EP4119258A1 - Thixomolding machine and method for operating a thixomolding machine - Google Patents

Abstract

The invention relates to a method for operating a thixomolding machine (1), which has an injection unit (10) with a cylinder (2) and a screw (3) accommodated in the cylinder (2), for plasticizing a material (4), in particular magnesium and/or or zinc and/or aluminum, and for injecting the plasticized material (4) into a casting tool (5), comprising the steps of: determining a dwell time of the material (4), in particular a shot volume of an upcoming shot (40), in the injection unit (10), comparing the determined dwell time with a predefined dwell time range, actuating a heater (6) of the injection unit (10) based on the determined dwell time if the dwell time is within the dwell time range, and controlling the injection unit (10) such that the dwell time remains within the dwell time range, or stopping the injection unit (10) when the determined dwell time exceeds the dwell time t area leaves.

Description

The invention relates to a method for operating a thixomolding machine and a thixomolding machine.

Thixomolding machines are known from the prior art in a variety of designs. Powdered material is usually introduced into a screw-cylinder combination, plasticized there and then injected into a tool. In order to operate the production processes on thixomolding machines, various machine parameters such as cycle times, injection times, screw stroke or the like are controlled during operation of the thixomolding machine. The thixomolding machine is usually designed with regard to such parameters for a special product to be manufactured. In the case of a product change in particular, an adjustment of the parameters in order to obtain optimal material properties for the product is often only possible by manual and iterative adjustment. In particular, this usually leads to high material and energy consumption.

It is the object of the invention to provide a method for operating a thixomolding machine and a thixomolding machine, in which case optimal utilization of the thixomolding machine can always be made possible in order to be able to inject metal parts efficiently with low energy consumption, low material consumption and low costs.

This problem is solved by a method for operating a thixomolding machine with the features of claim 1, and with a thixomolding machine with the features of claim 14.

The method according to the invention for operating a thixomolding machine offers the advantage that different types of high-quality components can be reliably produced with low material and energy expenditure.

• Ermitteln einer Verweilzeit des Werkstoffs, welcher sich innerhalb der Spritzeinheit befindet,
• Vergleich der ermittelten Verweilzeit mit einem vordefinierten Verweilzeit-Bereich,
• Betätigen einer Heizvorrichtung der Spritzeinheit basierend auf der ermittelten Verweilzeit, wenn sich die Verweilzeit innerhalb des Verweilzeit-Bereichs befindet, und
• Stoppen der Spritzeinheit, wenn die ermittelte Verweilzeit den Verweilzeit-Bereich verlässt, oder Regeln der Spritzeinheit derart, dass die Verweilzeit innerhalb des Verweilzeit-Bereichs verbleibt.

This is achieved according to the invention by a method for operating a thixomolding machine, wherein the thixomolding machine has an injection unit with a cylinder and a screw accommodated in the cylinder in order to plasticize a material and inject the plasticized material into a casting tool, and the method comprises the following steps :

• Determination of a dwell time of the material, which is located within the injection unit,
• Comparison of the determined residence time with a predefined residence time range,
• actuating a heater of the injection unit based on the determined dwell time when the dwell time is within the dwell time range, and
• Stopping the injection unit when the determined dwell time leaves the dwell time range, or controlling the injection unit such that the dwell time remains within the dwell time range.

A dwell time is considered to be a time that a certain part of the material spends inside the injection unit, that is, which has elapsed since this part of the material was filled into the injection unit. In particular, the dwell time corresponds to the time for which the material is plasticized in the injection unit, that is, for example, it is heated or kept at the right temperature.

The casting tool is preferably an injection molding tool and/or a die casting tool.

The dwell time is preferably determined specifically for a shot volume of an upcoming shot in the injection unit. The shot volume corresponds to the proportion of material within the injection unit that is sprayed off in the next injection cycle. In this case, the maximum dwell time can preferably be viewed as the total time that the part of the material in the shot volume spends within the injection unit until it is ejected.

By determining the dwell time, particularly precise information about the current material condition of the material within the injection unit can be obtained. The residence time is largely responsible for the quality of the component to be manufactured. For example, if material is injected after too short a dwell time, it may happen that the material is not yet fully plasticized. As a result, unmelted solid parts can still be present in the melted material to be ejected.

