EP0955114A2 - Procédé et moule pour la compression à froid de poudre à fritter - Google Patents

Procédé et moule pour la compression à froid de poudre à fritter Download PDF

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Publication number
EP0955114A2
EP0955114A2 EP99108817A EP99108817A EP0955114A2 EP 0955114 A2 EP0955114 A2 EP 0955114A2 EP 99108817 A EP99108817 A EP 99108817A EP 99108817 A EP99108817 A EP 99108817A EP 0955114 A2 EP0955114 A2 EP 0955114A2
Authority
EP
European Patent Office
Prior art keywords
core
pressing means
mould
powder
powders
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.)
Granted
Application number
EP99108817A
Other languages
German (de)
English (en)
Other versions
EP0955114B1 (fr
EP0955114A3 (fr
Inventor
Claudio Sinico
Giannino Bonato
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.)
Sintech Srl
Said SpA
Original Assignee
Sintech Srl
Said SpA
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
Application filed by Sintech Srl, Said SpA filed Critical Sintech Srl
Publication of EP0955114A2 publication Critical patent/EP0955114A2/fr
Publication of EP0955114A3 publication Critical patent/EP0955114A3/fr
Application granted granted Critical
Publication of EP0955114B1 publication Critical patent/EP0955114B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F7/00—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression
    • B22F7/06—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of composite workpieces or articles from parts, e.g. to form tipped tools
    • B22F7/08—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of composite workpieces or articles from parts, e.g. to form tipped tools with one or more parts not made from powder
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/02—Compacting only
    • B22F3/03—Press-moulding apparatus therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B30—PRESSES
    • B30B—PRESSES IN GENERAL
    • B30B11/00—Presses specially adapted for forming shaped articles from material in particulate or plastic state, e.g. briquetting presses, tabletting presses
    • B30B11/02—Presses specially adapted for forming shaped articles from material in particulate or plastic state, e.g. briquetting presses, tabletting presses using a ram exerting pressure on the material in a moulding space
    • B30B11/027—Particular press methods or systems
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F5/00—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product
    • B22F2005/001—Cutting tools, earth boring or grinding tool other than table ware
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F2999/00—Aspects linked to processes or compositions used in powder metallurgy

