CN102489703A - Method for preparing magnet green body through pressing by adopting high-precision die - Google Patents

Method for preparing magnet green body through pressing by adopting high-precision die Download PDF

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Publication number
CN102489703A
CN102489703A CN2011104283701A CN201110428370A CN102489703A CN 102489703 A CN102489703 A CN 102489703A CN 2011104283701 A CN2011104283701 A CN 2011104283701A CN 201110428370 A CN201110428370 A CN 201110428370A CN 102489703 A CN102489703 A CN 102489703A
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CN
China
Prior art keywords
template
die
plug
punch
magnet
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Pending
Application number
CN2011104283701A
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Chinese (zh)
Inventor
龚海洲
饶晓雷
李纲
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Beijing Zhong Ke San Huan High Tech Co Ltd
Shanghai Epson Magnetics Co Ltd
Original Assignee
Beijing Zhong Ke San Huan High Tech Co Ltd
Shanghai Epson Magnetics Co Ltd
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Publication date
Application filed by Beijing Zhong Ke San Huan High Tech Co Ltd, Shanghai Epson Magnetics Co Ltd filed Critical Beijing Zhong Ke San Huan High Tech Co Ltd
Priority to CN2011104283701A priority Critical patent/CN102489703A/en
Publication of CN102489703A publication Critical patent/CN102489703A/en
Pending legal-status Critical Current

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Abstract

The invention provides a method for preparing a magnet green body through pressing by adopting a high-precision die. The method comprises the following steps of: a stamping device of a press controls an upper male die to move downward to press the magnetic powder in a die cavity formed by a female die, a lower male die and a core rod into a magnet green body with a certain pressure and keeping the pressure for a while; a die release device of the press drives the core rod on a core rod template and a female die template fixedly connected with the core rod template to move downward together until the upper end face of the lower male die is parallel to the upper surface of a cylinder at the lower end of the core rod and staying for a while; and the die release device of the press adopts a second T-shaped joint to control the core rod template to continuously move downward for a distance equal to the height of a magnet until the magnet green body completely breaks away from the die cavity, thus completing die release. Compared with the prior art, the method has the following beneficial effects that: the full release process of the inner stress of the magnet is added in the process of upward die release of the magnet, so the problem in the prior art that the magnet tolerance is big as the inner stress of the magnet is quickly released and then delayed elasticity happens can be solved.

