JPH10176227A - Device for recycling aluminum machining scrap - Google Patents

Abstract

PROBLEM TO BE SOLVED: To recycle aluminum turnings in high yield while saving manpower, energy and space. SOLUTION: A device for recycling aluminum machining scrap is constituted of a preliminary molding apparatus 1 for preliminarily molding prescribed quantity of aluminum machining scarp, a heating apparatus 11 for heating the preliminary moldings P molded by the preliminary molding apparatus 1 to a temp. of >=480 deg.C and less than m.p. in a nonoxidizing atmosphere and a hot pressing apparatus 20 which is disposed adjacently to the heating apparatus 11 and sinters the preliminary moldings P under pressing while maintaining at a prescribed temp. within a temp. range described above.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a facility for recycling aluminum swarf, and more particularly to a facility for recycling aluminum alloy cutting chips to which cutting oil has adhered as a compact having the same physical properties as the original aluminum alloy. .

[0002]

2. Description of the Related Art In general, manufacturers of aluminum products generate a large amount of powdery, chip-like or thin-plate-like aluminum cutting chips (hereinafter referred to as aluminum die powder) to which cutting oil has adhered. This aluminum Dalai powder usually has little scrap value, is collected by a recycling company as industrial waste, degreased in a rotary kiln, etc., remelted in a melting furnace, and delivered to the manufacturer as an ingot. It is recycled in.

[0003]

However, since the manufacturer and the reprocessing company are generally far apart,
Both of the above-mentioned recycling methods have a problem that not only requires a storage place for the aluminum Dalai powder, but also requires a great deal of labor and cost for its collection and transportation. In addition, facilities such as a rotary kiln and a melting furnace require a large installation space and a large amount of fuel, and there is a problem that oxidation of aluminum is inevitable during degreasing and melting. In particular, since the aluminum dalai powder has a large surface area, if the aluminum dalai powder is poured into the molten metal as it is, it rises above the molten metal and oxidizes the surface to generate a large amount of oxide (so-called dross) at the time of melting, thereby lowering the yield. Yield is 60-7
0% was the limit. In order to solve this problem, it is conceivable to devise whirlpools in the molten metal by electromagnetic induction or to change the flow of the molten metal with a pump or the like to quickly sink the aluminum alloy into the molten metal. A new problem arises in that costs and running costs are high and heat loss is also high.

On the other hand, as means for solving the problem in the above recycling method, Japanese Patent Publication No. 61-41961 discloses a method of compressing aluminum dalai powder into a predetermined shape at a pressure of 4 ton / cm ² to produce a compact. A method has been proposed in which the compact is placed in a die and heated at a temperature of 470 ° C. while applying a pressure of 80 kg / cm ² by a suitable pressurizing means to produce a sintered part. However, in this method, is extremely low compared to the tensile strength of the sintered part is 4.3 kg / mm ² and the aluminum or aluminum alloy original tensile strength (16~28kg / mm ^2), and specific gravity Only a material having a specific gravity smaller than that of the aluminum alloy can be obtained, and it is difficult to practically use this as a mechanical part. Therefore, in order to reuse the sintered part, re-melting is required as in the conventional case. However, when the sintered part is put into the molten metal, the sintered part floats on the molten metal and surface oxidation occurs to generate dross. However, it has been found that there is a problem that not only the yield is lowered but also the melting takes time.

[0005] Therefore, the present invention is to save labor, energy,
It is an object of the present invention to make it possible to recycle aluminum Dalai powder with good yield while saving space.

[0006]

According to the present invention, as a means for solving the above-mentioned problems, a preforming apparatus for preforming a predetermined amount of aluminum cuttings, and a preformed body formed by the preforming apparatus are non-oxidized. A heating device for heating to a temperature range of 480 ° C. or more and less than the melting point in a neutral atmosphere, and pressure sintering the preformed body disposed adjacent to the heating device while maintaining the preformed body at a predetermined temperature within the temperature range. This is to constitute a facility for recycling aluminum cutting waste comprising a hot press device.

The heating device comprises a housing forming a heating chamber in a non-oxidizing atmosphere, a guide rail for supporting the preform, and an induction heating coil for heating the preform on the guide rail. I have. The preform is heated from room temperature to a temperature of 480 ° C. or higher and lower than the melting point by induction heating in a heating chamber, and cutting oil remaining in the preform is removed.

