WO2013161746A1

WO2013161746A1 - Device for high-density molding and method for high-density molding of mixed powder

Info

Publication number: WO2013161746A1
Application number: PCT/JP2013/061741
Authority: WO
Inventors: 長谷川　和宏; 佳樹平井
Original assignee: アイダエンジニアリング株式会社
Priority date: 2012-04-23
Filing date: 2013-04-22
Publication date: 2013-10-31
Also published as: KR20150011810A; JPWO2013161746A1; CN103418791A; EP2842666A1; US20150132175A1; EP2842666A4; TW201408404A; JP5881822B2; CN203253924U

Abstract

In the present invention, a mixed powder (100) filling the inside of a container cavity (24) is transferred into the cavity of a first die, a first applied pressure is applied to the mixed powder (100) in the first die (31), molding an intermediate powder compact (110), the post-molding first die (31) and intermediate powder compact (110) are heated, causing the intermediate powder compact (110) to be warmed to the melting-point-equivalent temperature of a lubricant, the post-warming intermediate powder compact (110) is transferred into the cavity of a second die (61) and a second applied pressure is applied, thus molding a high-density completed powder compact.

Description

High density molding method and high density molding apparatus for mixed powder

The present invention relates to a high-density molding method and a high-density molding apparatus capable of molding a green compact with a high density (for example, 7.75 g / cm ³ ) by pressing the mixed powder twice.

In general, in the powder metallurgy technique, a metal powder is pressed (compressed) to form a green compact having a predetermined shape, and then the green compact is heated to a temperature near the melting point of the metal powder to form an interparticle bond ( It is a series of techniques for performing a sintering process that promotes solidification. As a result, it is possible to manufacture a mechanical component having a complicated shape and high precision in a low cost.

With the demand for further reduction in size and weight of machine parts, it is required to improve the mechanical strength of the green compact. On the other hand, it is said that when the green compact is exposed to a high temperature atmosphere, the magnetic properties are deteriorated. Thus, for example, in the actual production of the green compact for a magnetic core, the subsequent high-temperature treatment (sintering treatment) may be omitted. In other words, a method for increasing the mechanical strength without searching for a high temperature (sintering) is being sought.

Here, the mechanical strength is said to increase significantly (hyperbolic) as the density of the green compact is increased. As a typical densification method, a method of pressure forming while reducing frictional resistance by mixing a lubricant with metal powder is proposed (for example, JP-A-1-219101 (Patent Document 1)). ) In general, a mixed powder obtained by mixing a base metal powder with about 1 wt% (1 wt%) of a lubricant is pressed. Many proposals aiming at further higher density have been made. These proposals can be broadly divided into improvements in the lubricant itself and improvements in processes related to pressure forming and sintering.

The former belongs to the proposal that the lubricant is a carbon molecule composite in which ball-like carbon molecules and plate-like carbon molecules are combined (Japanese Patent Laid-Open No. 2009-280908 (Patent Document 2)), penetration at 25 ° C. Can be mentioned as a lubricant having a thickness of 0.3 to 10 mm (Japanese Patent Laid-Open No. 2010-37632 (Patent Document 3)). Both are ideas for reducing the frictional resistance between metal powders and between metal powder and a mold.

The latter belongs to the warm forming / sintered powder metallurgy method (Japanese Patent Laid-Open No. 2-156002 (Patent Document 4)) and the pre-warm formed powder metallurgy method (Japanese Patent Laid-Open No. 2000-87104). (Patent Document 5)) 2 times press-2 times sintered powder metallurgy method (Japanese Patent Laid-Open No. 4-231404 (Patent Document 6)) and 1 time molding-sintered powder metallurgy method (Japanese Patent Laid-Open No. 2001-181701) (Patent Document 7)) is known.

The first warm forming / sintering powder metallurgy method is to preheat a metal powder mixed with a solid lubricant and a liquid lubricant to melt part (or all) of the lubricant and to apply the lubricant between the particles. Disperse. Thus, the moldability is improved by reducing the frictional resistance between the particles and between the particles and the mold. A pre-warm forming powder metallurgy method that facilitates handling is a primary forming step of forming a primary compact that can be handled by pressurizing the mixed powder prior to the warm forming step (eg, density ratio is less than 76%). The secondary molded body (green compact) is obtained by carrying out a secondary molding step while the primary molded body is temporarily collapsed while the primary molded body is at a temperature lower than the temperature at which blue brittleness occurs. is there. In the twice-pressed-two-sintered powder metallurgy method, an iron powder mixture containing alloying components is pressed in a die to produce a green compact, and this compact (compact) is pressed at 870 ° C. for 5 minutes. The pre-sintered body is preliminarily sintered to generate a pre-sintered body, and the pre-sintered body is pressed to generate a pre-sintered body that has been pressed twice, and then the pre-sintered body that has been pressed twice is 1000 This is a method for producing a sintered part by sintering at 5 ° C. for 5 minutes. In the last one-time molding-sintered powder metallurgy method, the mold is pre-heated and the lubricant is charged and adhered to the inner surface, and then the iron-based powder mixture (iron-based powder + lubricated) heated in the mold. Agent powder), press-molded at a predetermined temperature to form an iron-based powder molded body, then subject the iron-based powder molded body to sintering treatment, further bright quenching, and then tempering treatment. This is a method for producing an iron-based sintered body.

As described above, the density of the green compact is at most about 7.4 g / cm ³ (94% of the true density) in any improvement measures concerning the lubricant and the pressure forming / sintering process. Insufficient mechanical strength. Furthermore, when performing sintering treatment (high temperature atmosphere), oxidation proceeds according to temperature and time, so that the lubricant in the powder particle coating state burns and a residue is generated. The density in production will be 7.3 g / cm ³ or less because it causes quality degradation. In addition, any improvement measures are likely to be complicated and expensive. Handling is cumbersome and there are difficulties in practicality.

In particular, considering the production of magnetic cores (magnetic cores) for electromagnetic equipment (motors, transformers, etc.) from green compacts, it is pointed out that this level of density (7.3 g / cm ³ or less) is extremely unsatisfactory. strong. In order to reduce the loss (iron loss, hysteresis loss) and increase the magnetic flux density, it is necessary to further increase the density of the green compact. For example, it is clear from the presentation materials (provided by Toyota Central Research Institute, Inc.) at the 2009 Fall Meeting of the Powder and Powder Metallurgy Association. It has been pointed out that even if the density of the magnetic core is 7.5 g / cm ³ , for example, not only the magnetic properties but also the mechanical strength is unsatisfactory.

Regarding the production of the green compact for magnetic core, a two-time molding-one-time sintering (one-time annealing) powder metallurgy method (Japanese Patent Laid-Open No. 2002-343657 (Patent Document 8)) has been proposed. This proposed powder metallurgy method is based on the technical matter that if a coating containing a silicone resin and a pigment is formed on the surface of a magnetic metal powder, the insulation will not deteriorate even if a high temperature treatment is subsequently applied. It is. That is, the method for producing a dust core is to preform a magnetic powder whose surface is coated with a coating containing a silicone resin and a pigment to form a preform, and heat-treat the preform at a temperature of 500 ° C. or higher. To form a heat treated body, and then the heat treated body is subjected to compression molding. If the temperature for the heat treatment is 500 ° C. or lower, fracture is likely to occur during the subsequent compression molding, and if it is 1000 ° C. or higher, the insulating coating is decomposed and the insulating properties are burned out. This high temperature treatment is performed in vacuum, in an inert gas atmosphere or in a reducing gas atmosphere from the viewpoint of preventing oxidation of the preform. Thus, it is described that a dust core having a true density of 98% (7.7 g / cm ³ ) can be produced.

However, the two-time molding-one-time sintering powder metallurgy method (Patent Document 8) is more complicated and individualized than the other proposed methods, and is difficult to implement and implement. Incurs a significant increase. Further, it is a requirement that the preform is heat-treated at 500 ° C. or higher. Since the quality of the dust core must be performed in a special atmosphere in order to prevent deterioration, it is not suitable for mass production. In particular, in the case of a vitreous film-coated magnetic metal powder, the vitreous material is altered and dissolved, and thus cannot be applied.

In any of the above proposed methods / apparatuses (Patent Documents 1 to 8), there is a description that can be carried out with respect to a sintering process in a relatively high temperature atmosphere, but details regarding the pressure forming process are not clear. Neither the specification / function of the pressure molding machine, the relationship between the applied pressure and density, nor the analysis of its limitations, can be described for new improvements.

Thus, the development of methods and equipment that can produce high-density green compacts (especially high-density green compacts for magnetic cores) reliably, stably, and at low cost, in view of the need for further mechanical strength associated with the reduction in size and weight. Is urgently needed.

An object of the present invention is to provide a mixed powder high-density molding method capable of producing a high-density green compact by performing two times of pressure forming with the heating sandwiched between the mixed powders and greatly reducing the production cost. And providing a high-density molding apparatus.

Since the green compact is manufactured by sintering metallurgy technology, it has been essential to subject the pressed green compact to a sintering treatment in a high temperature atmosphere (for example, 800 ° C. or higher). However, the high temperature treatment for sintering not only consumes a large amount of energy and has a huge cost burden, but also has a great negative effect on global environmental protection, so it needs to be reviewed.

Conventionally, the pressure molding process establishes the mixed powder as a specific form, and has been considered as a pre-stage (preliminary) mechanical process of the high-temperature sintering process and has been treated as such. However, only in the case of producing a green compact for use in an electromagnetic device (motor, transformer, etc.), the actual situation is that the high-temperature treatment for sintering is omitted exceptionally. This is to avoid adverse effects (deterioration of magnetic properties) caused by high temperature treatment. In other words, they were forced to obey dissatisfaction with the mechanical strength. Insufficient mechanical strength is a matter of density, and of course, the magnetic properties were also insufficient.

