EP3749501A1

EP3749501A1 - Method for operating an extruder, and extruder

Info

Publication number: EP3749501A1
Application number: EP19701835.1A
Authority: EP
Inventors: Harald Hepke
Original assignee: KraussMaffei Extrusion GmbH
Current assignee: KraussMaffei Extrusion GmbH
Priority date: 2018-02-07
Filing date: 2019-01-24
Publication date: 2020-12-16
Also published as: TW201934307A; CN111670103B; US20200361131A1; DE102018102738A1; DE102018102738B4; WO2019154631A1; CN111670103A; TWI785181B

Abstract

The invention relates to a method for operating an extruder (10) that has a screw (14), comprising the steps: (a) detection of a formulation identifier (Ri) which is associated with material (20) to be extruded and which encodes at least one operating variable, from which an ideal screw rotational frequency (f_i,soll) of the screw (14), which is to be set for the extrusion process, can be determined, (b) time-dependent detection of a throughput parameter (M), from which a throughput (m) of the extruder (12) can be deduced, (c) detection of a non-conformance (t_p) point in time, at which the material (20) can no longer be produced with a predefined quality, owing to excessive wear of the extruder (12), and (d) calculation of a limit throughput parameter (Mi(t_p)) from the throughput parameter (M), linking of the limit throughput parameter to the formulation identifier (R_i), and storing of the limit throughput parameter (Mi(t_p)).

Description

Method of operating an extruder and extruder

The invention relates to a method for operating an extruder. According to a second aspect, the invention relates to an extruder.

More particularly, the invention relates to a method for producing automobile tires and components of automobile tires, for example treads, by means of an extruder. Extruders have a screw which travels in a cylinder to convey and thereby knead optionally extruded material, which is a rubber composition according to a preferred embodiment, and optionally to heat and finally discharge under pressure to a spray head.

The snail wears out. This increases a gap between the outer edge of the screw and an inner surface of the cylinder in which the screw is running. Through this gap flows to be extruded material against a

Material flow direction. In order to achieve a given throughput, a rotational frequency of the screw must be increased, the greater the wear. The throughput is that amount of extruded material that is released to the spray head during operation of the extruder.

The higher the flow of material to be extruded, which flows through the gap entge the material flow direction, and the higher in response to the Drehfre frequency of the screw is set to achieve a predetermined target throughput, the more heat is in the introduced extruding material. Although it is possible and according to a preferred embodiment of the procedural rule provided that the material to be extruded is cooled by means of a cooling device of the extruder. Nevertheless, an increase in the Schneckendrehfre frequency usually causes the temperature of the extruding material at the point where the material leaves the extruder increases. If a critical temperature is exceeded, this leads to the fact that the rubber composition is partially vulcanised and thus becomes unusable for further processing. For this reason, the screw must be replaced if the wear has progressed too far. The measurement of wear is so far consuming. For this it is necessary, for example, to expand and measure the screw. For this reason, the screw is changed after a predetermined number of operating hours regardless of the actual wear. This avoids that the wear during the production becomes too high and thus a production break occurs. A disadvantage of this

The procedure is that the screw is usually changed too early.

The invention is based on the object to reduce disadvantages in the prior art.

The invention solves the problem by a method for operating an extruder comprising a screw, comprising the steps of (a) detecting a recipe identifier associated with material to be extruded and at least one operating quantity indicative of a desired screw rotational frequency f, the screw, (b) time-dependent detection of a flow rate parameter, from which a throughput of the extruder, in particular per revolution of the screw can be concluded, (c) detecting an error time tp, to which the Extruder is no longer operable due to excessive wear, and (d) calculating a limiting flow rate parameter Mi (tp) from the flow rate parameter M, linking the Grenzdurchsatz- Parame ters Mi (tp) with the recipe identifier R, (and optionally the Error time tp) and storing the limit flow rate parameter M, (ίr).

An advantage of this method is that information is obtained in this way, at which throughput the introduced thermal power at a given recipe is so great that a given quality of the extruded product is no longer given. In the context of the present description, the recipe identifier is understood as meaning, in particular, a date, for example a number, an amount of numbers or a vector, which codes the information necessary for processing a particular material. In particular, it is determined from the recipe identifier, which material is to be extruded and thus supplied to the extruder.