[0008] The hot press apparatus basically includes a press die composed of a movable die and a fixed die, a hot plate for heating and maintaining the press die at a predetermined temperature, and a preparatory body for taking a preform in the heating device into the press die. Molded body taking-in mechanism,
A cylinder that presses the movable die against a fixed die to press the preform in the press die, and a hot press housing that forms a processing chamber in a non-oxidizing atmosphere. In addition to a sintered body taking-out mechanism for taking out the sintered body from the press die, a release agent spray device for spray-applying a release agent to the cavity surface of the press die is provided as necessary to facilitate the peeling of the sintered body from the press die. .

[0009] The processing conditions in the hot press apparatus differ depending on the components and composition of the aluminum die-spray powder.
And temperature T are represented by the general formula: P = a−bT (P is pressure kg / cm ² , T
Is degrees Celsius, a and b are constants, 900 ≦ a ≦ 126
0, 1.5 ≦ b ≦ 2.2). For example, Al-Cu powder is Al-Cu
In the case of a Si-based alloy, particularly a casting type B (AC2B) specified in JIS H5202, the pressing pressure is expressed by the following formula:
P is set to a value equal to or greater than 926-1.5T,
More specifically, the temperature is set to 480 to 580 ° C., the press pressure is set to 80 to 300 kg / mm ² , and the equation: P = 926-1.5T is set. In the upper limit the calculated value 150 kg / cm ² higher than P ₁ of the pressing pressure, which is the lower than calculated value is press pressure is given by the equation, the specific gravity is smaller than the aluminum alloy original value , Calculated value P
_{This is} because even if it is set to ₁ + 150 kg / cm ³ or more, improvement in specific gravity cannot be expected.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. As shown in FIG. 1, the aluminum cutting waste recycling equipment according to the present invention basically includes a preforming apparatus 1 for preforming a predetermined amount of aluminum die powder at a low pressure, and a non-oxidizing preformed body. A heating device 11 for heating to a predetermined temperature in an atmosphere and a hot press device 20 for sintering the preform under pressure in a non-oxidizing atmosphere at a predetermined temperature are provided in series.

The preforming apparatus 1 comprises an aluminum die powder supply mechanism 1A and a compression mechanism 1B disposed adjacent thereto.
The aluminum dust powder supply mechanism 1A is provided with a hopper 2 for accommodating aluminum dust powder, a semi-cylindrical casing 3 integrally formed at the bottom of the hopper 2, and disposed in the casing 3 coaxially therewith. Screw feeder 4
And a drive motor 5 connected to one end of the screw feeder 4. The drive motor 5 is connected to one end of the screw feeder 4 via a speed reducer (not shown), and is electrically connected to a control device (not shown) for controlling energization of the drive motor 5. Then, the screw feeder 4 is driven for a predetermined time to supply a constant amount of aluminum powder.

The compression mechanism 1B has a cylinder barrel 6a having an inner diameter of 70 to 150 mm and having an inner diameter of 70 to 150 mm. The press ram 6b is provided in the cylinder barrel 6a so as to be able to advance and retreat. Pressurizing hydraulic cylinder 7 and cylinder barrel 6a
And a gate plate 8 disposed at the lower side to open and close a lower end opening thereof. The upper end of the cylinder barrel 6 a is opened adjacent to the discharge end of the casing 3.

The gate plate 8 includes a reciprocating cylinder 9.
The cylinder 9 is moved by the cylinder 9 in a direction parallel to the axial direction of the screw feeder 4, and the cylinder barrel 6a
Forming position and cylinder barrel 6a for closing the lower end opening of the cylinder
And a charging position for transferring the preform into the heating device 11. Hopper 2
When the press ram 6b is raised and retracted to the outside of the cylinder barrel 6a, a predetermined amount of the aluminum alloy powder is supplied into the cylinder barrel 6a by driving the screw feeder 4. The aluminum die powder in the cylinder barrel 6a is compression-molded at a low pressure of, for example, about 1 ton / cm ² when the press ram 6b is lowered to enter the cylinder barrel 6a. An oil receiver (not shown) is provided below the molding position to collect cutting oil coming out of the aluminum die powder during compression molding.

In the preformed body P formed in the cylinder barrel 6a, the gate plate 8 is retracted to a standby position (left side in FIG. 1) after slightly raising the press ram 6b, and the press ram 6b is moved to the cylinder barrel 6a. It is discharged onto the press table 10 by lowering it to the lower end opening. Next, the press ram 6b is moved to the cylinder barrel 6
When the gate plate 8 is moved up to the loading position by raising the aluminum plate to the filling position above a, the preform P is loaded into the heating device 11.

