JP3251790B2 - Powder coating equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder coating apparatus having an improved production capacity.

[0002]

2. Description of the Related Art When a metal film, an inorganic film or the like is formed on powder particles of metals, ceramics, plastics, etc., characteristics different from those of the original powder particles can be given. For example, when tungsten particles, diamond particles, and the like are coated with copper, sinterability is improved, and a sintered body having excellent thermal conductivity is obtained. The copper-coated powder is also used as a filler for electromagnetic shielding. As a means for coating the powder particles, there are known a method of performing electroplating or electroless plating with the powder in a suspended state, a method of forming a predetermined film on the powder in a fluidized state by sputtering, and the like. The present inventors also introduced a sputtering apparatus using a rotary barrel in Japanese Patent Application Laid-Open No. 2-153068 as an apparatus for coating powder by sputtering.

[0003] In this powder coating apparatus, as shown in FIG. 1, a reduced pressure heat treatment chamber 1 containing a raw material powder P is connected to a rotary barrel 2, and the raw material powder is subjected to sputtering coating by a sputtering source 3. The raw material powder P is accommodated in a container 1b provided with a heating coil 1a, and is supplied to the inside of the rotary barrel 2 via a supply conduit 1e by a screw feeder 1d driven by a motor 1c. The supply conduit 1 e is provided with a bearing 1 provided on one end face of the rotary barrel 2.
supported by f. An inert gas introduction pipe 1g provided concentrically with the supply conduit 1e faces the inside of the rotary barrel 2.

[0004] The rotary barrel 2 is supported by a driving roll 2a and a driven roll 2b. The drive roll 2a receives power from the motor 2c and rotates the rotary barrel 2 around a horizontal axis. The sputtering source 3 is fixedly arranged in the rotary barrel 2 by an arm 3b hermetically supported by a bearing 3a at an end face opposite to the end face into which the supply conduit 1e is inserted, and is slightly larger than the axial length of the rotary barrel 2. The short target 3c is arranged obliquely downward. Raw material powder P supplied to the axial end of the rotary barrel 2 from the supply conduit 1e
Are distributed over the entire length of the barrel shaft as the rotary barrel 2 rotates, and flow on the inner bottom surface of the rotary barrel 2. The coating material is beaten from the target 3c by the impact of the plasma of Ar or the like, flies in the rotary barrel 2 and adheres to the raw material powder P in a flowing state. When a predetermined coating layer is formed, the rotating barrel 2 is opened to take out the coated raw material powder P. Alternatively, the thickness of the coating layer can be increased by providing an appropriate external circulation path and repeatedly exposing the raw material powder P to sputtering in the rotary barrel 2.

[0005]

When the size of the equipment is increased in order to increase the production capacity of the powder coating apparatus shown in FIG. 1, various problems that have not been taken into account in a laboratory-scale apparatus become apparent. For example, keeping the distance between the raw material powder P and the target 3c constant, exhausting the inside of the rotating barrel 2, bending deformation of the sputtering source 3, and rotating barrel 2
Impact when rotating, maintenance inside rotating barrel 2
There are inspections. The present inventors have developed a mechanism suitable for a large-sized device which has solved these problems, and has disclosed in Japanese Patent Application No. 4-97375.
And Japanese Patent Application Nos. 4-97376 and 4-97379. In particular, in a large-sized apparatus, it is important to distribute the raw material powder to the rotating barrel with a uniform distribution density in the barrel axis direction. If the distribution is non-uniform, the raw material powder will be uneven in the barrel axial direction. This unevenness is eliminated to some extent by rotating the rotary barrel 11 during sputtering, but may continue throughout the sputtering period.

[0006] In places where the raw material powder is densely distributed, the number of powder particles increases as compared with the coating material flying from the target, and the coating layer formed on the surface of each particle becomes thinner, or an uncoated portion occurs. . Conversely, where the raw material powder is coarsely distributed, the coating material is applied to a small number of powder particles, so that a thick coating layer is formed or a coating layer in which the powder particles are interconnected is formed. As a result, the overall coating efficiency decreases. In addition, as the size of the apparatus increases, the axial length of the rotary barrel increases, and the depth from the opening side increases. It is difficult to distribute the raw material powder with a uniform density distribution in the barrel axis direction of such a rotating barrel. When manual work is performed, the raw material powder is easily distributed coarsely on the depth side and densely on the front side. In addition, since the distribution operation itself is performed in a dust environment, the distribution operation is easily disliked by workers. The present invention has been devised to solve such a problem, and incorporates a reversible powder supply gutter for accommodating a raw material powder at a uniform density in the longitudinal direction, thereby enabling a barrel to be used in a large-sized rotary barrel. It is an object of the present invention to provide an apparatus capable of distributing raw material powder at a uniform distribution density in the axial direction and efficiently performing powder coating.

