JPS59177154A - Plasma spraying apparatus - Google Patents

Abstract

PURPOSE:To suppress the wastefulness of a plasma spraying material by enabling plasma spraying to various small complicated functional parts, by additionally providing a flowline change-over mechanism to a powdery plasma spraying material flowline. CONSTITUTION:A plasma spray apparatus is constituted of a powdery plasma spraying material supply apparatus 1, a plasma spraying gun 2 and powdery plasma spraying material flowlines 31, 32, 33 connecting both of them and a flowline change-over mechanism 4 is additionally provided to the position directly before the plasma spraying gun 2 of the flowline. The flowline change- over mechanism 4 is equipped with a powdery plasma spraying material inflow port A, an outflow ports B, C and the outflow port C is connected to the powdery plasma spraying material supply port D of the plasma spraying gun 2 through a flowline 32 while the outflow port B is connected to the supply apparatus 1 through the recirculation flowline 33. In this case, the inflow port A, the outflow port B and the outflow port C are constituted so as to connect or block the circuit connecting respective ports A, B, C by the indicating order from the outside.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a thermal spraying apparatus, and more particularly, the present invention relates to a thermal spraying apparatus, and more particularly, to a thermal spraying apparatus that allows fine adjustment of the supply of thermal spray material powder to a thermal spray gun in a short time,
The present invention also relates to a thermal spraying apparatus that can suppress wastage of thermal spraying material powder and is highly economical.

[Technical background of the invention and its problems]

Thermal spraying uses molten or semi-molten metal.

It is one of the surface treatment methods in which fine particles of alloys, ceramics, organic synthetic materials, etc. are sprayed onto the surface of the material to be thermally sprayed, and the particles are laminated to form a film, and its application fields are wide.

Various methods are known for thermal spraying, but since the recent introduction of methods that use powder as the thermal spraying material (powder thermal spraying method) and methods that use plasma jet as the thermal spraying flame, there have been changes in the thermal spraying material and the material to be thermally sprayed. The scope of application is expanding dramatically.

As a result, various functional parts (for example, capacitors) that were previously considered unsuitable for thermal spraying.

It is now possible to thermal spray onto recording heads and dentures).

However, in this case, the following problems have arisen industrially. That is, this is a problem associated with the configuration of the thermal spraying apparatus used in the powder thermal spraying method.

Generally, this type of thermal spraying apparatus is comprised of a thermal spraying material powder supply device that supplies thermal spraying material powder at a predetermined flow rate on a supply gas, a thermal spraying gun, and a thermal spraying material powder flow path that connects the two. The flow path is usually a hose with a length of about 2 m. Therefore, even if the supply amount of the thermal spray material powder is adjusted by operating the supply device, a time lag corresponding to the flow path length inevitably occurs before the result appears in the thermal spray gun. Furthermore, if the flow path length is large, there is an increased tendency for the thermal spray material powder to remain irregularly in the flow path during intermittent thermal spraying, and the smooth progress of the overall thermal spray material powder supply is inhibited.

Generally speaking, functional parts are often small and complex in shape. Therefore, while it may be possible to use a small amount of thermal spray material for functional parts, on the other hand, it is often an expensive material.

Therefore, when an expensive thermal spraying material is sprayed onto a small and complicated area, the yield of the thermal spraying apparatus having the above-mentioned configuration is extremely poor, the thermal spraying material is wasted, and economic efficiency is reduced.

Therefore, there has been a desire in the industry to develop a thermal spraying device that can finely adjust the response of a thermal spray gun to the supply amount of thermal spray material powder without causing a time lag even for a short period of time.

[Purpose of the invention]

An object of the present invention is to provide a powder type thermal spraying apparatus that can solve the above-mentioned problems by attaching an extremely simple mechanism to a flow path system.

[Summary of the invention]

The present inventors have focused on the fact that in order to efficiently apply the thermal spraying method to functional parts, it is sufficient to supply thermal spray powder to the thermal spray gun in the required amount at the required time. On top of that, ■ By adjusting the supply of thermal spray material powder to the thermal spray gun immediately before the thermal spray material powder supply port of the thermal spray gun, the effect of the above-mentioned flow path length can be eliminated; ■ The thermal spray gun We came up with the following two points: the presence or absence or interruption of the supply of thermal spray material powder to the flow path can be made possible by switching the flow path, rather than the presence or absence or interruption of the flow of thermal spray material powder into the flow path. completed.

That is, the apparatus of the present invention is a thermal spraying apparatus consisting of a thermal spraying material powder device, a thermal spraying gun, and a thermal spraying material powder flow path connecting the two.
The present invention is characterized in that a flow path switching mechanism is interposed in the flow path at a position immediately before the thermal spray gun.

The device of the present invention will be explained based on a conceptual diagram illustrating the device.