The heating device 11 includes a housing 12, a guide rail 13 arranged at the same level in the extension direction of the press table 10 of the preforming device 1, and a heating device 11 arranged inside the housing 12 so as to surround the guide rail 13. And an induction heating coil 14,
A shutter mechanism 15 for shutting off the inside of the housing 12 from the outside air is disposed at a. This shutter mechanism 15
It is composed of a lifting / lowering partition plate 15a and a lifting / lowering cylinder 15b. The loading opening 12a is opened only when the preform P is loaded.

The housing 12 has a flexible seal blade 17 disposed therein so as to reduce the diffusion of furnace gas when the charging port 12a is opened. The housing 12 has an exhaust port 12b formed in the upper part on the loading side thereof and an atmosphere gas supply port (not shown) such as a nitrogen gas, an argon gas, or a mixed gas of a nitrogen gas and a hydrogen gas. Is provided.

The preformed body P sent into the housing 12 is pushed toward the discharge end every time the subsequent preformed body P is sequentially fed, and moves intermittently on the guide rail 13 while being non-oxidized. In a neutral atmosphere, the substrate is heated from room temperature to a temperature of 480 ° C. or higher and lower than the melting point, for example, 540 ° C. by induction heating. The residual cutting oil in the preform P is gasified while moving in the housing 12, and is exhausted from the exhaust port 12b.

The hot press apparatus 20 basically includes a press die 23 comprising a movable die 21 and a fixed die 22;
It comprises a hydraulic cylinder for press 24 that raises and lowers the movable die 21 and a hot press housing 25 that forms a processing chamber in a non-oxidizing atmosphere. The movable die 21 is made of a flat plate, and as shown in FIG.
A guide table 30 supported by a bellows 29 is disposed around the lower frame 28 via the lower frame 28. The surface of the movable die 21 at the lowering point is slightly lower than the surface of the guide table 30. The lower frame 28 itself is slidably mounted on a column at a corner, and the lower frame 28 has a shaft 2 of a hydraulic cylinder 24 for pressing.
4a is attached.

On the other hand, the fixed die 22 has a truncated conical recess at the bottom thereof and a cylindrical cavity 22a connected thereto, and is fixed to the upper frame 33 via the hot plate 31 and the heat insulating plate 32 like the movable die 21. ing. A hydraulic cylinder 35 for press release is attached to the upper part of the upper frame 33 via a water cooling jacket 34, and its shaft 35 a has holes provided in the water cooling jacket 34, the upper frame 33, the heat insulating plate 32 and the hot plate 31. It penetrates and is connected to the fixed die 22.

The hot press device 20 includes a heating device 1
A preformed body taking-in mechanism 37 for taking the preformed body P in the housing 12 into the hot press device 20; a sintered body taking-out mechanism 50 for taking out the sintered body S obtained by hot pressing from the press die 23; It has. In order to facilitate the separation of the sintered body S from the press die 23, a release agent spraying device (not shown) for spraying and applying a release agent to the cavity surface of the press die 23 may be provided as necessary.

The preform take-in mechanism 37 is provided at a position facing the heating device 11 with the press die 23 interposed therebetween. As shown in FIGS. 1 and 2, a pair of arms 38 and
An opening / closing cylinder 40 connected to the arm 38 via a link 39 and a moving cylinder 41 for moving the opening / closing cylinder 40 forward and backward are provided. The opening / closing cylinder 40 is fixed to a movable plate 42. This movable plate 42
Is slidably held by a spacer 44 provided on a support plate 43, and a lower portion thereof is connected to a shaft 41 a of a moving cylinder 41 fixed to the supporting plate 43. They are going to retreat. A pair of arms 38 and a link 39 connected to the opening / closing cylinder 40 are connected to the casing 25.
When the opening / closing cylinder 40 is extended, the pair of arms 38 are opened with the support shaft 46 as a fulcrum, and when the opening / closing cylinder 40 is contracted, the pair of arms 38 are closed to hold the preform P. I can do it.

When the preform P is taken in, the movable plate 41 is moved forward with the arm 38 opened to advance the movable plate 42, and the arm 38 enters the housing 12 of the heating device 11, where it is moved. When the arm 38 is closed by operating and contracting the opening / closing cylinder 40, two preforms P on the discharge end side of the preforms P arranged in a line are sandwiched as shown in FIG. When the arm 38 is retracted by the moving cylinder 41 to the position of the movable die 21 and the arm 38 is opened, two preforms P are set on the fixed die 22.