On the one hand, this can lead to surface defects and a negative impact on the mechanical parameters of the component to be manufactured. On the other hand, a material that has not yet completely melted is more viscous, which can lead to higher loads and even damage to the injection unit. On the other hand, if the dwell time is too long due to excessive heat input, this can lead to color changes and a reduction in the mechanical properties of the material. In addition, if the heat load is too long, substances can be released which, for example, attack the injection unit corrosively and can lead to increased or premature wear.

Taking the dwell time into account when operating the thixomolding machine offers numerous advantages when injection molding components. In particular, by influencing the operation of the thixomolding machine in such a way that the dwell time is always kept within the dwell time range, optimal material properties can be ensured during injection molding. This enables, on the one hand, a high quality of the component to be produced and, on the other hand, a low-wear operation of the thixomolding machine. Alternatively, in the event that the determined dwell time leaves the dwell time range, the injection unit can be stopped so that damage to the injection unit and ejection of the material with insufficient material properties can be avoided. In addition, material consumption when operating the thixomolding machine can be kept particularly low because, for example, rejects due to dwell times outside the dwell time range can be avoided.

The method thus allows permanent calculation, observation and monitoring of the utilization of the injection unit.

For this purpose, on the one hand, the heating device of the injection unit can be actuated automatically based on the determined dwell time, provided the dwell time is still within the dwell time range. The heating device is preferably actuated in such a way that when the dwell time falls compared to an optimal dwell time, the heating output of the heating device is increased in order to enable the desired optimal material properties of the component to be produced. If the dwell time is increased, the heat output of the heating device can preferably be reduced in order to avoid excessive heating when the material is being plasticized. Such a proactive heating control offers the further advantage of a particularly low energy consumption of the thixomolding machine. In particular, the energy consumption of the thixomolding machine can be reduced, for example compared to operation with the same predetermined heating control throughout the entire operation.

Furthermore, particularly when the dwell time approaches one of the limits of the dwell time range, further measures can be taken to avoid a deterioration in component quality or damage to the thixomolding machine due to insufficient or excessive plasticization of the material. For this purpose, on the one hand, the injection unit can be regulated in such a way that the dwell time remains within the dwell time range. In this case, for example, the operating parameters can be automatically adjusted by the thixomolding machine itself. Alternatively, for example, if the thixomolding machine is operated manually by the operator, the injection unit can be stopped as an emergency measure to prevent damage to the thixomolding machine or to avoid rejects in the components to be manufactured if the determined dwell time exceeds the dwell time range leaves.

The dependent claims relate to preferred developments of the invention.

The residence time is preferably determined based on a screw channel volume and/or a screw position and/or a cycle time, and in particular a geometry of the screw and barrel. The screw position is particularly preferably viewed in a state after an injection process. This means that a mass cushion of the material volume still present in the injection unit can be taken into account. The residence time can thus be determined with particular precision in order to obtain optimal component properties. The cycle time is the time between two consecutive injection processes. As a result, the time available for plasticizing the material can be taken into account simply and directly.

The thixomolding machine particularly preferably also has a hot runner on the tool side. The dwell time is determined based on a volume of the hot runner. This means that in the case of a thixomolding machine with a hot runner, the volume of the material in the hot runner is also taken into account, which means that the optimal operating parameters with regard to the dwell time can be monitored and set particularly precisely.

The predefined dwell time range is preferably determined based on material properties of the material. This means that the dwell time range is determined depending on the physical properties of the material to be processed using the thixomolding machine. The operator of the thixomolding machine can preferably enter a designation and/or the material properties of the material to be processed, in particular by means of an input device, so that the thixomolding machine can automatically determine the corresponding dwell time range. In particular, the Thixomolding machines can therefore optimally process a wide variety of materials, so that high-quality components with the desired material properties can always be produced even if the material properties of different materials differ significantly.

More preferably, one or more of the following operating parameters of the injection unit are controlled to control the injection unit of the thixomolding machine, especially if the dwell time is to remain within the dwell time range: cycle time, screw speed, dynamic pressure, screw stroke. In this case, the thixomolding machine can preferably be operated automatically, with the thixomolding machine automatically regulating the corresponding operating parameters of the injection unit. As a result, the thixomolding machine can be operated in a particularly simple manner that is convenient for the operator, so that components with high material quality can be produced in a short time and with low material consumption.

