WO2010072855A1 - Ejector intended for submarine runners located on the fixed parts of thermoplastic injection moulds - Google Patents

Ejector intended for submarine runners located on the fixed parts of thermoplastic injection moulds Download PDF

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Publication number
WO2010072855A1
WO2010072855A1 PCT/ES2009/000345 ES2009000345W WO2010072855A1 WO 2010072855 A1 WO2010072855 A1 WO 2010072855A1 ES 2009000345 W ES2009000345 W ES 2009000345W WO 2010072855 A1 WO2010072855 A1 WO 2010072855A1
Authority
WO
WIPO (PCT)
Prior art keywords
fixed parts
thermoplastic injection
submarine
ejector
injection moulds
Prior art date
Application number
PCT/ES2009/000345
Other languages
Spanish (es)
French (fr)
Inventor
Miguel Angel Torres Portero
Original Assignee
Universidad De Zaragoza
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 Universidad De Zaragoza filed Critical Universidad De Zaragoza
Publication of WO2010072855A1 publication Critical patent/WO2010072855A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/17—Component parts, details or accessories; Auxiliary operations
    • B29C45/40—Removing or ejecting moulded articles
    • B29C45/4005—Ejector constructions; Ejector operating mechanisms
    • B29C45/401—Ejector pin constructions or mountings

Definitions

  • the main object of the present invention is to simplify, facilitate and ensure the extraction of underwater castings located in the fixed part of the injection molds for thermoplastics.
  • the plastic injection processes consist of heating the pellets of a thermoplastic material to transform them into a mass type through a plasticizing cylinder, giving the mold the final shape.
  • Injection machines have hydraulic systems, which control the movement of injection and closure systems; and electrical systems, which control temperatures, water flow, oil, etc.
  • Cold casting is a component of the Injected part and needs longer injection cycles. This system is applied for small parts.
  • the cold channels take the plastic to the mold cavities and do not have temperature control systems such as hot and cast channel systems.
  • the main features of cold cast and channel plastic injection molds are: high cycle times, complicated demoulding mechanism, large amount of material waste, difficult product repeatability, very large mold opening distances (runs) and projection / distribution of complex cavities.
  • the path of the material to the cavity should be as short as possible to, among other things, minimize pressure and heat losses.
  • the injected parts contract on the mold males, for their demolding different types of ejectors are applied: rod, tubular, extractor plate, flat, combined, pneumatic, with cam, etc.
  • the type of extractor or ejector is a function of the shape of the piece to be injected.
  • the surface pressure on the piece to be ejected must be the minimum possible to avoid deformations.
  • the ejectors serve not only for demolding, but also for the evacuation of gases from the cavity.
  • a defective exit of the cavity can have as a consequence a partial filling of the cavity, defective union of material fronts or the so-called Diesel effect
  • the ejector object of this invention has some advantages of application that derive from the possibility of performing standardized and automated injection processes on those parts in which manipulation is required to separate them from the casting.
  • the high risk of damage to the mold is reduced, avoiding functional wear due to friction.
  • the ejector comprises a metal rod that has as its main feature its upper end, head, which shows a fungiform configuration, establishing its dimensions depending on the size of the casting and the thermoplastic part to be extracted.
  • the ejector simplifies, facilitates (by anchoring in the fixed part, between the ejector plates, an injection mold for thermoplastics) and ensures the extraction of underwater castings located in the fixed (female) part of the injection molds for thermoplastics, holding them at the time of opening the mold and thus avoiding unwanted grip of the same, which would force to interrupt the injection process and proceed to the manual extraction of the laundry.
  • the ejector is preferably conceived of steel F521 tempered to core 54 HRC and nitrided to the outside> 950 HV 0.3, in order to avoid functional wear by friction. DESCRIPTION OF THE DRAWINGS
  • Figure 1. Shows an elevation view of a fungiform ejector for injection molds made in accordance with the object of the present invention.
  • a preferred embodiment of the ejector object of the invention which, as observed in the figure, basically comprises: a metal rod (1) of hardened and nitrided steel, of variable geometric shape and size, depending on the size of the laundry and of the thermoplastic part to be extracted, a lower body (2) and a fungiform head (3) that represents the main feature of the invention and that avoids functional wear due to friction, reducing the high risk of damage to the mold.
  • the rod (1) is cylindrical.
  • the rod (1) is of rectangular section with its faces parallel two to two, which allows machining and subsequent grinding of all its faces is much cheaper and it is possible to do it with conventional machinery.