On the other hand, as shown in FIG. 3, the sintered body take-out mechanism 50 includes a cylinder 51 and a guide plate 30 which are arranged on the front side of the preforming apparatus 1 and opposed to the press die 23.
A push plate 52 is attached to the tip of the cylinder 51 so as to advance and retreat in a direction perpendicular to the preform taking-in direction. It is made to fall inside. Hot press housing 2
An atmosphere gas supply line 55 is connected to the casing 25b surrounding the side wall of the housing 5 and the sintered body take-out mechanism 50, and a non-oxidizing gas is supplied from an atmosphere gas supply source (not shown). Are maintained in a non-oxidizing atmosphere. As the non-oxidizing gas, a nitrogen gas, an argon gas, a mixed gas of a nitrogen gas and a hydrogen gas, or the like is supplied.

At the time of use, the aluminum die powder in the hopper 2 of the preforming device 1 is fed into the cylinder barrel 6a by a predetermined amount by the screw feeder 4, where it is compression-molded by the press ram 6b, and simultaneously with the aluminum die powder. Part of the attached cutting oil is removed. Next, the press ram 6b is slightly raised to remove the pressing force applied to the preform P, and the gate plate 8 is retracted to the standby position. After that, the press ram 6b is lowered again. It is extruded from the inside and falls on the press table 10. Thereafter, the press ram 6b is raised for the next cycle, and the gate plate 8 is advanced to the loading position.
The preform P dropped on the upper side is sent out into the heating device 11.

In the heating device 11, the preforms P are sequentially supplied from the preformation device 1, and the preforms P are heated in a non-oxidizing atmosphere for 2 to 30 minutes so that the preforms P are heated from room temperature to a temperature higher than the boiling point of the cutting oil. Heating is performed to a temperature lower than the melting point of aluminum, for example, a predetermined temperature in the range of 480 ° C to 580 ° C. In this process, the cutting oil is gasified by evaporation and thermal decomposition and completely removed from the preform P, and its exhaust gas
(Fume) is discharged from the exhaust port 12b.

Preformed body P set on movable die 21
The movable die 21 is raised by the driving of the pressurizing hydraulic cylinder 24, and hot-pressed by receiving a pressing pressure of, for example, 200 kg / cm ² by the movable die 21 and the fixed die 22 kept at 540 ° C. The sintered body S obtained by hot pressing is dropped from the fixed die 22 onto the movable die 21 by the action of the releasing hydraulic cylinder 35. The movable die 21 is stopped as it descends to a position slightly above the guide table 30, and when the hydraulic cylinder 51 of the sintered body take-out mechanism 50 is driven, the sintered body S
Is extracted out of the press by the push plate 52 and stored in the bucket truck 54 via the discharge plate 53. Next, the push plate 52 of the sintered body take-out mechanism 50 is returned to the original position, and graphite and other release agents are sprayed on the surfaces of the movable die 21 and the fixed die 22.

In the apparatus according to the present invention, a sintered body having a specific gravity comparable to that of an aluminum alloy and having a tensile strength equivalent thereto can be obtained. By the way, spiral or helical aluminum cutting chips (Al-Cu-Si type alloy of casting type 2 B) having a width of 2 to 10 mm and a length of 10 to 30 mm are 64 mm in diameter,
A disk-shaped preform having a thickness of 20 mm and a bulk specific gravity of 2.0,
This was heated to 480 ° C. in a nitrogen atmosphere by a heating device and hot-pressed under the conditions of a temperature of 480 ° C. and a pressing pressure of 227 kg / cm ² , a specific gravity of 2.701 kg / cm ² and a tensile strength of 27.1 kg / cm ² . A sintered body of mm ² was obtained.

In the present embodiment, the preforming body P is heated and hot-pressed in a non-oxidizing atmosphere such as nitrogen gas, argon gas, or a mixed gas of nitrogen gas and hydrogen gas. May be performed in a vacuum atmosphere. In the above-described embodiment, the case where the hot pressing is performed by the upward compression molding has been described, but the downward compression molding may be performed. Further, in the above-described embodiment, the preforming device, the heating device, and the hot press device are connected in series to move the non-processed material horizontally and in one direction. It goes without saying that you can also do things.

