DE102017101132A1 - Method and device for operating an injection molding machine - Google Patents

Abstract

The present invention relates to a method and a device for operating an injection molding machine. In order to regulate the startup processes based on empirically determined processes while reducing the amount of additional waste material described above and the associated costs of material, energy and system time, it is proposed that a use of key figures from a steady state of each production process is made to determine and set a respective number of Abspritz cycles.

Description

The present invention relates to a method and apparatus for operating an injection molding machine.

Various approaches for methods and apparatus for operating injection molding machines while optimizing both a material and energy requirement, as well as a power stroke are known from the prior art. Particularly noteworthy is one from the DE 10 2013 111 257 B3 Known method for process control of a mold filling of an injection molding machine, which holds a volumetrically correct filling of a mold cavity of a respective mold in an optimal range, even with changing environmental parameters in an optimal range based on a steady state in the current production of an injection molding machine to continuously products without errors or so-called. Make good parts.

However, this known as "APC" method of the Applicant only regulates an ongoing injection molding process and thus can only intervene during a continuous production with a particular tool. If, however, production interruptions occur, as may occur, for example, as a result of a malfunction in the tool or the machine, but also due to shift changes, weekend breaks or other business interruptions, then a pending start-up process is a largely unregulated operating situation in each injection molding machine. Such processes of restarting on the same or on a modified injection mold are generally based on empirically determined processes, which are accordingly not necessarily reproducible or optimally adjusted. In the context of such start-up processes, the melt that has remained in the injection molding machine for a respective standstill phase must be completely ejected. Due to downtimes in the range of about 20 minutes to even over several hours away remaining in a plasticizing the respective injection molding machine residual material has changed by a permanent heating or a continuous entry of heat energy or even partially degraded. Already when setting up tools, a plasticized material that is ready to be processed ready for use is much longer in a plasticizing unit and theoretically degrades or degenerates. Regularly occurs in the course of any excessive heating by too long residence time of plasticizing material in a plasticizing unit of an injection molding machine, a shortening of molecular chain lengths within the plasticized material. This is accompanied by significant changes in the properties of the plasticized material, starting with color changes to altered material properties, such as a shift of solidification points or increased ability of adhesive adhesion of the material within an injection mold.

Already to protect the partially very complex and thus possibly due to material changes within the plasticizable injutable injection molds, it is necessary that in the plasticizing unit of the injection molding leftover residual material in the course of a startup process completely removed from the plasticizing unit and new or fresh and in a temporal Process correctly molten material is replaced. This is done regularly by a so-called. Cumshot, wherein a separation between a tip of the actual injection molding machine and the associated tool under discharge of the material contained in the plasticizing unit is made outside. The screw threads within the plasticizing unit are flushed by spraying with new granules and fresh melt formed therefrom. When spraying the melt into the open, of course, this lost and regularly not reusable material is collected in a container and there optionally also cooled extra. Depending on a particular injection molding machine used and a downtime but significant amounts of waste material can be generated here.

It is an object of the present invention to regulate the starting processes based on empirically determined processes while reducing the amount of the additional scrap material described above and the associated costs of material, energy and system time.

This object is achieved by the features of the independent claims characterized in that a use of key figures from a steady state of each production process is performed to determine a respective number of Abspritz cycles and adjust, which implies an adjustment of a scheme. According to the invention, a method for controlling a startup process provides for the use of key figures from a steady state state of a respective production process. On this basis, an assessment, optimization and control of a respective startup process is performed.

Advantageous developments are the subject of the respective dependent claims. Accordingly, the key figures of the respective production process are also obtained by comparison with those of similar production processes. In this case, a similar production process is determined with regard to the specific properties, inter alia, a pairing of a respective tool and an injection molding machine used.

According to one embodiment of the invention, the key figures are obtained using key figures from an "APC" module and / or using a database. Here too, in addition to an existing production process, similar production processes can be used to further expand the database.

Preferably, an optimization is carried out using so-called melt state information, which are used on the basis of "APC" key figures for the control and regulation of a spray program.

