Connect public, paid and private patent data with Google Patents Public Datasets

Method of pressing powder compacts

Download PDF

Info

Publication number
US2747231A
US2747231A US33305553A US2747231A US 2747231 A US2747231 A US 2747231A US 33305553 A US33305553 A US 33305553A US 2747231 A US2747231 A US 2747231A
Authority
US
Grant status
Grant
Patent type
Prior art keywords
powder
punch
pressing
die
preform
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
Inventor
Herbert P Reinhardt
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.)
P R Mallory and Co Inc
Original Assignee
P R Mallory and Co Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Grant date

Links

Images

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22FWORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER
    • B22F3/00Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/02Compacting only
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10STECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S264/00Plastic and nonmetallic article shaping or treating: processes
    • Y10S264/66Processes of reshaping and reforming

Description

May 29, 1956 H. P. REINHARDT 2,747,231

METHOD OF PRES-SING POWDER COMPACTS Filed Jan. 26, 1953 IN V EN TOR.

flzrzri P Fem/midi 4 TTUR'NE Y METHOD OF PRESSING POWDER COMPACTS Herbert P. Reinhardt, Indianapolis, Ind., assignor to P. R. Mallory & Co., Inc., Indianapolis, Ind a corporation of Delaware Application January 26, 1953, Serial No. 333,055

4 Claims. (Cl. 18--59.3)

The present invention relates to the art of powder metallurgy and, more particularly, to a novel method of molding or pressing coherent bodies, or compacts, from metallic powder.

As is known, the manufacture of parts by pressed powder techniques is relatively simple when the part is of a simple, uniform or symmetrical shape. Considerable difiiculties are experienced, however, when the part has an irregular or complicated shape, the thickness of which, measured in the direction of pressing, is greatly different in different regions. Parts of this character, when made by the conventional procedure of filling the die with metallic powder and striking off the excess powder will display a more or less non-uniform pressed density, depending upon the configuration incorporated in the die. Various expedients have been used to produce compacts of complicated shape to substantially uniform pressed density. These include pressing in several stages, spring-loaded punches, multiple punch motions, rubber dies, and the like. None of these prior procedures, however, is capable of satisfactorily producing on an industrial scale parts of continuously varying cross section of such configurations as will be described in the following.

It has been discovered that the outstanding problem may be solved in a remarkably simple manner.

It is an object of the present invention to improve the methods of molding compacts from powders, specifically from metallic powders.

It is another object of the present invention to provide a novel and improved method of pressing coherent bodies of complicated shape and having uniform pressed densities.

It is a further object of the present invention to provide a simple and efiicient method of producing pressed compacts characterized by uniform densities throughout and having such complex shapes that they cannot be efiiciently produced by any conventional method.

Other and further objects and advantages of the invention will appear from the following description and from the accompanying drawing, in which Figures 1 to 4 are diagrammatic views, somewhat fragmentary in character, illustrating step-by-step the preferred manner in which the method of the invention may be practiced;

Figure 5 is a vertical sectional view of the finished compact made by the method of invention; and

Figures 6 to 8 are similar views of other complicated shapes which may be made by the method of the invention.

Broadly stated, in accordance with the principles of the present invention, the powder is prepositioned in the containing member or die in such a manner that upon subsequent pressing or compacting the pressed density will be substantially uniform throughout the compact. The correct amount of powder is placed in the containing member or die and then a preform member or punch is placed in the die on top of the powder.

The powder will then assume the shape of the cavity nited States Patent ice defined by the die and the preform member, if it can be made to flow. According to the invention, this flow is accomplished by subjecting the die or container to mechanical vibrations. Light pressure, exerted by hand or other means, on this preform punch, while the die is being vibrated produces the desired positioning of the powder which will be caused to accurately conform to the shape of the cavity. The preform punch is 'then removed and the final compacting is made preferably by the use of a second pressing member or punch. Thus, the prepositioning of the powder in conjunction with the final pressing produces a finished compact which will have uniform pressed density throughout.

In general, the shape of the preform punch is so determined as to pile the powder to the proper depth prior to pressing or, in other words, that the powder prepositioned thereby, upon subsequent compression, establishes the desired final and uniform pressed density. Of course, the proper fill ratio of the powder must be known and in some cases it is desirable to make a few simple preliminary tests to determine the configuration of the preform punch that is most suitable for the purpose. Thus, depending upon the shape of the compact to be pressed, the shape of the preform punch may be similar to that of the pressing punch or may be completely different therefrom. In some rare instances the shapes of the preform and pressing punches may be identical although this is a rather remote possibility.