Abstract

The invention consists of: a metal rod (1) made from tempered, nitrided steel, having a size and geometrical shape that vary depending on the size of the runner and the thermoplastic part to be ejected, with cylindrical models being the most commonly used; a lower body (2); and a mushroom-shaped head (3) which represents the main characteristic of the invention and prevents functional wear due to friction, reducing the high risk of damage to the mould, as well as providing the resulting savings in time and money.

Description

EXPULSOR PARA COLAPA SUBMARINA EN PARTES FIJAS DE MOLDES DE INYECCIÓN TERMOPLÁSTICOS EXPULSOR FOR SUBMARINE LAYER IN FIXED PARTS OF THERMOPLASTIC INJECTION MOLDS
D E S C R I P C I Ó ND E S C R I P C I Ó N
OBJETO DE LA INVENCIÓNOBJECT OF THE INVENTION
Los sectores de Ia técnica a los que se refiere Ia presente invención • son el metal y el químico, y dentro de los mismos, y de forma conjunta, su aplicación principal se circunscribe a Ia inyección de moldes con coladas submarinas de piezas de material termoplástico.The sectors of the technique to which the present invention refers • are metal and chemical, and within them, and together, its main application is limited to the injection of molds with underwater castings of thermoplastic material parts .
El objeto principal de Ia presente invención es simplificar, facilitar y asegurar Ia extracción de coladas submarinas localizadas en Ia parte fija de los moldes de inyección para termoplásticos.The main object of the present invention is to simplify, facilitate and ensure the extraction of underwater castings located in the fixed part of the injection molds for thermoplastics.
ANTECEDENTES DE LA INVENCIÓNBACKGROUND OF THE INVENTION
Los procesos de inyección de plástico consisten en calentar los pellets de un material termoplástico para transformarlos en un tipo masa a través de un cilindro de plastificación, dándole Ia forma final al molde.The plastic injection processes consist of heating the pellets of a thermoplastic material to transform them into a mass type through a plasticizing cylinder, giving the mold the final shape.
Cuando el plástico está en el molde, se enfría por medio de circuitos donde fluye agua y finalmente, se abre el molde para obtener una pieza sólida.When the plastic is in the mold, it is cooled by means of circuits where water flows and finally, the mold is opened to obtain a solid piece.
Las máquinas de inyección tienen sistemas hidráulicos, los cuales controlan el movimiento de los sistemas de inyección y cierre; y sistemas eléctricos, que controlan temperaturas, flujo de agua, aceite, etc. La colada fría es un componente de Ia pieza Inyectada y necesita ciclos de inyección más largos. Este sistema es aplicado para piezas pequeñas. Los canales fríos llevan el plástico a las cavidades del molde y no cuentan con sistemas de control de temperatura como los sistemas de colada y canal calientes.Injection machines have hydraulic systems, which control the movement of injection and closure systems; and electrical systems, which control temperatures, water flow, oil, etc. Cold casting is a component of the Injected part and needs longer injection cycles. This system is applied for small parts. The cold channels take the plastic to the mold cavities and do not have temperature control systems such as hot and cast channel systems.
Las principales características de los moldes de inyección de plástico de colada y canal fríos son: tiempos de ciclo altos, mecanismo de desmoldeo complicado, gran cantidad de desperdicio de material, difícil repetitividad del producto, distancias (carreras) de apertura del molde muy grandes y proyección / distribución de las cavidades compleja.The main features of cold cast and channel plastic injection molds are: high cycle times, complicated demoulding mechanism, large amount of material waste, difficult product repeatability, very large mold opening distances (runs) and projection / distribution of complex cavities.
Además, en aquellas piezas en las que es necesaria una manipulación para separarlas de Ia colada, hay que afrontar el consiguiente encarecimiento de coste en tiempo y dinero.In addition, in those parts where manipulation is necessary to separate them from the laundry, the consequent increase in cost in time and money must be faced.
El camino del material hasta Ia cavidad debe ser Io más corto posible para, entre otras cosas, minimizar las pérdidas de presión y calor. Las piezas inyectadas se contraen sobre los machos del molde, para su desmoldeo se aplican diferentes tipos de expulsores: de varilla, tubular, de placa extractora, plano, combinado, neumático, con leva, etc.The path of the material to the cavity should be as short as possible to, among other things, minimize pressure and heat losses. The injected parts contract on the mold males, for their demolding different types of ejectors are applied: rod, tubular, extractor plate, flat, combined, pneumatic, with cam, etc.
El tipo de extractor o expulsor está en función de Ia forma de Ia pieza a inyectar. La presión superficial sobre Ia pieza a expulsar debe ser Ia mínima posible para evitar deformaciones.The type of extractor or ejector is a function of the shape of the piece to be injected. The surface pressure on the piece to be ejected must be the minimum possible to avoid deformations.
Los expulsores sirven no sólo para el desmoldeo, sino también para Ia evacuación de los gases de Ia cavidad. Una salida defectuosa de Ia cavidad puede tener como consecuencias un llenado parcial de Ia cavidad, unión defectuosa de frentes de material o el denominado efecto DieselThe ejectors serve not only for demolding, but also for the evacuation of gases from the cavity. A defective exit of the cavity can have as a consequence a partial filling of the cavity, defective union of material fronts or the so-called Diesel effect