In the figure, 1 is a thermal spray material powder supply device, and 2 is a thermal spray gun. 3
4 is a thermal spray material powder flow path, and 4 is a flow path switching mechanism according to the present invention. It is generally preferable that the flow path switching mechanism 4 is a three-way valve as shown in the figure, and the direction of the flow path can be changed by an external operation command signal. Thermal spray gun 2
The thermal spraying material powder supplied to is thermally sprayed onto the surface of the material to be thermally sprayed 5.

In the apparatus of the present invention shown in the figure, the flow path switching mechanism 4 is equipped with a thermal spray material powder inlet A, an outlet B, and an outlet C. The outflow port B is connected to the supply device 1 through the circulation channel 33.
is connected to. The circuits connecting the inlet A, the outlet B, and the outlet C are connected or disconnected by an external command signal.

For example, if the inlet A and the outlet B are connected and the circuit between the inlet A and the outlet C is cut off, the thermal spray material powder supplied from the supply device 1 through the flow path 3 will be transferred to the spray can 2. from the outlet B through the flow path 33 without being supplied to the supply device 1.
Reflux to. Then, when thermal spraying is to be performed, if the inlet A and outlet C are connected and the circuit between the inlet ROM and the outlet B is interrupted for a predetermined period of time, a predetermined amount of thermal spray material powder will be transferred from the flow path 3□ to the thermal spray gun 2.
and is sprayed onto the surface of the material 5 to be thermally sprayed. in this case,
Since the switching mechanism 4 is attached to a position directly in front of or very close to the thermal spray gun 2, the length of the flow path 32 between the switching mechanism and the thermal spray gun 20 is extremely short, so that the thermal spray material powder cannot be removed by operating the switching mechanism 4. The presence or absence or interruption of the supply amount will immediately appear in the thermal spray gun 2 without a large time lag.

If the operation of the switching mechanism 4 is programmed in advance, automatic thermal spraying can also be made possible.

[Embodiments of the invention]

Example 1 Diameter 100 run? ; The surface of a cylinder made of 5US304 with a 100mm diameter was sandblasted with alumina powder having a particle size of 1mm. Place this on the designated rotary table and turn it for 33.3rp.
Rotate at a speed of 125 m and spray the surface (side) at a distance of 125 mm.
The Ni-Cr alloy was plasma sprayed under conditions of a current value of 700 A and a voltage value of 34 V. The equipment shown in the figure is Ni
-Feeding pattern of Cr alloy powder is 0.9 second supply -〇,
The 9-second interruption was repeated.

As a result, a Ni(:r sprayed layer (thickness: 200 μm) was formed only on half of the side surface of the cylinder, and no sprayed layer was formed on the remaining half, which remained 5US304.

For comparison, an attempt was made to form a sprayed layer of the same thickness on only half of the cylindrical side surface by operating the supply device 1 using a conventional device with the switching mechanism 4 removed.

The ratio of the amount of Ni--Cr powder consumed was 1:2, and the device of the invention could save about 50 tons of material.

Example 2 The entire surface of an aluminum piece measuring 100 x 50 x 3 mm thick was sandblasted with alumina powder having a grain size of 1. This specimen was placed on the thermal spraying table position, and it was made to reciprocate once in the transverse direction at a speed of 300 roux over a distance of 300 mm, and then vertically for 5
Plasma spraying of alumina powder was performed for 0.35 seconds at 0.65 second intervals using the apparatus of the present invention while repeating the movement of moving the cylinder. The thermal spraying dispute concerns the thermal spraying distance of 95
The current value was 900 A and the p voltage value was 36 V.

For comparison, similar plasma spraying was performed using a conventional device with the switching device removed. The ratio of the amount of alumina powder consumed to form a sprayed alumina layer of the same thickness was 35:100, and in the case of the apparatus of the present invention, it was possible to save about 65 parts.

〔Effect of the invention〕

As is clear from the above explanation, the device of the present invention is equipped with an extremely simple mechanism and can finely adjust the supply of thermal spray material powder to the thermal spray gun with good responsiveness without causing a time lag. It can be thermally sprayed onto various functional parts, and it is highly economical as waste of thermal spraying material is suppressed, so its industrial value is great.

[Brief explanation of drawings]

The figure is a conceptual diagram of the device of the present invention. 1... Thermal spray material powder supply device, 2... Thermal spray gun, 3.
．． 3. ．． 33... Thermal spray material powder flow path, 4... The flow path switching mechanism, 5... Thermal sprayed material.

Claims (1)

[Scope of Claims] 1. In a thermal spraying device comprising a thermal spraying material powder supply device, a thermal spraying gun, and a thermal spraying material powder flow path connecting the two, a flow path switching mechanism is interposed in the flow path in front of the thermal spraying gun. A thermal spraying device characterized by: 2. The thermal spraying apparatus according to claim 1, wherein the flow path switching mechanism is a three-way pulp operated by an operation command signal.