JPH03238176A - Method and device for removing nozzle deposit in plasma cutter - Google Patents

Abstract

PURPOSE:To allow stable automatic plasma cutting by disposing a torch to face the deposite removing device and operating the deposite removing device for a prescribed period of time at every proper interval during the course of a cutting operation. CONSTITUTION:The torch 20 is moved relative to a plate material W and a current is supplied between an electrode 21 and the plate material W. The deposite removing device consisting of a friction member 30 having a friction surface 31 is provided in the prescribed position on a table 11 and the deposits sticking to the nozzle tip of the torch 20 are removed by this device. The torch 20 is moved to the position facing the deposite removing device 30 and the deposite removing device 30 is operated for the prescribed period of time at every proper interval during the course of the cutting operation of the plate material W. The damage of the nozzle at the tip of the plasma torch is prevented in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for removing deposits from a nozzle in a plasma cutting device.

[Prior Art] Plasma cutting devices that locally melt and cut workpieces made of metal or non-metal materials using the thermal energy of a plasma arc are well known. In this type of plasma cutting, a through hole is first drilled in a plate-shaped workpiece to serve as a starting hole, and then a linear cutting process is performed continuously through the starting hole.

By the way, in the machining of the start hole, as shown in FIG. 6(a), the workpiece W melted by the plasma arc 1 is
Since there is no place for the material to escape, it may be scattered around as spatter 2, a part of which may become a reflected flow and be blown onto the nozzle 22, and may adhere to the nozzle 22 as deposits 3. If this is left as it is and the deposits 3 on the nozzle 22 become large, as shown in FIG. 6(b), in addition to the main arc 1 from the electrode 21 to the workpiece W, Arcs 4 and 5 also occur between the workpiece W and the workpiece W, resulting in a so-called double arc state. The presence of such double arcs 4 and 5 extremely reduces machining ability and deteriorates the condition of the cut surface. Furthermore, if the deposit 3 becomes larger, as shown in FIG. 6(c), the deposit 3 will come into contact with the workpiece W, causing the main arc 1 to the workpiece W.
disappears, and a large arc 6 is generated between the electrode 21 and the inner peripheral surface of the nozzle 22, which may damage the nozzle 22.

Conventional plasma cutting devices do not take the above-mentioned deposit 3 into consideration, and the fact is that the operator manually removes it using a file or the like.

[Problems to be Solved by the Invention] However, manual removal of deposits is troublesome, and it is difficult for an operator to monitor the adhesion status of deposits 3 during operation of a plasma cutting device that is automatically operated using NC. ,
There is a problem in that the necessity to perform manual removal operations from time to time significantly deteriorates work efficiency.

The present invention has been made to solve the above problems, and its purpose is to automatically remove the deposits 3 attached to the nozzle 22, and to eliminate the double arc 4
, 5 can be prevented from occurring in advance, and to provide a method and device for removing deposits from a nozzle in a cutting device.

[Means for Solving the Problems] In order to achieve the above object, the present invention has a table on which a plate-shaped material is placed and fixed, a working gas supply nozzle and an electrode, and faces the plate-shaped material. A plasma comprising a plasma torch, means for moving the torch relative to the plate-like material, and means for supplying a direct current and/or a pulsed current between the electrode and the plate-like material. In the cutting device, a deposit removing device is provided at a predetermined position on the table to act on the tip of the nozzle to remove deposits attached to the tip of the nozzle. Provided is a method and apparatus for removing deposits from a nozzle in a plasma cutting device, characterized in that the torch is moved to a position facing the deposit removal device at every interval, and the deposit removal device is operated for a predetermined period of time. .

[Function] In the nozzle deposit removal method and device in the plasma cutting device configured as described above, the torch is placed at a position facing the deposit removal device at appropriate intervals during the cutting operation of the plate-shaped interest. By moving the torch to the torch and operating the deposit removal device for a predetermined period of time, deposits on the tip of the torch are removed before they grow large.