Preferably, the recipe identifier also encodes a product dimension.

The recipe code also encodes an operating variable from which the desired screw rotational frequency of the screw can be determined. For example, the operating variable is the desired screw rotational frequency itself. Alternatively, the operating variable may be the output of the extruder to be set, a nominal throughput in weight per unit of time, and / or a nominal production speed. However, it is basically conceivable and encompassed by the invention that the recipe code encodes a corresponding operating variable. In other words, it is sufficient that the recipe identifier

is assigned exclusively to the material to be extruded.

The time-dependent detection of the throughput parameter is understood in particular to mean that the throughput parameter is recorded at least once per minute, preferably at least once per 10 seconds, preferably at least once per second. It is possible that the time-dependent detection is performed on the basis of an external signal, for example from a central control unit.

By the feature that from the flow rate parameter on the throughput of the extruder can be concluded, is in particular understood that the throughput indicates which mass of extruded material per unit time or per revolution of the screw is discharged from the extruder. When speaking of time, it is either the real time or one

Machine time meant that increases with the real time in operation strictly monotonous. However, unlike the real time, the machine time may stall, for example, when the extruder is not operated or reset, for example after a screw change.

The error time is preferably indicated in the machine time, for example in number of hours since the last change of the screw of the corresponding extruder.

The error time is that time at which the extruder delivers extruded material that no longer meets the required quality of the product and / or to which the extruder no longer reaches a predetermined target production speed. For example, this quality refers to whether the material is completely unvulcanized. It is possible, but not necessary, for the quality of the product to be described in objectively measurable parameters.

All that matters is that the time of error encodes the point in time at which the extruded material is no longer acceptable.

For example, the error time is that time at which a predetermined maximum temperature of the extruded material is at least locally exceeded. It is possible, but not necessary, for the temperature of the extruded material to be measured and for the time of failure thereby to be determined from this temperature, in particular by setting the time of exceeding the maximum temperature as the time of error.

After some wear, the screw rotation frequency must be increased to reach the target production speed. If a further increase in the screw rotational frequency is not possible because this would lead to too high a thermal load, the production speed drops below the target production speed. This is one possible criterion for assuming a too worn worm. By the feature that the cutoff parameter is calculated from the throughput parameter, it is understood, in particular, that the cutoff parameter is set equal to the throughput parameter at a time that is within a DC wear interval around the fault time. The DC wear interval is a time interval in which it can be assumed that the wear of the worm has not changed significantly.

For example, the interval length of the DC wear interval is at most three months, in particular at most one month and / or at least one day.

Under the feature that the threshold flow rate parameter is linked to the recipe identifier, is understood in particular that the corresponding data are stored so that when querying the threshold flow rate parameter is uniquely identifiable to which recipe identifier this belongs. It is convenient, but not necessary, for the error time t _{P to be} linked to the limiting flow rate parameter and the recipe recognition. The limit flow rate parameter associated with the recipe identifier and, if applicable, the time of error forms an error record.

It is favorable if the recipe codes the production rate with which the material to be extruded must be dispensed.

According to a preferred embodiment, for recipe identifiers of

Material processed within the equal wear interval at the time of error, the flow rate parameter associated with the corresponding recipe identifier and a timestamp for inferring the error time, as an equivalent flow rate parameter Miq _q ( tp) stored. In particular, this throughput parameter is linked to the error time tp itself, even if the material is not processed exactly at the error time. Material to be extruded, which belongs to different prescription identifiers, may react differently to the wear of the extruder. It is commonly known heuristically that a particular material sensitive or insensitive to wear. If it is known that the material reacts insensitive to wear, it can be processed, although the previous material could no longer be processed.

It is also possible that the new material with the new recipe identifier is processed only for the purpose of determining whether even with this material, the wear of the extruder is already so great that the required throughput can not be achieved with the specified quality. This data results in a collection of data that can be extracted in the form of a throughput map at which specific throughput the material having a particular recipe identifier can no longer be processed.