A great variety of vibrators available on the market may be used, such as so-called electronic vibrators, and the like. The frequency of the mechanical vibrations imparted to the die and thus to the powder is quite low, generally between 20 and 400 'cycles per second although certain advantages are obtainable by subjecting the die or powder to high frequency vibrations where the increased cost of th'e'equipment is not objectionable. While light hand pressure exerted on the preform punch is sufficient to cause the powder to flow and fill out the vibrated die cavity, mechanical means may be provided for producing such moderate pressure. Of course, the pressed compacts are subjected to further powder metallurgical operations, such as sintering and, in some cases, repressing, as those skilled in the art will readily understand.

Referring now to Fig. 1 of the drawing, reference numeral '10 denotes a die having straight sidewalls 11 and a convex bottom punch 12 inserted therein. As shown in Fig. 2, a measured amount of metallic powder is poured into the die to constitute a body 13 of loose powder therein having a substantially level top surface. A preform punch 14, having a convex face 15 is now inserted into the die (Fig. 3) and the entire assembly is subjected to mechanical vibrations. As diagrammatically illustrated in the drawing, this is accomplished by placing the assembly on a table or platform 16 maintained in vibration by means of a vibratory motor 17. Of course, the same result may be accomplished by various other types of conventional vibrators.

The vibration causes the powder to be set into motion, particularly adjacent to the die walls. As a result of this motion, assisted by light hand pressure applied to the preform punch, the cavity is completely filled with the powder 13 which is lightly compacted. The shape of the preform punch is so predetermined that the powder, as now prepositioned, upon subsequent compression, establishes the final pressed density. The preform punch 14 is then removed-and a pressing punch 18, having a convex pressure exerting face 19 is inserted (Fig. 4) whereby the final high pressure compacting of the part is accomplished. The finished compact 20 is shown in section in Fig. 5 and has concave top and bottom surfaces, which accurately conform to the corresponding surfaces 12 and 19 of the bottom punch and pressing punch respectively.

It has been found that a compart made according to the method of the invention is characterized by as nearly uniform pressed density as is commensurate with unidirectional or bidirectional pressing. The pressed compact may now be subjected to the usual sintering and possibly to a repressing operation. Of course, the method of the invention may be applied to the production of a great variety of irregular or complicated shapes, other than the one described in the foregoing, such as are shown in Figs. 6-8 of the drawing. For example, to press a compact having the shape shown in Fig. 6, it is preferred to use a die with straight side walls, similar to die 10 shown in Fig. 1 in combination with a bottom punch having a concave face. The preform punch is likewise of concave shape so that the prepositioned powder is confined between the straight side walls of the die and two concave punch surfaces. The pressing punch is provided with a fiat pressing face so that the finished pressed compact will be characterized by a fiat top surface combined with a convex bottom surface.

Although the present invention has been disclosed in connection with a preferred embodiment thereof, variations and modifications may be resorted to by those skilled in the art without departing from the principles of the present invention. All of these variations and modifications are considered to be within the true spirit and scope of the present invention, as disclosed in the foregoing description and defined by the appended claims.

What is claimed is:

1. The method of pressing from metallic powder a coherent body which comprises introducing a measured amount of the powder into a die, applying a preform punch of predetermined configuration against the top surface of said powder in the substantial absence of pressure, vibrating said die to cause the powder to flow and to assume the shape of the cavity defined by said die and punch, replacing said preform punch with a pressing punch of the desired configuration, and then pressing said powder into a coherent body, the shape of said preform punch being so determined with respect to that of said pressing punch as to pile the powder in each region of said preform punch in accordance with the fill ratio of the powder and the thickness of the pressed body in such region measured in the direction of pressing.

2. The method of pressing from metallic powder a coherent compart the thickness of which varies considerably in the direction of pressing which comprises introducing a measured amount of the powder into the die,

applying a preform punch against the top surface of said powder at a pressure not exceeding light hand pressure, subjecting the die to mechanical vibration to cause the powder to flow and to conform to the shape of the cavity defined by said die and punch, replacing said preform punch with a pressing punch having a shape corresponding to that of the desired compact, and then pressing said powder into a coherent compact of substantially uniform density, the shape of said preform punch being so determined with respect to that of said pressing punch as to pile the powder in each region of said preform punch in accordance with the fill ratio of the powder and the thickness of the pressed body in such region measured in the direction of pressing.

3. The method of pressing from metallic powder a coherent compact the thickness of which varies considerably in the direction of pressing which comprises filling the die with a measured amount of powder, placing a preform punch on the top surface of said powder, subjecting said die to mechanical vibration while applying pressure not exceeding light hand pressure to the punch to cause the powder to flow and to conform to the shape of the cavity defined by said die and punch, the shape of said preform punch being so correlated to the desired shape of the compact and to the proper fill ratio of the powder as to pile the powder in each region to the correct depth prior to pressing corresponding to the thickness of the finished compact in such region measured in the direction of pressing, replacing said preform punch with a pressing punch having a shape accurately corresponding to that of the desired compact, and then pressing said powder into a coherent compact of substantially uniform density.

