WO1992013692A1 - Procede et dispositif de fabrication de corps moules en masses pateuses ayant des dimensions prescrites - Google Patents

Procede et dispositif de fabrication de corps moules en masses pateuses ayant des dimensions prescrites Download PDF

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Publication number
WO1992013692A1
WO1992013692A1 PCT/DE1992/000029 DE9200029W WO9213692A1 WO 1992013692 A1 WO1992013692 A1 WO 1992013692A1 DE 9200029 W DE9200029 W DE 9200029W WO 9213692 A1 WO9213692 A1 WO 9213692A1
Authority
WO
WIPO (PCT)
Prior art keywords
die
press
mass
travel
control electronics
Prior art date
Application number
PCT/DE1992/000029
Other languages
German (de)
English (en)
Inventor
Lutz Beyer
Peter Kluge
Original Assignee
Robert Bosch Gmbh
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 Robert Bosch Gmbh filed Critical Robert Bosch Gmbh
Publication of WO1992013692A1 publication Critical patent/WO1992013692A1/fr

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B13/00—Feeding the unshaped material to moulds or apparatus for producing shaped articles; Discharging shaped articles from such moulds or apparatus
    • B28B13/02—Feeding the unshaped material to moulds or apparatus for producing shaped articles
    • B28B13/021—Feeding the unshaped material to moulds or apparatus for producing shaped articles by fluid pressure acting directly on the material, e.g. using vacuum, air pressure
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B17/00—Details of, or accessories for, apparatus for shaping the material; Auxiliary measures taken in connection with such shaping
    • B28B17/0063—Control arrangements
    • B28B17/0081—Process control
    • 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
    • B30B11/005—Control arrangements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B30—PRESSES
    • B30B—PRESSES IN GENERAL
    • B30B15/00—Details of, or accessories for, presses; Auxiliary measures in connection with pressing
    • B30B15/30—Feeding material to presses
    • B30B15/302—Feeding material in particulate or plastic state to moulding presses