Description

A kind of method of high-precision mold pressing magnetic body green compact
Technical field
The present invention relates to a kind of manufacturing approach of magnet green compact, relate in particular to a kind of method of utilizing high accuracy compression mold compacting rare-earth permanent magnet green compact.
Background technology
Boned neodymium iron boron permanent magnet is the built-up magnet that contains rare earth element, has overall merits such as magnetic property height, dimensional accuracy is high, machinability is strong, uses very extensive in modern times in the industry.For example can be applied in various hard disk drives; Do driver magnet in the DVD drive; Can be applied in printer; Doing the driving motor magnet in the duplicator, also can be applied in automobile micro machine, the Magnetic Sensor, is various precision electric motors in the modern industry, the indispensable functional material of small and special electric machine.
Compressing and forming process is to produce the modal technology of boned neodymium iron boron permanent magnet.With behind the fast quenching NdFeB magnetic powder crushing and classification and binding resin; Other processing aid fully mixes, mixes; Magnetic compound after utilizing dry powder press or hydraulic press to mix is pressed into the Agglutinate neodymium-iron-boron magnet green compact of circular or tile; Then green compact are solidified under the temperature about 200 ℃, through grinding, become final product behind the coating process again.In the above step, utilize mould that magnetic is pressed into the key that green compact are control magnet size precision.
Along with development of technology, various device is increasingly high to using therein boned neodymium iron boron permanent magnet to require, and is example with the hard disk drive of main flow; Conventional driver magnet is circular, and magnet thickness is merely 1.5 mm~2mm, and tolerance is 0.04 mm~0.06mm; Along with the volume of hard disk is more and more littler, rotating speed is increasingly high, and boned neodymium iron boron permanent magnet has proposed more harsh dimensional requirement to using therein; Become 0.8 mm~1mm like magnet thickness, tolerance≤± 0.03mm.
In the prior art, utilize the mould in the dry powder press that magnetic is pressed into the production process that magnet green compact right and wrong are usually seen, and the structure of mould comprise the epirelief film; Die, lower punch, four critical pieces of plug; Being separately fixed on the diverse location of mould bases, also is conventional technology.According to knowhow, magnetic is pressed into green compact, mainly comprise following step: (1) filling, utilize dry powder press that the magnetic mixture is filled in the die cavity; (2) compacting, the epirelief film enters into die cavity under the drive of press, under certain pressure, the magnetic mixture is pressed into the magnet green compact; (3) demoulding moves on the epirelief film, and plug and die move down, and it is motionless that lower punch keeps, and magnet is ejected die cavity, accomplishes the demoulding.
This method has been brought into play important effect in the process of producing fast magnet in enormous quantities, but mould and the method for utilizing prior art the accuracy of manufacture require higher for example tolerance≤± 0.03mm, during the magnet of wall thickness 0.8 mm~1mm, can not meet the demands.Its reason is that in the knockout course, the magnet green compact are inner because the effect of internal stress can produce elastic after effect, and in the extremely short time, the magnet green compact inside and outside wall that has broken away from the die cavity constraint can outwards expand, thereby influences the dimensional accuracy of magnet.
Summary of the invention
In order to solve the problems of the technologies described above, the invention provides a kind of method of high-precision mold pressing magnetic body green compact, can effectively solve the technical barrier that magnet reduces the precision of magnet owing to the internal stress effect in knockout course.
The method of a kind of high-precision mold pressing magnetic body green compact of the present invention, wherein, this high-precision mold comprises punch, last punch template, lower punch, lower punch template, die, die template, plug, plug template;
Wherein go up punch and be fixedly mounted on the punch template, epirelief film template is connected through the decompressor of first T junction and press, and under the control of press decompressor, accomplishes the punching press action; Epirelief film template is connected with the die template through two springs, and the die template is fixedly connected with the plug template through firm post, and lower punch is fixedly mounted on the lower punch template; The lower punch template is fixedly connected with the press stand through side plate, and the lower punch upper end closely is enclosed within the die, and die is fixedly mounted in the die template; Last punch central axis and lower punch central axes; The plug upper end closely is enclosed within the lower punch, and the plug bottom is fixed on the plug template, and the plug template is connected through the stripper apparatus of second T junction and press; And can under the drive of demoulding control device, move up and down; Thereby drive and be fixed on the plug on the plug template, and move up and down, accomplish demoulding action through the die template of firm post with its fixed connection;
The lower punch upper end closely is enclosed within the die, die, and lower punch forms die cavity between the plug; Under the original state, the upper surface of plug and the upper surface of die and die installing plate are on same horizontal plane;
Described epirelief film and lower punch are the hollow circular cylinder of band mounting seat, and epirelief film and lower punch diameter, and wall thickness is all identical;
Described plug is made up of two parts, and its lower end is the cylinder of band mount pad, and the upper end also is a cylinder, and the cylindrical radius in upper end is less than the cylindrical radius in lower end.
This method comprises:
Step 1: first T junction control epirelief film template of passing through of described press decompressor is moved down; Thereby make the epirelief film that is fixed on the epirelief film template be moved downward to die; Lower punch; In the die cavity that plug is formed, with certain pressure magnetic is pressed into the magnet green compact, and keep-ups pressure a period of time.
