EP0512630A1 - Control of an injection moulding device - Google Patents
Control of an injection moulding device Download PDFInfo
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- EP0512630A1 EP0512630A1 EP92201229A EP92201229A EP0512630A1 EP 0512630 A1 EP0512630 A1 EP 0512630A1 EP 92201229 A EP92201229 A EP 92201229A EP 92201229 A EP92201229 A EP 92201229A EP 0512630 A1 EP0512630 A1 EP 0512630A1
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- pressure
- molten metal
- mold
- pump
- discharged
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D17/00—Pressure die casting or injection die casting, i.e. casting in which the metal is forced into a mould under high pressure
- B22D17/20—Accessories: Details
- B22D17/32—Controlling equipment
Definitions
- the present invention relates to a method for molding a fusible core from molten metal in which the molten metal is pressed under pressure into a suitable mold.
- a technique widely used for the molding of fusible cores consists in pushing back the molten metal, in a pipe connected to the mold, under the effect of a gas pressure.
- Another possible technique consists in using a positive displacement pump which allows an unequivocal relation between the level reached by the front of molten metal in the mold and the quantity of molten metal delivered by the pump.
- this technique does not, a priori, allow regular filling of the molds, in particular, in the case of molds having variable sections and / or requiring one or more tilting operations during filling.
- the present invention therefore relates to a process for molding fusible cores by means of a positive displacement pump which allows, in a simple manner, regular production of fusible cores practically free from defects.
- the present invention therefore relates to a method for molding a fusible core from a molten metal in which the molten metal is discharged into a mold by means of a positive displacement pump which is characterized in that 'The pressure of the pumped metal is measured and in that the flow rate of the pump is adapted so that the increasing pressure imposed on the pumped molten metal does not undergo sudden variation during the entire duration of the mold filling cycle.
- the positive displacement pump can be of any type adapted to the nature of the material, molten metal, to be treated. However, it is preferred to use a piston type positive displacement pump because this type of pump allows a unique relationship between the position of the piston and the quantity of molten metal discharged into the mold. In this case, during filling of the mold, the speed of displacement imposed on the piston of the positive displacement pump is controlled so as to avoid any sudden variation in the pressure exerted on the molten metal discharged into the mold during its filling.
- a first molding is carried out by imposing a constant speed of movement on the piston and the positions of the piston are noted for which a variation is recorded sudden pressure of the molten metal discharged (passage of the front of molten metal discharged into variable sections of the mold).
- the examination of the diagram of the variation of the pressures recorded as a function of the successive positions of the piston makes it possible, moreover, to determine the variation of speed to be imposed on the displacement of the piston, in these raised positions, to maintain a filling under an increasing pressure of regularly and without abrupt variation.
- the Applicant prefers to use a hydraulic type control to control the displacements of the piston but it is obvious that other types of controls such as, for example, a control by an electric motor, can be exploited within the framework of the process according to the invention.
- the aim of the adjustment to be made is therefore to adapt, by a prior test, the speed of displacement of the piston in a given range so that the pressure profile of the metal discharged into the mold does not undergo sudden variation over time, this procedure being iterative until the mold is completely filled.
- the degassing vents provided in the mold do not have a constant behavior over time, the latter possibly, in fact, having a tendency to clog gradually or suddenly with the direct consequence of the development of '' a strong back pressure in the mold. Since this back pressure can have a negative influence on the pressure measured on the molten metal, it is important that the procedure for perfecting the molding cycles is carried out with molds whose vents are kept clear. As soon as this development procedure is completed and, consequently, during the subsequent industrial production cycle, a possible plugging of one or more vents becomes without effect on the filling of the mold since the latter is volumetric. In fact, the plugging of a vent is revealed only by a drift of the pressures measured during the successive fillings.
- tilting the mold during filling may prove essential, when making certain types of fusible cores, to avoid a spill of molten metal which can cause waves and thus lead to the production of faulty fuse cores.
- the process according to the invention can be easily adapted to the filling of molds requiring such a tilting.
- the displacement dimensions of the piston of the pump are determined which correspond to the filling levels of the mold for which it is necessary to impose one or more successive tiltings. in the mold.
- a first filling of the mold is carried out at a constant speed of displacement of the piston by tilting the mold to the appropriate dimensions and the diagram of variation of the pressure of the metal expelled is noted.