In a further development of the invention, further characteristic numbers or indices for a fast start-up process are determined and used. These new figures take into account in particular the difference from the one mentioned APC Approach missing back pressure during the injection process.

Among other things, a respective selection of materials, a total time of a production interruption and further codes or indices for controlling a start-up process are preferably used for a regulation of a starting process. Essentially different from the "APC" modules and formation methods mentioned at the beginning, an "APC" control in the current production process is based on a backpressure generated by the respective tool in the course of the filling process. In the present case of an ejection, however, the injection molding machine is separated from the tool for spraying a respective residual material out of the plasticizing unit. Thus, known "APC" data are used in this sense to utilize a control of the ejection process based on a correlation of the existing "APC" data for the relevant tool on an application without a tool back pressure.

• A1: Ein Werkzeug wird zum ersten Mal angefahren, es ist kein Datensatz vorhanden. Damit können APC-Daten nicht genutzt werden, es kann aber auf APC-Daten zu ähnlichen Anwendungsfällen zurückgegriffen werden. Damit wird auf Kennwerte aus einer Datenbank für eine vergleichbare Anwendung bzw. Material zurückgegriffen, um eine Verbesserungen beim Anfahren erzielen. Damit ist das neue Werkzeug bzw. dessen Kennung oder Kennnummer etc. der Trigger zum Erkennen dieser Anfahrsituation.
• A2: Ein Werkzeug wird erneut gerüstet und angefahren oder nach einer Pause aufgrund einer Unterbrechung wieder angefahren. Es gibt damit also gespeicherte Werte eines APC-Datensatzes aus einem vorangehenden Produktionsbetrieb, auf deren Grundlage das „Anfahren“ optimiert wird. Eine „Lernphase“ zur Ermittlung eines speziellen APC-Datensatzes kann minimiert werden. Hier ist damit die Unterbrechungszeit das wesentliche Merkmal für diese Anfahrsituation.
• A3: Ein Werkzeug befindet sich in Produktion und es muss nach einer kurzen Störung oder Maschinenstopp wieder „angefahren“ werden: Die APC-Steuerung optimiert mit den aktuell in der Steuerung ermittelten und vorliegenden Kennzahlen das Fortführen der Produktion. Im Prinzip ist also keine Lernphase mehr notwendig, es folgt im Wesentlichen ein „Standard“-APC-Ablauf in der Spritzgießmaschine. Damit ist diese Anfahrsituation dadurch gekennzeichnet, dass das Werkzeug nicht gewechselt wurde und zudem eine Unterbrechung der Produktion zeitlich in bestimmten Grenzen bleibt. Diese Parameter werden durch ein erfindungsgemäßes Verfahren in einer entsprechenden Vorrichtung überwacht, um nachfolgende Prozesse entsprechend zu steuern.

In a development of the invention, a method and a device for its implementation are able to distinguish between different "starting situations":

• A1: A tool is approached for the first time, there is no data record. With that you can APC Data can not be used, but it can work APC Data can be used for similar applications. This is used for characteristic values from a database for a comparable application or material in order to achieve an improvement when starting up. Thus, the new tool or its identifier or identification number, etc., the trigger for detecting this Anfahrsituation.
• A2: A tool is re-equipped and started or restarted after a break due to an interruption. So there are stored values of one APC Data set from a previous production plant, on the basis of which "start-up" is optimized. A "learning phase" to identify a special APC Record can be minimized. Here, the interruption time is the essential feature for this starting situation.
• A3: A tool is in production and it has to be restarted after a short malfunction or machine stop: the APC Control optimizes the continuation of production with the key figures determined and present in the control. In principle, therefore, no more learning phase is necessary, it essentially follows a "standard" - APC Run in the injection molding machine. Thus, this Anfahrsituation is characterized in that the tool has not been changed and also an interruption of production within certain limits. These parameters are monitored by an inventive method in a corresponding device to control subsequent processes accordingly.

Advantageously, it is ensured by one or more of the features listed above that, for example, only as many Abspritz strokes are passed through until the melt reaches a predetermined actual state and thus the actual production can be restarted while saving time, energy and material ,

Furthermore, the object is also achieved by a device for controlling a starting process of an injection molding machine, which is designed to implement a method according to one of the preceding claims characterized in that the device means for using key figures from a steady state of each production process or due to process parameters comparable Has production processes, based on which a respective number of Abspritz cycles can be determined and set.