[Example] Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view showing a plasma cutting device.

A gate-shaped movable frame 12 is placed on the table 11 in the front-rear direction (Y
direction). The movable frame 12 is moved by a Y-axis motor 3 fixed to the table 11. A saddle 14 is supported movably in the left-right direction (X direction) by a horizontal guide 18 provided on the movable frame 12, and is moved by an X-axis motor 5 fixed to the movable frame 12.

A head 16 is disposed on the saddle 14 so as to be movable in the vertical direction (Z direction).
It is raised and lowered by a shaft motor 17. A plasma torch 20 capable of ejecting a plasma arc is fixed to the tip of the head 16. Further, a workpiece W to be cut can be placed on the table 11 at a position facing the tip of the plasma torch 20. Furthermore, a friction member 30 having a friction surface 31 on which the tip of the plasma torch 20 can slide is fixed on the table 11 . Each axis motor 13゜1
5.17 and the torch 20 are connected to and controlled by the control device 50. The control device 50 is provided with a CRT (display device) 51 and a keyboard 52.

FIG. 2 is a block diagram showing the control device. Control device 5
0 is CPU (central processing unit) 5B, ROM54.
It is equipped with a computer consisting of a RAM 55, etc., and operates the X-axis motor 15.
Y-axis motor 13. The Z-axis motor 17 is controlled and the operating status is displayed on the CRT 51. Further, the CPU 53 is connected to a plasma arc power supply device 56 and a gas supply device 57 to control them. The plasma arc power supply device 56 is for generating a direct current to be supplied to the electrode 21 of the torch 20 according to instructions from the CPU 53 using a commercial power source as an input source. The gas supply device 57 is a plasma torch 20
This is a device that supplies gas such as oxygen gas to the

The plasma torch 20 has an electrode 21 provided inside a nozzle 22 made of copper, and a gas such as oxygen is blown toward the workpiece W from a spout 23 of the nozzle 22. The positive terminal of the plasma arc power supply device 56 is connected to the workpiece W, and the negative terminal is connected to the electrode 21.

The plasma arc generated between the electrode 21 and the workpiece W becomes a plasma jet and is blown onto the workpiece W by the gas blown out from the nozzle.

FIG. 3 is a perspective view showing the friction member 30. FIG. Here, a flat grindstone is used as the friction member 30. A friction member 30 made of a flat grindstone is fixed onto the table 11 through a bolt hole 33 .

However, the friction member is not limited to a grindstone. For example, sandpaper may simply be fixed on the table, or a wire brush 34 with bristles raised upright may be fixed on the table 11 as shown in FIG.

FIG. 5 is a flowchart showing the processing in the control device. When the process 100 is started, initial settings, processing data reading, etc. are performed, and then the process proceeds to step 111. In step 111, the plasma power supply device 56 and the gas supply device 57 are driven to perform piercing of a start hole. When the drilling of the start hole is completed, the process proceeds to step 112, where cutting is performed. Here, the X-axis cutter 5 and the Y-axis cutter 3 are driven according to a cutting program stored in advance in the RAM 55, and the workpiece W is cut into a predetermined shape.

When the series of cutting processing is completed, the process proceeds to step 113. In step 113, the number of times the start hole has been drilled so far is checked.

If the number of drilling operations has reached a predetermined number, for example seven, the process proceeds to step 115, and if it is less than the predetermined number, the process proceeds to step 114. In step 114, the keyboard 5
2, it is checked whether or not a command to instruct a deposit removal operation has been issued. If the command has been given, step 11
The process proceeds to step 5, and if no command has been issued, the process proceeds to step 116 without executing anything.

In step 115, a deposit removal operation is performed. Here, the plasma torch 20 is moved away from the workpiece W by driving each axis motor 13, 15, 17, and moved above the friction member 30 on the table 11.