- the positions of the piston for which it is necessary to act on the speed of the piston and the variations of speeds to be imposed on the piston in these places so as to carry out a molding cycle such as the pressure molten metal discharged into the mold grows according to a predetermined profile and this without abrupt variation during each industrial production cycle.
- the pump it also appears advantageous to equip the pump with a pressure regulator whose function is to limit the maximum pressure exerted by the pump on the molten metal discharged.
- the pressure regulator limit the maximum pressure exerted on the molten metal to a value slightly greater than the monometric height corresponding to the total filling of the mold.
- a growing profile is predetermined for the pressure of the molten metal to be discharged into the mold, the pressure of the molten metal discharged is continuously noted. during manufacture and, from this measurement, the flow rate of the positive displacement pump is continuously adjusted so as to comply with the predetermined increasing pressure profile.
- the method according to this variant can advantageously be carried out by using an automatic comparator-regulator system which at any time during the manufacturing cycle compares the measured pressure of the molten metal discharged with the instantaneous value of the predetermined pressure and which, in the event of a disparity between these pressure values, acts on the pump flow in order to compensate for this disparity.
- the device as illustrated in FIG. 1 comprises a mold 1 suitable for molding a fusible core, the cavity of which is connected by a pipe 2 to a positive displacement pump 3 with piston 4 designed to allow the delivery of a molten metal into the cavity of the mold 1.
- the pipe 2 is provided with a measuring device 5 making it possible to record the pressure of the molten metal discharged.
- the piston 4 is controlled by a hydraulic cylinder 6 and is equipped with a device 7 making it possible to continuously record the successive positions occupied by the piston 4.
- the hydraulic cylinder 6 is supplied via a distributor proportional 8 connected to a pressurized hydraulic fluid supply circuit comprising a storage tank 9, a pump 10 and a pressure regulator 11 which limits the pressure of the hydraulic fluid delivered to a value of 20 bars.
- the device is completed by a rapid regulation loop 12 which controls, via the control 13, the proportional distributor 8, this loop being connected to the device 7 raising the instantaneous position of the piston 4.
- the device as described is used as follows for the production of a series of fusible cores.
- a first fusible core is produced by imposing a constant speed of movement on the piston 4 and therefore under a constant flow rate of molten metal repelled and, during this production cycle, it is continuously detected using the device 5, the pressure of the molten metal discharged and, using the device 7, the corresponding successive positions of the piston 4.
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- Mechanical Engineering (AREA)
- Injection Moulding Of Plastics Or The Like (AREA)
- Moulds For Moulding Plastics Or The Like (AREA)
Abstract
Description
La présente invention concerne un procédé pour le moulage d'un noyau fusible à partir de métal fondu dans lequel le métal fondu est refoulé sous pression dans un moule approprié.The present invention relates to a method for molding a fusible core from molten metal in which the molten metal is pressed under pressure into a suitable mold.
Les noyaux fusibles utilisés pour mouler des pièces en matière plastique creuses présentant des parties en contre-dépouille doivent être exempts :
- de stries de coulées, de telles stries étant généralement produites par des variations brusques de sections de remplissage ou par des vitesses de remplissage inadéquates provoquées notamment par des contrepressions dans le moule qui sont difficilement maîtrisables.
- de bavures et ce en réalisant des plans de joint de moule aussi parfaits que possible. Toutefois, de tels plans ont pour effet d'augmenter la contrepression ce qui implique la nécessité de prévoir des évents de dégazage, ces derniers n'ayant pas un comportement constant et fiable dans le temps.
- de trous superficiels recouverts d'une mince pellicule métallique qui, par effondrement de cette pellicule lors de l'utilisation subséquente du noyau fusible dans le cadre d'un moulage par injection, donnent naissance à des défauts de surface dans les pièces en matière plastique moulées par injection.
- flow streaks, such streaks generally being produced by sudden variations in filling sections or by inadequate filling speeds caused in particular by back pressures in the mold which are difficult to control.
- burrs by making the mold joint planes as perfect as possible. However, such plans have the effect of increasing the back pressure, which implies the need to provide degassing vents, the latter not having a constant and reliable behavior over time.
- surface holes covered with a thin metallic film which, by collapsing this film during the subsequent use of the fusible core in the context of an injection molding, give rise to surface defects in the molded plastic parts by injection.