The cylinder/or the screw and/or a tool-side hot runner of the thixomolding machine is preferably heated with dwell time control by means of the heating device of the thixomolding machine. This means that based on the dwell time of the material in the injection unit, the heating of the material by the heating device is automatically adjusted. For example, the heating power can be automatically reduced or increased in order to be able to achieve the best possible material properties of the component to be produced if the determined residence time deviates from a predetermined optimal residence time.

The current dwell time of the material is particularly preferably permanently displayed to the operator of the thixomolding machine by means of a display device. This means that in addition to automatic monitoring of the dwell time on the part of the thixomolding machine, the operator can always receive information about the current dwell time of the material, which, for example, also simplifies manual adjustment of the operating parameters of the thixomolding machine. The current dwell time is preferably displayed here in relation to the dwell time area.

A signal is preferably output to the operator of the thixomolding machine by means of a display device when the recorded dwell time approaches one of the limits of the dwell time range. Alternatively or additionally, a signal can be output if the current dwell time exceeds one of the limits of the dwell time range. This means that the operator receives a signal from the thixomolding machine, preferably an optical and/or acoustic and/or optical signal, which is used to indicate that the material is close to or outside the tolerable limits in the current mode of operation lying dwell time within the injection unit. This allows the operator, for example, to manually adjust the operating parameters of the thixomolding machine in order to optimize operation and improve the material properties.

A display device is preferably used to give the operator of the thixomolding machine instructions for adjusting the operating parameters of the thixomolding machine in order to optimize the casting process. For example, the operator can be shown information in the form of setpoint values for the operating parameters of the injection unit, which are suitable for optimal operation of the thixomolding machine with regard to a dwell time to be set to achieve desired material properties of the component to be produced. As a result, it is possible for the operator to operate the thixomolding machine in a particularly simple and comfortable manner.

Downtimes of the injection unit or the thixomolding machine are particularly preferably taken into account when determining the dwell time. This means that times when the injection unit or the entire thixomolding machine is at a standstill, for example when the material is not plasticized by rotating the screw and/or by heating, are included in the calculation of the dwell time. For example, even after the injection unit has come to a standstill, material with optimal properties can be injected particularly quickly into the casting tool. In particular, this means that high-quality components can be produced with few rejects and with low material consumption even when the operation of the injection unit or the thixomolding machine is interrupted.

The material is preferably plasticized in the injection unit in such a way that the material is in a thixotropic state when it is injected into the casting tool. In particular, a state is regarded as thixotropic in which, in the finished state, the material of the component has a microstructure in which finely distributed crystalline components are embedded in cohesive regions of melt. This means that the operating parameters of the injection unit are set in such a way that the material is injected into the casting tool in a thixotropic state and that there is a thixotropic proportion in the finished component.

• Ermitteln einer Soll-Verweilzeit basierend auf einem Sollwert eines thixotropen Anteils des zu spritzenden Bauteils, und
• Regeln der Spritzeinheit basierend auf der ermittelten Soll-Verweilzeit. Insbesondere kann der Sollwert des thixotropen Anteils dabei mittels einer Eingabevorrichtung, beispielsweise manuell vom Bediener, eingegeben werden. Vorzugsweise wird die Spritzeinheit hierbei so geregelt, dass die ermittelte Soll-Verweilzeit eingehalten wird, um exakt den gewünschten eingegebenen thixotropen Anteil zu erhalten. Damit können besonders einfach qualitativ hochwertige Metallbauteile mit den gewünschten Eigenschaften hergestellt werden.

More preferably, the method also includes the steps:

• Determination of a target dwell time based on a target value of a thixotropic portion of the component to be injected, and
• Controlling the injection unit based on the determined target dwell time. In particular, the target value of the thixotropic proportion can be entered by means of an input device, for example manually by the operator. Preferably the The injection unit is regulated in such a way that the determined target dwell time is adhered to in order to obtain exactly the desired thixotropic proportion that has been entered. This makes it particularly easy to produce high-quality metal components with the desired properties.