Here, if high-density molding of green compacts can be performed without high-temperature sintering treatment and only by pressure molding, the industrial use and spread of green compacts can be dramatically improved. The present invention relates to the effectiveness of the lubricant during pressurization, the compression limit including the lubricant powder, the spatial occupancy in the mixed powder of the lubricant powder, the spatial arrangement state of the base metal powder and the lubricant powder, Based on research on their behavior and the final disposal mode of lubricants, as well as analysis on the effects of general pressure molding machine characteristics, compression limit and density of green compacts on strength and magnetism, and in practice It was created as one that can meet the demands for higher efficiency of the mixed powder filling operation adapted to the manufacture of the first and second, smaller and lighter molds.

That is, according to the present invention, the mixed powder filled in the container cavity is transferred to the first mold, and the mixed powder is subjected to intermediate compression by the first pressurizing step while maintaining the powder state of the lubricant in the first mold. The body is molded, and then the lubricant is heated and liquefied to modify the lubrication aspect of the mixed powder intermediate compact, and then the mixed powder intermediate compact after heating is transferred to the second mold. And a 2nd pressurization process is given, and the high-density completed green compact close | similar to a true density is shape | molded. In other words, in connection with the creation of a new powder metallurgy technology (two pressure moldings sandwiching the liquefaction process of the lubricant) that has been removed from the conventional sintering metallurgy technology that requires high-temperature sintering treatment, It is an object of the present invention to provide an innovative and practical method and apparatus capable of reliably and stably producing a body at a low cost.

(1) Specifically, in the high density forming method of the mixed powder according to the first aspect of the present invention, the mixed powder which is a mixture of the base metal powder and the low melting point lubricant powder is filled in the container cavity, and the container The mixed powder in the cavity is transferred into the cavity of the first mold positioned corresponding to the container, and the first powder is applied to the mixed powder in the cavity of the first mold to mix the mixed powder intermediate compact. The first mold after molding and the mixed powder intermediate compact are heated to raise the temperature of the mixed powder intermediate compact to the melting point equivalent temperature, and the mixed powder intermediate compact after the temperature rise is Each mold is positioned corresponding to the second mold, and the mixed powder intermediate compressed body in the cavity of the first mold is moved into the cavity of the second mold positioned corresponding to the first mold. , Mixed powder intermediate compact in the cavity of the second mold Adding a second pressure molding the mixed powder finished compacts high density, characterized in that.

(2) In the invention of (1) above, the melting point of the lubricant powder can be a low melting point belonging to a temperature range of 90 to 190 ° C.

(3) In the invention of (1) or (2) above, the second mold can be warmed up to the melting point equivalent temperature before receiving the mixed powder intermediate compression body.

(4) In the invention of (1) or (2) above, the first mold can be warmed up after completion of the formation of the mixed powder intermediate compression body.

(5) In the invention of (1) or (2) above, the second applied pressure can be made equal to the first applied pressure.

Further, (6) the mixed powder high-density molding apparatus according to the second aspect of the present invention is a container in which a mixed powder, which is a mixture of a base metal powder and a low melting point lubricant powder, is positioned at a mixed powder filling position. A mixed powder feeder capable of filling in the cavity of the container, a mixed powder transfer device for transferring the mixed powder in the container cavity into the cavity of the first mold positioned corresponding to the container, and the cavity of the first mold A first pressure molding machine for forming a mixed powder intermediate compression body by applying a first pressing force to the mixed powder in the first punch from the first punch, a first mold positioned at a heating temperature raising position, and mixing The heating intermediate heating body for heating the powder intermediate compression body to raise the temperature of the mixed powder intermediate compression body to the temperature corresponding to the melting point, and the mixed powder intermediate compression body in the cavity of the first mold are positioned at the delivery relay position. Pull to the second mold A second pressing force is applied from the second punch to the mixed powder intermediate compression body in the cavity of the second mold positioned at the finished green compact molding position. A second pressure molding machine for forming a mixed powder finished compressed body having a density; and a product discharge device formed so that the mixed powder finished compressed body in the cavity of the second mold can be discharged at a product discharge position. It becomes.

(7) In the invention of (6), the first mold transfer device formed to be capable of positioning corresponding to the container positioned at the mixed powder filling position by transferring the first mold, A pre-heating green compact transfer device formed to be able to be positioned corresponding to the heating temperature rising position by transferring the first mold from the intermediate green compact molding position, and the first metal mold containing the mixed powder intermediate compression body After the mold is transferred from the heating temperature raising position, the post-heated green compact transfer device formed so as to be positioned corresponding to the transfer relay position and the second mold containing the mixed powder intermediate compression body are transferred from the transfer relay position. The second mold transfer device formed so as to be capable of positioning corresponding to the finished green compact molding position and the second mold containing the mixed powder finished compact are transported from the finished compact compact molding position. It is formed so that it can be positioned corresponding to the product discharge position. A completed green compact transfer device, and a second mold return transfer device configured to transfer the second mold containing the mixed powder completed compressed body from the product discharge position so as to be positioned corresponding to the underwriting relay position. Can be provided.

(8) In the invention of (6) above, the mixed powder filling position, the heating temperature raising position, and the delivery relay position are spaced apart on a first circular locus centered on the first axis and the delivery relay position, The finished green compact forming position and the product discharge position are spaced apart from each other on a second circular locus centered on the second axis, and the first mold transfer device, the pre-heating green compact transfer device, and the post-heating green compact A body transfer device is constructed using a first rotary table that is rotatable about a first axis, and a second mold transfer device, a finished green compact transfer device, and a second mold return transfer device Is constructed using a second rotary table that is rotatable about a second axis.

(9) In the invention of (6) or (7), the apparatus may further include a first warming-up device that warms up the first mold.

(10) In the invention of (6) or (7), the apparatus may further include a second warming-up device for warming up the second mold.

According to the invention of (1) above, high-density green compacts can be manufactured reliably and stably, and the manufacturing cost can be greatly reduced, and the mixed powder filling operation adapted to actual manufacturing is highly efficient. And miniaturization and weight reduction of the first and second molds.

According to the invention of (2) above, sufficient lubricating action of the lubricant during the first pressurizing step can be ensured. Moreover, the selectivity for the type of lubricant is wide.

According to the invention of the above (3), since the fluidity of the dissolved lubricant in all directions during the second pressure molding can be further enhanced, not only between the base metal particles but also the particles and the second mold. The frictional resistance between the two can be greatly reduced and maintained.

According to the invention of (4) above, it is possible to promote shortening of the production cycle time including the temperature raising time of the mixed powder intermediate compression body.

According to the invention of the above (5), it is easy to carry out and handle the pressure molding process, and it can contribute to further reduction in the cost of manufacturing the green compact indirectly.

Furthermore, according to the invention of (6), the mixed powder high-density molding method according to the above (1) to (5) can be surely carried out, and can be easily realized at low cost and handled. Simple.

Furthermore, according to the invention of the above (7), the apparatus can be simplified and the green compact can be transferred quickly and smoothly as compared with the case of the invention of the above (6).

Furthermore, according to the invention of (8) above, the apparatus can be further simplified as compared with the case of the invention of (7) above. Further simplification of the production line can be promoted, and handling becomes easier.

According to the invention of (9) above, it is possible to promote shortening of the manufacturing cycle time including the temperature rising time of the mixed powder intermediate compression body.

According to the invention of the above (10), the fluidity of the dissolved lubricant in all directions during the second pressure molding can be further enhanced, so that not only between the base metal particles but also the particles and the second mold The frictional resistance between the two can be greatly reduced and maintained.

Note that the configuration and effects of the present invention other than those described above will be apparent from the following description.

FIG. 1 is a diagram for explaining a high-density molding method according to the present invention. FIG. 2 is a plan view for explaining the high-density molding apparatus according to the first embodiment of the present invention. FIG. 3 is a longitudinal sectional view for explaining the operation from the mixed powder filling operation to the positioning of the intermediate green compact corresponding to the delivery relay position in the first embodiment of the present invention. FIG. 4 is a vertical cross-sectional view for explaining the operation from the operation of receiving the intermediate green compact to the discharge of the finished green compact (product) at the product discharge position in the first embodiment of the present invention. FIG. 5 is a graph for explaining the relationship between the applied pressure and the density obtained by the applied pressure in the first embodiment of the present invention, and the characteristic A indicated by the dotted line is the molding state in the first mold. A characteristic B indicated by a solid line indicates a molding state in the second mold. FIG. 6A is an external perspective view for explaining the finished green compact (intermediate green compact) in the first embodiment of the present invention, and shows a ring shape. FIG. 6B is an external perspective view for explaining the finished green compact (intermediate green compact) in the first embodiment of the present invention, and shows a cylindrical shape. FIG. 6C is an external perspective view for explaining the finished green compact (intermediate green compact) in the first embodiment of the present invention, and shows an elongated round shaft shape. FIG. 6D is an external perspective view for explaining the finished green compact (intermediate green compact) in the first embodiment of the present invention, and shows a disc shape. FIG. 6E is an external perspective view for explaining the finished green compact (intermediate green compact) in the first embodiment of the present invention, and shows a complicated shape. FIG. 7 is a longitudinal sectional view for explaining the operation from the mixed powder filling operation of the high-density molding apparatus according to the second embodiment of the present invention until the intermediate green compact is positioned corresponding to the delivery relay position. FIG. 8 is a vertical cross-sectional view for explaining the operation from the operation of taking the intermediate green compact to the discharge of the finished green compact (product) at the product discharge position in the second embodiment of the present invention.

Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

(First embodiment)
As shown in FIGS. 1 to 6E, the mixed powder high-density molding apparatus 1 includes a mixed powder feeder 10, a container 23, a mixed powder transfer device (lower punch 37), a first pressure molding machine 30, and a heating riser. A warming machine 40, an intermediate green compact transfer device (extrusion rod 50), a second pressure molding machine 60, and a product discharge device 70 are provided, and the mixed powder 100 shown in FIG. Powder filling step (PR1), mixed powder transfer step (PR2) for transferring the mixed powder 100 to the first mold 31, and mixing by adding the first pressure P1 to the mixed powder 100 in the first die 31 Intermediate green compact molding step (PR3) for molding a powder intermediate compact (sometimes referred to as intermediate green compact 110), and heating the molded intermediate green compact 110 to change its temperature to the melting point of the lubricant powder. Heating temperature raising process (PR4) that actively raises the temperature to the equivalent temperature Intermediate green compact transfer step (PR5) in which the heated intermediate green compact 110 is transferred to the second mold 61, and the second pressure P2 is applied to the intermediate green compact 110 in the second mold 61. A high-density molding method of the present mixed powder comprising a finished green compact forming step (PR6) and a product discharging step (PR7) for forming a finished compact of high-density mixed powder (sometimes referred to as a finished green compact 120) Is formed so that it can be carried out stably and reliably.

Further, in this embodiment, the first mold transfer for transferring the first mold 31 to the mixed powder filling position (intermediate green compact forming position) Z11, the heating temperature raising position Z12, and the delivery relay position Z13. An apparatus (first mold return transfer device) 81, a pre-heating green compact transfer device 82, and a post-heating green compact transfer device 83 are provided, a delivery relay position Z13 (reception relay position Z21), and a finished green compact forming position. A second mold transfer device 91, a finished green compact transfer device 92, and a second mold return transfer device 93 for transferring the second mold 61 to Z22 and the product discharge position Z23 are provided. Guarantees a quick and smooth transfer.

Furthermore, the first mold transfer device 81, the pre-heating green compact transfer device 82, and the post-heat green compact transfer device 83 have an integrated structure using the first rotary table 80 of FIG. The mold transfer device 91, the finished green compact transfer device 92, and the second mold return transfer device 93 are integrated with each other by using the second rotary table 90 of FIG. 2 to achieve the ultimate simplification. .

The mixed powder 100 in the present specification means a mixture of a base metal powder and a low melting point lubricant powder. In addition, as the base metal powder, there are a case where it consists of only one kind of main metal powder and a case where it consists of one kind of main metal powder and one or a plurality of alloying component powders. The case can be adapted. The low melting point means that the temperature (melting point) is significantly lower than the melting point (temperature) of the base metal powder (melting point) and the temperature (melting point) can greatly suppress oxidation of the base metal powder. .

In FIG. 3 showing the high-density molding apparatus 1, the mixed powder feeder 10 disposed at the mixed powder filling position Z 11 on the upstream side of the high-density molding line is an apparatus for filling the container 23 with the mixed powder 100. It is used when executing the mixed powder filling step (PR1) of FIG. It has a function to hold a certain amount of mixed powder 100 and a function to supply a fixed amount, and as a whole, it can selectively reciprocate between the initial position (the position not shown in the left direction in FIGS. 2 and 3) and the container device 20. It is.

The container device 20 includes a hollow cylindrical main body 21 having a stopper 22 at the top, a container 23 having a stopper 25 at the bottom and a hollow cylindrical container cavity 24 at the center, and the container 23 facing upward. The spring 26 is energized and is positioned at the mixed powder filling position Z11. A lower punch 37 that constitutes a part of the first pressure molding machine 30 (first mold 31) is slidably fitted in the container cavity 24, depending on the vertical position relative to the container 23. The filling amount of the mixed powder 100 to be filled is determined. The container 23 is held at the initial position in the vertical direction shown in FIG. 3A in a state where the stopper 25 is restrained by the stopper 22 by the urging force of the spring 26.

Rather than directly filling the mixed powder 100 into the cavity 33 of the die 32 constituting the first mold 31 of the first pressure molding machine 30, the container 23 (container cavity 24) is once filled and then the cavity 33 is filled. If the mixed powder 100 is transferred to the inside, a large amount of the mixed powder 100 can be filled in a state where the mixed powder 100 is slightly compressed by the preload. Moreover, it becomes easy to transfer the 1st metal mold | die 31 (die 32) with the mixed powder intermediate compression body 110 to the delivery relay position (heating temperature rising position Z12). Compared to the conventional example in which only the workpiece (green compact) is taken out from the first mold 31 and transferred to the second mold 31, the structure can be greatly simplified. The preload is given by the action of the mixed powder transfer device (lower punch 37) described later in detail.

Since it is important to uniformly and sufficiently fill the mixed powder 100 from the container 23 anywhere in the first mold 31 (die 32), the mixed powder 100 must be in a smooth state. That is, the form of the internal space (cavity 33) of the first metal mold 31 (die 32) is a form corresponding to the product form. Even if the product form is complicated or has a narrow part, non-uniform filling or insufficient filling is not preferable in order to guarantee the dimensional accuracy of the intermediate green compact 110.

The form (dimensions and shape) of the finished green compact 120 (intermediate green compact 110) is not particularly limited, but examples are shown in FIGS. 6A to 6E. 6A shows a ring shape, FIG. 6B shows a cylindrical shape, FIG. 6C shows an elongated round shaft shape, FIG. 6D shows a disk shape, and FIG. 6E shows a complicated shape. The intermediate green compact 110 (finished green compact 120) in this embodiment has a cylindrical shape shown in FIGS. 3 and 6B, and the form of the internal space (cavity 33) of the first mold 31 corresponds to this. It is finished in the form to do.

Here, the lubricant for reducing the frictional resistance between the base metal particles occupying the majority of the base metal powder and the frictional resistance between the base metal powder and the inner surface of the mold is a solid solid (very (Small grain). For example, when a liquid lubricant is used, the mixed powder 100 has a high viscosity and low fluidity, so uniform filling and sufficient filling cannot be performed.

Next, the lubricant is solid and stabilizes a predetermined lubricating action during the intermediate compacting performed in the first mold 31 (cavity 33) at room temperature and while applying the first pressure P1. Must be able to maintain. Even if there is a case where a slight temperature increase may occur due to the pressurization of the first pressurizing force P1, it should be kept stable as well.

On the other hand, from the viewpoint of the relationship with the heating temperature raising step (PR4) of FIG. 1 that is selectively performed after intermediate green compact molding and the suppression of oxidation of the base metal powder, the melting point of the lubricant powder is The melting point must be very low (low melting point) compared to the melting point.

The melting point of the lubricant powder is selected as a low melting point belonging to a temperature range of 90 to 190 ° C., for example. The lower temperature (90 ° C.) is an upper limit temperature (80 ° C.) of a value (for example, 70 to 80 ° C.) that will not reach this temperature even if a certain temperature rise occurs during intermediate compacting. ) With a margin (for example, 90 ° C.), and further, the melting point (for example, 110 ° C.) of another metal soap is selected. That is, the concern that the lubricating oil powder is dissolved (liquefied) and flows out during the pressure molding of the intermediate green compact 110 is eliminated.

The upper temperature (190 ° C.) is a minimum value from the viewpoint of expanding the selectivity regarding the type of lubricant powder, and is particularly selected as a maximum value from the viewpoint of suppressing oxidation of the base metal powder during the heating temperature raising step. is there. That is, the lower temperature and the upper temperature in this temperature range (for example, 90 to 190 ° C.) should be understood as boundary values rather than limit values.

Thus, many substances belonging to the metal soap (such as zinc stearate and magnesium stearate) can be selectively employed as the lubricant powder. Since the lubricant must be in a powder state, a viscous liquid such as zinc octylate cannot be used.

In this embodiment, zinc stearate powder having a melting point of 120 ° C. was used as the lubricant powder. In the present invention, as in the invention of Patent Document 7, a pressure molding is performed while using a lubricant having a temperature (melting point) lower than the mold temperature at the time of pressure molding and dissolving (liquefying) the lubricant from the beginning. The idea of performing is denied. If the dissolved lubricant flows out before the end of the molding of the intermediate green compact 110, it is easy to generate an insufficiently lubricated part on the way, so that sufficient pressure molding cannot be performed reliably and stably. Because.

The amount of lubricant powder shall be a value selected from experimental studies and empirical rules through actual production. In relation to the intermediate green compact forming step (PR3) according to this embodiment, the amount of the lubricant powder is 0.23 to 0.08 wt% of the total amount of the mixed powder. 0.08 wt% is a lower limit value that can ensure the lubricating action until the molding of the intermediate green compact 110 is completed, and 0.23 wt% obtains an expected compression ratio when the mixed powder 100 is used as the intermediate green compact 110. This is the upper limit value necessary for this purpose.

Next, the amount of lubricant powder in practical use is the value of the true density ratio of the intermediate green compact 110 formed by applying the first pressure P1 in the first mold 31 and the second gold. It should be determined that it can secure the sweating phenomenon in the mold. At this time, it should not be overlooked from the viewpoint of preventing the occurrence of liquid dripping (liquid dripping phenomenon) of the liquefied lubricant from the mold, which causes deterioration of the working environment.

In this embodiment, since the value of the true density ratio (ratio to the true density of 100%) of the intermediate green compact 110 is 80 to 90%, the amount of the lubricant powder is 0.2 to 0.1 wt%. The upper limit value (0.2 wt%) is determined from the viewpoint of preventing the occurrence of a dripping phenomenon, and the lower limit value (0.1 wt%) is determined from the viewpoint of allowing the necessary and sufficient sweating phenomenon to occur without excess or deficiency. . Compared to the conventional proposal example (1 wt%), the amount is extremely small, and the industrial utility can be greatly improved.

Prevention of dripping phenomenon is extremely important for actual production. At the desk plan or research stage, there is a tendency to mix excessive lubricants, which is concerned about the lack of lubricants from the viewpoint of reducing frictional resistance during pressurization. For example, since it is in the stage of trial and error as to whether a high density exceeding 7.3 g / cm ³ can be achieved, there is absolutely no interest in the event that excessive lubricant liquefies and flows out of the mold. There is no recognition of the dripping phenomenon. In other words, the dripping of the liquefied lubricant increases the cost due to an increase in the lubricant usage fee, reduces the productivity due to the deterioration of the work environment, and increases the burden on the worker. Does not lead to widespread use.