[0007]

In order to achieve the object, a powder coating apparatus according to the present invention comprises: a rotary barrel having a rotary shaft maintained horizontally in an outer cylinder serving as an outer shell of a vacuum chamber; Target inserted inside the
A long powder supply gutter having a powder container having a length corresponding to the effective sputtering area in the rotating barrel, which is open at the top, is disposed above the movement trajectory of the powder supply gutter, and a powder supply port is provided at the bottom. A powder tank provided, and a movement mechanism for moving the powder supply gutter along a movement trajectory in an axial direction of the rotary barrel, a direction parallel to the axial direction, and a direction orthogonal to the axial direction. The raw material powder is supplied from the powder tank to the powder supply gutter at a uniform packing density in the longitudinal direction. The powder supply gutter containing the raw material powder is inverted after being stored at a fixed position of the rotary barrel, so that the raw material powder uniformly stored along the longitudinal direction is uniformly distributed in the rotary barrel in the axial direction. Distribute by density distribution.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In a powder coating apparatus according to this embodiment, as shown in FIG. 2, a moving base 20 is arranged on one side of an apparatus main body 10, and a target 30 and a powder distribution mechanism 40 are mounted on the moving base 20. ing. As shown in FIG. 3, the apparatus main body 10 constitutes a double-structured vacuum chamber in which a rotary barrel 11 is surrounded by an outer cylinder 12. The apparatus main body 10 has one side closed by the moving flange 13 and the other side
Is closed by the flange 31. The rotary barrel 11 includes a flange 16 formed on a peripheral surface of a driven gear 15 that meshes with a drive gear 14 provided on the outer cylinder 12 side.
It rotates by the power transmitted through 4 and 15. In the vicinity of the bottom of the rotary barrel 11, a stirring screw 17 swinging in the same direction as the rotary barrel 11 and in the opposite direction is arranged. The stirring screw 17 is rotated by the power transmitted through the rotary barrel 11 and further oscillates by the power transmitted through the oscillating gear 18, thereby uniformly stirring the raw material powder P during sputtering. Further, in order to perform sputtering under a certain condition, a cooling pipe 19 is attached to the outer peripheral surface of the rotary barrel 11, and the temperature inside the rotary barrel 11 is compensated by cooling water flowing through the cooling pipe 19.

In the upper part of the outer cylinder 12, a suction duct 51 of an evacuation system 50 is opened. The inside of the device body 10
The pressure is reduced by the evacuation system 50, and the inside of the rotary barrel 11 is maintained in a reduced-pressure atmosphere suitable for sputtering. The movable gantry 20 is mounted on a gantry 21 so that the
It is installed in. The movable base 20 has a target 30 and a powder distribution mechanism 4 that are movable in the horizontal direction of FIG.
0 is mounted. Thereby, the target 30 and the powder distribution mechanism 40 can move in the axial direction and the orthogonal direction of the rotary barrel 11. Moving frame 20, target 30
The movement of the powder distribution mechanism 40 is controlled by a drive system controller 22 provided on the side surface of the gantry 21. The position indicated by the solid line in FIG. 2 is the fixed position of the target 30. The target 30 is inserted into the rotary barrel 11 from this position. The target 30 indicated by the dashed line is at a standby position for performing operations such as maintenance and inspection. Target 30
Has a plurality of target bodies 32 arranged in parallel in accordance with a large-sized equipment configuration, and mounted on a housing 33. The housing 33 is supported in a cantilevered state, and is inserted into the rotary barrel 11 from an opening on one side of the rotary barrel 11.