• Ermitteln einer Aufheizzeit des Werkstoffs in der Spritzeinheit, insbesondere vor einem ersten Produktionszyklus nach dem Artikelwechsel, und
• Ermitteln eines Anfahrprozesses nach dem Artikelwechsel und basierend auf der Aufheizzeit. Als Artikelwechsel wird dabei ein Wechsel des mittels der Thixomoldingmaschine herzustellenden Artikels angesehen. Vorzugsweise kann der ermittelte Anfahrprozess mittels einer Anzeigevorrichtung dem Bediener angezeigt werden. Alternativ kann die Thixomoldingmaschine den Anfahrprozess automatisch durchführen. Durch Ermitteln der Aufheizzeit und des Anfahrprozesses nach dem Artikelwechsel kann ein besonders effizienter und flexibler Betrieb der Thixomoldingmaschine bereitgestellt werden, da auch bei verschiedenen zu spritzenden Bauteilen stets die optimale Betriebsweise der Thixomoldingmaschine automatisch ermittelt wird und damit beispielsweise durch den Artikelwechsel verursachte Stillstandszeiten auf ein Minimum reduziert werden können.

Preferably, the method also includes the following steps, which are carried out in particular in the case of a change of article:

• Determining a heating-up time for the material in the injection unit, in particular before a first production cycle after changing the article, and
• Determination of a start-up process after the article change and based on the heating time. A change of the article to be produced by means of the thixomolding machine is regarded as an article change. The determined starting process can preferably be displayed to the operator by means of a display device. Alternatively, the thixomolding machine can carry out the start-up process automatically. By determining the heating-up time and the start-up process after the article change, a particularly efficient and flexible operation of the thixomolding machine can be provided, since the optimal operating mode of the thixomolding machine is always automatically determined, even with different components to be injected, and thus downtimes caused by the article change, for example, are reduced to a minimum can become.

Furthermore, the invention leads to a thixomolding machine which has a casting tool, an injection unit with a cylinder and a screw accommodated in the cylinder in order to plasticize a material, preferably magnesium and/or zinc and/or aluminum, and to inject the plasticized material into the casting tool , includes. The casting tool is preferably an injection molding tool and/or a die casting tool. Furthermore, the thixomolding machine includes a heating device, which is set up to heat the injection unit, a detection device, which is set up to determine a dwell time of the material in the injection unit, and a control device. The detection unit is preferably set up to determine a dwell time of the material of a shot volume of an impending shot. The control device is set up to actuate the heating device based on the determined dwell time if the dwell time is within the dwell time range. Furthermore, the control device is set up to stop the injection unit in the event that the determined dwell time leaves the dwell time range, or alternatively to regulate the injection unit in such a way that the dwell time remains within the dwell time range. The control device is particularly preferably set up to carry out the method described above. The thixomolding machine is characterized by the fact that a particularly simple and comfortable operation is made possible in order to be able to produce components with high quality in a simple manner and at low cost.

The heating device is preferably set up to heat the cylinder and/or the screw and/or a hot runner of the injection unit. As a result, energy can be introduced into the material in a particularly targeted manner, in particular in addition to the energy generated based on the rotation of the screw in the cylinder, in order to plasticize the material.

The thixomolding machine preferably also includes a display device which is set up to display the determined dwell time. In particular, further information can also be displayed with the display device, such as the dwell time range. Additionally or alternatively, other information supporting the operation of the thixomolding machine can also be displayed, such as instructions to the operator, which can indicate advantageous settings for operating parameters of the thixomolding machine, in particular in order to achieve optimal residence times with regard to high component quality. As a result, it is possible for the operator to operate the thixomolding machine in a particularly simple and comfortable manner.

The thixomolding machine particularly preferably also includes an input device, by means of which manual input of operating parameters is made possible. The operator can preferably choose between an automatic adjustment of one or more operating parameters and a manual setting option for the operating parameters.

Fig. 1

eine stark vereinfachte schematische Ansicht einer Thixomoldingmaschine gemäß einem bevorzugten Ausführungsbeispiel der Erfindung.