Step 2: described press decompressor control epirelief film is moved up; Simultaneously; Described press stripper apparatus drives second T junction control plug template and moves down, and is fixed on the plug on the plug template thereby drive, and moves down through the die template of firm post with its fixed connection; Upper surface to lower punch is parallel with the cylindrical upper surface in plug lower end, and stays for some time.
Step 3: make described press stripper apparatus continue to move down through second T junction control plug template, to the die upper surface, the lower punch upper surface, the plug upper surface is in same horizontal plane, and the magnet green compact break away from die cavity fully, accomplish the demoulding.
Of the present inventionly further be improved to, the difference of plug lower end cylinder radius and plug upper cylinder radius is 0.01mm~0.05mm.
Of the present inventionly further be improved to, the cylindrical height in plug upper end is for making the height of magnet.
Of the present inventionly further be improved to, the described punch of going up, lower punch, die, the material of plug are carbide alloy.
Of the present inventionly further be improved to, in the step 1, it is 10 tons~20 tons that the pressing magnetic body green compact are exerted pressure, and the time of keep-uping pressure is 1~3 second.
Of the present inventionly further be improved to, in the step 2, the magnet green compact time of staying is 1~5 second.
Of the present inventionly further be improved to, in the step 3, the height that described press stripper apparatus drives the distance that moves down through second T junction control plug template and manufacturing magnet green compact is equal.
The manufacturing process of high accuracy magnet of the present invention; Compare with prior art; Because the plug up and down radius at two ends is different, many extra die cavities between the inner surface of the outer surface of plug upper end and die like this, when magnet in the process of the upwards demoulding; Can in this die cavity, carry out internal stress discharges; Therefore the dimensional accuracy of magnet is guaranteed, and can solve in the prior art, owing to the inner internal stress of magnet discharges fast the big difficult problem of magnet tolerance that elastic after effect causes takes place.
Description of drawings
The generalized section of Fig. 1 mould structure of the present invention.
The structure chart of Fig. 2 plug.
The specific embodiment
In order to make those skilled in the art understand spirit of the present invention clearer, accurately, specific embodiment of the present invention is elaborated below in conjunction with accompanying drawing.
Fig. 1 is the sketch map of the mould structure of the specific embodiment of the invention, and Fig. 2 is the mandrel structure sketch map of the specific embodiment of the invention shown in Figure 1.With reference to figure 1, Fig. 2.Before introducing method of the present invention, the high-precision mold that at first detailed introduction need be used.
High-precision mold of the present invention comprises punch 1, last punch template 5, lower punch 3, lower punch template 6, die 2, die template 7, plug 4, plug template 8.Wherein epirelief film 1 is the hollow circular cylinder of being with mounting seat with lower punch 3, and epirelief film 1 and lower punch 3 diameters, and wall thickness is all identical.Wherein go up punch 1 and be fixedly mounted on the punch template 5, lower punch 3 is fixedly mounted on the lower punch template 6, and lower punch 3 upper ends closely are enclosed within the die 2, and die 2 is fixedly mounted in the die template 7, last punch 1 central axis and lower punch 3 central axes; Plug 4 upper ends are enclosed within the lower punch 3, and plug 4 bottoms are fixed on the plug template 8, and lower punch 3 upper ends closely are enclosed within the die 2, die 2, and lower punch 3 forms die cavity between the plug 4; Under the original state, the upper surface of the upper surface of plug 4 and die 2 and the upper surface of die template 7 are on same horizontal plane.
Epirelief film template 5 is connected through the decompressor of first T junction 14 and press, and under the control of press decompressor, accomplishes the punching press action; Epirelief film template 5 is connected with die template 7 through two springs 10, and die template 7 is fixedly connected with plug template 8 through firm post 9.In a concrete embodiment, described firm post has 4, and runs through lower punch template 7.Lower punch template 7 is fixedly connected through pair of side plates 13 with press stand 12.Plug template 8 is connected through the stripper apparatus of second T junction 11 and press; And can under the drive of demoulding control device, move up and down; Thereby drive and be fixed on the plug 4 on the plug template 8, and move up and down, accomplish demoulding action through the die template 7 of firm post 9 with its fixed connection.
Special; With reference to figure 2, plug of the present invention is made up of two parts, and its lower end is the cylinder 4b of band mount pad; The upper end also is a cylinder 4a; Wherein, the radius r of plug upper end cylinder 4a is less than the radius R of plug lower end cylinder 4b, and the height H of plug upper end cylinder 4a is the height of manufacturing magnet.
Preferably; The difference of plug lower end cylinder radius R and plug upper cylinder radius r is 0.01mm~0.05mm; Concrete numerical value equates with the required precision that reaches of production magnet; If the dimensional accuracy that magnet requires is high, then the difference of plug lower end cylinder radius R and upper cylinder radius r is just little.In a concrete embodiment, the dimensional tolerance of magnet is controlled to be ± 0.01mm, and then the difference of plug lower end cylinder radius R and plug upper end cylinder radius r is 0.01mm, and is corresponding, makes the time of these magnet green compact and will extend.In another specific embodiment, the dimensional tolerance of magnet is controlled to be ± 0.05mm, and then the difference of plug lower end cylinder radius R and plug upper end cylinder radius r is 0.05mm, and the manufacturing time of these magnet green compact will shorten.