(daños térmicos de Ia pieza). DESCRIPCIÓN DE LA INVENCIÓN(thermal damage of the piece). DESCRIPTION OF THE INVENTION
El expulsor objeto de esta invención presenta unas ventajas de aplicación que se derivan de Ia posibilidad de realizar los procesos de inyección normalizados y automatizados sobre aquellas piezas en las que es obligada una manipulación para separarlas de Ia colada. Además y de forma comparativa con los actuales sistemas de expulsión disponibles comercialmente, se disminuye el alto riesgo de daño sobre el molde, evitando el desgaste funcional por rozamiento.The ejector object of this invention has some advantages of application that derive from the possibility of performing standardized and automated injection processes on those parts in which manipulation is required to separate them from the casting. In addition and in a comparative way with the current commercially available ejection systems, the high risk of damage to the mold is reduced, avoiding functional wear due to friction.
El expulsor comprende una varilla metálica que presenta como característica principal su extremo superior, cabezal, que muestra una configuración fungiforme, estableciendo sus dimensiones en función del tamaño de Ia colada y de Ia pieza termoplástica a extraer.The ejector comprises a metal rod that has as its main feature its upper end, head, which shows a fungiform configuration, establishing its dimensions depending on the size of the casting and the thermoplastic part to be extracted.
El expulsor simplifica, facilita (mediante su anclaje en Ia parte fija, entre las placas expulsadoras, de un molde de inyección para termoplásticos) y asegura Ia extracción de coladas submarinas localizadas en Ia parte fija (hembra) de los moldes de inyección para termoplásticos, sujetándolas en el momento de apertura del molde y evitando por tanto el agarre no deseado de las mismas, Io que obligaría a interrumpir el proceso de inyección y proceder a Ia extracción manual de Ia colada.The ejector simplifies, facilitates (by anchoring in the fixed part, between the ejector plates, an injection mold for thermoplastics) and ensures the extraction of underwater castings located in the fixed (female) part of the injection molds for thermoplastics, holding them at the time of opening the mold and thus avoiding unwanted grip of the same, which would force to interrupt the injection process and proceed to the manual extraction of the laundry.
El expulsor se concibe preferiblemente de acero F521 templado al núcleo 54 HRC y nitrurado al exterior > 950 HV 0.3, a fin de evitar el desgaste funcional por rozamiento. DESCRIPCIÓN DE LOS DIBUJOSThe ejector is preferably conceived of steel F521 tempered to core 54 HRC and nitrided to the outside> 950 HV 0.3, in order to avoid functional wear by friction. DESCRIPTION OF THE DRAWINGS
Para complementar Ia descripción que se está realizando y con objeto de ayudar a una mejor comprensión de las características de Ia invención, de acuerdo con un ejemplo preferente de realización práctica de Ia misma, se acompaña como parte integrante de dicha descripción, un juego de dibujos en donde con carácter ilustrativo y no limitativo, se ha representado Io siguiente:To complement the description that is being made and in order to help a better understanding of the characteristics of the invention, according to a preferred example of practical implementation thereof, a set of drawings is attached as an integral part of said description. where, for the purposes of illustration and not limitation, the following has been represented:
Figura 1.- Muestra una vista en alzado de un expulsor fungiforme para moldes de inyección realizado de acuerdo con el objeto de Ia presente invención.Figure 1.- Shows an elevation view of a fungiform ejector for injection molds made in accordance with the object of the present invention.
REALIZACIÓN PREFERENTE DE LA INVENCIÓNPREFERRED EMBODIMENT OF THE INVENTION
A continuación se describe un modo de realización preferente del expulsor objeto de Ia invención, que tal y como se observa en Ia figura comprende fundamentalmente: una varilla (1) metálica de acero templado y nitrurado, de dimensión y forma geométrica variables, en función del tamaño de Ia colada y de Ia pieza termoplástico a extraer, un cuerpo inferior (2) y un cabezal (3) fungiforme que representa Ia característica principal de Ia invención y que evita el desgaste funcional por rozamiento, disminuyendo el alto riesgo de daño sobre el molde.Next, a preferred embodiment of the ejector object of the invention is described, which, as observed in the figure, basically comprises: a metal rod (1) of hardened and nitrided steel, of variable geometric shape and size, depending on the size of the laundry and of the thermoplastic part to be extracted, a lower body (2) and a fungiform head (3) that represents the main feature of the invention and that avoids functional wear due to friction, reducing the high risk of damage to the mold.
De acuerdo con una primera realización preferente de Ia invención, ilustrada en Ia figura 1 , Ia varilla (1) es cilindrica.According to a first preferred embodiment of the invention, illustrated in Figure 1, the rod (1) is cylindrical.
De acuerdo con una segunda realización preferente de Ia invención, no representada, Ia varilla (1) es de sección rectangular con sus caras paralelas dos a dos, Io cual permite que el mecanizado y posterior rectificado de todas sus caras resulte mucho más económico y sea posible realizarlo con maquinaria convencional. In accordance with a second preferred embodiment of the invention, not shown, the rod (1) is of rectangular section with its faces parallel two to two, which allows machining and subsequent grinding of all its faces is much cheaper and it is possible to do it with conventional machinery.