Une technique largement utilisée pour le moulage de noyaux fusibles consiste à refouler le métal fondu, dans une canalisation reliée au moule, sous l'effet d'une pression gazeuse.A technique widely used for the molding of fusible cores consists in pushing back the molten metal, in a pipe connected to the mold, under the effect of a gas pressure.
Cette technique présente toutefois deux graves défauts :
- la contrepression dans le moule varie dans le temps suivant notamment l'état des évents de dégazage qui ont tendance à se boucher et, dès lors, même en imposant un profil de pression lors du moulage, il n'est pas possible, lors d'une succession de cycles de moulage, de connaître à tout moment le niveau de remplissage du moule en particulier lorsque ce dernier présente des sections variables.
- le métal est refoulé de façon oscillante et contient souvent des bulles de gaz ce qui entraîne la production de stries et la formation de trous dans les noyaux fusibles ainsi produits.
- the backpressure in the mold varies over time depending in particular on the state of the degassing vents which tend to become blocked and, therefore, even when imposing a pressure profile during molding, it is not possible, during a succession molding cycles, to know at any time the filling level of the mold, in particular when the latter has variable sections.
- the metal is driven in an oscillating fashion and often contains gas bubbles which leads to the production of streaks and the formation of holes in the fusible cores thus produced.
En outre, lors du moulage de certains types de noyaux fusibles, il importe de pouvoir faire basculer le moule durant son remplissage pour éviter tout déversement de métal et partant la formation de vagues.In addition, when molding certain types of fusible cores, it is important to be able to tilt the mold during filling to avoid any spillage of metal and hence the formation of waves.
Dans ce cas, le recours à la technique sus-décrite doit être exclu car, celle-ci ne permettant pas de connaître à tout moment le niveau du front de métal dans le moule, il devient impossible de déterminer le moment précis imposant un basculement du moule.In this case, recourse to the above-described technique must be excluded because, since this does not make it possible to know at all times the level of the metal front in the mold, it becomes impossible to determine the precise moment imposing a tilting of the mold.
Une autre technique possible consiste à utiliser une pompe volumétrique qui permet une relation non équivoque entre le niveau atteint par le front de métal fondu dans le moule et la quantité de métal fondu délivré par la pompe.Another possible technique consists in using a positive displacement pump which allows an unequivocal relation between the level reached by the front of molten metal in the mold and the quantity of molten metal delivered by the pump.
Toutefois, cette technique ne permet pas, a priori, un remplissage régulier des moules, en particulier, dans le cas de moules présentant des sections variables et/ou nécessitant un ou plusieurs basculements en cours de remplissage.However, this technique does not, a priori, allow regular filling of the molds, in particular, in the case of molds having variable sections and / or requiring one or more tilting operations during filling.
Il est également connu (Giesserei 1991, 78, Nr 5, 4 mars, p. 146-150) d'injecter le métal fondu dans le moule de formage par l'intermédiaire, par exemple, d'une pompe à piston et, dans ce cas, de mesurer la pression du fluide entraînant la pompe et d'asservir cette pression à un profil prédéterminé, par exemple, par intermédiaire d'une boucle de régulation.It is also known (Giesserei 1991, 78,
Toutefois, dans de tels procédés, il n'est pas tenu compte des accroissements parasites de pression dus, par exemple, à des frottements qui peuvent être très importants et même prépondérants compte tenu de la faible viscosité du métal fondu. Il en résulte que la pression mesurée et contrôlée ne reflète pas le degré de remplissage du moule et que, dès lors, ces procédés ne permettent pas un contrôle efficace du remplissage du moule et partant la production de noyaux fusibles exempts de défauts.However, in such methods, no account is taken of parasitic increases in pressure due, for example, to friction which can be very high and even preponderant in view of the low viscosity of the molten metal. It follows that the pressure measured and controlled does not reflect the degree of filling of the mold and that, therefore, these methods do not allow effective control of the filling of the mold and therefore the production of fusible cores free from defects.
La présente invention concerne, dès lors, un procédé de moulage de noyaux fusibles à l'intervention d'une pompe volumétrique qui permet, de façon simple, une production régulière de noyaux fusibles pratiquement exempts de défauts.The present invention therefore relates to a process for molding fusible cores by means of a positive displacement pump which allows, in a simple manner, regular production of fusible cores practically free from defects.