[Claim 3] The method preferably comprises the steps

(a) at a change time tw change of the material to be extruded from a current material with a current recipe identifier R, to a future material with a future recipe identifier R _j ,

(B) detecting the flow rate parameter Mj (t _w ) for the material with the current recipe identifier R, at the change time tw or an equivalent Wech selzeitpunkt t _{w, ä} , within the Gleichverschleiß- interval l _a to the

Change time t _w is,

(c) detecting the flow rate parameter M _j (t _w ) for the material with the future gene Recognition R _j at the change time t _w or an equivalent change time t _{w, ä} , within the Gleichverschleiß interval l _ä to the change time ( t _w ), and

(d) storing an equivalent flow rate map containing the flow rate parameter Mi (t _w ) for the material with the current recipe identifier R, at the change time t _w or equivalent change time t _{w, ä} with the flow rate parameter M _j ( tw) for the material with the second recipe identifier R _j at the change time (tw) or equivalent change time (tw _{, ä} ) linked.

The detection of the throughput parameters at the time within the DC wear interval is based on the knowledge that the wear within of the DC wear interval only to a negligibly small extent. Each time the recipe is changed, it will give an indication of the influence that the viscosity in the other properties of the material with a given recipe identifier has on the throughput at an unknown but given wear. On the basis of this data, a conclusion can be drawn as to which wear is to be expected if the material is changed over with an already presumed recipe code. In particular, by the method steps mentioned above, a throughput parameter for a material with a first, current recipe identifier can be used to infer the expected throughput parameter through the material with a second, future recipe identifier.

[Claim 4] It is favorable if, prior to a change of material with the current recipe identifier to the material with the future recipe identifier (i), the current throughput parameter for the material with the current recipe identifier is detected and (ii) the equivalent throughput map is interpolated, so from the

Throughput parameter for the material with the current recipe identifier at the current time of change of the throughput parameters for the material with the future recipe identifier at the current change time is obtained. In this way, an estimated flow rate parameter is obtained.

It is favorable that a warning message is issued if the throughput parameter, which has been calculated in this way for the material with the future recipe, falls below a predetermined minimum throughput parameter associated with the recipe identifier. This minimum throughput parameter is preferably the limit flow rate parameter that is obtained when a time of error has been detected for the corresponding recipe identifier. If no error time has been detected, a predetermined estimated value which was estimated, for example, is preferably used as the minimum throughput parameter. According to a preferred embodiment, prior to a change from a current material with a current recipe identifier to a future material with a future recipe identifier, the following steps are performed: (a) determining the closest time to which the throughput parameter with the current recipe identifier is equivalent Throughput parameter for the future recipe identifier exists, (b) determining a difference between the throughput parameters, (c) adding a wear progress value calculated from this difference to the throughput parameter of the current one

Recipe Recognition to obtain an estimated flow rate parameter for the future Recipe Recognition, and (d) if the estimated flow rate parameter is below the threshold flow rate parameter of the prospective material with the future Recipe Recognition, issue a warning message.

By calculating the wear progress value from the difference between the two flow rate parameters, it is particularly understood in the simplest case that the wear progress value is equal to the difference. However, it is also possible that this difference is multiplied by a correction value, which is calculated for example from the wear curves for the two recipe identifiers. The basis for this method is the assumption that the differences in the throughputs change little with increasing wear.

By issuing a warning message, it is understood, in particular, that a signal perceivable or imperceptible by humans is emitted, which encodes the circumstance that it is to be expected that the predefined quality will not be reached when the future material is extruded. It is possible that the warning message will be sent to a remote central computer, such as a computer that is in the hands of or serviced by a manufacturer or maintenance company of the extruder, so that the

Delivery of a new snail can be triggered.

Alternatively or additionally, before changing from the current material to the future material, the closest point in time is determined, to which for the Throughput parameter with the current recipe identifier an equivalent throughput parameter for the future recipe identifier exists, then the quotient of the throughput parameters is determined. This quotient becomes a

Calculated wear progress factor, wherein the wear progress factor may be the quotient itself. The wear progress factor is multiplied by the flow rate parameter of the current recipe identifier to obtain a second estimated flow rate parameter. If the second estimated flow rate parameter is below the threshold flow rate parameter of the future material with the future recipe flag, the warning message is issued.

