 1 is a diagram showing an example of a material to be cut for cutting a plurality of members, FIG. 2 is a diagram illustrating a method for setting the height of a torch according to the present invention, and FIG. 3 is a diagram illustrating a height setting device mounted on a plasma cutting device. FIG. 4 is a side view for explaining the configuration, FIG. 4 is a diagram for explaining a main part of the height setting device, FIG. 5 is a block diagram of a control system, and FIG. 6 is a perspective view for explaining the entire configuration of the plasma cutting device.

The method for setting the height of the torch according to the present invention comprises the steps of: setting a torch 1 selected from a plasma cutting torch, a laser cutting torch, and a gas cutting torch in a height setting device A described later; When continuously cutting a plurality of members I to III, after cutting one member and moving to the next member, by rationally setting the height of the torch at the piercing point of the member, The configuration is such that the torch elevating time at the piercing point of the member to be newly cut can be reduced as much as possible.

For example, as shown in FIG.
One of the members I to III is set, and piercing points Ip to IIIp, which are cutting start points of each member, are set.
When the cutting order of the member III is set and the dimension L serving as a reference for dividing the pattern when setting the height of the torch 1 is set, the height of the torch 1 is set as shown in FIG. Is done.

When the torch 1 is moved while holding the torch 1 at an appropriate height (moving height) higher than the piercing height, when the piercing point of a new member is reached, Even if it is lowered from the moving height directly to the piercing height at the point, it is a dimension that can guarantee that the piercing performance of the torch 1 is exhibited substantially as specified regardless of the undulation of the workpiece B, Material to be cut B
Is empirically set according to the material and thickness, particularly the thickness.
For example, when the material to be cut B is a mild steel plate having a thickness of about 9 mm, the dimension L is set to 300 mm. In addition, when the thickness becomes larger, the undulation becomes smaller, and the reference dimension can be set to a value of 300 mm or more.

Next, the structure of the torch height setting device A,
The configuration of the cutting device C to which the height setting device A is applied will be described, and a method of setting the height of the torch shown in FIG. 2 will be described.

The torch height setting device A according to the present embodiment
In a cutting device configured by selectively using a plasma cutting torch, a laser cutting torch, or a gas cutting torch, when cutting, the height of the tip of the torch 1 from the surface of the workpiece B is set. Material to be cut B
The height of the torch 1 can be accurately set irrespective of whether there is a bend or a local deformation that may occur in the torch. In particular, in the present embodiment, a description will be given of a plasma cutting apparatus C equipped with a height setting apparatus A.

As shown in FIG. 6, the plasma cutting device C
Has a traveling frame 22 that travels along a pair of rails 21 laid in parallel. This running frame 22
It comprises a saddle 22a placed on the rail 21 and a cross garter 22b arranged in a direction perpendicular to the direction in which the rail 21 is laid and fixed to the saddle 22a. The cross garter 22b is mounted with a traversing carriage 23 that traverses along the cross garter 22b, and the traversing carriage 23 constitutes a height setting device A.

A traveling motor 24 is disposed on the saddle 22a. The traveling frame 22 travels along the rail 21 at a desired speed by controlling the rotation of the traveling motor 24.
The traversing carriage 23 is provided with a traversing motor 25. By controlling the rotation of the traversing motor 25, the traversing carriage 23 traverses at a desired speed. Accordingly, by controlling the motors 24 and 25 in association with each other, the torch 1 provided on the traversing carriage 23 can be two-dimensionally moved in a desired direction.

An operation panel 26 is mounted on a saddle 22a constituting the traveling frame 22. The operation panel 26 has a built-in numerical controller (NC controller) for controlling the rotation of each of the motors 24 and 25 and the operation of the torch 1, and has a control unit 11 for controlling the height setting device A. Built-in.

The plasma cutting apparatus C configured as described above
In the operation panel, graphic information to be cut with respect to the material to be cut B, information on a cutting speed corresponding to the material and thickness of the material to be cut A, information on a reference dimension L, and other necessary information are displayed on an operation panel. 26 N
Then, the motors 24 and 25 are driven to move the torch 1 to reach a predetermined cutting start point (piercing point Ip of the member I), and then the cutting operation is started at the position. Then, piercing is performed in accordance with a preset program, and a series of disconnections can be executed starting from the piercing point Ip.

Next, an example of the configuration of the height setting device A will be described with reference to FIGS. The height setting device A according to the embodiment described below is a preferred example, and is not necessarily limited to this configuration.