La présente invention concerne, dès lors, un procédé pour le moulage d'un noyau fusible à partir d'un métal fondu dans lequel le métal fondu est refoulé dans un moule par l'intermédiaire d'une pompe volumétrique qui se caractérise en ce qu'on mesure la pression du métal refoulé et en ce qu'on adapte le débit de la pompe de façon telle que la pression croissante imposée au métal fondu refoulé ne subisse pas de variation brusque durant toute la durée du cycle de remplissage du moule.The present invention therefore relates to a method for molding a fusible core from a molten metal in which the molten metal is discharged into a mold by means of a positive displacement pump which is characterized in that 'The pressure of the pumped metal is measured and in that the flow rate of the pump is adapted so that the increasing pressure imposed on the pumped molten metal does not undergo sudden variation during the entire duration of the mold filling cycle.
La pompe volumétrique peut être de n'importe quel type adapté à la nature du matériau, métal fondu, à traiter. On préfère toutefois utiliser une pompe volumétrique du type à piston car ce type de pompe permet une relation univoque entre la position du piston et la quantité de métal fondu refoulé dans le moule. Dans ce cas, durant le remplissage du moule, la vitesse de déplacement imposée au piston de la pompe volumétrique est contrôlée de façon à éviter toute variation brusque de la pression exercée sur le métal fondu refoulé dans le moule durant son remplissage.The positive displacement pump can be of any type adapted to the nature of the material, molten metal, to be treated. However, it is preferred to use a piston type positive displacement pump because this type of pump allows a unique relationship between the position of the piston and the quantity of molten metal discharged into the mold. In this case, during filling of the mold, the speed of displacement imposed on the piston of the positive displacement pump is controlled so as to avoid any sudden variation in the pressure exerted on the molten metal discharged into the mold during its filling.
Selon un mode de réalisation très simple du procédé conforme à l'invention, pour la réalisation d'un noyau fusible on effectue un premier moulage en imposant une vitesse de déplacement constante au piston et on relève les positions du piston pour lesquelles on enregistre une variation brusque de pression du métal fondu refoulé (passage du front de métal fondu refoulé dans des sections variables du moule). L'examen du diagramme de la variation des pressions relevées en fonction des positions successives du piston permet, par ailleurs, de déterminer la variation de vitesse à imposer au déplacement du piston, dans ces positions relevées, pour maintenir un remplissage sous une pression croissant de façon régulière et sans variation brusque.According to a very simple embodiment of the method according to the invention, for the production of a fusible core a first molding is carried out by imposing a constant speed of movement on the piston and the positions of the piston are noted for which a variation is recorded sudden pressure of the molten metal discharged (passage of the front of molten metal discharged into variable sections of the mold). The examination of the diagram of the variation of the pressures recorded as a function of the successive positions of the piston makes it possible, moreover, to determine the variation of speed to be imposed on the displacement of the piston, in these raised positions, to maintain a filling under an increasing pressure of regularly and without abrupt variation.
On peut, dès lors, par le recours, par exemple, à une boucle de régulation rapide et à un distributeur hydraulique proportionnel alimentant le cylindre de commande du piston de la pompe volumétrique, imposer au déplacement du piston une vitesse variable telle que la pression croissante imposée au métal fondu refoulé ne subisse pas de variation brusque durant toute la durée de chaque cycle de remplissage du moule lors des cycles de moulage ultérieurs.It is therefore possible, for example, to use a rapid regulation loop and a hydraulic distributor proportional supplying the control cylinder of the displacement pump piston, impose on the displacement of the piston a variable speed such that the increasing pressure imposed on the molten metal discharged does not undergo abrupt variation during the duration of each mold filling cycle during subsequent molding cycles.
La demanderesse préfère recourir à une commande de type hydraulique pour contrôler les déplacements du piston mais il est bien évident que d'autres types de commandes tels que, par exemple, une commande par un moteur électrique, peuvent être exploités dans le cadre du procédé selon l'invention.The Applicant prefers to use a hydraulic type control to control the displacements of the piston but it is obvious that other types of controls such as, for example, a control by an electric motor, can be exploited within the framework of the process according to the invention.
Le but du réglage à effectuer est donc d'adapter, par un essai préalable, la vitesse de déplacement du piston dans une plage donnée pour que le profil de pression du métal refoulé dans le moule ne subisse pas de variation brusque dans le temps, cette procédure étant itérative jusqu'au remplissage complet du moule.The aim of the adjustment to be made is therefore to adapt, by a prior test, the speed of displacement of the piston in a given range so that the pressure profile of the metal discharged into the mold does not undergo sudden variation over time, this procedure being iterative until the mold is completely filled.