It should be noted that the name is second estimated

Flow rate parameter does not necessarily mean that the first flow rate parameter must be calculated. It is just a simpler form of naming. It is also possible that the first and the second estimated flow rate parameters are calculated, and for the comparison with the

Boundary flow rate parameter, optionally weighted average, is used from both estimated flow rate parameters.

Preferably, the method comprises the steps (a) for at least one

predetermined recipe identifier, which may be referred to as a reference recipe, determining the throughput parameter as a function of time, in particular also throughput parameters when extruding materials and other recipe identifiers, and (b) calculating a defect time estimate to which the Minimal throughput parameters for the given recipe identifier would be less than the minimum throughput parameter associated with the recipe identifier, by extrapolating the throughput parameter versus time. It is favorable if the error time estimated value is output in the form of a message.

Preferably, the method comprises the step of obtaining fit parameters for a given set of recipes which are fitted according to the throughput parameter with a parameterized model function, whereby the extrapolation of the throughput parameter takes place on the basis of the model function with the fit parameters.

In the simplest case, the model function can be a linear function. In this case, the throughput parameter is described as a linear function versus time measured in operating hours. However, it is also possible that the model function contains terms of higher order, in particular those which depend on the quadratic or third power of the time.

Preferably, the method comprises the step of zeroing the time after replacement of the screw. It is possible to carry out said process only over the period over which a given screw is used. But it can be assumed with good reasons that the wear behavior of the screw is substantially the same, so from the wear behavior of a screw on the wear behavior of the following

Snail can be closed.

The invention also solves the problem by a method of operating an extruder having a screw, comprising the steps of: (a) detecting a recipe ID Ri associated with material to be extruded and at least one operating quantity indicative of a desired screw rotational frequency f , which is determinable of the screw to be preset in the extrusion, encodes (b) time-dependent

Detecting a flow rate parameter Mj (t), from which on a throughput Am of the extruder, in particular to a throughput per revolution of the screw, ge closed, (c) at a change time t _Wi switching the ex trudierenden material on a material With a second recipe identifier R _j , (d) He summarize the throughput parameter Mj (t _Wi ) for the material with the first recipe identifier R, at the change time t _Wi or an equivalent change time point t _{Wi, ä} , within a Gleichverschleiß -interval l _ä, in particular, within a period of one week, to the change time point is twi, (e) detecting the

Throughput parameter M _j (t _Wi ) for the material with the second recipe identifier R _j at the change time t _Wi or an equivalent change time t _w -i _{, ä} , (f) storing an equivalent flow rate map K containing the flow rate parameter M, (twi) for the material having the first recipe identifier R, at the time of change twi or the equivalent time of change twi .a with the throughput parameter M _j (twi) for the material with the second recipe identifier R _j at the change time twi.ä linked.

If additional material changes take place within the DC wear interval l _a , the throughput parameters for the corresponding recipes are accordingly recorded in the procedure for the material with the second recipe identifier and stored in the equivalent enforcement characteristic field.

The method preferably comprises the steps of (a) determining a recipe as reference recipe identifier and (b) determining the DC wear interval from the change times t _{Wk of} the recipe reference recipe identifier. In other words, there is a recipe, which is preferably the most commonly used recipe relative to which the enforcement parameters are referenced.

Preferably, the method comprises the steps of (a) detecting an error time point tp at which the extruder is no longer operable with the desired screw rotational frequency due to excessive wear (because otherwise the required quality of the product is no longer guaranteed), (b ) Determining the flow rate parameter Mi (tp) at a time t _P in the equal wear interval l _a , (c) determining the minimum flow rate parameter M n from this flow rate parameter M i (ΐr), in particular by setting minimum flow rate equal Parameters Mi min and throughput parameters Mj (t _P ). The advantage of this is that, as described above, a throughput parameter is obtained which is known that the material with the associated recipe identifier can not be processed at the given wear. The particular embodiments described above for the first aspect of the invention also relate to the second

inventive method. According to the invention, there is also a method for operating an extrusion line which has a first extruder, a second extruder and at least one third extruder, the method being carried out for the majority of the extruders, in particular for all extruders.

According to the invention, an extruder is also provided with a cylinder, at least one screw running in the cylinder, and a control unit which is arranged to automatically carry out a method according to the invention. Preference, the control unit has a digital memory in which a program is stored, which encodes the method.