The height setting device A is provided on the traversing carriage 23. That is, the traversing carriage 23 is provided with an elevating motor 2 which constitutes an elevating means, for example, a ball screw driven by the elevating motor 2, is driven by the ball screw, and is vertically guided by the elevating guide 3 to ascend and descend. A lifting bracket 4 is provided.

The elevating motor 2 has a built-in rotary encoder. A plus or minus pulse signal is generated with the rotation of the elevating motor 2, and the generated pulse number is added to or subtracted from the current value. The vertical position of the lifting bracket 4 can be checked.

The elevating bracket 4 is provided with a guide member 5 serving as a vertical guide member. The guide member 5 includes a guide rail 5a provided vertically and a guide bracket 5b that moves up and down along the guide rail 5a, and a holder 6 to which the torch 1 is attached is fixed to the guide bracket 5b.

A spring 7 serving as an urging member is provided at a predetermined position of the lifting bracket 4 (to the right of the guide rail 5a when viewed from the torch 1 side), and the holder 6 is urged downward by the spring 7. ing.

Further, at a predetermined position of the lifting bracket 4 (on the left side of the guide rail 5a when viewed from the torch 1 side), a sensor 8 constituting detecting means is provided. The sensor 8 is in a non-detection state when the torch 1 is not in contact with the surface of the workpiece B, the torch 1 contacts the surface of the workpiece B, and the torch 1 (holder 6) is , A detection state occurs when the signal rises relative to the signal, and a signal is generated.

As the sensor 8, a contact type sensor such as a micro switch or a non-contact type sensor such as a proximity switch or an optical sensor can be used. In this embodiment, a microswitch is used as the sensor 8, and the holder 6 is provided with a dog 8 a that comes into contact with the actuator of the sensor 8.

The sensors 9a to 9a
9c is arranged. These sensors 9a to 9c
The sensor 9 detects the lifting bracket 4 that moves up and down along the lifting guide 3 and generates a unique signal.
a detects that the lifting bracket 4 has reached the lower limit, the sensor 9b detects that the lifting bracket 4 has reached the lower limit, and the sensor 9c has reached the height at which the lifting bracket 4 should change the lifting speed. This is to detect that it has been done.

Next, the control system of the height setting device A will be described with reference to FIG. In the figure, reference numeral 11 denotes a control unit which stores data of the ascending position of the torch 1 set in advance according to a reference dimension L, and a program of an ascending / descending pattern of the torch 1 according to the dimension L. Lifting motor 2
The current position of the torch 1 is confirmed by counting the pulse signals generated with the rotation of the sensors.
When the signal from 9c is transmitted, the drive of the elevating motor 2 is controlled in accordance with each signal.

Reference numeral 12 denotes an input device such as a keyboard for inputting a value of the height of the torch 1 or inputting a new value when changing the value. Data input from the input device 12 is transmitted to the control unit 11 via the interface 13.

Next, a procedure for setting the height of the torch 1 by the height setting device A configured as described above will be described with reference to FIG. It is assumed that the torch 1 has already reached the piercing point Ip where cutting of the member I should be started, and the lifting bracket 4 has reached the ascending limit. Has been maintained. In this state, the torch 1 is
, The weight of the torch 1 acts on the holder 6, and the holder 6 (guide bracket 5b)
It is located at the lower limit of a. For this reason, the dog 8 a is separated from the sensor 8, and no signal is generated from the sensor 8.

In the above state, the lifting motor 2 is driven to lower the lifting bracket 4. When the lifting bracket 4 is lowered from the lifting limit, the lifting bracket 4 is
high-speed operation until contact is made (step S
1).

When the lifting bracket 4 is detected by the sensor 9c and a signal is generated, the lifting motor 2
Is operated at a low speed by reducing the number of rotations, and the lifting bracket 4 is lowered at a low speed. When the torch 1 comes into contact with the surface of the workpiece B as the lifting bracket 4 descends, the torch 1 is stopped by being restricted by the workpiece B. During this time, since the lifting bracket 4 continues to descend, the holder 6 rises relatively to the lifting bracket 4. Then, when the dog 8a comes into contact with the sensor 8, a signal is generated from the sensor 8 and transmitted to the control unit 11 to recognize that the torch 1 has come into contact with the workpiece B (step S2).