Ainsi qu'il a été dit précédemment, les évents de dégazage prévus dans le moule n'ont pas un comportement constant dans le temps, ces derniers pouvant, en fait, avoir tendance à se boucher progressivement ou brusquement avec pour conséquence directe le développement d'une forte contrepression dans le moule. Cette contrepression pouvant influencer néfastement la pression mesurée sur le métal fondu, il importe que la procédure de mise au point des cycles de moulage soit réalisée avec des moules dont les évents sont maintenus dégagés. Dès que cette procédure de mise au point est terminée et, par conséquent, lors du cycle de production industriel subséquent un bouchage éventuel d'un ou plusieurs évents devient sans incidence sur le remplissage du moule puisque ce dernier est volumétrique. En fait, le bouchage d'un évent se révèle uniquement par une dérive des pressions mesurées durant les remplissages successifs.As has been said previously, the degassing vents provided in the mold do not have a constant behavior over time, the latter possibly, in fact, having a tendency to clog gradually or suddenly with the direct consequence of the development of '' a strong back pressure in the mold. Since this back pressure can have a negative influence on the pressure measured on the molten metal, it is important that the procedure for perfecting the molding cycles is carried out with molds whose vents are kept clear. As soon as this development procedure is completed and, consequently, during the subsequent industrial production cycle, a possible plugging of one or more vents becomes without effect on the filling of the mold since the latter is volumetric. In fact, the plugging of a vent is revealed only by a drift of the pressures measured during the successive fillings.
Ainsi qu'il a été mentionné précédemment, un basculement du moule durant son remplissage peut se révéler indispensable, lors de la réalisation de certains types de noyaux fusibles, pour éviter un déversement du métal fondu pouvant engendrer des vagues et ainsi conduire à la production de noyaux fusibles défectueux.As mentioned above, tilting the mold during filling may prove essential, when making certain types of fusible cores, to avoid a spill of molten metal which can cause waves and thus lead to the production of faulty fuse cores.
Le procédé conforme à l'invention peut être facilement adapté au remplissage de moules exigeant un tel basculement.The process according to the invention can be easily adapted to the filling of molds requiring such a tilting.
Dans ce cas, en réalisant dans un premier essai de production des noyaux fusibles imcomplets, on détermine les cotes de déplacement du piston de la pompe qui correspondent à des niveaux de remplisssage du moule pour lesquelles il est nécessaire d'imposer un ou plusieurs basculements successifs au moule.In this case, by carrying out in a first test of production of the fusible cores incomplete, the displacement dimensions of the piston of the pump are determined which correspond to the filling levels of the mold for which it is necessary to impose one or more successive tiltings. in the mold.
Dès que ce ou ces points sont déterminés, on effectue de nouveau un premier remplissage du moule à vitesse constante de déplacement du piston en faisant basculer le moule aux cotes appropriées et on relève le diagramme de variation de la pression du métal refoulé. Sur base de ce diagramme, on peut alors déterminer les positions du piston pour lesquelles il convient d'agir sur la vitesse du piston et les variations de vitesses à imposer au piston en ces endroits de façon à réaliser un cycle de moulage tel que la pression du métal fondu refoulé dans le moule croisse selon un profil prédéterminé et ce sans variation brusque durant chaque cycle de production industrielle.As soon as this or these points are determined, a first filling of the mold is carried out at a constant speed of displacement of the piston by tilting the mold to the appropriate dimensions and the diagram of variation of the pressure of the metal expelled is noted. On the basis of this diagram, one can then determine the positions of the piston for which it is necessary to act on the speed of the piston and the variations of speeds to be imposed on the piston in these places so as to carry out a molding cycle such as the pressure molten metal discharged into the mold grows according to a predetermined profile and this without abrupt variation during each industrial production cycle.