According to a preferred embodiment, the control unit is provided with a

Data network connected or connectable to send the throughput parameters or parameters calculated therefrom, in particular Fit parameters, to a spatially spaced central computer. The central computer may, for example, be located more than one kilometer away from the control unit nearest to it. This allows the manufacturer of the extruder or a

Service companies to monitor the evolution of wear and to deliver in time, for example, an exchange screw.

According to the invention, an extrusion system with at least three extruders, each having at least one screw, as well as a control unit, which is set up for automatically performing an inventive

Process. It is possible, but not necessary, for the control unit to be distributed among several sub-control units. In the following the invention will be explained in more detail with reference to the accompanying drawings. It shows

Figure 1 shows an inventive extrusion system with inventive

Extruders for carrying out a method according to the invention,

FIG. 2 shows a diagram in which the course of the throughput parameters for a plurality of recipe identifiers is plotted over time,

FIG. 3 shows a diagram similar to that according to FIG. 2, wherein the time over which a recipe is processed in each case is shorter than in the case of FIG. 2.

FIG. 1 shows an extrusion system 10 according to the invention with a first extruder 12.1, a second extruder 12.2 and a third extruder 12.3. The first extruder has a first screw 14.1, which runs in a cylinder 16.1. By means of a material supply 18.1 to be extruded material 20.1 is fed to the extruder 12.1.

The extruder 12.1 has a drive 22.1 in the form of an electric motor for rotating the worm 14.1. A control unit 24.1 controls the drive 22.1 so that it causes a predetermined screw rotational frequency f. The control unit 24.1 can communicate with a central computer 26. It is possible that an intermediate computer 28 is used for this purpose. The control unit 24 comprises a digital memory in which a program is stored which, when working, causes the method described below to be executed.

First, a recipe identifier R, is detected by extruded material. The index i is a run index, which could also be referred to as a recipe index, as it numbers the different recipes. A recipe contains, for example, an indication of the constituents of the material 20.1 which is fed to the extruder 14.1. The recipe R, also includes an indication of a desired screw rotational frequency fi. _soii , which should be preset when _extruding material 20.1. As a rule, this desired screw _{rotational frequency f.sub.o.sub.ii} refers to a predetermined throughput m, which relates to the amount of material which is discharged by the extruder 12.1 per revolution of the screw 14.1. From the throughput m and the screw rotational frequency f, it is thus possible to calculate a mass throughput which is measured in kilograms per unit of time and indicates how many kilograms of extruded material per unit of time is output by the extruder 12.1.

The extruder 12.1 delivers the extruded material by means of a line 30.1 to a spray head 32. The other extruders of the extrusion system 10, in the present case, the extruder 12.2 and 12.3, via corresponding lines 30.2, 30.3 each extruded material to the spray head 32, where from the combined streams a profile 34 is injected. The profile 34 runs on a conveyor 36, for example a belt conveyor, for further processing.

A scale 38 determines the weight of a portion of the profile 34 so that a line weight G, also called the meter weight, of the profile 34 can be determined. Since the proportion of the material coming from a specific extruder is known on the profile, from this information and the measured meter weight and a speed with which the profile 34 moves, the throughput in kilograms per unit time of all extruders can be determined. The speed at which the profile 34 moves is also measured, for example, by measuring a rotational speed of a roller over which the profile 34 rolls. The extruders 12.2 and 12.3 and any further existing extruders are each constructed the same, but it is also possible that they differ in their design. However, the essential characteristics of the extruders relevant to the invention are those described above.

The respective control units 24 (reference numbers without counting index refer to all corresponding objects in each case) detect the respective worm rotational speed. f ,. As a rule, the throughput in mass per unit time is given and according to a preferred embodiment is part of the recipe, can be calculated from the screw rotational frequency f, the throughput per screw revolution, namely as a quotient of throughput in weight or mass per unit time at the target throughput according to recipe. The nominal flow rate is given in mass or weight per minute. If it comes to wear, then the screw rotation frequency f, must be increased in order to achieve the desired throughput. This is usually done manually, but can also be done automatically.