Preferably, the height H of upper end cylinder 4a is identical with the height of manufacturing magnet.
In order to guarantee the service life of mould, the critical piece of mould according to the invention such as epirelief film 1, die 2, lower punch 3, the material of plug 4 is carbide alloy, in concrete embodiment, is preferably the wolfram steel in the carbide alloy series.
Method of the present invention comprises following several steps:
Step 1: first T junction, the 14 control epirelief film templates 5 of passing through of described press decompressor are moved down; Thereby make the epirelief film 1 that is fixed on the epirelief film template 5 be moved downward to die 2; Lower punch 3; In the die cavity that plug is formed, with certain pressure magnetic is pressed into the magnet green compact, and keep-ups pressure a period of time.
Among the present invention, it is 10 tons~20 tons that the pressing magnetic body green compact are exerted pressure, and the time of keep-uping pressure is 1~3 second.Size of being exerted pressure and dwell time are determined according to concrete magnet, and according to knowhow, if the top surface area of annular magnetic is big more, pressing magnetic body institute applied pressure is just big more, and the dwell time also increases relatively.
Step 2: described press decompressor control epirelief film 1 is moved up; Simultaneously; Described press stripper apparatus drives second T junction, 11 control plug templates 8 and moves down, and is fixed on the plug 4 on the plug template 8 thereby drive, and moves down through the die template 7 of firm post 9 with its fixed connection; Upper surface to lower punch 3 is parallel with the upper surface of plug 4 lower end cylinder 4b, and stays for some time.
This step is a pilot process in the magnet green compact knockout course, and the press stripper apparatus moves down through second T junction control plug template, is fixed on the plug on the plug template thereby drive; And move down through the die template of firm post with its fixed connection, in this process, it is motionless that lower punch keeps; Upper surface to lower punch is parallel with the cylindrical upper surface in plug lower end, the magnet green compact die inner surface that relatively moves, lower punch upper surface; In the die cavity that plug upper end cylindrical inner surface is formed, and stopped 1~5 second, the purpose of this process is that the inner internal stress of magnet is fully discharged; In knockout course, because internal stress discharges fast the difficult problem that magnet precision that elastic after effect causes reduces taking place thereby reduce magnet, also is the committed step that the present invention is different from the knockout course of routine, specifically the time of staying; Below be called slow-release time; Be to confirm according to the precision that the magnet needs reach, the required precision that general magnet need reach is high more, and then slow-release time is just long more.
Step 3: described press stripper apparatus is driven through second T junction, 11 control plug templates 8 continue to move down; The height of displacement and manufacturing magnet green compact equates; To die 2 upper surfaces, lower punch 3 upper surfaces, plug 4 upper surfaces are in same horizontal plane; This moment, the magnet green compact can break away from die cavity fully, accomplished demoulding action.
Following table is to utilize the process conditions table of 5 specific embodiments of method of the present invention:
More than in 5 specific embodiments, the magnet external diameter, internal diameter is radius.Among the present invention, the press stripper apparatus that relates to, the press decompressor is mechanical transmission structure common in the powder press, no longer specifically gives unnecessary details among the present invention.Simultaneously, the present invention has only paid close attention to the compacting of magnet green compact, knockout course, the process of the filling (magnetic) before magnet is pressed is the same with prior art.Conventional magnet green compact are being pressed and knockout course carries out continuously, and Just because of this, conventional method is being brought into play important effect in enormous quantities the manufacturing in the magnet process fast; But have some drawbacks, for example the dimensional accuracy of magnet is not high yet, main because: in the knockout course; The magnet green compact are breaking away from fast die, when lower punch, die cavity that plug is formed; The magnet green compact that lost the die cavity constraint are under the effect of the inner internal stress of magnet; Can discharge stress to magnet inner surface and outer surface both direction simultaneously, be called the generation elastic after effect in the industry again, so the dimensional accuracy of magnet can receive very big influence.
The manufacturing approach of magnet green compact provided by the present invention; Because the plug up and down radius at two ends is different, many extra die cavities between the inner surface of the outer surface of plug upper end and die like this, when magnet in the process of the upwards demoulding; Can in this die cavity, carry out internal stress discharges; Therefore the dimensional accuracy of magnet is guaranteed, and can solve in the prior art, owing to the inner internal stress of magnet discharges fast the big difficult problem of magnet tolerance that elastic after effect causes takes place.Obvious; Method of the present invention only is applicable to the production of annular magnetic, when utilizing method pressing magnetic body green compact of the present invention, with conventional method relatively; Manufacturing time has inevitably increased, but can satisfy the occasion higher to the magnet size required precision.
It is understandable that the detailed description of the foregoing description is in order to set forth and explain principle of the present invention rather than to the qualification of protection scope of the present invention.Under the prerequisite that does not break away from purport of the present invention, one of ordinary skill in the art can be made modification through the understanding to the principle that is disclosed of technique scheme on these embodiment bases, changes and changes.Therefore protection scope of the present invention appended claim with and be equal to and limit.