In the case of the intermediate green compact 110 obtained by compressing the 0.2 wt% mixed powder 100 to a true density ratio of 80%, when the temperature is positively raised to the melting point equivalent temperature of the lubricant powder in the heating temperature raising step (PR3), The powder lubricant interspersed in the intermediate green compact 110 melts to fill the voids between the metal powder grains, and then passes between the metal powder grains and uniformly on the surface of the intermediate green compact 110. Exudes (spouts). That is, a sweating phenomenon is induced. When this intermediate green compact 11 is compressed by applying the second pressure P2 in the second mold, the frictional resistance between the base metal powder and the cavity inner wall is greatly reduced.

In the case of the intermediate green compact 110 obtained by compressing the 0.1 wt% mixed powder 100 to a true density ratio of 90%, the mixed powder 100 having a value exceeding 0.1 wt% and less than 0.2 wt% is also true density. In the case of the intermediate green compact 110 compressed to a value within the range of less than 90% and exceeding 80%, a similar sweating phenomenon can be expressed. The occurrence of dripping phenomenon can also be prevented.

Thus, high-density molding can be performed, and a green compact (for example, a magnetic core) that satisfies not only magnetic properties but also mechanical strength can be manufactured. Moreover, the amount of lubricant consumed can be greatly reduced, and the liquid lubricant can be prevented from flowing from the mold, resulting in a favorable working environment. As a whole, the productivity can be improved and the green compact manufacturing cost can be reduced, so the industrial applicability can be greatly improved.

Incidentally, none of the above-described conventional methods / apparatuses (Patent Documents 1 to 8) recognizes the relationship between the content of the lubricant and the compressibility of the mixed powder 100, the dripping phenomenon due to the amount of the lubricant, and the sweating phenomenon. . In particular, even with the warm powder metallurgy method (Patent Document 5), it can be understood that the purpose is to facilitate handling or to form a primary compact with a density ratio of less than 76%. However, nothing is disclosed about the technical basis and feasible matters regarding high-density molding. In fact, once the primary molded body (intermediate green compact 120) is collapsed and then the secondary molded body (finished green compact) is molded, the density of the primary molding and secondary molding is increased. It is nothing other than denying the technical idea to make it easier.

The first pressure molding machine 30 applies a first pressure P1 to the mixed powder 100 supplied to the first mold 31 (cavity 33) using the mixed powder supply machine 10 to mix the mixed powder intermediate compact. 110 is a press machine structure in this embodiment.

3 (A) and 3 (B), the first die 31 is composed of a lower die (die 32, lower punch 37) on the bolster side and an upper die (upper punch 36) on the slide (not shown) side. As described above, the cavity 33 of the die 32 has a shape (hollow cylindrical shape) corresponding to the form (columnar shape) of the intermediate green compact 110 shown in FIG. This corresponds to the shape of the container cavity 24. The upper punch 36 is moved up and down by an upper slide (not shown). The lower surface of the upper punch 36 has a planar shape and can close the upper portion of the cavity 33. That is, it contacts most of the upper surface of the die 32.

Since the cavity 33 of the die 32 of the first pressure molding machine 30 has a shape corresponding to the form (shape) of the intermediate green compact 110, the form of the intermediate green compact 110 is shown in FIGS. 6A and 6C. Also in the case shown in FIG. 6E, the shape corresponds to each. In the case of the ring shape shown in FIG. 6A, the ring shape is formed. In the case of the elongated round shaft shape shown in FIG. 6C, the shape is the same as the cylindrical shape of FIG. 6B, but is long in the vertical direction. In the case of the disc shape shown in FIG. 6D, the same shape is obtained, but it is short (thin) in the vertical direction. In the case of the complex shape shown in FIG. 6E, the corresponding complex shape is obtained. The same applies to the cavity 63 of the die 62 of the second pressure molding machine 60 (second mold 61).

The mixed powder transfer device is a device that transfers the mixed powder 100 in the container cavity into the cavity 33 of the first mold 31 positioned corresponding to the container 23, and includes a lower punch 37, and includes an upper punch 36 and a die 32. Transition operation is performed in cooperation with.

That is, in FIG. 3A, the upper punch 36 descends and comes into contact with the upper surface of the die 32 held by the first rotary table 80 (die holding part 85). The die 32 is pushed down. Since the lower surface of the die 32 is in contact with the upper surface of the container 23, the container 23 is pushed down. There is no change in the vertical position of the lower punch 37. Therefore, the mixed powder 100 in the container cavity 24 is pushed up by the lower punch 37 and transferred into the die 32 (cavity 33) of the first mold 31. At this time, since the vertical dimension of the container cavity 24 is larger than the vertical dimension of the cavity 33, the mixed powder 100 in the container cavity 24 is transferred into the cavity 33 while being pre-compressed by the preload effect. That is, the mixed powder transfer device (upper punch 36, lower punch 37) can transfer the mixed powder 100 in the container cavity 24 into the cavity 33 of the first mold 31 positioned corresponding to the container 23.

As shown in FIG. 3B, in the state where the upper punch 36 is lowered to the lower position (lowest lower limit position), the intermediate green compact 110 in which the mixed powder 100 is compressed in cooperation with the lower punch 37 can be formed. it can. That is, as the first pressure molding machine 30, the mixed powder 100 is compressed by applying the first pressure P1 from the first punch (upper punch 36) to the mixed powder 100 in the cavity 33 of the first mold 31. The body (intermediate green compact 110) is formed. Since a mixed powder transfer device (lower punch 37) is provided, a large amount of the mixed powder 100 can be supplied and compressed and transferred as compared with the case where the cavity 33 is directly filled. Easy to densify. The dimensional accuracy of the intermediate green compact 110 is also high. When the slide is raised, the upper punch 36 is raised to the upper position shown in FIG. At this time, the first rotary table 80 rises to the upper limit position. The container 23 is returned to the original position shown in FIG.

Refer to FIG. 5 for the relationship between the applied pressure P (first applied pressure P1) in the first pressure molding machine 30 and the true density ratio (density ρ) of the intermediate green compact 110 obtained correspondingly. To explain. The horizontal axis indicates the applied pressure P as an index. The maximum capacity (pressing force P) in this embodiment is 10 Ton / cm ² , and this is taken as the horizontal axis index 100. Pb is a mold breakage pressure and has a horizontal axis index of 140 (14 Ton / cm ² ). The vertical axis indicates the true density ratio (density ρ) as an index. The vertical axis index 100 corresponds to a true density ratio (density ρ) of 97% (7.6 g / cm ³ ).

In this embodiment, the base metal powder is an iron powder coated with a glassy insulating coating for a magnetic core, the lubricant powder is a zinc stearate powder in the range of 0.2 to 0.1 wt%, and the first pressure is applied. P1 can compress the mixed powder intermediate compact (intermediate compact 110) to a true density ratio of 80 to 90% corresponding to a longitudinal index of 82 to 92 [equivalent to density ρ (6.24 to 7.02 g / cm ³ )] Is selected.

Incidentally, the vertical axis index 102 corresponds to the density ρ (7.75 g / cm ³ ), and the true density ratio (density ρ) corresponds to 99%.

The base metal powder may be iron-based amorphous powder for magnetic core (Fe-Si alloy powder for magnetic core), iron-based amorphous powder for magnetic core, Fe-Si alloy powder for magnetic core, pure iron powder for machine parts, and the like.

When the first pressure P1 is increased, the density ρ obtained by the first pressure molding machine 30 increases according to the characteristic A (curve) indicated by the dotted line. The density ρ is 7.6 g / cm ^{3 at} the first pressure P1 (the horizontal axis index is 100). The true density ratio is 97%. Even if the first pressure P1 is increased to a value higher than this, the increase in the density ρ is minimal. Strong risk of mold damage.

Conventionally, if the density ρ obtained by pressing at the maximum capacity of a press molding machine (press machine) is not satisfactory, it has been necessary to equip a larger press machine. However, even if the maximum capacity is increased to, for example, 1.5 times, the increase in the density ρ is slight. Thus, it was the actual situation that compromised with a low density ρ (for example, 7.5 g / cm ³ ) which is currently available with a press machine.

Here, in particular, currently used as it is press machine, if the longitudinal axis index 100 (7.6g / cm ³⁾ to be increased to 102 (7.75g / cm ^3), it can be understood as innovative. That is, if the density ρ can be improved by 2%, the magnetic characteristics can be greatly improved (hyperbolic), and the mechanical strength can be dramatically improved. In addition, since the sintering process in a high-temperature atmosphere can be eliminated, oxidation of the green compact can be significantly suppressed (deterioration of magnetic core performance can be prevented). Note that the present invention can also be implemented by constructing or diverting a separate machine having a press function.

In order to realize the above, the intermediate green compact 110 molded by the first pressure molding machine 30 is heated to promote the dissolution (liquefaction) of the lubricant, and then the second pressure molding machine 60 It is formed so as to perform the second pressure molding process. When the intermediate green compact 110 is pressurized in the second pressure molding machine 60, the density is increased according to the characteristic B (straight line) shown by the solid line in FIG. 75 g / cm ³ ) can be achieved. Details will be added in the description of the second pressure molding machine 60.

3 (D) and 3 (E), heating heating device 40 heats first mold 31 and mixed powder intermediate compact (intermediate green compact 110) positioned at heating temperature raising position Z12. Thus, the temperature of the intermediate green compact 110 is positively raised to the melting point equivalent temperature. The heating / heating device 40 includes a hollow cylindrical main body 41 having a stopper 42 at the upper part, a lifting rod 43 having a stopper 45 at the lower part and an accommodating part 44 for accommodating a heater 47 at the upper part, It comprises a spring 48 that urges the rod 43 upward. The lifting rod 43 is held at the initial upper position shown in FIG. 3D in a state where the stopper 45 is restrained by the stopper 42 by the biasing force of the spring 48.