FIG. 2 shows schematically that the throughput parameter M decreases with the time t measured in operating hours. At the beginning of the examination, in particular after the installation of a screw into the extruder, material with the recipe identifier Ri is first extruded. It can be seen that the target throughput is just under 500 grams per screw revolution.

This recipe identifier is detected by the control unit 24, for example, by being entered by an operator via an operator interface. From the recipe identifier Ri, the control unit 24 determines the first to be selected screw rotational frequency - During the extrusion of the throughput parameter M in the form of mass penetration per screw revolution is detected continuously, for example once a second or once per 10 seconds.

At a change time t _Wi , the respective current throughput parameter Mi (tw-i) is initially stored. Thereafter, the material according to a second recipe identifier R _{2 is} processed. At the beginning of processing, the throughput parameter M ₂ (t _Wi ) is determined. The same occurs at a time t _W 2 when changing from the material with the second recipe identifier to the material with the third recipe identifier R ₃ .

At a time t _W 5, at which the material is processed in accordance with the second recipe identifier R ₂ , the screw rotational frequency f ₂ would have to be selected to be so high, In order to achieve the predetermined target throughput that would lead to excessive heating of the material to be extruded and local vulcanization. The flow rate parameter M is M ₂ (t _P ) at this time. It is stored as a limit flow rate parameter. For a later recurring processing of the material according to the recipe identifier R _{2, it} is then known that it must be ensured that the throughput parameter M _{2 is} always above this limit flow rate parameter M _{2 min} .

FIG. 1 shows the case in which the materials are exchanged so rarely with respect to the corresponding recipe identifiers that the wear already clearly advances during the processing of only one material. However, more common is the case in which different materials with different recipe identifications are changed so frequently that wear during processing of the material with a particular recipe identifier is small. This case is schematically indicated in the diagram according to FIG. It can be seen that during a DC wear interval l _a, the wear decreases only so little that it can be regarded as constant. For this reason, in good approximation, the throughput parameters M _3, eq (tp), M ₂ (tp), M _4, etc. _q (tp) are considered to belong to the same wear condition as.

If, for example, at a significantly later time tw9 the material with the recipe identifier R _{3 changes} to the recipe identifier R ₄ , it can be assumed in an approximation that a difference DM = M ₃ (t _W n) -M ₄ (t _W n ) remained the same. Therefore, this difference, which in this case is regarded as wear progress margin, is added to the flow rate parameter M ₄ (T _W 9). Should it be found out that the value thus obtained is below the threshold flow rate parameter M _{3 min} for the recipe recovery R ₃ , which is shown schematically, a warning message is issued.

Alternatively, it is possible that the quotient of the throughput parameters is formed instead of the difference, in the present case this would be M ₃ (t _W n) / M ₄ (t _W n). If material with a recipe ID is used very often, it makes sense to regard this recipe ID as the reference recipe ID.

FIG. 2 schematically shows the measuring points at which the throughput parameters are determined at least for the recipe with the recipe identifier R ₂ . If a large number of these parameters exist, then the wear curve can be adapted with a model curve, which in the present case is shown with dashed lines. For example, as in the case shown in FIG. 2, it is a straight line. With sufficiently many measuring points, the parameters of the model function can be selected so that the model function is optimally adapted to the measured data. This curve fitting belongs to the prior art and will therefore not be described further.

By adapting to the model function, fit parameters are obtained which describe the time course of the throughput parameter M for the material with the recipe identifier R. As soon as these have been obtained, it is possible to determine from that time that the preset or determined minimum flow rate parameter Mi _min would also be undershot. This value can be queried automatically or on a corresponding request from the user via the user interface of the respective control unit 24 or via the intermediate computer 28 or by the central computer 26.

LIST OF REFERENCE NUMBERS

Claims

claims

A method of operating an extruder (10) having a screw (14), comprising the steps of:

(a) detecting a recipe identifier (R,) that

- Is assigned to extruded material (20) and

at least one operating variable from which a desired screw rotational frequency (f _{i SOii} ) of the screw (14) to be preset during the extrusion can be determined, coded,

(b) time-dependent detection of a flow rate parameter (M) from which a throughput (m) of the extruder (12) can be deduced,

(c) detecting a time of error (t _P ) to which the material (20) due

too high a wear of the extruder (12) can no longer be produced with a predetermined quality and

(d) calculating a limit flow rate parameter (M, (t _p )) from the flow rate parameter (M), associating with the recipe identifier (R,) and storing the flow rate parameter (Mi (t _p )).