Definitions

  • the invention relates to a further embodiment and improvement of the methods and devices known per se for the production of moldings from pasty materials in the wet pressing process / as are used, for example, in the production of oxide magnets from metal oxide pastes, and the moldings produced as such.
  • the aim of these processes is to produce high product quality, that is to say defect-free molded articles which are dimensionally stable within narrow tolerance limits and are homogeneous over the entire volume, with short cycle times.
  • a process for producing oxide magnets by wet pressing metal oxide mass is described in DE-OS 33 47 035. There are two levels. In the first stage, the filling process, the die, which corresponds to the shape of the desired compact, is filled with pasty metal oxide paste.
  • the pressing process the paste in the die is pressed (or compacted) into the shaped body (or compact).
  • the process improves previously known working methods by ensuring that the optimal maximum filling pressure is maintained for an optimal period in the first stage.
  • the pasty mass is fed into the die by means of a mass pump through a filling line via a controllable, pressure-regulating shut-off valve.
  • a pressure sensor is arranged between the shut-off valve and the die, which measures the filling pressure and reports it to control electronics. This controls it Shut-off valve so that a predetermined maximum filling pressure, for example between 30 and 50 bar, is maintained for a predetermined time, for example between 0.3 and 1.0 sec, and the die is thereby optimally filled.
  • control electronics also automatically initiates the second stage of the process, the pressing process, by acting on the hydraulics of the punch, which generates a predetermined maximum pressing pressure in the die, which is, for example, between 200 and 800 bar .
  • the check valve is closed in this phase, so that no backflow of pasty mass can take place in the mass pump.
  • the process delivers moldings of better quality than the older, unregulated processes.
  • the control device for timing the filling pressure when filling a pressing tool according to DE-0S 38 44 334 avoids this disadvantage.
  • the maximum filling pressure is predetermined by the pressure of the mass pump, so there is no regulation of the maximum filling pressure.
  • the pressure sensor (or pressure sensor) sends its signal to a first threshold level and, in parallel, to a second threshold level via a differentiator.
  • the output signals of both threshold value levels arrive in a logic gate which transmits a trigger signal to a downstream timing element if at the same time a first threshold value - a predetermined voltage - is exceeded in the first threshold value level and a second threshold value - a predetermined differential guotient of the voltage over time - in the second Below the threshold level.
  • the timing element has a holding time which corresponds to the previously determined optimal holding time for the maximum filling pressure and thus ensures an optimal filling of the die.
  • the control device according to DE-OS provides results which are as good as the method according to DE-OS 33 47 035 with reduced effort. However, the dimensional accuracy of the shaped bodies is not always sufficiently good.
  • the devices and methods according to the claims provide moldings with improved dimensional stability, since the control system starts at the press path of the press ram, into which the end position of the press ram goes, which in turn determines the dimension of the molded body in the pressing direction. This is the critical dimension for dimensional accuracy, since the other dimensions are clearly defined by the walls of the die.
  • the control according to the invention therefore starts directly at the critical parameter.
  • the self-adjustment of individual parameters is an important prerequisite for the fully automatic operation of a pressing tool for producing molded articles from pasty materials.
  • Fluctuations in the properties of the pasty mass, in particular in the flow and filling properties, as well as discontinuities from another cause, are compensated for by sensible control processes, which ensure that the hydraulic mass pump pressure, filling pressure, filling quantity, pressing weight and pressing thickness are always optimally matched.
  • FIG. 1 shows a block diagram of a device according to claim 1
  • FIG. 2 shows the press travel for a press process as a function of time
  • FIG. 3 shows the press travel as a function of the press cycles in an iterative approximation process which leads to a shaped body in the desired range.
  • the pasty mass - in the example of the production of an oxide magnet, the finely ground (particle size 0.1 to 2.0U / m) metal oxides, pasted with water and the usual auxiliaries to a paste with 60 to 80% by weight solids content - is from the mass pump 1 pumped through the delivery line (2). If necessary, it then passes through a sieve that holds back the large portions. The pasty mass then arrives.
  • the pressure sensor 5 measures the filling pressure immediately before the die 6.
  • the die which corresponds in its internal shape to the dimensions of the desired shaped body, has a press ram 7 which is expediently actuated hydraulically and, in the case of the production of oxide magnets, generally permits pressures of 200 to 800 bar to be exerted on the pasty mass in the die . He continues to push the molded body upwards after the pressing process as soon as the upper limit of the die clears the way.
  • the measuring element or the displacement sensor 8 which is attached to the press ram or to its extension, and the following components form the measuring and control electronics, which is an essential feature of the invention.
  • the displacement transducer can work according to various measuring systems, for example analog as a capacitive, inductive or resistance displacement transducer or digital with optical measurement on one marked glass rod (increment holder). He tracks the relative movements between the punch and the die.
  • the displacement measurement signal is fed via the measuring amplifier 9 and, if an analog displacement transducer is used, via the A / D converter 10 to the computing element 11. This is where the difference is formed between the initial value (filling position of the press ram) and the travel measurement value X continuously supplied during the displacement. In this way, the entire travel-time curve of the pressing process is recorded. Two such curves are shown in FIG.
  • Curve 1 shows the course for a pressing process, which leads to a shaped body in the target area.
  • Curve 2 relates to the case "press travel too short - molded part too thick", curve 3 the opposite case "press travel too long - molded part too thin”.
  • the comparator compares the reported X value with the tolerance range (the so-called window width). If the reported X value lies outside the window width, the comparator sets a positive or negative counting pulse on the counting memory 14, depending on the direction of deviation.
  • the change in the counting memory setting is converted via the D / A converter 15 into a corresponding change in the control voltage of the hydraulic pressure control valve 16 of the mass pump 1.
  • a proportional pressure reducing valve with nominal pressure 0 to 70 bar and with a control voltage range from 0 to 10 V as well an 8 bit memory corresponds to one
  • Comparator 13 increments the count memory setting
  • Pressure control valve 16 reduces, again accordingly, gradually the filling pressure of the mass pump 1 and thus the amount in the die
  • control electronics is shown in the form of individual components for better clarity. All these individual components are known to the person skilled in the art. Of course, their functions can also be performed by an appropriately dimensioned and programmed computer.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Ceramic Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Manufacturing & Machinery (AREA)
  • Automation & Control Theory (AREA)
  • Control Of Presses (AREA)

Abstract

L'invention concerne un dispositif de fabrication de corps moulés en masses pâteuses ayant des dimensions prescrites, par exemple des aimants en oxydes, par un procédé humide de pressage, un procédé de fabrication de ces corps moulés et les corps moulés proprement dits. La masse pâteuse est refoulée par ume pompe (1) dans la matrice de moulage (6) qui contient un fouloir (7) capable d'exercer une pression sur la masse pâteuse. Selon l'invention, les éléments électroniques de mesure et de régulation comprennent un organe de mesure (8) qui capte le déplacement relatif entre le fouloir (7) et la matrice (6), ainsi qu'un organe électronique de réglage qui déduit des valeurs captées la course de compression du fouloir et qui régle la pression de refoulement de la pompe (1) lorsque la course de compression sort d'un domaine prescrit prédéterminé.
PCT/DE1992/000029 1991-02-05 1992-01-18 Procede et dispositif de fabrication de corps moules en masses pateuses ayant des dimensions prescrites WO1992013692A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4103408A DE4103408A1 (de) 1991-02-05 1991-02-05 Vorrichtung und verfahren zur herstellung von masshaltigen formkoerpern aus pastoesen massen
DEP4103408.2 1991-02-05