Further details, advantages and features of the present invention result from the following description of an exemplary embodiment with reference to the drawing. Components that are functionally the same are always identified by the same reference symbols. It shows:

1

a greatly simplified schematic view of a thixomolding machine according to a preferred embodiment of the invention.

In the figure 1 is a highly simplified schematic view of a thixomolding machine 1 according to a preferred embodiment of the invention. The thixomolding machine 1 comprises an injection unit 10 with a cylinder 2 and with a screw 3 which is accommodated in the cylinder 2 . A material 4 can be supplied to the screw 3 from a material reservoir 45 . In particular, the material 4 is aluminum, which is present in the material reservoir 45 as granulate or powder.

The material 4 can be plasticized, ie melted, inside the cylinder 2 by rotating the screw 3 about an axis of rotation 35 and conveyed along the axis of rotation 35 in the direction of a casting tool 5 . By axially displacing the screw 3 in the cylinder 2 along the axis of rotation 35, a specific Shot volume of a shot 40 indicated by way of example is injected into a mold 50 of the casting tool 5, in order thereby to produce metal components. The plasticized material 4 is injected into the casting tool 5 via a channel 11 .

The thixomolding machine 1 also has a heating device 6, which is set up for heating the injection unit 10. In detail, the cylinder 2 can be heated here. Preferably, alternatively or additionally, the screw 3 can also be heated by means of the heating device 6 .

The thixomolding machine 1 has a so-called hot runner 7, within which the duct 11 is located. The material 4 can be further heated in the hot runner 7 . Alternatively, a thixomolding machine 1 without a hot runner 7 can also be provided. In this case, the plasticized material 4 would be injected directly into the casting tool 5 from the end of the cylinder 2 .

The thixomolding machine 1, in particular the injection unit 10 with the screw 3, the heating device 6 and the hot runner 7, is actuated by means of a control device 15. The control device 15 is set up to carry out either an automatic actuation or the actuation based on a manual input to be carried out by an operator of the thixomolding machine 1. For this purpose, the thixomolding machine 1 includes an input device 16, by means of which the operator can enter operating parameters of the thixomolding machine 1 manually.

Furthermore, the thixomolding machine 1 includes a detection device 9 which is set up to determine a dwell time of the material 4 within the injection unit 10 . In particular, a dwell time of a shot volume of the forthcoming shot 40 is determined here. A dwell time is considered to be a time for which the corresponding part of the material 4 has been inside the cylinder 2 since it was filled at a filling opening 46, ie a total duration for which the material 4 was plasticized at the current time. The maximum possible dwell time results from the duration for which the material 4 is inside the injection unit 10 , ie between the filling opening 46 and an outlet opening 51 of the hot runner 7 .

The dwell time is determined based on a current screw position, a cycle time of an injection cycle and known geometric properties of the injection unit, such as a screw channel volume and, for example, a pitch of the screw and a number of turns of the screw. This means that based on the previously known geometric properties and the current operating position of the screw, it is possible to estimate the dwell time of any partial areas of the material 4 in the injection unit 10 .

The thixomolding machine 1 also includes a display device 8 which is connected to the detection device 9 and which is set up to display the determined dwell time.

The determined dwell time can serve as a basis for optimizing the operation of the thixomolding machine 1, since the dwell time can be used to obtain information about the current state of the material 4, in particular the forthcoming shot 40. Based on this, the operating parameters of the thixomolding machine 1 can be adjusted so that, on the one hand, components can be produced with the highest possible material quality and, on the other hand, in order to avoid damage to the thixomolding machine 1 .

For this purpose, the dwell time determined in each case is compared with a predetermined dwell time range. The dwell time range is based on characteristic values of the thixomolding machine 1 and material properties of the material 4 to be injected. In particular, the dwell time range specifies a range within which the dwell time may lie, and outside which optimal material properties of the material 4 no longer exist. This means that the current dwell time should always be within the dwell time range in order to avoid damage to the thixomolding machine 1 and inadequate material properties of the components to be produced.

The operator can input the material 4 or specific properties of the material 4 using the input device 16 . The control device 15 then automatically calculates the dwell time range. In addition, an optimal setpoint residence time, which lies within the residence time range, is preferably determined.