In this state, when the first mold 31 (die 32) is placed (corresponding positioning) in the accommodating portion 44, the first rotary table 80 is lowered to the lower limit position and the state of FIG. Become. Then, the heater 47 is turned on and the intermediate green compact 110 is heated and heated. The timing for turning on the heater 47 can be changed. For example, the timing at which the intermediate green compact 110 is placed as shown in FIG. As long as it is allowed from the power situation, production cycle, etc., it is possible to keep it always ON.

The technical significance of the low-temperature heating process in the first pressure molding machine 30 will be described in relation to the first pressure molding process. When the mixed powder 100 filled in the first mold 31 (die 32) is observed, the presence of the lubricant powder is relatively sparse in relation to the base metal powder (sparse part). A dense part (dense part) is recognized. The dense portion can reduce the frictional resistance between the particles of the base metal powder and the frictional resistance between the base metal powder and the inner surface of the mold. The sparse part should increase the frictional resistance.

During compression with the first pressure molding machine 30, the dense portion has low friction, so that the compressibility is superior and the compression progresses easily. Since the sparse part has high friction, the compressibility is inferior and the compression is delayed. In any case, a compression progression difficulty phenomenon occurs in accordance with a preset value of the first pressure P1. That is, a compression limit occurs. Under this condition, when the fracture surface of the intermediate green compact 110 taken out from the die 32 is enlarged and observed, the base metal powder is pressed in an integral manner in the dense portion. However, lubricant powder is also mixed in. In the sparse part, a slight gap (space) remains between the pressed base metal powders. Almost no lubricant powder is found.

Thus, if the lubricant powder is removed from the dense part, a compressible gap is created. If the lubricant can be replenished in the gap between the sparse parts, the compressibility of the parts can be improved.

That is, the intermediate green compact 110 after the completion of the first pressure molding is heated to a temperature corresponding to the melting point of the lubricant powder (for example, 120 ° C.) to dissolve (liquefy) the lubricant powder. Increase fluidity. The lubricant that has melted out from the dense part soaks into the periphery and is replenished to the part that has been sparse. Therefore, the frictional resistance between the particles of the base metal powder can be reduced, and the space occupied by the lubricant powder can also be compressed. The frictional resistance between the base metal powder particles and the inner surface of the mold can also be reduced. That is, the second pressure molding process is performed while promoting the liquefaction of the lubricant.

The intermediate green compact transfer device (extrusion rod 50) includes a second die 61 (die) in which the intermediate green compact 110 in the cavity 33 of the first die 31 (die 32) is positioned at the delivery relay position Z13. 62) is a device for transfer to the cavity 63.

3 (F) and FIG. 4 (G), the intermediate green compact transfer device is formed from an extrusion rod 50 and a delivery relay stand 55 positioned at the delivery relay position Z13. ) And a lower limit position shown in FIG. 4G can be reciprocated up and down. The rod diameter may be equal to or slightly smaller than the diameter of the upper punch 66 shown in FIG.

In FIG. 3F, after the second mold 61 is positioned corresponding to the upper surface of the delivery relay stand 55, the first mold 31 is lowered from the upper limit position to the lower limit position, and the second mold 61 The case where it mounts on the upper surface of is shown. Under this state, if the extrusion rod 50 is lowered, the mixed powder intermediate compression body 110 in the cavity 33 of the first mold 31 can be transferred into the cavity 63 of the second mold 61.

That is, the intermediate green compact 110 can be delivered from the first mold 31 to the second mold 61 at the delivery relay position Z13 shown in FIG. When viewed from the second mold 61, the intermediate green compact 110 is received from the first mold 31 at the underwriting relay position Z21. That is, the delivery relay position Z13 and the acceptance relay position Z21 are the same position.

The second pressure molding machine 60 shown in FIG. 4 (H) performs a second pressure molding process for applying the second pressure P2 to the intermediate green compact 110 set in the second mold 61. And a high-density mixed powder finished compact (finished green compact 120).

The second die 61 is composed of a lower die (die 62, lower punch equivalent base 67) on the bolster side and an upper die (upper punch 66) on the slide (not shown) side, and is positioned at a finished green compact forming position Z22. Has been. The shape of the cavity 63 of the die 62 corresponds to the shape of the cavity 33 of the first mold 31 (die 32). That is, it has a shape (hollow cylindrical shape) corresponding to the form (columnar shape) of the finished green compact 120 shown in FIG. The upper side of the die 62 is slightly larger than that of the die 32 in order to easily receive the intermediate green compact 110.

In FIG. 4H, the upper punch 66 is pushed into the cavity by a slide (not shown) that can move up and down between an upper position and a lower position, and applies a second pressure P2 to the intermediate green compact 110. In addition, a high density finished green compact 120 is formed. The lower punch equivalent base 67 that receives the second pressure P2 has the same structure as the delivery relay base 55, but may have a similar structure including the lower punch 37 shown in FIG.

Note that the maximum capacity (pressing force P) of the second pressure molding machine 60 in this embodiment is 10 Ton / cm ² as in the case of the first pressure molding machine 30. Thus, the first pressure molding machine 30 and the second pressure molding machine 60 are configured as a single press machine, and are constructed so that the dies 31 and 61 can be moved up and down synchronously with a common slide. You can also. From this point, the apparatus economy is advantageous, and the manufacturing cost of the finished green compact 120 can be reduced.

The relationship between the applied pressure (second applied pressure P2) in the second pressure molding machine 60 and the density ρ of the finished green compact 120 obtained correspondingly will be described with reference to FIG.

The density ρ obtained by the second pressure molding machine 60 follows the characteristic B indicated by the solid line. That is, in the case of the first pressure molding machine 30 [according to the characteristic A indicated by the dotted line. ], The density ρ does not gradually increase as the second pressure P2 is increased. That is, the density ρ does not increase until the final first pressure P1 (for example, the horizontal axis index 50, 75, or 85) in the first pressure molding step (PR3) is exceeded. When the second pressure P2 exceeds the final first pressure P1, the density ρ increases at a stretch. It is understood that the second pressure molding is performed as if the first pressure molding was continuously taken over.

Thus, in the first pressure molding step, it is not necessary to perform an operation in which the first pressure P1 is increased to a value (horizontal axis index 100) corresponding to the maximum capacity at any time. That is, it is possible to eliminate energy consumption for a useless time when the first pressure molding is continued after the compression limit. This leads to reduced manufacturing costs. Moreover, since it becomes easy to avoid the overload operation exceeding the horizontal axis index 100, there is no fear of die damage. Overall, handling is easy and safe and stable operation is possible.

The product discharge device 70 is a device for discharging the finished green compact 120 in the cavity 63 of the second mold 61 to the outside at the product discharge position Z23. In FIG. 4I, the product discharge device 70 includes a discharge rod 71 positioned corresponding to the product discharge position Z23 and a shooter 73 incorporated in the discharge stand 77, and is completed by pushing the discharge rod 71 into the cavity 63. The green compact 120 can be discharged.

That is, the discharge rod 71 can reciprocate up and down between an upper limit position (not shown) and a lower limit position shown in FIG. The rod diameter is equal to or slightly smaller than the diameter of the upper punch 66 shown in FIG. If the discharge rod 71 is lowered to the lower limit position after the second mold 61 is positioned corresponding to the upper surface of the discharge table 77, the finished green compact in the cavity 63 of the die 62 constituting the second mold 61 will be described. The body 120 can be discharged to the shooter 73.

Since the method for transferring (conveying) the green compact determines the slow speed of the production cycle, it is important to decide which method to use. In addition, how to make a specific configuration / structure is also important because it directly affects the device economy, handling / maintenance, and manufacturing costs. Incidentally, in the conventional example, the workpiece is often transferred (conveyed) in a linear direction.

In the present invention, a rotary transfer system using two rotary tables 80 and 90 is adopted. In FIG. 2, the mixed powder filling position Z11, the heating temperature raising position Z12, and the delivery relay position Z13 are spaced apart on a first circular locus R1 centered on the first axis Z1. Further, the underwriting relay position Z21, the finished green compact forming position Z22, and the product discharge position Z23 are spaced apart on a second circular locus R2 centered on the second axis Z2. In this embodiment, each of them is arranged in three equal parts (120 degrees). And it is constructed | assembled as a transfer apparatus using the 1st rotation table 80 which can be rotated centering on the 1st axis line Z1, and the 2nd rotation table 90 which can be rotated centering on the 2nd axis line Z2.

The distance between the first axis Z1 and the second axis Z2 is determined so that the delivery relay position (vertical axis) Z13 and the acceptance relay position (vertical axis) Z21 are the same position. The first rotary table 80 can be intermittently rotated in the DRL (counterclockwise) direction around the first axis Z1, and the mold holder 85 is moved to the mixed powder filling position Z11, the heating temperature raising position Z12, and the delivery relay position Z13. It can be positioned corresponding to any of these, and can be stopped and held at that position.

The first rotary table 80 can be moved up and down between the upper limit position and the lower limit position, and can be stopped and held at both the upper limit position and the lower limit position. The upper limit position is a position in the state shown in FIGS. 3A, 3C, 3D and 3F, and the lower limit position is shown in FIGS. 3B, 3E and 3F. And it is a position which will be in the state shown in Drawing 4 (G). The first rotary table 80 generates a pressing force that lowers the lifting rod 43 to the lower limit position against the biasing force of the spring 48 shown in FIGS.

