JPS5835059A - Tip for plasma cutting - Google Patents

Abstract

PURPOSE:To decrease and prevent the generation of a damage on the surface of a tip for plasma cutting and to improve the durability thereof by coating and insulating the surface of said tip with a rubber adhesive agent. CONSTITUTION:The surface of a tip 2, more particularly, the bottom surface facing a material 3 to be cut is wated and insulated with an adhesive agent 21 of rubber base roughly over the entire surface. Gaseous plasma 5 is supplied into a holder 7 and a high frequency voltage is applied between an electrode 2 and the tip 20 by a DC power source 1, thereby firing a pilot arc. If the material 3 is disposed right under the tip 20 after the firing of the arc no-load electric voltage is applied to fire a main arc, by which the plasma cutting of the material 3 is effected. The tip 20 is exposed to water during the cutting and while the arc is off, but since the tip is coated and insulated with the adhesive agent 21, the oxidized area of the surface of the tip 20 is small and the damage of the tip is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cutting tip for nine-piece cutting which reduces and prevents damage to the tip surface and improves durability.

As shown in Fig. 1, the plasma cutting device generates a plasma arc between a non-consumable electrode 2 connected to the negative terminal of a DC power source 10 and a material to be cut 3 connected to the positive terminal. The material to be cut 8 is locally melted by strongly constrained and guided by the tip 4 and the plasma gas S, and the molten metal is removed and cut by the highly directional plasma fItS.
The chip is formed into a cylindrical shape with a bottom by 4Fi copper, and a screw is formed outside the upper end of the cylindrical shape.
4 m is formed on the inner circumferential surface of the lower end of the cylindrical holder T by screwing it into the internal thread * T m.
A through hole S through which one Kuzuma #E@ passes is formed in the center of the picture. And electrode 2ti holder I
If the FC is inserted, and such a plasma cutting unit is used underwater, the surface of the chip 40 will always be in water as shown in Figure 112.
As a result, the plasma arc becomes unstable due to the oxidation state. On the 709th day, a series arc 10 occurred, and the JIIj
Traces of series arc lO 11 as shown in Figure (-)
There was a serious lack of I:L in which a hole 3112 occurred and chip 4 was damaged.

Therefore, recently, as shown in Fig. 4-, a chip 14 is coated with a heat-resistant material 18 to prevent chip insertion and leakage, and a chip 1 is coated with a cover 15 made of a heat-resistant material as shown in Fig. 5. @ Seven times used to fix damage to the tip. However: HK shot coach-in l and nine chitsu 114 are heat resistant #1s with poor elasticity, and the buttocks are wet in water.
When used for V-cutting, heat-resistant *tSS tends to peel off in a short time,
It has the disadvantage of lacking durability. On the other hand, the manufacturing cost of the chip 16 equipped with the cover 1s is high. If the cover 1s comes into contact with the material to be cut by mistake, the p-bar 1s will be damaged and there is an extremely high risk of damaging the tick 16.
Tatami mats had the disadvantage of being difficult to manufacture for use with cutting torches.

The present invention has been made in view of the above-mentioned points, and is based on the chip li! For plasma cutting, the surface is insulated and coated with a rubber-based O adhesive, which makes it possible to reduce the price and make it possible to perform underwater one-turn cutting more stably and for a longer period of time, greatly improving durability. Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

FIG. 6(a), (closed is an enlarged cross-sectional VFI diagram and a Takaji diagram showing one part of the plasma cutting tip according to the present invention,
Figure jI7 is a block diagram of a %f%9 underwater plasma cutting device using the same chip. Components that are the same as those in Figures 1 and 2 are designated by the same reference numerals, and 70*Vt is omitted. On the narrow side of the chip 2g, the lower part 19 facing the cut piece 3 is insulated and coated over the entire surface with a rubber-based O binding agent 21. When attaching this adhesive grade 311210, after cleaning and drying the chip 2. Apply it to the lower surface of 120 and leave it to dry for about 24W# to harden.

A plasma cutting device Kj? equipped with a tip 2Q having such a configuration? Then, put the holder inside the Putzuma Gas Jsl.
After applying a high-frequency electric current E between the electrode 2 and the tip 20 using the electric light, and igniting the pilot arc, place the workpiece 8t below the tip 200.
When a no-load voltage is applied and the main arc is ignited, plasma cutting of the material to be cut 3 is started. step 20
The chip 20 is exposed to water during cutting and during arc cessation, but since it is insulated with the adhesive 21, the chip 20o
*As shown in FIG. 8, the surface lI to be oxidized is extremely small, preventing damage, and even if the tip 20 comes into contact with the material 3 to be cut, it will not be damaged! The arc can be maintained stably.0 Figure 9 shows how a stainless steel plate with an EIO thickness of 100 mm is cut in water using the conventional continuous firing chip 114 (see Figure 4) and the tick 20 according to the present invention under the cutting conditions shown in the table below. FIG. 6 is a diagram showing a change in shape when it is closed.

As is clear from the figure, the tip 20 according to the present invention hardly changes the internal shape of the tip even though the cutting time is about four times longer than that of the thermally sprayed tip 114. It will be appreciated that there is also less damage to the nine surfaces.

As explained above, the plasma cutting tip according to the present invention! ! 94 The image is insulated and covered with a rubber adhesive.
Because of this, the absolute Il effect is greater than that of conventional chips without surface protection, and series arcs are less likely to be seen. It has excellent effects, such as being able to maintain the arc stably even when exposed to influences such as arc blowback, arc blow-back, and dross from mineral rebound, and being able to extend the cutting time underwater by more than 5 times.

9. Even when compared to the conventional surface-protecting 9-chip 1, the insulation effect is greater, and there is no risk of damaging the tip itself even if it comes into contact with the material to be cut.Furthermore, the manufacturing cost is low. It has many advantages, such as being easy to manufacture, difficult to peel off the adhesive, easy to recode even if removed, and providing a highly durable tick.

Table A brief look at the drawings - Figure 1 is a configuration diagram of a plasma cutting device in the atmosphere, Figure 2 is a configuration diagram of a plasma cutting device in water, #I3
Figures (&) and 伽) are an enlarged cross-sectional view and a bottom view showing the shape of a conventional tip when cut underwater for a long time.
$II4wA (a), (b) An enlarged cross-sectional view of a conventional thermal spray tip and I & Wi. Figure 5 (a), 佽) is an enlarged cross-sectional view and bottom view of a conventional tip with a protective cover, $
1611(a), 弽) is a book! An enlarged cross-sectional view and a bottom view showing an embodiment of the chip according to the present invention; Fig. 7; a block diagram of underwater plasma cutting using the chip according to the present invention; and Fig. 8 (a) * (b). An enlarged cross-sectional view and a side view showing changes in the shape of the chin 10 according to the present invention, FIG. 9 is a book@
FIG. 2 is an enlarged cross-sectional view of the tip showing the change in shape of the chip and the sprayed chip 1 due to brightness.

8...Through hole, 20...Tick, 21-...
Rubber adhesive.

Patent applicant: Mitsui Engineering & Shipbuilding Co., Ltd. Agent Masaki Yamakawa (and 1 other person) Figure 1 Figure 2 Figure 3 CG) (b)

Claims (1)

[Claims] Plasma cutting chip 0 characterized in that the chip surface is insulated and coated with a rubber adhesive.