JPH0310681B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to an apparatus for producing an abrasive material made of metal particles, which is used for shotplast or shotpeening the surfaces of aluminum, zinc, or other metal casting products, molds, etc. using an abrasive device. In particular, it is intended to enable mass production of abrasives having a spherical or nearly spherical shape easily and efficiently with a controlled particle size. [Prior Art] Conventional apparatuses for manufacturing metal particles for abrasives (abrasives) include, for example, those that cut stainless steel wire rods of a predetermined thickness into predetermined lengths using a cutting machine to obtain stainless steel cut wires. be. According to this, the initial shape is cylindrical with sharp corners, and the cleaning ability is relatively high.
Moreover, an abrasive material with excellent corrosion resistance can be obtained. Other abrasive materials that focus on the corrosion resistance of stainless steel include stainless steel beads and stainless steel grids, which are widely used. [Problems to be solved by the invention] However, stainless steel abrasives obtained using such conventional manufacturing equipment have problems in various aspects such as their fluidity, lifespan, price, and manufacturing difficulty. There's a problem. For example, stainless steel cut wire has cutting burrs because it is obtained by cutting the wire, and when using it by projecting it onto the object to be polished with a polishing device, it is necessary to round the corners by separately projecting it in advance. The finish of the object to be polished becomes inconsistent. Further, as a polishing device such as a shotplast device repeatedly sprays abrasive onto an object to be polished, the fluidity of the abrasive changes and the amount of spray tends to pulsate. Furthermore, especially when obtaining particles with a small size, cutting is troublesome and the cost is relatively high. Stainless steel beads, on the other hand, are more expensive than cut wire, and also have the problem of being easily crushed during blasting due to shrinkage cavities formed inside them during the manufacturing process, resulting in a short lifespan as an abrasive material. It was hot. Stainless steel grit is relatively inexpensive and has high grinding performance because of the large amount of edges that are always present. However, on the other hand, there were problems in that it was difficult to achieve a smooth finish on the object to be polished, and the service life was relatively short. This invention was made by focusing on such conventional problems, and its purpose is to utilize a manufacturing device different from the above-mentioned wire cutting and casting, and a device with a simple structure. The object of the present invention is to enable efficient mass production of abrasives having a spherical or nearly spherical shape with controlled particle size. [Means for solving the problem] A metal feeder is equipped with a plurality of impeller blades that are attached to an output shaft and rotate together, and a distributor located at the center of rotation of the impeller blades, and metal fed through the distributor is provided. A projection device that projects small metal flakes at a predetermined speed using the rotating centrifugal force of an impeller blade; a collision device including a collision plate; a conveyance device for transporting a projectile by a bucket elevator disposed between a downstream side of the collision device and an upstream side of the projection device;
A first aspect of the present invention provides an abrasive production apparatus characterized by comprising: a control means for controlling the number of times the projection device projects small metal flakes onto the collision device to a predetermined number of times; A projection device includes a compressed air source communicating with the user and a nozzle attached to the tip of an introduction tube, and projects small metal flakes fed into the introduction tube from the nozzle at a predetermined speed using compressed air; A collision device consisting of a collision plate made of a high hardness material, which is installed at a predetermined angle with respect to the projection direction, facing a projection port for projecting flakes, and between the downstream side of this collision device and the upstream side of the projection device. A polishing machine characterized by comprising: a conveying device for transporting a projecting object using a bucket elevator provided therein; and a control means for controlling the number of times the projecting device projects small metal flakes onto a collision device to a predetermined number of times. A scavenging material manufacturing device is provided as a second invention. [Function] In this invention, the projection device enables
A small metal flake is repeatedly struck against a high-hardness body at a speed of 100 m/sec to roll the small metal flake into a spherical or nearly spherical shape. At this time, the number of repetitions of projection is controlled based on the relationship between the projection speed and number of projections determined in advance and the particle size of the obtained metal particles, and the particle size of the metal particles is optimally adjusted as an abrasive.
In this way, it is possible to continuously produce a large amount of inexpensive abrasive material that has a predetermined particle size distribution, has stable fluidity, has a long life, and has a long life. [Example] Hereinafter, this development will be explained based on the drawings. 1 to 10 are diagrams showing one embodiment of the present invention. First, to explain the configuration, in the abrasive material manufacturing apparatus shown in FIGS. A rotary drive device 3 fixed to the upper part of the body 2 and consisting of an electric motor, for example.
An impeller section 4 is coupled to an output shaft 3a of the motor. The impeller section 4 includes a plurality of impeller blades 5 that rotate integrally with the output shaft 3a, and impeller blades 5 that are attached to the end of the output shaft 3a.
a distributor 6 located at the rotation center of the
The impeller box 7 covers them. A suction port 6a is formed at one end of the distributor 6, and a plurality of discharge ports 6b are formed at the side surface. A projection port 8 communicating with the inside of the box 2 is formed on the lower surface of the impeller box 7, and a receiving tray 9 facing the suction port 6a of the distributor is provided on the side surface. In addition, 10 is a control gauge, which is connected to the distributor 6.
It is formed inside the impeller box 7 so as to cover the impeller box 7, and controls the discharge amount of the discharge port 6b. 11 is a bearing for the output shaft 3a. A collision device 12 is disposed above the inside of the box 2, facing the projection port 8 formed on the top surface thereof.
is attached via a hanger 13. The collision device 12 of this embodiment is composed of a reflector 12A made of a high hardness material such as 27cr cast iron, and a reflector 12B disposed adjacent to and parallel to the reflector 12A. An apron plate 14 is formed inside the box 2 and partitions diagonally from the top to the bottom, and guides particles after colliding with the collision device 12 to a reservoir 15 at the bottom. On the side of the box 2, a conveying device 16 is provided that extends upward from the reservoir 15 and reaches a position above the projection device 1. The figure shows a bucket elevator equipped with a large number of bucket carts 16a that are reversely circulated in the vertical direction. Housing 17 containing the above-mentioned transport device 16
A hopper 18 is provided at the top of the hopper 18 into which the abrasive particles transported by the bucket 16a are thrown.
Further, on the inlet side of the hopper 18, a dust wind separator 19 is installed to wind-select fine particles among the particles. On the other hand, on the exit side of the hopper 18, a flow rate regulator 20 is installed between it and the receiving tray 9 of the projection device 1. By setting the opening degree of this flow rate regulator 20, the volume or weight of particles flowing out from the hopper 18 per unit time is regulated. C is a control device that controls the rotational drive of the projection device 1 and the operation of the conveyance device 16, and has a built-in timer for controlling the number of times of projection. Next, an experimental example of this invention will be explained. As the raw metal thin flakes M, for example, the bowl-shaped metal chips M having a diameter of 0.5 to 1.0 mm and a thickness of 0.3 mm (No. Figure 3) was used. FIG. 4 shows an apparatus for manufacturing this bowl-shaped metal chip M. This melting tank 21 is first filled with molten metal 22 having the composition shown in Table 1. This is SUS304, scrap material, Fe-Si, Fe
-The composition was adjusted using Cr and Fe-Ni and melted in a high-frequency induction furnace. This molten metal 2
2, insert the tip of a bowl-shaped protrusion 24 provided on the outer periphery of a rotating drum 23 made of copper. Then, while adjusting the temperature with the heating element 25 and adjusting the molten metal level by raising and lowering the level adjustment block 26, the rotary drum 23 is rotated at a rotation speed of about 200 to 300 rpm, and the tip of the protrusion 24 is heated. The attached molten metal is at least partially solidified to form the protrusion 24.
By peeling it off, a bowl-shaped metal chip M was obtained.