In FIG. 2, the first rotary table 80 is supported by a transfer drive shaft 87 (rotation drive shaft 88, elevating shaft 89). The rotation drive shaft 88 is controlled by the servo motor so that the rotation angle of the first rotation table 80 can be stopped and held at the set angle. Therefore, the mold holding portion 85 is accurately positioned corresponding to each position Z11, Z12, Z13. Can do. The lift shaft 89 splined to the rotary drive shaft 88 can be positioned by correspondingly raising and lowering the first rotary table 80 to either the upper limit position or the lower limit position by the cylinder device. The first mold 31 (die 32) is attached to the mold holding portion 85.

The second turntable 90 can be intermittently rotated in the DRR (clockwise) direction around the second axis Z2, and the mold holding portion 95 can be placed in the acceptance relay position Z21, the finished green compact forming position Z22, and the product discharge position. Positioning corresponding to any position of Z23. Moreover, it can be stopped and held at each position. The transfer rotating shaft 97 is dedicated for rotational driving, and does not have a lifting / lowering function in this embodiment. That is, the second turntable 90 is maintained in the state shown in FIG. 3F, FIG. 4G, FIG. 4H, and FIG. A second mold 61 (die 62) is attached to the mold holding portion 95.

In this embodiment, a plurality of (three) mold holders 85 are arranged in three equal isometric angles (120 degrees) on the first rotary table 80, and each mold holder 85 has a first mold. 31 is attached. Similarly, a plurality (three) of mold holders 95 are arranged in three equal isometric angles (120 degrees) on the second rotary table 90, and the second mold 61 is attached to each mold holder 95. It has been.

Note that each of the rotary tables 80 and 90 is formed using a large-diameter disk, but a plurality of arm-tree members are arranged in three equal angles (120 degrees), and each arm-tree member is first, It is good also as a structure mounted | worn so that synchronous rotation was possible centering on the 2 axis lines Z1 and Z2.

Here, the first mold transfer device 81, the pre-heating green compact transfer device 82, and the post-heat green compact transfer device 83 are the first rotary table 80 (first mold transfer device 81, pre-heating pressure). It is understood that the powder transfer device 82 and the heated green compact transfer device 83) are integrally constructed. Each

transfer device

81, 82, 83 uses the intermittent rotation in the DRL direction around the first axis Z1 of the first rotary table 80 to move the mold holding portion 85 along the first circular locus R1. The first mold 31 is transferred while being transferred. The raising and lowering of the first rotary table 80 is combined on the way.

The first mold transfer device 81 transfers the first mold 31 located at the delivery relay position Z13 shown in FIG. 3 (F) to the mixed powder filling position Z11 shown in FIG. The first mold 31 is positioned corresponding to the container 23 at the position Z11. On the way, the first mold 31 is raised from the lower limit position to the upper limit position. This first mold transfer device 81 may be said to be a first mold return transfer device in view of the function of returning the first mold 31 from the delivery relay position Z13 to the mixed powder filling position Z11.

The pre-heating green compact transfer device 82 moves the first die 31 located at the intermediate green compact molding position (mixed powder filling position Z11) shown in FIG. The position is transferred from the position Z11) to the heating temperature raising position Z12 shown in FIG. 3E, and the first mold 31 is positioned corresponding to the heating temperature raising position Z12. On the way, the first mold 31 is raised from the lower limit position shown in FIG. 3 (B) to the upper limit position shown in FIG. 3 (C). Next, by the rotation of the first turntable 80, the first mold 31 is transferred to the heating temperature raising position Z12 shown in FIG. Then, the first mold 31 is mounted (corresponding positioning) in the accommodating portion 44 at the upper limit position, and then lowered to the lower limit position by the lowering operation of the lifting rod 43.

After heating, the green compact transfer device 83 moves the first mold 31 containing the mixed powder intermediate compression body 110 from the heating temperature raising position Z12 shown in FIG. 3 (E) to the delivery relay position Z13 shown in FIG. 3 (F). Transport to. The first die 31 is raised to the upper limit position by the raising / lowering operation of the first rotary table 80, and after being positioned corresponding to the delivery relay position Z13, is lowered to the lower limit position.

The second mold transfer device 91, the finished green compact transfer device 92, and the second mold return transfer device 93 include a second rotary table 90 (second mold transfer device 91, finished green compact). It is understood that the transfer device 92 and the second mold return transfer device 93) are integrally constructed. Each of the

transfer devices

91, 92, 93 uses the intermittent rotation in the DRR direction around the second axis Z2 of the second rotary table 90 to move the mold holding portion 95 along the second circular locus R2. The second mold 61 is transferred while being transferred.

The second mold transfer device 91 is a finished green compact shown in FIG. 4 (H) in the second mold 61 located in the underwriting relay position Z21 shown in FIG. 4 (G) and containing the intermediate green compact 110. The sheet is transferred to the forming position Z22 and positioned corresponding to the lower punch equivalent base 67 at the finished green compact forming position Z22. The second turntable 90 is rotated by 120 °.

The finished green compact transfer device 92 transfers the second mold 61 containing the finished green compact 120 from the finished compact forming position Z22 shown in FIG. 4 (H) and the product shown in FIG. 4 (I). The second mold 61 is positioned corresponding to the discharge position Z23. The second turntable 90 is rotated by 120 ° in the DRR direction.

The second mold return transfer device 93 transfers the second mold 61 after discharging the finished green compact 120 from the product discharge position Z23 to the underwriting relay position (product discharge position Z23) shown in FIG. Then, the second mold 61 is positioned corresponding to the underwriting relay position (product discharge position Z23). That is, the second mold 61 is returned before the next cycle.

The green compact transfer device has a rotary table structure and transfers along a circular locus. In addition, as shown in FIGS. 3 (F) and 4 (G), the green compact is delivered by directly extruding from the first mold 31 to the second mold 61 and delivering it. With this type of rotary transfer / extrusion delivery method, there is no risk of workpiece dropout compared to the conventional transfer method (using a robot or transfer device to transfer the workpiece in a single linear direction), and the workpiece and slide or gold The problem of avoiding collision with the mold is easy to solve, and quick and accurate transfer is possible. The delivery of the mixed powder 100 shown in FIGS. 3A and 3B is the same.

In the mixed powder high-density molding apparatus 1 according to the embodiment, the high-density molding method is performed by the following steps. Description will be made with reference to the processing steps shown in FIG. 1 (A) and the transfer operation (B) described corresponding thereto. In addition, the code | symbol (for example, Z22) parenthesized in the block which shows each process shows the position (complete green compacting position) where the said process is performed.

(Procurement of mixed powder)
A mixed powder 100 in a smooth state is procured by mixing a base metal powder (iron powder coated with a glassy insulating coating for magnetic core) and 0.2 wt% lubricant powder (zinc stearate powder). A predetermined amount is supplied to the mixed powder feeder 10 (step PR0 in FIG. 1).

(Mixed powder filling)
At a predetermined timing, the mixed powder feeder 10 is transferred from a predetermined position (not shown) to a replenishment position (dotted line) shown in FIG. Next, the supply port of the mixed powder supplier 10 is opened, and a fixed amount of the mixed powder 100 is filled in the container device 20 [empty container cavity 24] (step PR1 in FIG. 1). For example, it can be filled in 2 seconds. After filling, the supply port is closed and the mixed powder supply machine 10 returns to a predetermined position. At this time, the first mold transfer device 81 works, and the first mold 31 (die 32) is returned from the state of FIG. 3 (F) to the state of FIG. 3 (A).

(Mixed powder transfer)
When the upper punch 36 is lowered in the state shown in FIG. 3A, the first mold 31 is lowered together with the first rotary table 80. The upper punch 36 overcomes the urging force of the spring 26 and pushes down the first mold 31 and the container 23. Since the lower punch 37 is positioned and fixed at a predetermined position, the mixed powder 100 in the container 23 is transferred into the cavity 33 of the first die 31 (die 32) while being pre-compressed. That is, the mixed powder transfer device (lower punch 37) works.

(Molding green compact)
Further, the upper punch 36 descends and pressurizes the mixed powder 100 in the die 32 (cavity 33) with the first pressure P1. In FIG. 3B, the first pressure molding process (process PR3 in FIG. 1) is executed. Powder (solid) lubricants provide sufficient lubrication. The density ρ of the compressed intermediate green compact 110 increases according to the characteristic A (dotted line) in FIG. When the first applied pressure P1 becomes a pressure (3.0 Ton / cm ² ) corresponding to the horizontal axis index (for example, 30), the true density ratio is 85%, that is, the density ρ is 6.63 g / cm ³ (vertical axis index 87 Equivalent). For example, pressure molding for 8 seconds is completed. The formed intermediate green compact 110 remains in the cavity 33 of the first mold 31.

(Transfer of intermediate green compact)
In FIG. 3 (C), the pre-heating green compact transfer device 82 works. After the upper punch 36 is raised to the upper position, the first die 31 is raised to the upper limit position (position below the upper position of the upper punch 36) while accommodating the intermediate green compact 110. Next, the first mold 31 and the intermediate green compact 110 are transferred from the intermediate green compact molding position (mixed powder filling position Z11) to the heating temperature raising position Z12 shown in FIG. The first rotary table 80 rotates by 120 ° in the DRL direction of FIG. In preparation for the next cycle, the container 23 is returned from the lower limit position to the initial position (upper limit position) shown in FIG. By the biasing force of the spring 26. As shown in FIG. 3 (D), the first mold 31 has a heating temperature riser 40 at the heating temperature raising position Z12 and at the upper limit position (lower than the upper limit position of the first mold 31). It is positioned corresponding to (accommodating portion 44). Subsequently, the elevating rod 43 is lowered to position the first mold 31 corresponding to the lower limit position (heating position) shown in FIG.

(Heating temperature)
In FIG. 3 (E), when the accommodating portion 44 is lowered to the lower limit position (lower than the lower limit position of the first mold 31), the heating temperature riser 40 (heater 47) is activated. The intermediate green compact 110 in the die 32 is heated to a temperature corresponding to the melting point of the lubricant powder (for example, 120 ° C.) (step PR4 in FIG. 1). That is, the lubricant is dissolved, and the lubricant distribution in the intermediate green compact 110 is uniformly modified by the flow of the lubricant. The heating temperature raising time is, for example, 8 to 10 seconds. The start timing of the heater 47 is not limited to this. For example, activation may be started from the state shown in FIG.

