JPH06651A - Plasma cutting method and cutting device - Google Patents

Abstract

PURPOSE:To always perform cutting in a slag-free state regardless of an increase in the working time of a nozzle fitted to a plasma torch and to reduce the cost required for cutting. CONSTITUTION:The working time of the nozzle 3 fitted to the plasma torch 1 is measured by a measurement part 8, which is compared with the data of a proper cutting speed line stored in a storage part 10a and the cutting speed capable of cutting a material 5 to be cut in a state free from slag is set. The proper cutting speed line is obtained experimentally. Consequently, the material 5 to be cut can be always cut in a state free from slag till the nozzle 3 is completely consumed and it is not necessary to abandon the usable nozzle 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma cutting method which can always set the cutting speed of a plasma torch to an appropriate speed when cutting a steel plate or the like using a plasma torch, and can carry out this method. The present invention relates to a cutting device.

[0002]

2. Description of the Related Art In plasma cutting, arc discharge is performed between an electrode arranged inside a torch and a material to be cut, and a cutting gas is supplied to the periphery of the arc, and the cutting gas is heated to a high temperature by the thermal energy of the arc. High-speed plasma gas is used, and this plasma gas is jetted toward the material to be cut from a nozzle attached to the tip of the torch, whereby the material to be cut is melted and oxidized, and at the same time blown off to cut.

A nozzle mounted on the tip of the plasma torch has a function of restraining plasma gas. However, since this nozzle is constantly exposed to the plasma gas, the hole diameter gradually expands and wears out as the usage time increases, and eventually it becomes unusable. Due to the exhaustion of the nozzle, the restraint to the plasma gas decreases and slag adheres to the cut surface. To obtain a slag-free (a state where no slag adheres to the cut surface), the cutting speed must be reduced. I won't. For this reason, it is common to perform an operation of decreasing the cutting speed as the usage time of the nozzle is increased, based on the empirical judgment of an operator who performs the cutting work.

[0004]

Recently, the operation of a cutting machine has been automated, and the number of skilled workers who can change the cutting speed during work has decreased.
Due to such circumstances, it becomes difficult to adjust the cutting speed while monitoring the condition of slag adhering to the cut surface during the cutting work. Therefore, the usage time of the nozzle that can obtain a slag-free cut surface is set based on a constant speed, and the nozzle is discarded when this usage time has elapsed. That is, even if the nozzle is still usable, this nozzle is discarded when a predetermined time has passed. Therefore, there is a problem that the cost required for plasma cutting increases.

An object of the present invention is to provide a cutting method capable of cutting in a slag-free state until a nozzle becomes unusable due to exhaustion, and a cutting apparatus for carrying out this method.

[0006]

In order to solve the above-mentioned problems, a plasma cutting method according to the present invention has an appropriate cutting speed that does not cause slag to adhere to a cutting surface according to a usage time of a nozzle for passing a plasma arc. In advance,
It is characterized in that after a new nozzle is attached to the plasma torch, the cutting speed is reduced in accordance with the increase in the usage time of the nozzle.

Further, the plasma cutting apparatus includes a storage section for storing data of an appropriate cutting speed corresponding to the usage time of the nozzle, a measuring section for measuring the usage time of the nozzle attached to the plasma torch, and the measuring section. A plasma torch is calculated based on the cutting speed calculated by the calculation unit and the calculation unit that calculates the cutting speed of the nozzle from the data of the appropriate cutting speed stored in the storage unit corresponding to the measured usage time of the nozzle. And a control unit for controlling the speed of the moving means to be moved.

[0008]

According to the above plasma cutting method, the material to be cut can be cut at an appropriate cutting speed until the nozzle is completely consumed. That is, the proper cutting speed according to the usage time of the nozzle can be obtained by an experiment. Therefore, from the above result, it is possible to obtain an appropriate cutting speed corresponding to the total use time from the start of use of the nozzle to the complete consumption thereof. Therefore, by accumulating the usage time of the nozzles mounted on the plasma torch, it is possible to set an appropriate cutting speed at the time of cutting.

The above plasma cutting device (hereinafter referred to as "cutting device")
According to the above), the operating time of the nozzle is calculated by the calculating unit, and the cutting speed corresponding to this operating time is calculated from the data of the proper cutting speed corresponding to the operating time of the nozzle stored in the storage unit. By controlling the speed of the moving means for moving the plasma torch based on the data, the material to be cut can be cut by setting the nozzle attached to the plasma torch at an appropriate cutting speed.

[0010]

EXAMPLES Specific examples of the plasma cutting method and the cutting apparatus will be described below with reference to the drawings. FIG. 1 is a block diagram of a cutting device according to this embodiment, FIG. 2 is a diagram showing data of an appropriate cutting speed corresponding to a usage time of a nozzle, and FIG. 3 is a perspective view illustrating an example of a cutting machine. The plasma cutting method according to the present invention, when cutting the material to be cut using the same nozzle, is cut based on an appropriate cutting speed capable of obtaining a slag-free cutting surface regardless of the increase in the operating time. It is possible to cut the material. Further, the cutting device is for carrying out the plasma cutting method, and is configured to measure the usage time of the nozzle and set an appropriate cutting speed according to the increase of the usage time of the nozzle.