As shown in FIG. 4, the powder distribution mechanism 40
A powder supply gutter 42 protrudes in a cantilevered state from a body 41 running along a rail 23 provided on the movable gantry 20. The powder supply gutter 42 has a powder container having a length corresponding to the effective sputtering area in the rotary barrel 11 and extends along the rail 23. The powder supply gutter 42 has a substantially U-shaped cross section with the upper part opened, and the inside serves as a powder container. The powder supply gutter 42 is attached to the rotating part 43 of the body 41. Thus, the powder supply gutter 42 is connected to the rail 2
3 can be rotated in addition to moving forward and backward. Since the fed raw material powder P is discharged by reversing the powder supply gutter 42, the powder supply gutter 42 may have an upwardly open cross-sectional shape that does not have an acute corner like a rectangular cross section. preferable. The body 41 is provided with a powder recovery mechanism 60. A collection pipe 63 extends from a collection tank 61 of the powder collection mechanism 60 via a cyclone 62,
The tip of the collection tube 63 is open downward. A suction tube 64 connected to a compression source (not shown) is connected to the cyclone 62. When removing the coated powder after the sputtering from the rotary barrel 11, the compression source is operated, and the powder stored at the bottom of the rotary barrel 11 is sucked in by the recovery pipe 63. The sucked powder is separated into solid and gas by the cyclone 62 and then collected in the collection tank 61. A part of the recovery pipe 63 can be used to clean the inside of the powder supply gutter 42 while facing the inside of the powder supply gutter 42.

A support frame 4 is provided above the powder supply gutter 42.
The powder tank 45 supported by 4 is arranged (FIG. 2). The powder tank 45, as shown in FIG.
6 or a powder supply port 47 provided with a flow control valve is provided at the lower end. The raw powder P is fed from the powder tank 45 to the entire length of the accommodating portion of the powder supply gutter 42 while moving the powder supply gutter 42 in the direction of the arrow. It is preferable to provide a leveling plate 48 in the main body of the powder tank 45 or the powder supply port 47. The leveling plate 48 levels the surface of the raw material powder P sent from the powder tank 45 to the powder supply gutter 42, and makes the filling height of the raw material powder P constant in the longitudinal direction of the powder supply gutter 42. Further, the position of the powder supply gutter 42 can be detected by a sensor 49 (FIG. 2) provided on the support frame 44, and the running state of the powder supply gutter 42 can be controlled based on this position information.

The powder supply gutter 42 has a direction parallel to the axis of the rotary barrel 11 (-direction in FIG. 2), a direction perpendicular to the axis of the rotary barrel 11 (same -direction), and
It is movable along three axial directions (similarly, -direction). The −direction and −direction movement is obtained by running the base 41 along the rail 23.
The movement in the minus direction is obtained by running the movable gantry 20 on the gantry 21. These movements are entirely controlled by the power control panel 71 and the drive system controller 22. Using the movement of the powder supply gutter 42, the raw material powder P is distributed in the rotary barrel 11 with a uniform density distribution in the axial direction in the following procedure. In addition, the raw material powder P to be sputter-coated is, if necessary,
(FIG. 2). Prior to charging the raw material powder P,
The powder supply gutter 42 is at the position shown in FIG. That is, the movable gantry 20 is moved rightward in FIG. 6, and the powder supply gutter 42 is positioned below the powder tank 45. Further, the machine body 41 is caused to travel along the rail 23 so that the powder supply port 47 of the powder tank 45 faces one end of the powder supply gutter 42.

In this state, the on-off valve 46 is opened, and the raw material powder P is sent from the powder tank 45 to the powder supply gutter 42. At the same time, the powder supply gutter 42 is moved upward in FIG. 6 (b). By associating the supply speed of the raw material powder P with the moving speed of the powder supply gutter 42, a fixed amount of the raw material powder P is fed in the longitudinal direction of the powder supply gutter 42. The sensor 49 (FIG. 2) detects that the base end of the powder supply gutter 42 has reached the vicinity of the powder supply port 47. Therefore, the on-off valve 46 is closed, and the powder supply gutter 42 is switched from forward to backward, and returned to the initial position (c).
The returned powder supply gutter 42 is uniformly filled with the raw material powder P over the entire length of the powder container. Next, the movable gantry 20 is moved to the left in FIG. 6, and the powder supply gutter 42 is aligned with the axis of the rotary barrel 11 (d). This position is detected and controlled by the controller 22 provided on the gantry 21.