[Table] The bowl-shaped metal chip M manufactured in this way is
When the dust is put into the bottom of the box 2 shown in FIG.
It is guided to the impeller part 4 of the projection device 1 at a flow rate controlled by the flow rate, and is projected from the projection port 8 by the rotational centrifugal force of the impeller blade 5. and collision device 1
After colliding with the second reflecting plate 12A to 12B, it slides down on the apron plate 14, falls into the pool 15, and is again transported to the hopper 18 by the transport device 16. As the above steps are repeated, the impact of the collision gradually shapes the metal particles from a bowl shape to a spherical shape. A small amount of dust generated during this time is separated by a dust wind separator 19 and collected by a bag filter (not shown). The number of repetitions of the above projection cycle is
For example, the operation time of the projection device 1 can be controlled by a timer in the control device C. In other words, if we put 100 kg of bowl-shaped metal chips M into the hopper 18 and adjust the flow rate regulator 20 to 100 kg/min, one cycle will take 1 minute, and to make 100 shots, we need to set the timer for 100 minutes. You can set it to . In this way, the spheroidized material was made into spheres by repeated blows by continuous projection, and after passing through a 4000 μm sieve, a 105 μm
By passing through a sieve, an abrasive having a particle size of 105 to 4000 μm can be easily obtained. For example, Table 2 shows an example of the particle size structure of the sieved metal particles for polishing obtained by performing the above-mentioned treatment for 1 to 24 hours.