Dans le procédé conforme à l'invention, il se révèle, en outre, avantageux d'équiper la pompe d'un régulateur de pression ayant pour fonction de limiter la pression maximale exercée par la pompe sur le métal fondu refoulé. De cette façon, on réduit tout risque d'accident éventuel en cours de production industrielle et on empêche l'application d'une pression trop élévée en fin de remplissage du moule qui pourrait favoriser la formation de bavures indésirables sur les noyaux fusibles moulés. En règle générale, la demanderesse préfère que le régulateur de pression limite la pression maximum exercée sur le métal fondu à une valeur légèrement supérieure à la hauteur monométrique correspondant au remplissage total du moule.In the process according to the invention, it also appears advantageous to equip the pump with a pressure regulator whose function is to limit the maximum pressure exerted by the pump on the molten metal discharged. In this way, any risk of possible accident during industrial production is reduced and the application of excessively high pressure at the end of filling the mold is prevented, which could favor the formation of undesirable burrs on the molded fusible cores. As a general rule, the applicant prefers that the pressure regulator limit the maximum pressure exerted on the molten metal to a value slightly greater than the monometric height corresponding to the total filling of the mold.
Selon un autre mode de réalisation du procédé conforme à l'invention qui présente l'avantage d'être automatisé, on prédétermine un profil croissant pour la pression du métal fondu à refouler dans le moule, on relève en continu la pression du métal fondu refoulé en cours de fabrication et, à partir de cette mesure, on règle en continu le débit de la pompe volumétrique de façon à respecter le profil croissant de pression prédéterminé.According to another embodiment of the method according to the invention which has the advantage of being automated, a growing profile is predetermined for the pressure of the molten metal to be discharged into the mold, the pressure of the molten metal discharged is continuously noted. during manufacture and, from this measurement, the flow rate of the positive displacement pump is continuously adjusted so as to comply with the predetermined increasing pressure profile.
Le procédé selon cette variante peut être avantageusement réalisé en faisant appel à un système automatique comparateurrégulateur qui en tout moment du cycle de fabrication compare la pression relevée du métal fondu refoulé avec la valeur instantanée de la pression prédéterminée et qui, en cas de disparité entre ces valeurs de pressions, agit sur le débit de la pompe de façon à compenser cette disparité.The method according to this variant can advantageously be carried out by using an automatic comparator-regulator system which at any time during the manufacturing cycle compares the measured pressure of the molten metal discharged with the instantaneous value of the predetermined pressure and which, in the event of a disparity between these pressure values, acts on the pump flow in order to compensate for this disparity.
Le procédé selon l'invention est, par ailleurs, explicité de façon plus détaillée dans la description, qui va suivre, de son premier mode de réalisation et dans laquelle, on se réfèrera aux figures des dessins annexés dans lesquelles :
- la fig. 1 est une vue schématique d'un dispositif de moulage de noyaux fusibles convenant pour réaliser le procédé selon l'invention, ce dispositif faisant appel à une pompe volumétrique à piston.
- la fig. 2 est un diagramme de variation de pression du métal fondu refoulé relevé lors du moulage initial, le piston de la pompe volumétrique étant animé d'une vitesse de déplacement constante.
- la fig. 3 est un diagramme de variation de pression du métal fondu refoulé et de vitesse de déplacement du piston imposé dans le procédé conforme à l'invention.
- fig. 1 is a schematic view of a device for molding fusible cores suitable for carrying out the method according to the invention, this device using a positive displacement piston pump.
- fig. 2 is a diagram of the pressure variation of the molten metal discharged during the initial molding, the piston of the positive displacement pump being driven by a constant speed of movement.
- fig. 3 is a diagram of variation in pressure of the molten metal discharged and speed of displacement of the piston imposed in the process according to the invention.
Le dispositif tel qu'illustré par la fig. 1 comporte un moule 1 adapté pour le moulage d'un noyau fusible dont la cavité est raccordée par une canalisation 2 à une pompe volumétrique 3 à piston 4 conçue pour permettre le refoulement d'un métal fondu dans la cavité du moule 1.The device as illustrated in FIG. 1 comprises a
Conformément à l'invention, la canalisation 2 est pourvue d'un dispositif de mesure 5 permettant d'enregistrer la pression du métal fondu refoulé.According to the invention, the pipe 2 is provided with a
Le piston 4 est commandé par un vérin hydraulique 6 et est équipé d'un dispositif 7 permettant de relever en continu les positions successives occupées par le piston 4.The piston 4 is controlled by a
Le vérin hydraulique 6 est alimenté via un distributeur proportionnel 8 raccordé à un circuit d'alimentation en fluide hydraulique sous pression comportant une cuve de stockage 9, une pompe 10 et un régulateur de pression 11 qui limite la pression du fluide hydraulique délivré à une valeur de 20 bars.The
Le dispositif est complété par une boucle de régulation rapide 12 qui contrôle, via la commande 13, le distributeur proportionnel 8, cette boucle étant raccordée au dispositif 7 relevant la position instantanée du piston 4.The device is completed by a
Conformément au procédé selon l'invention, le dispositif tel que décrit est exploité comme suit en vue de la production d'une série de noyaux fusibles.According to the method according to the invention, the device as described is used as follows for the production of a series of fusible cores.