The cutting speed for the material to be cut is set by the control system configured as shown in FIG. In the figure, an electrode 2 is detachably attached inside a plasma torch 1, and a nozzle 3 is detachably attached at the tip. The electrode 2 and the nozzle 3 are consumable parts, respectively. The plasma torch 1 and the nozzle 3 are forcibly cooled by the cooling water supplied inside. Gas such as oxygen and nitrogen is supplied from the gas supply source 4 to the plasma torch 1 in accordance with the material of the material to be cut 5. In this embodiment, a mild steel plate is used as the material to be cut 5, and oxygen gas is used as the gas supplied to the plasma torch 1.

The electrode 2, the nozzle 3 and the material to be cut 5 are connected to a power source 6, respectively, and while supplying oxygen gas from a gas supply source 4, an arc discharge is caused between the electrode 2 and the nozzle 3 to generate a pilot arc. Then, arc discharge is performed between the electrode 2 and the material 5 to be cut to form a main arc. Along with the formation of the pilot arc and the main arc, the oxygen gas supplied to the plasma torch 1 is turned into plasma and jetted from the nozzle 3 toward the workpiece 5. When a main arc is formed between the electrode 2 and the material 5 to be cut, the plasma gas melts and oxidizes the material 5 to be cut, and at the same time, the generated molten metal and oxidized molten metal are removed from the material 5 to be cut. The material 5 to be cut is blown off, whereby the material 5 to be cut is cut.

In the process of cutting the material 5 to be cut, the nozzle 3
Therefore, the time during which the plasma gas passes is the usage time of the nozzle 3. The hole diameter of the nozzle 3 is enlarged and consumed as the usage time increases. Further, as the hole diameter of the nozzle 3 increases, the value of the appropriate cutting speed at which a slag-free cutting surface can be obtained decreases.

The relationship between the operating time of the nozzle 3 and the proper cutting speed can be experimentally obtained. That is, the cutting conditions such as the material and plate thickness of the material 5 to be cut, the specifications of the electrode 2, the cutting current value, and the gas specifications are kept constant, and a new nozzle 3 is attached to the plasma torch 1 to obtain a slag-free cutting surface. By repeating the experiment, it is possible to obtain an appropriate cutting speed value according to the usage time of the nozzle 3. Therefore,
When the relationship of the proper cutting speed corresponding to the usage time of the nozzle 3 obtained from the above experiment is used as a chart, and the actual cutting time is set by referring to the chart while measuring the usage time of the nozzle 3, This cutting speed is an appropriate cutting speed for obtaining a slag-free cutting surface.

FIG. 2 is an example of a chart showing the relationship between the usage time of the nozzle 3 and the proper cutting speed obtained by the above-mentioned experiment. The cutting conditions in the figure are the material to be cut, mild steel with a plate thickness of 16 mm, cutting current, 250 A, gas and oxygen gas.

As shown in FIG. 2, when a new nozzle 3 is used, the cutting speed is 2.1 m / min to 2.3 m / min at the start of use.
By setting the range to, it is possible to obtain a slag-free cut surface. When the nozzle 3 is continuously used and the usage time reaches 30 minutes, the cutting speed is 2.0 m / min to 2.
It is possible to obtain a slag-free cut surface by reducing it to the range of 2 m / min.

That is, when the nozzle 3 is used for 30 minutes, if the cutting is performed at the cutting speed at the start of use, slag will adhere to the cut surface. When the usage time of the nozzle 3 exceeds 60 minutes, the nozzle 3 is completely consumed,
It becomes impossible to cut the material 5 to be cut. At this time,
The nozzle 3 attached to the plasma torch 1 is discarded and replaced with a new nozzle 3 to cut the material 5 to be cut.

Therefore, a line connecting approximately the middle of the upper limit value and the lower limit value of the slag-free corresponding to the usage time of the nozzle 3 shown in FIG. 2 is set as the proper cutting speed line 7, and nozzles of different specifications are supported. By creating multiple charts similar to those in Figure 2, even if the plasma torch 1 is installed in an automatic cutting machine or semi-automatic cutting machine operated by an unskilled operator, the cutting speed is always set to an appropriate value. It is possible to obtain a slag-free cut surface.

In FIG. 1, the usage time of the nozzle 3 is measured by a measuring unit 8 connected to a power source 6. The measuring unit 8 accumulates and measures the energization time for the electrode 2, nozzle 3, and material 5 to be cut of the power source 6, and when the new nozzle 3 is attached to the plasma torch 1, the accumulated time is canceled by manual operation. Is configured to be able to. The data of the usage time of the nozzle 3 measured by the measuring unit 8 is transmitted to the control unit 10 via the interface 9.