Definitions

  • the invention concerns a method for the cold agglomeration of powders to be sintered and a mould suitable for implementing said method.
  • the method and the mould subject of the invention concern the agglomeration of abrasive powders on the edge of a disc-shaped metal core before the sintering process.
  • the sintering process consists in the cold compression of mixtures of very fine metallic and non-metallic powders into moulds with predefined shape and in their sintering inside furnaces at high temperatures; the non-metallic powders may contain even diamond powder.
  • the compression of the powders at high temperature is more properly called sintering and it is carried out at temperatures that usually correspond to 2/3 of the melting point of the most refractory material present in the powders, while the cold compression of the powders inside the moulds is called agglomeration.
  • sintering is used for the construction of abrasive discs that are obtained by sintering a mixture of metallic and non-metallic powders - the latter may even contain diamond powder - on the peripheral edge of a disc-shaped metal core.
  • the metal core in the processing phases the metal core must first of all be positioned in a mould and the powders to be sintered must be distributed circumferentially on the perimetral edge of the core and contained in an annular chamber properly obtained in the mould.
  • the powders After being uniformly distributed, the powders are cold-agglomerated by positioning the mould under a press provided with an apposite, properly shaped pressing element that compresses them and makes them adhere to the core.
  • the mould complete with the pressing element, is then introduced in a furnace, brought to the sintering temperature and left in the furnace for a pre-established time.
  • the mould is opened and the metal core is extracted together with the sintered annular edge stably fixed on to it.
  • the abrasive disc has thus been obtained.
  • a first drawback is represented by the fact that this method requires repeated handling of the cores and moulds, and therefore considerable labour and rather long execution times.
  • a further drawback is constituted by the fact that the manufacturer must have a high number of moulds, since one mould contains only one core for the whole sintering cycle, from the distribution and agglomeration of the powders to the extraction of the sintered item.
  • the aim of the present invention is to eliminate all the drawbacks described above.
  • one of the aims of the invention is the implementation of a method for the cold agglomeration of powders to be sintered that makes it possible to reduce the manual operations necessary to move the pieces and the moulds.
  • Another aim of the invention is that the method subject of the invention should make it possible to use a single mould for the agglomeration of the powders on more than one core.
  • a further aim of the invention is the implementation of a method that for the agglomeration of the powders requires the use of a single mould, in fixed position and operating only at cold temperatures.
  • the extraction of the core includes the following operations:
  • the mould is manufactured in such a way as to house disc-shaped cores made of metal plate.
  • the method subject of the invention and the mould suitable for implementing it ensure high productivity in comparison with the known methods and moulds.
  • Another advantage is represented by the fact that the method subject of the invention and the relevant mould can obviously be employed to obtain the agglomeration of powders on the edges of any core, independently of its shape.
  • the method subject of the invention can be implemented by means of a mould, which is also subject of the invention, is indicated as a whole by 1 and, as shown in the enclosed figures, comprises an upper plate 2 and a lower plate 2'; said plates are spaced and opposite each other, can be coupled to the reciprocally movable elements of a press not represented in the figure, and are joined through guide means, indicated as a whole by 3, suitable for keeping them parallel to each other during their reciprocal shifting.
  • Said guide means 3 comprise at least one column 4 fixed to the lower plate 2' and slidingly coupled to a sleeve 5 fixed to the upper plate 2.
  • the upper plate 2 is also provided with an upper body 6 that supports first core-pressing means constituted by an upper core-pressing means 7 and analogously the lower plate 2' is provided with a lower body 6' that supports second core-pressing means constituted by a lower core-pressing means 7'.
  • the core A is positioned between the lower core-pressing means 7' and the upper core-pressing means 7 and abrasive powder P is agglomerated on the peripheral edge B of the core according to the procedure described below.
  • An upper intermediate body 8 is interposed between the upper body 6 and the upper core-pressing means 7, housed in the upper body 6 and fixed to the upper core-pressing means 7.
  • a piston 9 belonging to the upper intermediate body 8 is inserted into an upper chamber 10 obtained in the upper body 6, within which the piston can slide in the direction defined by the longitudinal axis X of the mould, the upper intermediate body 8 being guided by pins 11.
  • Helical springs 12 cooperating with respective spring guides 13 make the movement of the piston 9 and of the relevant core-pressing means 7 elastic.
  • a lower intermediate body 8' is interposed between the lower body 6' and the lower core-pressing means 7'; together with the lower core-pressing means 7' it defines a first lower chamber 7'' and with the lower body 6' it defines a second lower chamber 6''.
  • the lower core-pressing means 7' slides axially with respect to the lower body 6' and is guided by one or more pins 14 passing through the lower intermediate body 8' and having one end fixed to the lower plate 2'.
  • Helical springs 15 coupled to respective spring guides 16 make the movement of the core-pressing means 7' elastic with respect to the lower intermediate body 8' and the movement of both of them elastic with respect to the lower body 6'.
  • the lower body 6' is fixed to the lower plate 2' by means of a bearing 17 with the vertical axis positioned so that the lower body 6', together with the lower intermediate body 8' and with the lower core-pressing means 7', can rotate on the vertical axis X of the mould.
  • a fifth wheel 18 is provided outside the lower body 6' and engages with a pinion 19 coupled to an actuator 20, preferably constituted by a fluid-operated motor, for example an air motor.
  • An annular body 21 is positioned between the lower core-pressing means 7' and the lower body 6' and is fixed to the lower intermediate body 8', thus defining - between the lower core-pressing means 7' and the lower body 6' - an annular chamber 22 that contains the powder P to be agglomerated.
  • a powder-pressing ring 23 is fixed to the upper body 6, in correspondence with its outer perimetral edge, said ring 23 being provided with an annular protrusion 24 whose profile is conjugated to the concave part defined by the annular chamber 22 and is therefore suitable for fitting inside it.
  • the powder agglomeration cycle begins when the mould is positioned open as indicated in Figure 1.
  • the core A is positioned inside the mould, resting on the lower core-pressing means 7' and centered with respect to the longitudinal axis X of the mould by means of a central reference pin 25 that fits into a corresponding central hole F made in the core A.
  • the motor 20 After the clamping of the core-pressing means the motor 20, through the kinematic chain constituted by the pinion 19 and the fifth wheel 18, sets the lower body 6' of the mould rotating on the axis X, together with the lower intermediate body 8', the lower core-pressing means 7' and the core A positioned on it.
  • an appropriate powder-distributing device introduces the powder P to be sintered into the annular chamber 22, as shown in Figure 2.
  • This powder is a mixture of metallic and non-metallic powders and the latter may even contain diamond powder.
  • the lower core-pressing means 7' lowers and strikes against the lower intermediate body 8' due to the disappearance of the first lower chamber 7''.
  • the lower intermediate body 8' therefore, constitutes the opposing element that reacts to the thrust of the press and contributes to the generation of the compressive action on the powder P in correspondence with the edge B of the core A.
  • a pressurized fluid preferably air
  • a pressurized fluid preferably air
  • the upper plane of the press keeps moving upwards in the direction V, lifting first of all the powder-pressing ring 23, as shown in Figure 5, and then the upper core-pressing means 7, as shown in Figure 6, with respect to the core A, thus creating the clearance L that makes it possible to extract the core with the powder agglomerated on its edge B.
  • the method subject of the invention and the mould suitable for implementing said method achieve all the fixed goals.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical & Material Sciences (AREA)
  • Composite Materials (AREA)
  • Materials Engineering (AREA)
  • Powder Metallurgy (AREA)
EP99108817A 1998-05-06 1999-05-04 Procédé et moule pour la compression à froid de poudre à fritter Expired - Lifetime EP0955114B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ITVI980091 1998-05-06
IT98VI000091A ITVI980091A1 (it) 1998-05-06 1998-05-06 Metodo per agglomerare a freddo polveri da sinterizzare e stampo atto a realizzare detto metodo