When the thixomolding machine 1 is in operation, the current dwell time is permanently monitored. If the instantaneous dwell time determined is within the dwell time range, the control device 15 automatically actuates the heating device 6 and/or the hot runner 7 based on the determined dwell time. Preferably, the heating device 6 and/or the heating channel 7 is actuated in such a way that the supply of heat to the material 4 is reduced if the current dwell time is greater than the target dwell time, and further in such a way that the supply of heat to the material 4 is increased when the current dwell time is less than the target dwell time. This means that the plasticization of the material 4 is adapted automatically and unnoticed by the operator in the background via the supply of heat. As a result, the optimal material properties can be ensured in the manufacture of the components in a simple manner that is particularly convenient for the operator.

The determined dwell time is permanently displayed to the operator of the thixomolding machine 1 by means of the display device 8 . In addition, the display device 8 Instructions for adjusting the operating parameters of the thixomolding machine 1 are displayed so that the operator can manually adjust the operating parameters, for example to achieve the optimal target dwell time.

If the current dwell time determined changes and one of the limits of the dwell time range approaches, which can occur, for example, if operating parameters such as the cycle time and/or a screw speed are changed, an acoustic and/or optical signal is displayed by means of the display device 8 issued to the operator of the thixomolding machine 1. An acoustic and/or visual signal is also output to the operator if the current dwell time exceeds one of the limits of the dwell time range. This informs the operator that the dwell time is leaving or has already left the permitted dwell time range.

There are various possibilities for the subsequent optimization of the operation of the thixomolding machine 1 . On the one hand, the control device 15 can automatically regulate the operating parameters of the injection unit 10 in such a way that the dwell time remains within the dwell time range. One or more of the following operating parameters are controlled here: cycle time, screw speed, dynamic pressure, screw stroke.

Alternatively, the setting of the operating parameters of the injection unit 10 can be left to the operator, in which case the operator can adjust the operating parameters of the injection unit 10 manually using the input device 16 .

In both cases, the injection unit 10 is stopped when the instantaneous dwell time determined leaves the dwell time range. This prevents, for example, material 4 that has not yet completely melted or material 4 that has been heated for too long from being injected into the casting tool 5 . Furthermore, this prevents the thixomolding machine 1 from being damaged, for example due to the material 4 having too tough flow properties within the injection unit 10 .

In the event that the dwell time exceeds an upper limit of the dwell time range, part of the material 4 inside the cylinder 2 is already damaged, so that it has to be discharged before a production cycle of the injection unit 10 can be started again. Depending on the dwell time, the detection device 8 is used to determine which volume of the entire material volume is to be discharged within the screw channel volume. If, for example, the part of the material volume that is in the front two turns of the screw 3 starting from a screw tip 31, identified by area A for example, has a dwell time that is above the upper limit of the dwell time range, then this material volume is present to discharge the start of the next production cycle of the injection unit 10. Based on With this determined volume of material to be discharged, a number of spray-down cycles is determined, which is to be carried out before the start of the next production cycle of the injection unit 10 . This determined number of spraying cycles is then displayed to the operator using the display device 8 . The operator can preferably choose whether to carry out this number of injection molding cycles manually or whether the thixomolding machine 1 carries this out automatically by means of control by the control device 15 .

The thixomolding machine 1 is thus characterized by particularly simple and convenient operation, which reliably enables components with optimal material properties to be produced by the residence time of the material 4 being constantly calculated, recorded and monitored. This also prevents the thixomolding machine 1 from being damaged by unsuitable material properties of the material 4 .

Furthermore, by monitoring and controlling the dwell time, the thixomolding machine 1 allows a particularly flexible mode of operation with regard to the most varied of components to be produced. In this way, when there is a change of article, the heating-up time of the material 4 can also be determined and, based on the heating-up time after the article change, a start-up process can be determined. The start-up process can also either be provided to the operator for manual operation and/or performed automatically by the controller 15 .

In addition to the above written description of the invention, the additional disclosure hereby explicitly refers to the graphic representation of the invention in 1 referenced.