After processing the head 16, the X-axis motor 15
Then, the Y-axis motor 13 is driven to move the plasma torch 20 so that the nozzle 22 at the tip of the plasma torch 20 comes into sliding contact with or approaches the friction surface 31 of the friction member 30 . As a result, the deposits 3 attached to the nozzle 22 at the tip of the plasma torch 20 come into sliding contact with the friction surface 31 of the friction member 30 and are peeled off from the plasma torch 20. When the deposit removal operation is completed, the process proceeds to step 116. Step 11
In step 6, it is checked whether the Canadian program has finished or not, and if it has not finished yet, the process returns to step 11.
1 or less processes are repeated. If the cutting of a predetermined number of workpieces W has been completed and the cutting program has been completed, the process proceeds from step 116 to step 117, and the process 100 is ended.

In the above embodiment, the number of times the start hole is machined is counted, and the deposit removal operation is performed every time the number of times the start hole is machined reaches a predetermined number, but the conditions for starting the deposit removal operation are not limited to this. . For example, the machining time required for drilling the start hole and the subsequent cutting may be accumulated, and the deposit removal operation may be performed every predetermined machining time.Also, the machining distance of the cutting machining may be accumulated, and the machining distance The deposit removal operation may be started every time the distance reaches a predetermined distance.

Furthermore, the workpiece W on the table 11 may be replaced, and the number of operations of the processing start switch may be counted each time processing is started, and the deposit removal operation may be started every predetermined number of operations.

Alternatively, the voltage between the nozzle and the plate-like material may be measured, and each time the voltage drops to a specified voltage, the deposit removal operation may be started.

[Effects of the Invention] Since the present invention has the above-described configuration, it is possible to automatically remove deposits that adhere to the tip of the plasma torch, and prevent the occurrence of double arcs. This has an excellent effect. Therefore, even if the operator does not constantly stop the adhesion of deposits, damage to the nozzle at the tip of the plasma torch can be prevented, and stable automatic plasma cutting processing can be performed.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing a plasma cutting device which is an embodiment of the present invention, Fig. 2 is a block diagram, Figs. 3 and 4 are perspective views showing a friction member, and Fig. 5 is a processing by a control device. FIG. 6 is a sectional view illustrating the relationship between deposits and plasma arc. In the figure, 11 is a table, 13 is a Y-axis motor, 15 is an X-axis motor, 17 is a two-axis motor, 20 is a plasma torch, 2
1 is an electrode, 22 is a nozzle, 30 is a friction member 2, 31 is a friction surface, 50 is a control device, 53 is a CP
U, 56 is a plasma power supply device.

Claims (1)

[Claims] 1. A table for placing and fixing a plate-shaped material, a plasma torch having a working gas supply nozzle and an electrode and facing the plate-shaped material, and a plasma torch for directing the torch to the plate-shaped material. A plasma cutting apparatus comprising a means for relatively moving the electrode and a means for supplying a direct current and/or a pulsed current between the electrode and the plate-like material, the nozzle being placed at a predetermined position on the table. A deposit removing device is provided to act on the tip of the nozzle to remove deposits attached to the tip, and the torch is faced to the deposit removing device at appropriate intervals during the cutting operation of the plate-shaped material. 1. A method for removing deposits from a nozzle in a plasma cutting device, characterized in that the deposit removing device is operated for a predetermined period of time. 2. A table for placing and fixing a plate-shaped material, a plasma torch having a working gas supply nozzle and an electrode and facing the plate-shaped material, and for moving the torch relative to the plate-shaped material. a means for controlling the operation of the relative movement means, and a means for supplying a direct current and/or a pulsed current between the electrode and the plate-like material, the plasma cutting apparatus comprising: A deposit removing device is provided at a predetermined position of the nozzle for removing deposits adhering to the nozzle tip by acting on the nozzle tip, and the control device is operated at appropriate intervals during the cutting operation of the plate-shaped material. A nozzle deposit removal device for a plasma cutting device, characterized in that means is provided for moving the torch to a position facing the deposit removal device and operating the deposit removal device for a predetermined period of time.