[Table] As is clear from Table 2, the metal particles according to the present invention have a well-uniformed particle size, and meet the JIS G5903 S40
fully satisfies the specifications. The particle size, fluidity, cleaning performance, lifespan, etc. of metal particles as an abrasive material manufactured by the abrasive device shown in FIG. 1 will be explained below based on experimental results. (Regarding Particle Size) FIG. 5 shows the relationship between the particle size and the number of projections using the projection speed as a parameter. When bowl-shaped metal chips M with an initial particle size of 740 μm are repeatedly projected using the abrasive manufacturing device shown in Fig. 1, they are gradually bent and spheroidized, and their central particle size (50 μm when sieved with a sieve mesh) % equivalent particle size) changes. In this case, the faster the projection speed is, the fewer times the projection is required to form a sphere, and at a projection speed of 70 m/sec, it will become spherical approximately 150 times.
At 50 m/sec, almost spherical metal particles with a center particle diameter of about 500 μm were obtained after about 300 cycles. Figure 6 shows the number of times a bowl-shaped metal chip M with an initial particle diameter of 740 μm is repeatedly projected using the abrasive material manufacturing apparatus shown in Figure 1 until abrasive particles with a center diameter of about 500 μm are obtained. This represents the relationship with projection speed. As is clear from the figure, when the projection speed is less than 20 m/sec, the central particle size remains unchanged even after repeated projections of 1000 times or more.
Metal particles with a diameter of 500 μm cannot be obtained. On the other hand, when the projection speed exceeds 100 m/sec, the effect of increasing the projection speed disappears. In other words, the projection speed in this invention is 20m/
A range of sec to 100 m/sec is appropriate. Figure 7 shows the projection of bowl-shaped metal chips M with an initial particle size of 740 μm using the apparatus shown in Figure 1 using a single reflector 12A until abrasive particles with a center particle size of 500 μm are obtained The number of times and the inclination angle θ of the reflection plate 12A
A relationship with is required. That is, when the angle θ is between 0 and 30 degrees, there is almost no influence of the inclination angle on the particle size. on the other hand,
When the inclination angle θ is 70 degrees or more, the number of projections is required to be twice or more compared to the above. From this fact, the collision device 12 tilts one or two reflectors 12A at an inclination angle θ=0 to 30 degrees.
It is appropriate to have a variable or fixed configuration. (About fluidity) When a cast product is shot blasted with abrasive particles, the changes in fluidity of the abrasive particles before and after 500 shots are compared with the abrasive material obtained by this invention. A comparison was made with commercially available abrasive materials, steel shot and stainless steel cut wire. The fluidity in this case was measured using the flow angle measuring device 30 shown in FIG.
A sample of abrasive material 33 is placed on the surface of a flow plate 32 made of mild steel plate supported at an upward slope, and when the flow plate 32 is gradually tilted, the angle of inclination is the point at which the abrasive material 33 begins to slide down. (Flow angle) α was measured with a protractor 34. Note that 35 is a rotation axis of the flow plate 32. Reference numeral 36 denotes a flow plate support roller, which is attached to a slider 38 that is attached to a support rod 37 so as to be movable up and down. Table 3 shows the flow angle measurement results. As is clear from this table, before projection (unprojected)
The abrasive particles of the present invention and commercially available steel shot have approximately the same fluidity, but