Dans un premier stade, on réalise un premier noyau fusible en imposant une vitesse de déplacement constante au piston 4 et donc sous un débit constant de métal fondu réfoulé et, durant ce cycle de production, on relève, en continu, à l'aide du dispositif 5, la pression du métal fondu refoulé et, à l'aide du dispositif 7, les positions successives correspondantes du piston 4.In a first stage, a first fusible core is produced by imposing a constant speed of movement on the piston 4 and therefore under a constant flow rate of molten metal repelled and, during this production cycle, it is continuously detected using the
Sur base des indications ainsi relevées, il est, dès lors, possible d'établir un diagramme des variations de vitesse V de déplacement du piston 4 et de pression P du métal fondu refoulé en fonction du temps T qui, dans le cas de la production d'un noyau correspondant à l'empreinte du moule 1 représenté à la fig. 1, est illustré par la fig. 2.On the basis of the indications thus noted, it is therefore possible to establish a diagram of the variations in speed V of displacement of the piston 4 and in pressure P of the molten metal discharged as a function of time T which, in the case of production of a core corresponding to the imprint of the
Sur ce diagramme on constate, d'une part, que la vitesse de déplacement V du piston (représentée en traits pointillés) est constante et, d'autre part, que la pression du métal fondu refoulé P (représentée en trait plein) présente une variation brusque. Cette variation brusque de pression correspond, en fait, au passage du front de métal fondu refoulé dans une section de l'empreinte du moule présentant une variation de section accrue comme représenté sur la fig. 1.On this diagram it can be seen, on the one hand, that the speed of movement V of the piston (represented in dotted lines) is constant and, on the other hand, that the pressure of the discharged molten metal P (represented in solid lines) has a abrupt change. This sudden variation in pressure corresponds, in fact, to the passage of the front of molten metal discharged into a section of the mold cavity having an increased variation in section as shown in FIG. 1.
Sur base du diagramme de la figure 2, il devient donc possible de déterminer la position du piston correspondant à une variation brusque de pression et de calculer l'accroissement progressif de vitesse à imposer au déplacement du piston, en cet endroit, pour éviter cette variation de pression.On the basis of the diagram in FIG. 2, it therefore becomes possible to determine the position of the piston corresponding to an abrupt change in pressure and to calculate the progressive increase in speed to be imposed on the displacement of the piston, in this place, to avoid this pressure variation.
Lorque cette correction est imposée par le régulateur 12, on peut entreprendre un cycle de fabrication continu. Le diagramme des pressions du métal fondu refoulé et des vitesses de déplacement du piston relevées durant ces cycles est donné par la fig. 3.When this correction is imposed by the
Dans ce diagramme, on constate que la montée en pression P, illustrée en trait plein, est maintenue constante et ce, sans variation brusque, par une modification de la vitesse V de déplacement du piston illustrée en traits pointillés en cours de remplissage du moule (passage d'une vitesse V1 à une vitesse V2 plus élevée au moment où le front du métal refoulé dans le moule atteint une section accrue).In this diagram, it can be seen that the rise in pressure P, illustrated in solid lines, is kept constant and this, without abrupt variation, by a modification of the speed V of displacement of the piston illustrated in dotted lines during filling of the mold ( passage from a speed V1 to a higher speed V2 at the moment when the front of the metal forced into the mold reaches an increased section).