4. The method of claim 3 wherein the frequency to which the die and powder is subjected is between 20 and 400 cycles per second.

References Cited in the file of this patent UNITED STATES PATENTS

Claims (1)

1. THE METHOD OF PRESSING FROM METALLIC POWDER A COHERENT BODY WHICH COMPRISES INTRODUCING A MEASURED AMOUNT OF THE POWDER INTO A DIE, APPLYING A PREFORM PUNCH OF PREDETERMINED CONFIGURATION AGAINST THE TOP SURFACE OF SAID POWDER IN THE SUBSTANTIAL ABSENCE OF PRESSURE, VIBRATING SAID DIE TO CAUSE THE POWDER TO FLOW AND TO ASSUME THE SHAPE OF THE CAVITY DEFINED BY SAID DIE AND PUNCH, REPLACING SAID PREFORM PUNCH WITH A PRESSING
US2747231A 1953-01-26 1953-01-26 Method of pressing powder compacts Expired - Lifetime US2747231A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US2747231A US2747231A (en) 1953-01-26 1953-01-26 Method of pressing powder compacts

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US2747231A US2747231A (en) 1953-01-26 1953-01-26 Method of pressing powder compacts

Publications (1)

Publication Number Publication Date
US2747231A true US2747231A (en) 1956-05-29

Family

ID=23301063

Family Applications (1)

Application Number Title Priority Date Filing Date
US2747231A Expired - Lifetime US2747231A (en) 1953-01-26 1953-01-26 Method of pressing powder compacts

Country Status (1)

Country Link
US (1) US2747231A (en)

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2972785A (en) * 1956-01-13 1961-02-28 Enrique G Touceda Mechanical elements formed from alumina-filled polyester resins
US3100677A (en) * 1959-07-24 1963-08-13 A P Green Fire Brick Company Method of making refractory brick
US3111478A (en) * 1958-03-03 1963-11-19 Beckman Instruments Inc Molded metal-metal salt reference electrode
US3144683A (en) * 1960-07-26 1964-08-18 Clarence W Vogt Material compacting and mold charging apparatus
US3161937A (en) * 1962-05-04 1964-12-22 Paul R Gjertsen Mold apparatus used in making ceramic and abrasive products
US3244782A (en) * 1957-05-17 1966-04-05 Magnetics Inc Toroidal core pressure forming method
US3430172A (en) * 1957-05-17 1969-02-25 Magnetics Inc Magnetic core having tapered configuration
US3714319A (en) * 1971-03-10 1973-01-30 Bendix Corp Process for making semi-metallic arcuate brake lining segments
US4014965A (en) * 1972-11-24 1977-03-29 The Dow Chemical Company Process for scrapless forming of plastic articles
US4073851A (en) * 1970-07-15 1978-02-14 Werzalit Pressholzwerk J.F. Werz K.G. Method of making molded bodies from ligno-cellulose particles
US4126653A (en) * 1970-11-17 1978-11-21 Smith Dexter W Method of manufacturing silicon nitride products
FR2404519A1 (en) * 1977-10-03 1979-04-27 Combustion Eng Pellet mill for the production of uniform density briquettes
US4500272A (en) * 1982-05-04 1985-02-19 Legrand Floating core transmission member for ultrasonic assistance
US4767372A (en) * 1986-01-10 1988-08-30 Licentia Patent-Verwaltungs-Gmbh Process for the production of a porous pressed part
DE3713334A1 (en) * 1987-04-21 1988-11-03 Krupp Gmbh Pressing tool and of a thus-formed green compact sintered cutting insert
US5458867A (en) * 1994-09-09 1995-10-17 The United States Of America As Represented By The Secretary Of Commerce Process for the chemical preparation of bismuth telluride
US5918105A (en) * 1994-12-12 1999-06-29 Black & Decker Inc. Cutting tools for drilling concrete, aggregate, masonry or the like materials

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1995947A (en) * 1932-10-28 1935-03-26 E J Lavins And Company Means for molding articles
US2065618A (en) * 1933-12-28 1936-12-29 John A Dienner Metal and method of producing the same
US2193413A (en) * 1938-04-14 1940-03-12 Carl Eisen Process for producing hard metal carbide alloys
US2198612A (en) * 1937-12-15 1940-04-30 Hardy Metallurg Corp Powder metallurgy
US2241441A (en) * 1938-07-15 1941-05-13 Western Electric Co Manufacture of magnetic bodies
US2386604A (en) * 1943-10-30 1945-10-09 American Electro Metal Corp Method of molding under pressure metallic powders
GB580490A (en) * 1943-10-14 1946-09-10 Gen Electric Improvements in and relating to methods of consolidation of powdered metals