(Delivery and undertaking of heated intermediate green compact)
When the heating temperature rise is completed, the heated compact transfer device 83 works. As shown in FIGS. 3E and 3F, the heated intermediate green compact 110 is transferred from the heating temperature raising position Z12 to the delivery relay position Z13 while being housed in the first mold 31. Is done. That is, the first turntable 80 rotates by 120 ° in the DRL direction of FIG. Since it is not transferred in the atmosphere exposure state, the temperature drop of the intermediate green compact 110 is hardly recognized. Then, the first die 31 (die 32) is placed on the second die 61 that is on standby (corresponding positioning) on the delivery relay stand 55. Then, the intermediate green compact transfer device (extrusion rod 50) works. That is, as shown in FIG. 4 (G), the extrusion rod 50 descends from the upper position in FIG. 3 (F), and the heated intermediate green compact 110 accommodated in the first mold 31 is moved to the first position. 2 is moved into the second mold 61 (step PR5 in FIG. 1). After the transition is completed, the push rod 50 returns to the upper position.

(Return transfer of the first mold)
When the intermediate green compact 110 has been transferred from the first mold 31 to the second mold 61, the first mold transfer device 81 moves the first mold 31 shown in FIG. The position is raised to the upper limit position in FIG. 3 (F), and subsequently returned from the delivery relay position Z13 to the mixed powder filling position Z11 shown in FIG. 3 (A). Positioning corresponding to the container 23 is performed. Also at this time, the first rotary table 80 rotates by 120 ° in the DRL direction.

(Transfer of intermediate green compact)
On the other hand, the second mold transfer device 91 also works. The intermediate green compact 110 received at the underwriting relay position Z21 (delivery relay position Z13) in FIG. 3 (F) is transferred from the underwriting relay position Z21 in FIG. 4 (G) to the finished green compact forming position Z22 in FIG. 4 (H). Transport to. The intermediate green compact 110 is transferred while being accommodated in the second mold 61. The second turntable 90 rotates by 120 ° in the DRR direction shown in FIG.

(Completion of finished green compact)
In FIG. 4H, the upper punch 66 descends from the upper position together with the slide (not shown). The lower punch equivalent base 67 receives the second pressure P2 in a stationary state. That is, the heated intermediate green compact 110 in the die 62 (cavity 63) starts to be pressurized with the second pressure P2. Liquid lubricant provides sufficient lubrication. In particular, a sweating phenomenon occurs in which the lubricant flows in all directions as the pressure molding proceeds. The frictional resistance between the metal particles as well as between the base metal particles can be efficiently reduced. The density ρ of the compressed intermediate green compact 110 increases according to the characteristic B (solid line) in FIG. That is, when the second applied pressure P2 exceeds the horizontal axis index (for example, 30... Applied pressure 3.0 Ton / cm ² ), the density ρ suddenly increases from 6.63 g / cm ³ to the density ρ corresponding to the vertical axis index 102. It increases to (7.75 g / cm ³ ). When the second applied pressure P2 is increased to an abscissa index of 100 (10 Ton / cm ² ), the density ρ (7.75 g / cm ³ ) becomes uniform as a whole. Here, for example, when the second pressure forming process for 8 seconds is completed, the finished green compact 120 is formed in the mold (41) (step PR6 in FIG. 1). Thereafter, the upper punch 66 is raised to the upper position by the slide. In the finished green compact 120 having a density ρ (7.75 g / cm ³ ) corresponding to the ordinate index 102, the vitreous material does not change or melt because the lubricant powder has a low melting point. Therefore, it is understood that a high-quality magnetic core green compact with low eddy current loss and high magnetic flux density can be efficiently manufactured.

(Transfer of finished green compact)
Then, the finished green compact transfer device 92 works, and the finished green compact 120 is housed in the second mold 61 while the finished compact forming position Z22 in FIG. ) To the product discharge position Z23. The product is positioned corresponding to the product discharge position Z23, that is, the discharge table 77. During this period, the discharge rod 71 is waiting at the upper position. The second turntable 90 rotates by 120 ° in the DRR direction.

(Product discharge)
The product discharge device 70 works. In FIG. 4 (I), the discharge rod 71 descends from the upper position and pushes the finished green compact 120 in the second mold 61 to the lower shooter 73. Product discharge ends (step PR7 in FIG. 1). After completion, the discharge rod 71 rises to the upper position and enters a standby state.

(Second mold return transfer)
The second mold return transfer device 93 returns and transfers the second mold 61 from the product discharge position Z23 in FIG. 4 (I) to the acceptance relay position Z21 (delivery relay position Z13) in FIG. 3 (F). The second turntable 90 rotates by 120 ° in the DRR direction. Since it does not move up and down in the middle, it can be returned quickly.

(Manufacturing cycle)
According to the high-density molding method according to the above steps, the first pressure molding process, the heating temperature raising process, and the second pressure molding process for the metal powder (mixed powder 100) supplied and filled in order are synchronized. If constructed to be feasible, high-density green compact (completed) with a cycle time of 12 to 14 seconds, which is the longest heating and heating process time (10 seconds) plus the green compact transfer time (eg 2 to 4 seconds) It is possible to produce a green compact 120). That is, it is understood that the manufacturing / production time can be drastically improved in comparison with only the high temperature sintering process time of 30 minutes or more in the conventional example. For example, it is possible to stabilize the supply of small and light complex parts with high mechanical strength for automobile parts and electromagnetic equipment parts with excellent magnetic properties and mechanical strength, which can greatly contribute to the reduction of production costs.

Thus, according to this embodiment, the mixed powder 100 is filled in the container 23, and then the intermediate powder compact 110 is formed by moving into the first mold 31 and applying the first pressure P1. Then, the temperature is positively raised to a temperature corresponding to the melting point of the lubricant powder (for example, 120 ° C.), the intermediate green compact 110 is set in the second mold 61, and the second pressure P2 is applied. Because it is a high-density molding method for molding the finished green compact 120, it is possible to manufacture high-density green compact reliably and stably, greatly reducing the manufacturing cost, and a mixed powder suitable for actual production. It is possible to increase the efficiency of 100 filling operations and reduce the size and weight of the first mold 31 and the like.

Moreover, since the sintering process for a long time at a high temperature can be wiped out, not only the oxidation of the

green compacts

110 and 120 can be greatly suppressed, but also the energy consumption can be minimized and the manufacturing cost can be greatly reduced. Also welcomed for global environmental conservation.

Also, since the melting point of the lubricant powder is a low melting point in the temperature range of 90 to 190 ° C., it is possible to ensure a sufficient lubricating action of the lubricant during the first pressurizing step. In addition, the selectivity of the lubricant can be expanded while promoting oxidation inhibition.

Since the second mold 61 can be warmed up to the melting point equivalent temperature before receiving the intermediate green compact 110, the fluidity of the dissolved lubricant in all directions during the second pressure molding can be further enhanced. . That is, the frictional resistance between the particles and the second mold 61 as well as between the base metal particles can be greatly reduced and maintained.

Since the first mold 31 can be warmed up after the formation of the intermediate green compact 110, shortening of the manufacturing cycle time including the temperature rising time of the intermediate green compact 110 can be promoted.

Further, since the second applied pressure P2 can be made equal to the first applied pressure P1, the fluidity of the dissolved lubricant in all directions during the pressure molding can be further enhanced. The frictional resistance force between the particles and the second mold 61 as well as between the base metal particles can be greatly reduced and maintained. In addition, it is easy to carry out and handle the pressure molding process, and can indirectly contribute to further reducing the manufacturing cost of the green compact. In addition, when embodying the device, for example, it can be easily based on a single press machine. Can be built.

Even if the base metal powder is changed from the iron-coated amorphous powder for the magnetic core to the iron-based amorphous powder for the magnetic core or the Fe-Si alloy powder for the magnetic core, the other conditions are the same. Magnetic core parts having magnetic characteristics corresponding to the types can be manufactured efficiently and stably.

In consideration, the capacity of the conventional apparatus (for example, a press machine) (horizontal axis index 100 in FIG. 5) could not be increased beyond the density corresponding to the vertical axis index 100, according to the present invention. For example, it is possible to increase the density corresponding to the vertical index 102 with the same apparatus. This fact is commended as a breakthrough in the art.

Further, the densification device 1 includes a mixed powder feeder 10, a mixed powder transfer device (lower punch 37), a first pressure molding machine 30, a heating temperature raising device 40, and an intermediate green compact transfer device (extrusion rod 50). ), The second pressure molding machine 60, and the product discharge device 70, the above-described densification method can be implemented reliably and stably, and can be realized at low cost. Easy to handle.

A first mold transfer device 81 for transferring the first mold 31, a pre-heating green compact transfer device 82, and a post-heating green compact transfer device 83 are provided, and a second mold 61 is transferred. Since the mold transfer device 91, the finished green compact transfer device 92 and the second mold return transfer device 93 are provided, the apparatus can be simplified and the green compact can be transferred quickly and smoothly. .

Furthermore, the mixed powder filling position Z11, the heating temperature raising position Z12, and the delivery relay position Z13 are spaced apart on the first circular locus R1 centered on the first axis Z1, and the acceptance relay position Z21, the finished green compact. The molding position Z22 and the product discharge position Z23 are spaced apart from each other on the second circular locus R2 centered on the second axis Z2, and each

transfer device

81, 82, 83 can be rotated about the first axis Z1. Since each of the

transfer devices

91, 92, and 93 is constructed using the first rotary table 90 that is rotatable about the second axis Z2, the second rotary table 90 is constructed. Therefore, the apparatus can be simplified further. Further simplification of the production line can be promoted and handling becomes easier. Compared with the conventional linear conveyance direction, rapid transfer and reduction in size and weight can be achieved as a whole.