2. The method according to claim 1, characterized by the step:

for recipe identifications (R _j ) of material (20) which is processed within a week of equal wear (l _a ), in particular within one week, at the error time point (tp):

Storing the flow rate parameter (M, (t)) linked to the recipe identifier (R _j ) and a time stamp (t _P ), based on which the error time (t _P )

can be closed, as an equivalent throughput parameter (Mi _, _q (t _P )).

3. The method according to any one of the preceding claims, characterized by the steps:

(a) at a change time (t _w ) change of the to be extruded

Material (20) from a current material (20) with a current recipe identifier (Ri) to a future material (20) with a future recipe identifier (R _j ),

(B) detecting the flow rate parameter (M, (t _w )) for the material (20) with the current recipe identifier (R,) at the change time (t _w ) or one to equivalent replacement time (tw. _etc.), which, within the Gleichverschleiß- interval (l _ä) around the change time (tw) casts,

(c) detecting the flow rate parameter (M _j (t _w )) for the material (20) with the future recipe identifier (R _j ) at the time of change (tw) or an equivalent change time (tw _ä ) within the DC wear - Interval (l _a ) is around the change time (tw), and

(d) storing an equivalent flow rate map

the throughput parameter (M, (tw)) for the material (20) with the current recipe identifier (R,) at the change time (tw) or equivalent change time (tw _{, ä} ) with

the throughput parameter (M _j (tw)) for the material (20) with the second recipe identifier (R _j ) at the change time (t _w ) or equivalent change time (tw _{, ä} ) linked.

4. The method according to claim 3, characterized by the steps:

(i) before a change of material (20) with a current recipe identifier (R _a ) to material (20) with a future recipe identifier (R _z )

Detecting the current throughput parameter (M _a (twa)) for the material (20) with the current recipe identifier (R _a ) at the current change time (t _Wa ) and

(ii) interpolating the equivalent flow rate map such that

Throughput parameters (M _a (t _Wa )) for the material (20) with the current recipe identifier (R _a ) at the current time of change (tw _a )

the throughput parameter (M _z (tw _a )) for the material (20) with the future recipe identifier (R _z ) at the current change time (t _Wa ) is obtained.

5. The method according to any one of the preceding claims, characterized by the steps:

before a change from a current material (20) with a current recipe identifier (Ri) on a future material (20) with a future

Recipe Recognition (R _j ):

(a) determining the nearest time point (t _Wn ) at which an appropriate one for the flow rate parameter (Mi (twn)) with a current recipe identifier (R,) Throughput parameter (Mj (twn)) for the future recipe identifier (R _j ) exists,

(b) determining a difference (DM = Mi (twn)) -Mj (twn))) between the throughput parameters (Mj (twn)),

(c) adding a wear progress sum resulting from the difference

(DM = Mi (twn)) - Mj (twn))), to the flow rate parameter (Mi (twn)) of the current recipe identifier, so that an estimated flow rate parameter (Mi (twn)) is obtained, and

(d) if the estimated flow rate parameter is below the threshold flow rate parameter (M _j (t _p )) of the future material (20) with the future recipe identifier (R _j ), issuing a warning message.

6. The method according to any one of the preceding claims, characterized by the

Steps: before switching from a current material (20) to a current one

Recipe Recognition (R,) on a future material (20) with a future one

Recipe Recognition (R _j ):

(a) determining the nearest time (twn) at which, for the flow rate parameter (Mi (twn)) having a current recipe identifier (R,), an equivalent flow rate parameter (M _j (t _Wn )) for the future recipe identifier ( R _j ) exists,

(b) determining a quotient (Q = Mi (twn)) / Mj (twn))) of the throughput parameters (Mi (twn), Mj (twn)),

(c) multiplying a wear progress factor calculated from the quotient (Q) by the flow rate parameter (Mi (t _Wn )) of the current recipe identifier such that a second estimated flow rate parameter (Mi (twn)) is obtained, and

(d) if the second estimated flow rate parameter is below the threshold flow rate parameter (M _j (t _p )) of the future material (20) with the future recipe identifier (R _j ), issuing a warning message.