According to a further development of the device APC Module and a database of historical values and comparison values and formed using parameters for selecting a controller from predefined cases of startup processes.

Next, the plasticizing unit is provided with an integrated start-up valve downstream of the screw tip for targeted discharge of the Anfahrmaterials eg directly into a collecting container and / or with a closing nozzle with a corresponding additional opening to the outside and an additional closure position. Both solutions can facilitate the discharge of no longer usable Plastilat.

Further features and advantages of embodiments according to the invention will be explained in more detail below with reference to an embodiment. In the figure are symbolically an injection molding machine 1 and a cutout of a tool 2 shown. The injection molding machine 1 and the tool 2 are separated as indicated. In this case, a situation indicative of a starting process is indicated by the fact that the injection molding machine 1 a way d so far from the tool 2 driven away that one in a plasticizing unit 3 the injection molding machine 1 Inadmissibly long remaining and overheated melting material as so-called starting material while cleaning a screw 4 the plasticizing unit 3 must be targeted. This starting material, not shown in the drawing, thus certainly does not get into the tool 2 In particular, otherwise possible damage or complex cleaning of the tool 2 to avoid. Important parameters here are an ejected material flow m ' as well as melt state information.

A dashed line around a part of the injection molding machine 1 around suggests a range of parameters and measures, as according to the teaching of DE 10 2013 111 257 B3 as part of a APC Control device can be used to produce good parts over parameter fluctuations in a current production. Exemplary here are a speed n as well as a speed v the snail 4 , a mass M supplied fresh granules at a temperature θ _s of the fresh granules when fed into the plasticizing unit 3 as well as a material stream m ' and a temperature θ _p of the plastilate at the exit of the plasticizing unit 3 specified as used parameters in non-exhaustive enumeration. This number of parameters for the APC Control device is now in the implementation of the present invention to a tool identifier W and a production interruption time .DELTA.t extended to form a device for optimizing different scenarios or predefined cases of startup processes. On the basis of the mentioned parameters, key figures of the respective production process and, if necessary, also compared with those of similar production processes are obtained in order to determine and set a respective number of injection cycles

1. 1. Wiederanfahren nach Produktionsunterbrechung: Durch die Messung der Produktionsunterbrechungszeit Δt erkennt die Vorrichtung eine Fortsetzung einer an und für sich laufenden Produktion und entnimmt einer Datenbank DB entsprechende Maßnahmen zum Schutz des betreffenden Werkzeugs vor Beschädigungen durch inzwischen unbrauchbar gewordenes, in der Plastifizierungseinheit 3 anliegendes Schmelzgut. Einer möglichen Degenerierung des Schmelzgutes entsprechend wird durch die Steuerung nun ein Austragen des Schmelzgutes unter Nachführung frisch erschmolzenem Granulates bewirkt, bis die Plastifizierungseinheit 3 ausreichend gereinigt ist. Dieser von einer jeweiligen Plastifizierungseinheit 3 und einem eingesetzten Material in Zeit und Materialvolumen abhängige Prozess wird ebenfalls anhand von Werten aus der Datenbank bestimmt.
2. 2. Werkzeugtausch: Anhand einer geänderten Werkzeugkennung W erkennt die Vorrichtung einen Werkzeugtausch. Eine neue Werkzeugkennung W wird der Datenbank DB übermittelt, um dort entweder APC-Werte eines vorangehenden Fertigungsprozesses oder aber APC-Werte eines ähnlichen Werkzeugs. Unter Berücksichtigung einer Produktionsunterbrechungszeit Δt wird auf Basis dieser Werte nun ein Anfahrprozess gesteuert und überwacht.
3. 3. Wiederaufnahme einer Produktion: Hier zeigen die Werte für eine Produktionsunterbrechungszeit Δt zu hohe Werte auf, oder im Zuge eines Werkzeugwechsels wird anhand einer bestimmten Werkzeugkennung W ein bekanntes Werkzeug wieder an der Spritzgießmaschine 1 eingesetzt. Entsprechend der jeweiligen Situation ist dieser Fall eine Spielart eines oder beider vorstehender Szenarien, so dass ein Anfahrprozess entsprechend gesteuert wird.