For example, the hydraulic unit is moved to the rear of the preforming device, the preforming device is directly installed on the floor, and the heating means and the hot press device are arranged in parallel with the preforming device. An escalator-type conveyor conveys the space between the molded body discharge port and the inlet of the heating device located at a high position, and the conveying means of the heating device preforms the preformed body in a direction orthogonal to the direction of conveyance of the escalator-type conveyor. It is preferable to dispose a heating device so as to convey the aluminum Dalai powder in a direction opposite to the moving direction. In this case, the pre-formed body formed by the pre-forming apparatus is supplied to the heating device by an escalator-type conveyor, and the aluminum die liquor powder in the pre-forming device in the direction orthogonal to the conveying direction of the conveying conveyor by the conveying means of the heating device. While being conveyed in the direction opposite to the moving direction, it is induction-heated in a non-oxidizing atmosphere, and is fed into a hot press device by a charging cylinder arranged on the discharge end side of the heating device. In this way, the height of the preforming device can be reduced, so that its stability is improved.
Since the preforming device, the heating device and the hot press device can be arranged side by side, the overall length of the system can be shortened.

In order to separate the cutting oil before the aluminum dough powder is put into the hopper of the preforming device, a large hopper for storing aluminum dory powder and a cutting oil separating device are arranged upstream of the preforming device. Escalator-type conveyors are arranged between the large storage hopper and the cutting oil separator and between the cutting oil separator and the hopper of the preforming device, respectively, and during the storage and from the large storage hopper to the preforming device. During this time, the cutting oil attached to the aluminum powder may be removed.

Further, a plurality of preforming devices are provided independently of only the preforming device which does not cause the oxidation of the aluminum alloy powder, and the preforms formed by the plurality of preforming devices are connected to a series of heating devices and a series of heating devices. The processing may be performed by a hot press device.

[0032]

As is apparent from the above description, according to the present invention, the removal of the residual cutting oil of the pre-formed aluminum Dalai powder and the hot pressing can be continuously performed, thereby saving labor and energy. Can be planned, and
Since a rotary kiln and a melting furnace, which require a large installation space, are not required, space can be saved. In addition, since the individual devices can be made compact and easily put in a non-oxidizing atmosphere, dross is not generated in the recycling process, and the yield at the time of aluminum recovery can be made close to 100%. Further, since the sintered body produced by the above-mentioned apparatus has a specific gravity comparable to that of an aluminum alloy and has a tensile strength equivalent thereto, it can be used as a part as it is.

[Brief description of the drawings]

FIG. 1 is a partial sectional front view of an aluminum cutting waste recycling facility according to the present invention.

FIG. 2 is an explanatory view of a main part of a mechanism for removing a sintered body of the apparatus of FIG. 1;

FIG. 3 is an explanatory partial sectional view taken along line AA in FIG. 1;

FIG. 4 is an explanatory sectional view showing a main part of a hot press device of the device shown in FIG. 1;

[Explanation of symbols]

 1: Pre-forming device 1a: Aluminum dust powder supply mechanism 1b: Compression mechanism 2: Hopper 3: Semi-cylindrical casing 4: Screw feeder 5: Drive motor 7: Hydraulic cylinder for pressurizing 8: Gate plate 11: Heating device 12: Housing 13: Guide rail 14: Induction heating coil 21: Movable die 22: Fixed die 23: Press die 24: Hydraulic cylinder for pressurization 25: Hot press housing 30: Guide table

Claims (3)

[Claims] 1. A preforming apparatus for preforming a predetermined amount of aluminum shavings, and heating for heating a preform formed by the preforming apparatus to a temperature range of 480 ° C. or more and less than a melting point in a non-oxidizing atmosphere. A device for recycling aluminum cuttings, comprising: an apparatus; and a hot press apparatus disposed adjacent to the heating apparatus and sintering under pressure while maintaining the preform at a predetermined temperature within the temperature range. 2. A heating device comprising: a housing forming a heating chamber in a non-oxidizing atmosphere; a guide rail penetrating the housing to support a preform; 2. The recycling facility according to claim 1, comprising an induction heating coil for heating the molded body. 3. The hot press apparatus comprises: a press die comprising a movable die and a fixed die; a hot plate for heating and maintaining the press die at a predetermined temperature; and a preformed body taking in the preformed body in the heating device. And a hot press housing for forming a processing chamber in a non-oxidizing atmosphere, comprising: a cylinder for pressing a preform in a press die by pressing the movable die against a fixed die; Recycling equipment as described.