Claims (4)
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR9105857 | 1991-05-10 | ||
| FR9105857A FR2676190B1 (en) | 1991-05-10 | 1991-05-10 | PROCESS FOR MOLDING A FUSE CORE. |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0512630A1 true EP0512630A1 (en) | 1992-11-11 |
| EP0512630B1 EP0512630B1 (en) | 1996-08-28 |
Family
ID=9412790
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP92201229A Expired - Lifetime EP0512630B1 (en) | 1991-05-10 | 1992-05-02 | Control of an injection moulding device |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US5240064A (en) |
| EP (1) | EP0512630B1 (en) |
| DE (1) | DE69213086T2 (en) |
| FR (1) | FR2676190B1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0697263A1 (en) * | 1994-08-18 | 1996-02-21 | Toyota Jidosha Kabushiki Kaisha | Pressure casting method through pressurizing pin advancement speed control |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3142811A1 (en) * | 1981-10-28 | 1983-05-05 | Idra Pressen GmbH, 7000 Stuttgart | Method and apparatus for controlling the movement of a casting piston during the injection process on a die-casting machine |
| DE3410228A1 (en) * | 1983-03-23 | 1984-10-04 | Toshiba Kikai K.K., Tokio/Tokyo | PRESSURE PRESSURE MONITORING METHOD AND DEVICE FOR IMPLEMENTING THE METHOD |
| GB2138174A (en) * | 1983-04-12 | 1984-10-17 | Ube Industries | Method of controlling cylinder speed injection molding apparatus |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3893792A (en) * | 1973-04-06 | 1975-07-08 | Bbf Group Inc | Controller for injection molding machine |
| JPS5418218B2 (en) * | 1974-02-12 | 1979-07-05 | ||
| JPS591059A (en) * | 1982-06-25 | 1984-01-06 | Toshiba Mach Co Ltd | Method for controlling injection speed of die casting machine |
| JPS59150652A (en) * | 1983-02-17 | 1984-08-28 | Ube Ind Ltd | Method for measuring metal pressure in die casting machine |
| CH668385A5 (en) * | 1985-10-24 | 1988-12-30 | Buehler Ag Geb | INJECTION UNIT FOR A CASTING MACHINE. |
| IT1215434B (en) * | 1987-04-21 | 1990-02-14 | Sgs Microelettronica Spa | SATURATION. AMPLIFIER STAGE WITH COLLECTOR OUTPUT, WITH CONTROL OF |
| JPS6415260A (en) * | 1987-07-06 | 1989-01-19 | Toshiba Corp | Method and apparatus for pressurized-casting |
-
1991
- 1991-05-10 FR FR9105857A patent/FR2676190B1/en not_active Expired - Fee Related
-
1992
- 1992-05-02 DE DE69213086T patent/DE69213086T2/en not_active Expired - Lifetime
- 1992-05-02 EP EP92201229A patent/EP0512630B1/en not_active Expired - Lifetime
- 1992-05-11 US US07/880,658 patent/US5240064A/en not_active Expired - Lifetime
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3142811A1 (en) * | 1981-10-28 | 1983-05-05 | Idra Pressen GmbH, 7000 Stuttgart | Method and apparatus for controlling the movement of a casting piston during the injection process on a die-casting machine |
| DE3410228A1 (en) * | 1983-03-23 | 1984-10-04 | Toshiba Kikai K.K., Tokio/Tokyo | PRESSURE PRESSURE MONITORING METHOD AND DEVICE FOR IMPLEMENTING THE METHOD |
| GB2138174A (en) * | 1983-04-12 | 1984-10-17 | Ube Industries | Method of controlling cylinder speed injection molding apparatus |
Non-Patent Citations (2)
| Title |
|---|
| GIESSEREI vol. 78, no. 5, 1991, DUESSELDORF pages 146 - 150; L. ITEN: 'Neue Druckgussmaschinen mit digitaler Echtzeitregelung des Giessvorgangs' * |
| PATENT ABSTRACTS OF JAPAN vol. 8, no. 280 (M-347)(1717) 21 Décembre 1984 & JP-A-59 150 652 ( UBE KOSAN K.K. ) 28 Août 1984 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0697263A1 (en) * | 1994-08-18 | 1996-02-21 | Toyota Jidosha Kabushiki Kaisha | Pressure casting method through pressurizing pin advancement speed control |
| US5671797A (en) * | 1994-08-18 | 1997-09-30 | Toyota Jidosha Kabushiki Kaisha | Pressure casting method through pressurizing pin advancement speed control |
Also Published As
| Publication number | Publication date |
|---|---|
| DE69213086T2 (en) | 1997-03-27 |
| FR2676190A1 (en) | 1992-11-13 |
| US5240064A (en) | 1993-08-31 |
| DE69213086D1 (en) | 1996-10-02 |
| EP0512630B1 (en) | 1996-08-28 |
| FR2676190B1 (en) | 1996-01-05 |
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