The control unit 10 is configured as a control unit of the cutting machine 11 which will be described later, and stores the data of the proper cutting speed line 7 and the operation program of the cutting machine 11 shown in FIG.
And a temporary storage unit 10b for temporarily storing the data of the usage time of the nozzle 3 transmitted from the measurement unit 8 and the data of the cutting shape for cutting the workpiece 5, and the data of the proper cutting speed line 7 from the storage unit 10a. At the same time as reading, the data of the usage time of the nozzle 3 stored in the temporary storage unit 10b is read, and these data are compared to calculate an appropriate cutting speed according to the current nozzle 3, and the calculation result will be described later, for example. The cutting unit 11 includes a traveling motor 12 and a traverse motor 13, and a computing unit 10b that transmits a driving signal to drivers 14 and 15 that drive the traversing motor 13.

In the cutting device constructed as described above, a new nozzle 3 is attached to the plasma torch 1 to cancel the cumulative time of the measuring unit 8, and the power supply 6 is operated while supplying oxygen gas from the gas supply source 4. And the plasma gas is jetted from the nozzle 3 toward the material 5 to be cut, and at the same time, the measuring unit 8
Then, the usage time of the nozzle 3 is measured and the measured data is sent to the control
Communicate to 10. The control unit 10 sets a cutting speed (2.2 m / min) corresponding to the usage time of 0 minutes of the nozzle 3 from the appropriate cutting speed line 7 and transmits a drive signal corresponding to the set cutting speed to the drivers 14 and 15. To do. As a result, plasma torch 1
Cuts the material 5 to be cut at the set cutting speed.

When the usage time of the nozzle 3 is increased,
It is possible to cut the material 5 to be cut in a slag-free state by setting the cutting speed corresponding to the usage time of the nozzle 3 from the appropriate cutting speed line 7 in the same manner as the above operation.

Next, an example of a cutting machine to which the cutting device configured as described above is applied will be described with reference to FIG. In the figure, the cutting machine 11 is mounted on a pair of rails 16 laid in parallel,
It is configured so that it can run along the rail 16.
The cutting machine 11 is a traveling saddle 17 equipped with a traveling motor 12.
a and a carriage 17 composed of a cross girder 17b provided in a direction orthogonal to the rail 16, a traverse carriage 18 provided so as to traverse along the cross girder 17b, and the carriage 18 attached to the traverse carriage 18 And a traverse motor 13 that is driven. The plasma torch 1 is mounted on the traverse carriage 18.

The cutting machine 11 has a numerical control device (NC device) including the above-mentioned control unit 10 mounted on a carriage 17, and this NC
The apparatus 10 is configured as a numerically controlled cutting machine in which the movement of the carriage 17 and the traverse carriage 18 and the operation of the plasma torch 1 are controlled. In this cutting machine 11, the material to be cut 5
Is placed between the rails 16 and the control section 10 inputs information about a cutting line for the material to be cut 5 and information on the cutting speed to operate the material, thereby cutting the target shape from the material to be cut 5. It is possible.

In the above cutting machine 11, the nozzle 3 attached to the plasma torch 1 during the cutting operation for the material 5 to be cut.
By measuring the usage time of and comparing it with the proper cutting speed line 7 stored in the control unit 10, it is possible to always cut the material 5 to be cut in a slag-free state until the nozzle 3 is completely consumed. Is.

[0026]

As described in detail above, in the plasma cutting method according to the present invention, it is possible to always cut the material to be cut in the slag-free state regardless of the increase in the usage time of the nozzle attached to the plasma torch. The cutting speed can be set.

In the plasma cutting device according to the present invention,
It is possible to cut the material to be cut by automatically setting the appropriate cutting speed according to the increase in the usage time of the nozzle.

Therefore, the cut surface of the material to be cut can be maintained in a slag-free quality regardless of the increase in the usage time of the nozzle, and the nozzle can be used until it is completely consumed. Therefore, there is no need to discard the nozzle that is still in a usable state, and the cost required for cutting can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram of a cutting device according to an embodiment.

FIG. 2 is a diagram showing data of an appropriate cutting speed corresponding to a usage time of a nozzle.

FIG. 3 is a perspective view illustrating an example of a cutting machine.

[Explanation of symbols]

 1 Plasma torch 2 Electrode 3 Nozzle 4 Gas supply source 5 Material to be cut 6 Power supply 7 Proper cutting speed line 8 Measuring section 10 Control section 11 Cutting machine 12 Traction motor 13 Traverse motor 16 Rail 17 Truck 18 Traverse carriage

Claims (2)

[Claims] 1. An appropriate cutting speed that does not cause slag to adhere to a cut surface according to a use time of a nozzle that allows a plasma arc to pass is previously obtained, and a new nozzle is attached to a plasma torch, A plasma cutting method characterized in that the cutting speed is reduced in accordance with an increase in use time. 2. A storage unit that stores data of an appropriate cutting speed according to the usage time of the nozzle, a measurement unit that measures the usage time of the nozzle attached to the plasma torch, and a nozzle measured by the measurement unit. Calculating unit for calculating the cutting speed of the nozzle from the data of the appropriate cutting speed stored in the storage unit corresponding to the usage time of the plasma, and moving means for moving the plasma torch based on the cutting speed calculated by the calculating unit. And a control unit that controls the speed of the plasma cutting device.