When a signal from the sensor 8 is transmitted to the control unit 11, the lifting motor 2 stops based on this signal,
Immediately reverse rotation to raise the lifting bracket 4. This number of rotations is calculated by a pulse from the encoder of the lifting motor 2, and when it matches a preset piercing height value, the lifting motor 2 stops (step S).
3). Thereby, the torch 1 is located at a preset piercing height from the surface of the workpiece B. When the lifting bracket 4 is detected by the sensor 9b, the lifting motor 2 stops immediately based on the signal of the sensor 9b.

As described above, the tip of the torch 1 is
The holder 6 and the lifting bracket 4
Move relatively. Therefore, no impact acts on the torch 1 and the torch 1 is not damaged.

With the torch 1 set at the piercing height as described above, the torch 1 is operated, and the piercing point is set.
While or after piercing the Ip, the lifting motor 2 is driven to lower the torch 1 to a preset cutting height (step S).
4). Then, the member I is cut while maintaining the cutting height set on the torch 1.

When the cutting of the member I is completed and the member moves to the piercing point IIp of the member II, the torch 1 is moved at an appropriate moving height lower than the ascending limit and higher than the piercing height at the ending point (this embodiment). (About 30 mm) (Step S5), and in this state, the piercing point II of the member II
Move to p (step S6).

When the torch 1 reaches the piercing point IIp of the member II, it is compared whether the moving distance D of the torch 1 is larger or smaller than a predetermined reference dimension L. At the point IIp, the torch 1 moves up to the ascending limit to activate the sensor 9a, and then descends at a high speed until it reaches a certain height from the ascending limit (step S7). Thereafter, it is detected that the tip of the torch 1 has come in contact with the surface of the workpiece B at a low speed and stops (step S8). Further, the torch 1 rises to the piercing height (step S9). Then, while piercing the piercing point IIp with the piercing height set, or after the piercing is completed, the piercing is lowered to a preset cutting height (step S10) to cut the member II.

When the cutting of the member II is completed, the torch 1 is raised to the moving height at the end point (Step S).
11) Then, in this state, the member moves to the piercing point IIIp of the member III (step S12).

The torch 1 has a piercing point IIIp of the member III.
Is reached, the moving distance D of the torch 1 is compared to be larger or smaller than a predetermined reference dimension L. If smaller, the torch 1 at the moving height is directly lowered to perform piercing. When it reaches the height, it stops (step S13). Then, while piercing is performed at this position or after the piercing is completed, the torch 1 is lowered to a preset cutting height (step S14).
Perform a disconnection on III.

As described above, the member II is cut from the cutting end point of the member II.
In the operation reaching the piercing point IIIp of III and the operation at the piercing point IIIp, the piercing point IIIp
p is not at a position far away from the cutting end point of the member II and is smaller than a reference dimension L. For this reason, even if the material B to be cut has undulation, it can be assumed that the height difference between the cutting end point and the piercing point IIIp due to the undulation is about 1 mm.

For this reason, by raising the torch 1 to a preset moving height higher than the piercing height,
It is possible to avoid the possibility that the torch 1 collides with the surface of the workpiece B during movement. Therefore, by starting the movement without raising the torch 1 to the upper limit, it is possible to shorten the time from the end of the cutting to the start of the movement.

Similarly, at the piercing point IIIp, the cutting height of the torch 1 and the height raised in step S11 can be set without detecting the surface of the workpiece B again and setting the height of the torch 1. By lowering the torch 1 by making it correspond to the value obtained by subtracting the value of the piercing height from the value obtained by adding
It can be set to approximately the piercing height. That is,
The piercing height of the torch 1 set as described above does not greatly differ even if it is not an accurate value, and does not significantly affect the piercing operation.
Therefore, since the torch 1 is directly reached from the position higher than the piercing height without raising the torch 1 to the ascending limit, the time from reaching the piercing point to setting the piercing height can be reduced. It is possible.

When the cutting of the member III is completed, the presence or absence of the member to be cut next is confirmed. When it is confirmed that there is no member to be cut, the torch 1 is raised to the upper limit (step S15), and the sensor 9a, the position is maintained. Thus, a series of cutting is completed, and the plasma cutting device C is retracted to a predetermined position.

[0049]

As described above in detail, in the height setting method according to the present invention, when a plurality of members are continuously cut from the material to be cut, the cutting end point of one member is changed to the next member. The time required for cutting can be reduced as much as possible by setting the height of raising the torch according to the distance to the piercing point and the lowering operation at the piercing point.