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1995947A (en) * 1932-10-28 1935-03-26 E J Lavins And Company Means for molding articles
US2065618A (en) * 1933-12-28 1936-12-29 John A Dienner Metal and method of producing the same
US2198612A (en) * 1937-12-15 1940-04-30 Hardy Metallurg Corp Powder metallurgy
US2193413A (en) * 1938-04-14 1940-03-12 Carl Eisen Process for producing hard metal carbide alloys
US2241441A (en) * 1938-07-15 1941-05-13 Western Electric Co Manufacture of magnetic bodies
GB580490A (en) * 1943-10-14 1946-09-10 Gen Electric Improvements in and relating to methods of consolidation of powdered metals
US2386604A (en) * 1943-10-30 1945-10-09 American Electro Metal Corp Method of molding under pressure metallic powders

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2972785A (en) * 1956-01-13 1961-02-28 Enrique G Touceda Mechanical elements formed from alumina-filled polyester resins
US3244782A (en) * 1957-05-17 1966-04-05 Magnetics Inc Toroidal core pressure forming method
US3430172A (en) * 1957-05-17 1969-02-25 Magnetics Inc Magnetic core having tapered configuration
US3111478A (en) * 1958-03-03 1963-11-19 Beckman Instruments Inc Molded metal-metal salt reference electrode
US3100677A (en) * 1959-07-24 1963-08-13 A P Green Fire Brick Company Method of making refractory brick
US3144683A (en) * 1960-07-26 1964-08-18 Clarence W Vogt Material compacting and mold charging apparatus
US3161937A (en) * 1962-05-04 1964-12-22 Paul R Gjertsen Mold apparatus used in making ceramic and abrasive products
US4073851A (en) * 1970-07-15 1978-02-14 Werzalit Pressholzwerk J.F. Werz K.G. Method of making molded bodies from ligno-cellulose particles
US4126653A (en) * 1970-11-17 1978-11-21 Smith Dexter W Method of manufacturing silicon nitride products
US3714319A (en) * 1971-03-10 1973-01-30 Bendix Corp Process for making semi-metallic arcuate brake lining segments
US4014965A (en) * 1972-11-24 1977-03-29 The Dow Chemical Company Process for scrapless forming of plastic articles
FR2404519A1 (en) * 1977-10-03 1979-04-27 Combustion Eng Pellet mill for the production of uniform density briquettes
US4500272A (en) * 1982-05-04 1985-02-19 Legrand Floating core transmission member for ultrasonic assistance
US4767372A (en) * 1986-01-10 1988-08-30 Licentia Patent-Verwaltungs-Gmbh Process for the production of a porous pressed part
DE3713334A1 (en) * 1987-04-21 1988-11-03 Krupp Gmbh Pressing tool and of a thus-formed green compact sintered cutting insert
US4906294A (en) * 1987-04-21 1990-03-06 Fried. Krupp Gesellschaft Mit Beschrankter Haftung Cutting tool produced by sintering a blank formed by a pressing tool
US5458867A (en) * 1994-09-09 1995-10-17 The United States Of America As Represented By The Secretary Of Commerce Process for the chemical preparation of bismuth telluride
US5918105A (en) * 1994-12-12 1999-06-29 Black & Decker Inc. Cutting tools for drilling concrete, aggregate, masonry or the like materials

Similar Documents

Publication Publication Date Title
US3166617A (en) Method and apparatus for producing articles of molded particle board
US3034191A (en) Isostatic molding apparatus
US3534439A (en) Molding apparatus
US2569226A (en) Method of producing articles from powdered material
US2198612A (en) Powder metallurgy
US4518335A (en) Dilatant mold and dilatant molding apparatus
US5937263A (en) Cup-shaped porous metal ultra-high efficiency filter and method of making same
US3293703A (en) Vacuum molding apparatus
US3502755A (en) Method for forming indentations in isostaticly pressed articles
US2549939A (en) Threaded fastening device
US4401614A (en) Anvil assembly for a powder-compacting anvil press
US3982934A (en) Method of forming uniform density articles from powder metals
US2540457A (en) Method of making metal articles and products
US3038199A (en) Method and apparatus for pressing moldable material
US6325965B1 (en) Forming method and forming apparatus
US2052818A (en) Process for the manufacture of molded pieces or bodies from mortars or concrete
US1510745A (en) Briquette and method of making same
US1884528A (en) Forming articles from granular mixes
US2298885A (en) Method for producing high density sintered products
US3463035A (en) Method of preparing die plates
US2847708A (en) Means for making die inserts
US1648721A (en) Method of and machine for forming bodies by pressure
US4061452A (en) Apparatus for producing spherical articles
US3832100A (en) Tooling for receiving and supporting a quantity of powder material to be pressed into a self-supporting compact
US3824051A (en) Mold apparatus for isostatic pressing of hollow parts