Reference List

1

thixomolding machine

2

cylinder

3

Snail

4

material

5

casting tool

6

heating device

7

hot runner

8th

display device

9

detection device

10

injection unit

11

channel

15

control device

16

input device

31

snail tip

35

longitudinal axis

40

shot

45

material reservoir

46

filling hole

50

shape

51

exit port

A

Material volume to be discharged

Claims (17)

Method for operating a thixomolding machine (1), which has an injection unit (10) with a cylinder (2) and a screw (3) accommodated in the cylinder (2), for plasticizing a material (4), in particular magnesium and/or zinc and/or or aluminum, and for injecting the plasticized material (4) into a casting tool (5), comprising the steps: - Determining a residence time of the material (4), in particular a shot volume of an upcoming shot (40), in the injection unit (10), - Comparison of the determined residence time with a predefined residence time range, - actuating a heating device (6) of the injection unit (10) based on the determined dwell time if the dwell time is within the dwell time range, and - Controlling the injection unit (10) in such a way that the dwell time remains within the dwell time range, or stopping the injection unit (10) when the determined dwell time leaves the dwell time range. Method according to claim 1, wherein the residence time is determined based on a screw channel volume and/or a screw position, in particular after an injection process, and/or based on a cycle time. Method according to one of the preceding claims, wherein the thixomolding machine (1) further comprises a tool-side hot runner (7), and wherein the dwell time is determined based on a volume of the hot runner (7). Method according to one of the preceding claims, wherein the predefined dwell time range is determined on the basis of material properties of the material (4). Method according to one of the preceding claims, wherein one or more of the following operating parameters of the injection unit (10) are regulated to regulate the injection unit (10) of the thixomolding machine (1): cycle time, screw speed, dynamic pressure, screw stroke. Method according to one of the preceding claims, wherein the cylinder (2) and/or the screw (2) and/or a tool-side hot runner (7) of the thixomolding machine (1) is heated with dwell time control by means of the heating device (6) of the thixomolding machine (1). Method according to one of the preceding claims, in which the current dwell time of the material (4) is permanently displayed to the operator of the thixomolding machine (1) by means of a display device (8). Method according to one of the preceding claims, wherein a signal is output to an operator of the thixomolding machine (1) by means of a display device (8) when the dwell time approaches one of the limits of the dwell time range, and/or one of the limits of the dwell time range exceeds. Method according to one of the preceding claims, in which the operator of the thixomolding machine (1) is given instructions for adjusting the operating parameters of the injection unit (10) by means of a display device (8). Method according to one of the preceding claims, wherein downtimes of the injection unit (10) or the thixomolding machine (1) are taken into account when determining the dwell time. Method according to one of the preceding claims, in which the material (4) is plasticized in the injection unit (10) in such a way that the material (4) is in a thixotropic state when it is injected into the casting tool (5). The method of claim 11, the method further comprising the steps of: - Determination of a target dwell time based on a target value of a thixotropic portion of the component to be injected, which can be entered in particular by means of an input device (16), and - Regulating the injection unit (10) based on the determined target dwell time. Method according to one of the preceding claims, wherein in the case of an article change the method further comprises the following steps: - Determining a heating time of the material (4), and - Determination of a start-up process of the injection unit (10) after the article change and based on the heating-up time. Thixomolding machine including: - a casting tool (5), - an injection unit (10) with a cylinder (2) and a screw (3) accommodated in the cylinder (2), for plasticizing a material (4), in particular magnesium and/or aluminum, and for injecting the plasticized material (4) into a casting tool (5), - a heating device (6) which is set up to heat the injection unit (10), - a detection device (9) which is set up to determine a dwell time of the material (4), in particular a shot volume of an impending shot (40), in the injection unit (10), and - a control device (15), which is set up: - operate the heater (6) based on the determined dwell time if the dwell time is within the dwell time range, and - to stop the injection unit (10) when the determined dwell time leaves the dwell time range, or to regulate the injection unit (10) in such a way that the dwell time remains within the dwell time range. Thixomolding machine according to claim 14, wherein the heating device (6) is set up to heat the cylinder (2) and/or the screw (3) and/or a hot runner (7) of the injection unit (10). Thixomolding machine according to one of Claims 14 or 15, further comprising a display device (8) which is set up to display the determined dwell time. Thixomolding machine machine according to one of Claims 14 to 16, further comprising an input device (16) for manual input of operating parameters.

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