[Table] Stainless steel cut wire has a cylindrical shape, so its fluidity is extremely poor. After 500 shots, all of the abrasive materials became spherical, and the starting angles of the abrasives were the same. That is, the fluidity of the stainless steel cut wire changes significantly between before and after projection, and as a result, the flow rate during projection pulsates, resulting in an uneven finish on the object to be polished. Such an unstable phenomenon is not observed in the abrasive material according to the present invention. FIG. 9 shows the relationship between the flow angle α described above and the number of projections in the abrasive manufacturing apparatus of FIG. 1, using the projection speed as a parameter. As is clear from this figure, when the projection is repeated starting from the bowl-shaped metal chip M, the particles gradually become rounded and approach a spherical shape, the flow angle α of the particles decreases, and the fluidity increases, resulting in stable cleaning. wood is obtained. The change in fluidity at this time is similar to the change in central particle diameter shown in FIG. 5, and is largely influenced by the projection speed. (Regarding Lifespan) Table 4 shows the results of a comparative test on the lifespan of the abrasive material obtained by the present invention and commercially available stainless steel beads and stainless steel cut wires. The test method uses a shot blasting device.
The test abrasive material is continuously projected onto the casting product at a projection speed of 63 m/sec, and the life value is determined by the number of shots until the residual rate on the sieve of the specified sieve (1/2 of the sample abrasive material particle size) reaches 45%. It was evaluated as The abrasive particles according to the present invention were able to provide an abrasive life four times longer than commercially available stainless steel beads and equivalent to stainless steel cut wires.

[Table] (Regarding the cleaning effect) In order to see the cleaning effect of the abrasive material according to the present invention,
Shot blasting was performed on aluminum die-casting, and the surface finish was compared with that of commercially available stainless steel cut wire. Table 5 shows the results. The test method involved projecting abrasive particles at a projecting speed of 50 m/sec, and measuring the surface roughness of the polished aluminum die cast based on JISB-0601. As is clear from Table 5, the abrasive material of the present invention can obtain almost the same surface roughness as stainless steel cut wire with the same particle size under similar projection conditions, and can have similar abrasive effects. Admitted.

〔Effect of the invention〕

According to this invention, small metal flakes are repeatedly projected onto a high-hardness body at a projection speed within a predetermined range, and the number of projections is adjusted in accordance with the required particle size. Therefore, there is an effect that abrasive particles having the following characteristics can be provided at low cost. It has the optimum particle size depending on the object to be polished. Spherical or similar shape with no cutting burrs. Stable fluidity and uniform finish. Long lifespan. Further, according to the present invention, abrasive particles having desired characteristics can be efficiently mass-produced by combining devices with a simple structure.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway sectional view showing an embodiment of the abrasive manufacturing apparatus according to the present invention, FIG. 2 is an enlarged sectional view of the main part of FIG. 1, and FIG. 3 is an example of a small metal flake. FIG. 4 is a side view of the apparatus for manufacturing small metal flakes, FIG. 5 is a graph showing the relationship between particle size and number of projections using projection speed as a parameter, and FIG. 6 is a graph showing the relationship between particle size and projection speed. Graph showing the relationship, Figure 7 is a graph showing the relationship between particle size and impact angle on the collision device, Figure 8 is a side view of the flow angle measuring device that measures the fluidity of particles, and Figure 9 is the graph showing the relationship between particle size and impact angle on the collision device. FIG. 10 is a graph showing the relationship between the number of projections of abrasive particles and the flow angle obtained by the apparatus shown in the figure, and FIG. 10 is a partially cutaway sectional view showing another embodiment of the abrasive manufacturing apparatus according to the present invention. . 1 is a projection device, 12 is a collision device, 16 is a conveyance device, and C is a projection number control means.

Claims (1)

[Claims] 1. A device comprising a plurality of impeller blades that are attached to an output shaft and rotate together, and a distributor located at the center of rotation of the impeller blades,
A projection device that projects the small metal flakes fed through the distributor at a predetermined speed by the rotational centrifugal force of the impeller blade, and a projection port that projects the small metal flakes from this projection device in the direction of projection. A conveyance device that transports the object to be projected using a collision device consisting of a collision plate made of high-hardness material attached at a predetermined angle, and a bucket elevator disposed between the downstream side of this collision device and the upstream side of the projection device. and a control means for controlling the number of times the projection device projects small metal flakes onto the collision device to a predetermined number of times. 2. A projection device comprising a compressed air source communicating with an introduction pipe and a nozzle attached to the tip of the introduction pipe, and projecting small metal flakes fed into the introduction pipe from the nozzle at a predetermined speed using compressed air; A collision device consisting of a collision plate made of a high hardness material and mounted at a predetermined angle with respect to the projection direction, facing a projection port through which small metal flakes are projected from the device, and a downstream side of the collision device and an upstream side of the projection device. and a control means for controlling the number of times the projecting device projects small metal flakes onto the collision device to a predetermined number of times. Characteristic abrasive material manufacturing equipment.