Scenarios or predefined cases are in this embodiment in detail:

1. 1. Restart after production interruption: By measuring the production interruption time .DELTA.t The device recognizes a continuation of an ongoing production and takes a database DB appropriate measures to protect the tool in question against damage by now become useless, in the plasticizing unit 3 adjacent melt. In accordance with a possible degeneration of the melted material, the control now causes the melted product to be discharged while the freshly melted granules are being fed, until the plasticizing unit has been removed 3 is sufficiently cleaned. This from a respective plasticizing unit 3 and a material used in time and material volume dependent process is also determined based on values from the database.
2. 2. Tool replacement: Based on a changed tool identifier W the device recognizes a tool exchange. A new tool identifier W becomes the database DB transmitted to there either APC Values of a previous manufacturing process or APC Values of a similar tool. Taking into account a production interruption time .DELTA.t Based on these values, a startup process is now controlled and monitored.
3. 3. Resumption of a production: Here are the values for a production interruption time .DELTA.t Too high values, or in the course of a tool change is based on a specific tool identifier W a known tool back to the injection molding machine 1 used. Depending on the particular situation, this case is a variant of one or both of the above scenarios, so that a start-up process is controlled accordingly.

In an embodiment not shown, the plasticizing unit 3 provided with an integrated start-up valve downstream of the screw tip for targeted removal of the starting material eg directly into a collecting container, analogous to a starting valve at the IMC. An essential aim of this development is that the starting material can be disposed of directly without causing further break times for removing the material, for example, from the nozzle protection space. This goal can alternatively be achieved by a closure nozzle with a corresponding additional opening to the outside and an additional closure position.

Both constructive measures described above facilitate a discharge of no longer usable plastilate from the plasticizing unit 3 and thus speed up and simplify a start-up process.

LIST OF REFERENCE NUMBERS

1

injection molding machine

2

Tool

3

plasticizing

4

slug

APC

APC control unit

d

path

DB

Database

m '

material flow

n

Speed of the screw 4

.delta.t

Production interruption time

v

Speed of the screw 4

W

tool identification

θ _p

Temperature of the plastilate

θ _s

Temperature of the fresh granules when fed into the plasticizing unit 3

M

Mass supplied granules

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102013111257 B3 [0002, 0018]

Claims (9)

Method for controlling a starting process of an injection molding machine, characterized in that a use of key figures from a steady state of a respective production process is carried out to determine and set a respective number of Abspritz cycles. Method according to the preceding claim, characterized in that the characteristics of the respective production process are also obtained by comparison with those of similar production processes, wherein a similar production process with respect to the specific properties, including a pairing of a respective tool and a used injection molding machine, is determined , Method according to one of the preceding claims, characterized in that the key figures are obtained using key figures from an "APC" module and / or using a database (DB). Method according to one of the preceding claims, characterized in that the control is carried out using so-called melt state information of the plasticizing unit (3). Method according to one of the preceding claims, characterized in that the control using certain parameters (W, .DELTA.t) between at least two predefined cases of starting processes differs to optimize a respective starting process. Device for controlling a starting process of an injection molding machine, characterized in that it is designed to implement a method according to one of the preceding claims characterized in that the device comprises means for using key figures from a steady state of a respective production process or due to process parameters of comparable production processes on whose base a respective number of Abspritz cycles can be determined and set. Device according to the preceding claim, characterized in that the device comprises an APC module and a database (DB) with historical values and comparison values and is constructed using parameters (W, Δt) for selecting a control from predefined cases of startup processes. Device according to one of the preceding claims, characterized in that the plasticizing unit (3) is provided with an integrated start-up valve downstream of the screw tip for targeted removal of the starting material, for example directly into a collecting container. Device according to one of the preceding Claims 6 to 8th , characterized in that the plasticizing unit (3) has a closing nozzle with a corresponding additional opening to the outside and an additional closing position.

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