7. The method according to any one of the preceding claims, characterized by the steps:

(A) for at least one predetermined recipe identifier (Ri) determining the throughput parameter (Mi (t)) as a function of the time (t), in particular from throughput parameters when extruding materials (20) with other recipe identifiers (R ₂ , R ₃ ,), and

(b) calculating a fault time estimate (t _{P, est} ) at which the minimum throughput parameter (M _{1 min} ) for the given recipe identifier matches the mini maldurchsatz parameter (Mz.min) associated with the recipe identifier (R _z ) is below, by extrapolating the throughput parameter (Mi (t)).

8. The method according to claim 7, characterized by the step:

(a) for a given set of recipes

Applying a parametric model function to the measured throughput parameters (Mi (tw)) so that fit parameters are obtained,

(b) wherein extrapolating the flow rate parameter (M-i (t)) based on

Model function with the fit parameters.

9. A method of operating an extruder (12) having a screw (14), comprising the steps of:

(a) detecting a recipe identifier (R,) that

- Is assigned to extruded material (20) and

at least one operating variable, from which a desired screw rotational frequency (f,) of the screw (14) to be preset during the extrusion can be determined, is coded,

(B) time-dependent detection of a flow rate parameter (M, (t)) from which a throughput (Am) of the extruder (12), in particular a throughput per revolution of the screw (14), can be concluded

(c) at a time of change (t _Wi ) changing the one to be extruded

Material (20) onto a material (20) having a second recipe identifier (R _j ),

(D) detecting the flow rate parameter (M, (twi)) for the material (20) with the first recipe identifier (R,) at the change time (t _Wi ) or an equivalent change time point (t _w -i _{, ä} ), the within a DC wear Interval (), in particular within one week, around the change time point (twi),

(e) detecting the throughput parameter (M _j (t _Wi)) for the material (20) with the second recipe identifier (R _j) for changing timing (TWI) or an equivalent thereto change time point (twi. _etc.), the inside of the direct wear - Interval () at the time of change (twi),

(f) storing an equivalent flow rate map (K)

the throughput parameter (Mi (twi)) for the material (20) with the first recipe identifier (R,) at the change time (twi) or the equivalent change time (twi.ä)

associated with the throughput parameter (M _j (t _Wi )) for the material (20) with the second recipe identifier (R _j ) at the time of change (t _{Wi, ä} ).

10. The method according to claim 9, characterized by the steps:

(a) determining a recipe identifier as a reference recipe identifier, and

(b) determining the DC wear intervals (tw _k ) from the bills

times (t _Wk ) of the reference recipe identifier.

11. The method according to claim 9 or 10, characterized by the steps:

(a) detecting an error time (t _P ) to which the extruder (12) due

too high wear can no longer be operated with the set screw _{rotational frequency} (fi _{, SOii} ) (otherwise the required quality of the product is no longer guaranteed),

(b) determining the flow rate parameter (Mj (t _P )) at a point in time (t _P ) in the same wear interval (I _a ),

(c) determining the minimum flow rate parameter (Mi _{, min} ) from this flow rate parameter (Mi (t _P )), in particular by equating minimum flow rate parameters (Mi _min ) and flow rate parameters (M, (ΐ _R )).

12. A method for operating an extrusion plant (10), the

(a) a first extruder (12.1) and

(b) a second extruder (12.2) and

(c) at least one third extruder (12.3),

with the steps:

(D) performing a method according to any one of the preceding claims for the majority of the extruders, in particular for all extruders.

13. extruder (12) with

(a) a cylinder (16),

(B) at least one screw (14) running in the cylinder (16), and

(c) a control unit (24),

characterized in that

(D) the control unit (24) is arranged for automatically carrying out a method according to one of claims 1 to 12.

14. extrusion plant (10) with

(a) a first extruder (12.1) with a first screw (14.1),

(B) a second extruder (12.2) with a second screw (14.2) and

(c) at least one third extruder (12.3) with a third screw (14.3),

(d) at least one control unit (24) which is set up to automatically carry out a method according to one of claims 1 to 12.