The powder supply gutter 42 is inserted into the rotary barrel 11 by traveling of the body 41 along the rail 23 (e). After the sensor 49 detects that the powder accommodating portion of the powder supply gutter 42 has entered the rotary barrel 11, the powder supply gutter 42 is inverted via the rotation portion 43. The raw material powder P is sent out of the powder supply gutter 42 into the rotary barrel 11 by reversing the powder supply gutter 42 whose upper part is open. At this time, since the powder container of the powder supply gutter 42 is set to have a length corresponding to the effective sputtering area of the rotary barrel 11, the raw material powder P is distributed to the effective sputtering area with a uniform density distribution in the axial direction. . The powder supply gutter 42 retreats from the rotary barrel 11 after sending out the raw material powder P to the rotary barrel 11 (f). Next, the movable gantry 20 is moved rightward in FIG. 6 to reach the position shown in FIG. In this position, the target 30 coincides with the axis of the rotating barrel 11 as shown in FIG. Then, the target 30 is inserted into the rotary barrel 11, and the openings at both ends of the outer cylinder 12 are hermetically sealed with the moving flange 13 and the flange 31. The sealed apparatus main body 10 is depressurized to a predetermined atmospheric pressure by a vacuum exhaust system 50, a voltage is applied from a sputtering power supply 34 to the target main body 32, and sputtering is started.

After the sputtering is continued for a predetermined time, the apparatus main body 10 is opened, and the coated powder is taken out from the rotary barrel 11. At this time, the recovery pipe 63 of the powder recovery mechanism 60 integrated with the powder supply gutter 42 moves in the same manner as (d) to (f) of FIG. 6, and from the rotary barrel 11 via the recovery pipe 63 and the cyclone 62. The powder coated in the collection tank 61 is collected. In this way, the raw material powder P sent into the rotary barrel 11 using the powder supply gutter 42 is distributed to the effective sputtering region with a uniform density distribution in the axial direction. Therefore, in the rotary barrel 11, individual powder particles are exposed to uniform sputtering from the beginning, and a uniform coating is applied. Further, regardless of the axial length of the rotary barrel 11, the raw material powder P is easily fed under a constant condition. As a result, excess or deficiency of sputtering and uncoating are suppressed, and a coating powder of constant quality can be obtained with a high yield.

[0016]

As described above, in the powder coating apparatus of the present invention, the powder supply gutter filled with the raw material powder is inserted into the rotary barrel and inverted.
Raw material powder is distributed to the effective sputtering region with a uniform density distribution in the axial direction of the rotating barrel. for that reason,
The individual particles are uniformly sputter coated in the rotating barrel and a consistent quality coating powder is produced with high yield. In addition, by setting the length of the powder supply gutter according to the axial length of the rotary barrel, powder is supplied under constant conditions regardless of the size of the rotary barrel.
Therefore, work in an environment where dust is generated is omitted or reduced, and a remarkable effect is exhibited particularly in a large-sized coating apparatus.

[Brief description of the drawings]

FIG. 1 shows a powder coating apparatus proposed by the present inventors.

FIG. 2 is a layout of a powder coating apparatus according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view of a state in which a raw material powder is coated, as viewed from a barrel axial direction (a) and an orthogonal direction (b)

FIG. 4 Powder distribution mechanism with powder supply gutter

FIG. 5 shows a state in which raw material powder is being filled from a powder tank into a powder supply gutter.

FIG. 6 is a process of charging powder into a rotating barrel.

[Explanation of symbols]

11: rotating barrel 12: outer cylinder 30: target 20: moving frame 23: rail 40: powder distribution mechanism 41: body
42: powder supply gutter 45: powder tank 47: powder supply port

Continued on the front page (72) Inventor Takashi Shirokura 7-1 Takamachi Shinmachi, Ichikawa City, Chiba Prefecture Nisshin Steel Co., Ltd. New Materials Research Laboratory (72) Inventor Hiroyuki Kawakami 1-1-1 Kokubuncho, Hitachi City, Ibaraki Prefecture (56) References JP-A-2-153068 (JP, A) JP-A-3-153864 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) ) C23C 14/00-14/58 C23C 16/00-16/56 B22F 1/00-8/00

Claims (1)

(57) [Claims] 1. A rotating barrel having a rotating shaft maintained horizontally in an outer cylinder serving as an outer shell of a vacuum chamber, a target inserted into the rotating barrel, an upper part being opened , and rotating.
Powder of a length corresponding to the effective sputtering area in the barrel
A long powder supply gutter having a powder container, a powder tank disposed above the movement trajectory of the powder supply gutter, and having a powder supply port at the bottom, and an axial direction of the rotary barrel, A moving mechanism that moves the powder supply gutter along a moving trajectory in a direction parallel to and parallel to the axial direction,
A powder coating apparatus in which the powder supply gutter that uniformly accommodates raw material powders in a longitudinal direction is inverted after being charged in the rotating barrel.