Claims

REIVINDICACION ES REIVINDICATION EN
1. Expulsor para colada submarina en partes fijas de moldes de inyección termoplásticos que comprende, una varilla (1) metálica de acero templado y nitrurado, un cuerpo inferior (2) y un cabezal (3), caracterizado porque el cabezal (3) muestra una configuración fungiforme que evita el desgaste funcional por rozamiento.1. Expeller for underwater casting in fixed parts of thermoplastic injection molds comprising, a metal rod (1) made of tempered and nitrided steel, a lower body (2) and a head (3), characterized in that the head (3) shows a fungiform configuration that prevents functional wear due to friction.
2. Expulsor para colada submarina en partes fijas de moldes de inyección termoplásticos, según reivindicación 1, caracterizado porque Ia varilla (1) tiene forma cilindrica.2. Expeller for underwater casting in fixed parts of thermoplastic injection molds, according to claim 1, characterized in that the rod (1) has a cylindrical shape.
3. Expulsor para colada submarina en partes fijas de moldes de inyección termoplásticos, según reivindicación 1, caracterizado porque Ia varilla (1 ) es de sección rectangular con sus caras paralelas dos a dos. 3. Expeller for underwater casting in fixed parts of thermoplastic injection molds, according to claim 1, characterized in that the rod (1) is of rectangular section with its parallel faces two to two.
PCT/ES2009/000345 2008-12-22 2009-06-29 Ejector intended for submarine runners located on the fixed parts of thermoplastic injection moulds WO2010072855A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ESP200803641 2008-12-22
ES200803641A ES2341636B1 (en) 2008-12-22 2008-12-22 EXPULSOR FOR UNDERWATER COLADA IN FIXED PARTS OF MOLDING INJECTION THERMOPLASTICS.

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9238312B2 (en) 2010-09-29 2016-01-19 Comercial De Utiles Y Moldes, S.A. Plastic injection mould with inner air extraction and extraction method for extracting the air carried out with said mould

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0872068A (en) * 1994-09-01 1996-03-19 Sekisui Chem Co Ltd Pin for mold
US5639488A (en) * 1994-11-25 1997-06-17 Sumitomo Wiring Systems, Ltd. Molding apparatus
JPH10180809A (en) * 1996-12-24 1998-07-07 Asahi Chem Ind Co Ltd Die for gas jointly using injection molding
ES2170702A1 (en) * 2000-10-25 2002-08-01 Pruna Alberto Navarra Flexible ejector for injection molds

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0872068A (en) * 1994-09-01 1996-03-19 Sekisui Chem Co Ltd Pin for mold
US5639488A (en) * 1994-11-25 1997-06-17 Sumitomo Wiring Systems, Ltd. Molding apparatus
JPH10180809A (en) * 1996-12-24 1998-07-07 Asahi Chem Ind Co Ltd Die for gas jointly using injection molding
ES2170702A1 (en) * 2000-10-25 2002-08-01 Pruna Alberto Navarra Flexible ejector for injection molds

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
DATABASE WPI Derwent World Patents Index; AN 1996-204272, RETRIEVED *
DATABASE WPI Derwent World Patents Index; AN 1998-432395 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9238312B2 (en) 2010-09-29 2016-01-19 Comercial De Utiles Y Moldes, S.A. Plastic injection mould with inner air extraction and extraction method for extracting the air carried out with said mould

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Publication number Publication date
ES2341636B1 (en) 2011-08-12
ES2341636A1 (en) 2010-06-23

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