Publications (3)

Publication Number Publication Date
EP0955114A2 true EP0955114A2 (fr) 1999-11-10
EP0955114A3 EP0955114A3 (fr) 2001-08-01
EP0955114B1 EP0955114B1 (fr) 2004-07-21

Family

ID=11426704

Family Applications (1)

Application Number Title Priority Date Filing Date
EP99108817A Expired - Lifetime EP0955114B1 (fr) 1998-05-06 1999-05-04 Procédé et moule pour la compression à froid de poudre à fritter

Country Status (4)

Country Link
EP (1) EP0955114B1 (fr)
AT (1) ATE271435T1 (fr)
DE (1) DE69918742D1 (fr)
IT (1) ITVI980091A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108405853A (zh) * 2018-04-27 2018-08-17 遵义江星机械模具有限公司 用于制造水泵轮毂的模具

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2331909A (en) * 1940-12-04 1943-10-19 Mallory & Co Inc P R Gear and the like
US2686439A (en) * 1948-04-27 1954-08-17 Thoger G Jungersen Method of making cutting tools
US5016498A (en) * 1987-05-30 1991-05-21 Sanwa Diamond Industrial Co., Ltd. Method and apparatus for manufacturing super abrasive cutting saw

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2331909A (en) * 1940-12-04 1943-10-19 Mallory & Co Inc P R Gear and the like
US2686439A (en) * 1948-04-27 1954-08-17 Thoger G Jungersen Method of making cutting tools
US5016498A (en) * 1987-05-30 1991-05-21 Sanwa Diamond Industrial Co., Ltd. Method and apparatus for manufacturing super abrasive cutting saw

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108405853A (zh) * 2018-04-27 2018-08-17 遵义江星机械模具有限公司 用于制造水泵轮毂的模具

Also Published As

Publication number Publication date
EP0955114B1 (fr) 2004-07-21
EP0955114A3 (fr) 2001-08-01
ITVI980091A1 (it) 1999-11-06
ATE271435T1 (de) 2004-08-15
DE69918742D1 (de) 2004-08-26

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