In the setting device according to the present invention, the above setting method can be rationally carried out, and even when the torch is brought into direct contact with the surface of the material to be cut, there is a possibility that the torch may be generated at the time of contact. It can absorb shocks and prevent damage to the torch and set the exact height.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of a material to be cut for cutting a plurality of members.

FIG. 2 is a diagram illustrating a torch height setting method according to the present invention.

FIG. 3 is a side view illustrating a configuration in which a height setting device is mounted on a plasma cutting device.

FIG. 4 is a diagram illustrating a main part of the height setting device.

FIG. 5 is a block diagram of a control system.

FIG. 6 is a perspective view illustrating an overall configuration of a plasma cutting device.

FIG. 7 is a diagram showing a positional relationship between a torch and a sensor in a normal height setting device.

[Explanation of symbols]

 Reference Signs List A Height setting device B Material to be cut C Plasma cutting device 1 Torch 2 Lifting motor 3 Lifting guide 4 Lifting bracket 5 Guide member 5a Guide rail 5b Guide bracket 6 Holder 7 Spring 8 Sensor 8a Dog 9a to 9c Sensor 11 Control unit 12 Input Equipment 13 Interface 21 Rail 22 Travel frame 23 Traverse carriage 24 Travel motor 25 Traverse motor 26 Control panel

Claims (2)

[Claims] 1. A method for setting an initial height of a torch, wherein when cutting a plurality of members from a material to be cut, an initial height from a surface of the material to be cut to a tip of the torch is set when cutting of each member is started. When cutting the first member, lower the torch from the ascending limit height to contact the surface of the workpiece, and then raise the torch to a preset piercing height to perform piercing or piercing. After the cutting is completed, the torch is lowered to a predetermined cutting height to perform cutting, and then, when shifting to cutting for the second and subsequent members, the torch is lifted at the cutting end point of the already cut member. Lower than the piercing height and moved to the piercing point for the target member, and from the cutting end point of the already cut member to the piercing point of the target member. When the moving distance to the ashing point is smaller than the preset distance, the torch is lowered to the preset piercing height at the piercing point of the target member to perform the piercing, or the piercing is completed. Thereafter, the torch is lowered to a predetermined cutting height to perform cutting, and when the moving distance from the cutting end point of the already cut member to the piercing point of the target member is larger than a predetermined distance, At the piercing point for the target member, the torch is raised to the ascending limit of the torch, the torch is lowered from the ascending limit height, and brought into contact with the surface of the workpiece, and then raised to the preset piercing height. The torch is lowered by lowering the torch to a predetermined cutting height while piercing or after the piercing is completed. How to set. 2. A setting device for setting an initial height from a surface of a material to be cut to a tip of a torch when cutting a plurality of members from the material to be cut when starting cutting of each member, wherein the torch is moved up and down. Torch elevating means for causing, a detecting means for detecting that the tip of the torch has contacted the surface of the material to be cut, and inputting information on a plurality of members to be cut from the material to be cut, and piercing points in each member. An input device for inputting information of a cutting end point, and when the torch reaches the piercing point for the first member, drives the torch elevating means to lower the torch at the ascending limit, and the detecting means detects that the tip of the torch is When it is detected that the torch has been brought into contact with the surface of the workpiece, the torch elevating means is stopped to stop the descent of the torch and the torch elevating means is re-driven to set the torch in advance. After the piercing or after the piercing is completed, control is performed to lower the piercing height to a preset cutting height, and when cutting the second and subsequent members, the cutting of the already cut members is completed. At this point, the torch elevating means is driven to raise the torch to a position lower than the ascending limit of the torch and higher than the piercing height, from the cutting end point of the already cut member to the piercing point of the target member. When the moving distance is smaller than the preset distance, the torch elevating means is driven at the piercing point of the target member to lower the torch to the preset piercing height, and while piercing or after piercing is completed. The torch is lowered to a predetermined cutting height, and the piercing point of the target member from the cutting end point of the already cut member If the moving distance is larger than the preset distance, the torch raising / lowering means torch is raised to the ascending limit of the torch at the piercing point with respect to the target member, and the torch is further lowered from the ascending limit height. And causing the torch to descend to a predetermined cutting height while piercing or after piercing is completed, after the piercing height is increased to a preset piercing height. A torch height setting device.