(Second Embodiment)
This embodiment is shown in FIGS. The basic configuration / function is the same as in the case of the first embodiment (FIGS. 1 to 6E), but the second mold 61 (die 62) constituting the second pressure molding machine 60 is used. A second warm-up device 64 is provided. Further, a first warm-up device 34 is provided in a first mold 31 (die 32) constituting the first pressure molding machine 30.

That is, it is formed so as to prevent a temperature drop of the intermediate green compact 110 that has been heated and heated while the second mold 61 is warmed up. In addition, it is possible to perform preheating of the intermediate green compact 110 while warming up the first mold 31. In this embodiment, both the first warm-up device 34 and the second warm-up device 64 are provided, but either one may be provided depending on the working temperature environment or the like.

7 (FIG. 8) corresponds to FIG. 3 (FIG. 4) according to the first embodiment. Others (FIGS. 1, 2, 5, 6A to 6E) are the same as those in the first embodiment.

In practice, the temperature of the heated intermediate green compact 110 is lowered to a low temperature outside a certain temperature range by the time when the second pressing force P2 is applied in the second mold 61 to start molding. If not, the high-density molding of the present invention can be performed without warming up the second mold 61. Furthermore, it may not be necessary to warm up the first mold 31 and preheat the intermediate green compact 110 before the heating and heating step. In that case, a warm-up function for warming up the second mold 61 and the first mold 31 may not be provided.

However, when the heat capacity of the intermediate green compact 110 is small, when the transfer time to the second mold 61 and the transfer path are long, the temperature has been increased depending on the composition of the mixed powder 100, the form of the intermediate green compact 110, and the like. There is a possibility that the temperature of the intermediate green compact 110 will decrease by the time the molding of the finished green compact 120 starts. In such a case, it is possible to obtain a preferable molding effect when the second mold 61 is warmed up.

In FIG. 8, the second mold 61 (die 62) is provided with a second warm-up device (heater) 64 capable of changing the set temperature. The second warming-up device 64 has the second mold 61 at a temperature corresponding to the melting point of the lubricant powder (zinc stearate) (for example, 120 ° C.) until the intermediate green compact 110 is received (set). Warm up (warm up). The heated intermediate green compact 110 can be received without being cooled. As a result, the lubricating action can be ensured while preventing re-solidification of the previously dissolved (liquefied) lubricant.

This warm-up process is executed before the finished green compact forming process (PR6) in the first embodiment. This warm-up is formed so that it can be heated until the finished green compact 120 is completely pressed. In this way, the fluidity of the dissolved lubricant in all directions during pressure molding can be further enhanced, so that friction between not only the base metal particles but also the particles and the second die 61 (die 62) is achieved. The resistance can be greatly reduced and maintained.

Moreover, when the composition of the mixed powder 100 and the form of the intermediate green compact 110 are specific, when the mixed powder intermediate compression body 110 has a large heat capacity, when a large heating temperature riser cannot be provided, or when the working environment temperature is If the temperature is low, there is a risk of spending a long time for heating and heating the intermediate green compact 110. In such a case, it is preferable to warm up the first mold 31. Therefore, in this embodiment, the first mold 31 is warmed up.

Therefore, a first warm-up device (heater) 34 capable of changing the set temperature is built in the first mold 31 (die 32), and corresponds to FIG. 7 (A) [FIG. 3 (A). ], The first mold 31 can be warmed up by turning on the heater. In other words, it can be used as a part of the heating warmer 40. This preceding warm-up can reduce the heating time in the heating warmer 40 and is effective for shortening the production cycle. That is, as shown in FIGS. 7D and 7E, since both the

heaters

47 and 34 can be used for heating from the outer peripheral surface and the lower surface, the temperature of the intermediate green compact 110 can be increased quickly at an average temperature as a whole. .

This warm-up process is executed after the end of the intermediate green compact forming process (PR3) in the first embodiment. In this embodiment, it is formed so that it can be heated and warmed up until it is delivered to the heating warmer 40.

In this embodiment, the first warm-up device 34 and the second warm-up device 64 are of the electric heating system (electric heater). It can also be implemented with an apparatus or the like.

Therefore, according to this embodiment, in addition to being able to achieve the same operational effects as in the case of the first embodiment, the second mold 61 is formed in advance so that it can be warmed up. In addition, since the omnidirectional fluidity of the dissolved lubricant can be further enhanced during the pressure molding by the second pressure P2, the frictional resistance force between the particles and the second mold 61 as well as between the base metal particles can be increased. It can be greatly reduced and maintained.

Further, since the first mold 31 can be warmed up, if the warming-up execution is selected, the load on the heating warmer 40 can be reduced and the intermediate green compact 110 can be quickly heated. The production cycle can be shortened.

DESCRIPTION OF SYMBOLS 1 High density molding apparatus 10 Mixed powder supply machine 20 Container apparatus 23 Container 30 1st press molding machine 31 1st metal mold | die 34 1st warming-up apparatus 37 Lower punch (mixed powder transfer apparatus)
40 Heating temperature riser 50 Extrusion rod (intermediate green compact transfer device)
60 second pressure molding machine 61 second mold 64 second warm-up device 70 work discharge device 80 first rotary table (first mold transfer device, green compact transfer device before heating, after heating Compaction transfer device)
90 Second rotary table (second mold transfer device, finished green compact transfer device, second mold return transfer device)
100 Mixed powder 110 Intermediate green compact (Mixed powder intermediate compact)
120 Complete green compact (Compact powder compact)

Claims

Fill the container cavity with mixed powder, which is a mixture of base metal powder and low melting point lubricant powder,
Transferring the mixed powder in the container cavity into the cavity of the first mold positioned corresponding to the container;
Applying a first pressing force to the mixed powder in the cavity of the first mold to form a mixed powder intermediate compression body;
The first mold after molding and the mixed powder intermediate compact are heated to raise the temperature of the mixed powder intermediate compact to the melting point equivalent temperature,
The mixed powder intermediate compressed body after the temperature rise is positioned corresponding to the second mold together with the first mold,
Transferring the mixed powder intermediate compression body in the cavity of the first mold into the cavity of the second mold positioned corresponding to the first mold;
A mixed powder high-density molding method, comprising: applying a second pressure to a mixed powder intermediate compressed body in a cavity of a second mold to form a high-density mixed powder finished compressed body.
The method for high-density molding of mixed powder according to claim 1, wherein the melting point of the lubricant powder is a low melting point belonging to a temperature range of 90 to 190 ° C.
3. The mixed powder high-density molding method according to claim 1 or 2, wherein the second mold is warmed up before receiving the mixed powder intermediate compressed body.
3. The mixed powder high-density molding method according to claim 1 or 2, wherein the first mold is warmed up after completion of the molding of the mixed powder intermediate compression body.
3. The mixed powder high-density molding method according to claim 1 or 2, wherein the second pressing force is selected to be equal to the first pressing force.
A mixed powder feeder capable of filling a mixed powder, which is a mixture of a base metal powder and a low melting point lubricant powder, into a container cavity positioned at a mixed powder filling position;
A mixed powder transfer device for transferring the mixed powder in the container cavity into the cavity of the first mold positioned corresponding to the container;
A first pressure molding machine for forming a mixed powder intermediate compression body by applying a first pressing force from the first punch to the mixed powder in the cavity of the first mold;
A heating temperature riser for heating the first mold positioned at the heating temperature raising position and the mixed powder intermediate compression body to raise the temperature of the mixed powder intermediate compression body to a temperature corresponding to the melting point;
An intermediate green compact transfer device for transferring and transferring the mixed powder intermediate compressed body in the cavity of the first mold to the second mold positioned at the transfer relay position;
Secondly, a second pressing force is applied from the second punch to the mixed powder intermediate compressed body in the cavity of the second mold positioned at the finished compressed body forming position to form a high-density mixed powder finished compressed body. A pressure molding machine of
A mixed powder high-density molding apparatus, comprising: a product discharge device formed so that the mixed powder finished compact in the cavity of the second mold can be discharged at a product discharge position.
A first mold transfer device formed so as to be capable of positioning corresponding to a container positioned at a mixed powder filling position by transferring the first mold;
A pre-heating green compact transfer device formed so that the first mold is transferred from the intermediate green compact forming position and can be positioned corresponding to the heating temperature raising position;
A post-heating green compact transfer device formed so that the first mold containing the mixed powder intermediate compression body is transferred from the heating temperature raising position and can be positioned corresponding to the delivery relay position;
A second mold transfer device formed so as to be positioned corresponding to a finished green compact molding position by transferring the second mold containing the mixed powder intermediate compression body from a delivery relay position;
A finished green compact transfer device formed to be capable of positioning corresponding to the product discharge position by transferring the second mold containing the mixed powder finished compact from the finished green compact forming position;
The second mold returning and transferring device is provided, wherein the second mold containing the mixed powder finished compressed body is moved from the product discharge position and can be positioned corresponding to the underwriting relay position. High density molding equipment for mixed powder.
The mixed powder filling position, the heating temperature raising position, and the delivery relay position are spaced apart on a first circular locus centered on the first axis, and the delivery relay position, the finished green compact molding position, and the product discharge position are defined. Spaced apart on a second circular trajectory centered on the second axis;
The first mold transfer device, the pre-heating green compact transfer device, and the post-heat green compact transfer device are constructed using a first rotary table that can rotate around a first axis,
The second mold transfer device, the finished green compact transfer device, and the second mold return transfer device are constructed using a second rotary table that is rotatable about a second axis. The high-density molding apparatus according to claim 7.
The high-density molding apparatus according to claim 6 or 7, further comprising a first warm-up device for warming up the first mold.
The high-density molding apparatus according to claim 6 or 7, further comprising a second warming-up device for warming up the second mold.