Claims (7)

1. the method for high-precision mold pressing magnetic body green compact, wherein, this high-precision mold comprises punch, last punch template, lower punch, lower punch template, die, die template, plug, plug template;
Wherein go up punch and be fixedly mounted on the punch template, epirelief film template is connected through the decompressor of first T junction and press, and under the control of press decompressor, accomplishes the punching press action; Epirelief film template is connected with the die template through two springs, and the die template is fixedly connected with the plug template through firm post, and lower punch is fixedly mounted on the lower punch template; The lower punch template is fixedly connected with the press stand through side plate, and the lower punch upper end closely is enclosed within the die, and die is fixedly mounted in the die template; Last punch central axis and lower punch central axes; The plug upper end closely is enclosed within the lower punch, and the plug bottom is fixed on the plug template, and the plug template is connected through the stripper apparatus of second T junction and press; And can under the drive of demoulding control device, move up and down; Thereby drive and be fixed on the plug on the plug template, and move up and down, accomplish demoulding action through the die template of firm post with its fixed connection;
The lower punch upper end closely is enclosed within the die, die, and lower punch forms die cavity between the plug, and under the original state, the upper surface of plug and the upper surface of die and die installing plate are on same horizontal plane;
Described epirelief film and lower punch are the hollow circular cylinder of band mounting seat, and epirelief film and lower punch diameter, and wall thickness is all identical;
Described plug is made up of two parts, and its lower end is the cylinder of band mount pad, and the upper end also is a cylinder, and the cylindrical radius in upper end is less than the cylindrical radius in lower end;
It is characterized in that this method comprises:
Step 1: first T junction control epirelief film template of passing through of described press decompressor is moved down; Thereby make the epirelief film that is fixed on the epirelief film template be moved downward to die; Lower punch; In the die cavity that plug is formed, with certain pressure magnetic is pressed into the magnet green compact, and keep-ups pressure a period of time;
Step 2: described press decompressor control epirelief film is moved up; Simultaneously; Described press stripper apparatus drives second T junction control plug template and moves down, and is fixed on the plug on the plug template thereby drive, and moves down through the die template of firm post with its fixed connection; Upper surface to lower punch is parallel with the cylindrical upper surface in plug lower end, and stays for some time;
Step 3: make described press stripper apparatus continue to move down through second T junction control plug template, to the die upper surface, the lower punch upper surface, the plug upper surface is in same horizontal plane, and the magnet green compact break away from die cavity fully, accomplish the demoulding.
2. the method for as claimed in claim a kind of high-precision mold pressing magnetic body green compact is characterized in that, the difference of plug lower end cylinder radius and plug upper cylinder radius is 0.01mm~0.05mm.
3. the method for as claimed in claim 2 kind of high-precision mold pressing magnetic body green compact is characterized in that, the cylindrical height in plug upper end is for making the height of magnet.
4. the method for as claimed in claim 3 kind of high-precision mold pressing magnetic body green compact is characterized in that,, the described punch of going up, lower punch, die, the material of plug are carbide alloy.
5. the method for as claimed in claim a kind of high-precision mold pressing magnetic body green compact is characterized in that, in the step 1, it is 10 tons~20 tons that the pressing magnetic body green compact are exerted pressure, and the time of keep-uping pressure is 1~3 second.
6. the method for as claimed in claim a kind of high-precision mold pressing magnetic body green compact is characterized in that, in the step 2, the magnet green compact time of staying is 1~5 second.
7. the method for as claimed in claim a kind of high-precision mold pressing magnetic body green compact; It is characterized in that; In the step 3, the height that described press stripper apparatus drives the distance that moves down through second T junction control plug template and manufacturing magnet green compact is equal.
CN2011104283701A 2011-12-20 2011-12-20 Method for preparing magnet green body through pressing by adopting high-precision die Pending CN102489703A (en)

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CN2011104283701A CN102489703A (en) 2011-12-20 2011-12-20 Method for preparing magnet green body through pressing by adopting high-precision die

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CN2011104283701A CN102489703A (en) 2011-12-20 2011-12-20 Method for preparing magnet green body through pressing by adopting high-precision die

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102847937A (en) * 2012-08-15 2013-01-02 浙江恒成硬质合金有限公司 Alloy mandril
CN102909368A (en) * 2012-10-25 2013-02-06 无锡中彩新材料股份有限公司 Powder metallurgy finishing machine

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102847937A (en) * 2012-08-15 2013-01-02 浙江恒成硬质合金有限公司 Alloy mandril
CN102909368A (en) * 2012-10-25 2013-02-06 无锡中彩新材料股份有限公司 Powder metallurgy finishing machine

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Application publication date: 20120613

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