Publications (1)

Publication Number Publication Date
WO1992013692A1 true WO1992013692A1 (fr) 1992-08-20

Family

ID=6424402

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/DE1992/000029 WO1992013692A1 (fr) 1991-02-05 1992-01-18 Procede et dispositif de fabrication de corps moules en masses pateuses ayant des dimensions prescrites

Country Status (2)

Country Link
DE (1) DE4103408A1 (fr)
WO (1) WO1992013692A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0585850A1 (fr) * 1992-09-03 1994-03-09 ABBPATENT GmbH Moule pour la réalisation d'objets moulés
ES2112176A1 (es) * 1995-09-11 1998-03-16 Taulell S A Metodo de control automatico del ciclo de prensado en semiseco en el proceso de compactacion de baldosas ceramicas.
ES2144935A1 (es) * 1997-10-15 2000-06-16 Juguetes Oliver S A Procedimiento para la obtencion de figuras por moldeo y dispositivo para su puesta en practica.
US7641848B2 (en) * 2007-10-30 2010-01-05 Tdk Corporation Process for production of magnet, magnet obtained thereby and production apparatus for molded articles for magnet
WO2021143210A1 (fr) * 2020-01-15 2021-07-22 湖南航天磁电有限责任公司 Appareil d'injection assistée formant un aimant permanent en ferrite et procédé de fabrication d'aimant

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1127647A (en) * 1964-11-28 1968-09-18 Laeis Werke Ag Automatic control system for moulding presses
US4447198A (en) * 1982-10-26 1984-05-08 Wehr Corporation Hydraulic refractory press including product thickness or density control means
EP0130769A1 (fr) * 1983-06-28 1985-01-09 Technoplas Inc. Procédé de moulage par compression
EP0167631A1 (fr) * 1983-12-28 1986-01-15 Fanuc Ltd. Machine de moulage par injection
EP0359830A1 (fr) * 1988-03-24 1990-03-28 Kabushiki Kaisha Komatsu Seisakusho Machine de moulage par injection-compression et procede de moulage l'utilisant
WO1990007406A1 (fr) * 1988-12-30 1990-07-12 Robert Bosch Gmbh Dispositif de commande dans le temps de la pression de remplissage d'outils de moulage par compression

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1127647A (en) * 1964-11-28 1968-09-18 Laeis Werke Ag Automatic control system for moulding presses
US4447198A (en) * 1982-10-26 1984-05-08 Wehr Corporation Hydraulic refractory press including product thickness or density control means
EP0130769A1 (fr) * 1983-06-28 1985-01-09 Technoplas Inc. Procédé de moulage par compression
EP0167631A1 (fr) * 1983-12-28 1986-01-15 Fanuc Ltd. Machine de moulage par injection
EP0359830A1 (fr) * 1988-03-24 1990-03-28 Kabushiki Kaisha Komatsu Seisakusho Machine de moulage par injection-compression et procede de moulage l'utilisant
WO1990007406A1 (fr) * 1988-12-30 1990-07-12 Robert Bosch Gmbh Dispositif de commande dans le temps de la pression de remplissage d'outils de moulage par compression

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0585850A1 (fr) * 1992-09-03 1994-03-09 ABBPATENT GmbH Moule pour la réalisation d'objets moulés
ES2112176A1 (es) * 1995-09-11 1998-03-16 Taulell S A Metodo de control automatico del ciclo de prensado en semiseco en el proceso de compactacion de baldosas ceramicas.
ES2144935A1 (es) * 1997-10-15 2000-06-16 Juguetes Oliver S A Procedimiento para la obtencion de figuras por moldeo y dispositivo para su puesta en practica.
US7641848B2 (en) * 2007-10-30 2010-01-05 Tdk Corporation Process for production of magnet, magnet obtained thereby and production apparatus for molded articles for magnet
WO2021143210A1 (fr) * 2020-01-15 2021-07-22 湖南航天磁电有限责任公司 Appareil d'injection assistée formant un aimant permanent en ferrite et procédé de fabrication d'aimant

Also Published As

Publication number Publication date
DE4103408A1 (de) 1992-08-06

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