Method and device for determining viscosity index of melt in injection molding tool

Abstract

To provide a method and device that enable a highly cost-effective determination of the viscosity index of a melt in an injection molding tool.ding tool.SOLUTION: There is provided a method for determining a viscosity index of a melt in an injection molding tool. In which the injection molding tool includes: at least one cavity into which the melt is injected to fill an interior thereof; a pressure sensor unit disposed in the cavity; and at least one evaluation unit configured to evaluate sensor data generated with respect to an internal mold pressure of the melt in the cavity measured by the pressure sensor unit. The method carries out the evaluation through the steps of: determining a start time point at which a sign of a first derivative of the sensor data changes from zero to positive; determining a fill time point at which a sign of a second derivative of the sensor data changes from zero to positive; and calculating a pressure rise between the internal mold pressure at the fill time point and the internal mold pressure at the start time point; and calculating the viscosity index from the pressure rise and a time difference between the fill time point and the start time point.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a method and a device for determining the viscosity index of a melt in an injection molding tool according to the preambles of the independent claims. [Background technology]

[0002] Injection molding is a cyclical process in which an injection molding machine produces at least one product in repeated cycles over time. Each cycle includes multiple stages. An injection molding machine includes an injection molding tool containing a cavity. During the injection stage, material is injected into the cavity as a melt. The melt in the cavity is hotter than the material. The melt flows along a channel, filling the cavity. As an increase in pressure occurs, the melt assumes the shape of the cavity. During the holding pressure stage, the melt in the cavity is compressed, and additional melt is added to compensate for any possible volumetric shrinkage. The melt in the cavity is cooled during the cooling stage. The cooled melt forms the product. Finally, the product is removed from the cavity.

[0003] In injection molding, it is important to keep process parameters constant throughout the cycle to ensure a consistently high product quality. One of these process parameters is the viscosity of the melt. Viscosity indicates the resistance the melt must overcome as it flows along the flow path. For example, an increase in viscosity due to variations in material properties or a change in the material's moisture content increases resistance during cavity filling. As a result, the cavity may be incompletely filled with the melt, which can lead to the formation of defective molded parts and is therefore undesirable.

[0004] Viscosity can be expressed as a proportionality factor relating shear stress to shear rate. During filling, shear stress is proportional to the melt pressure at a particular location along the channel. Shear rate is proportional to the melt flow rate in the cavity. If the channel geometry is known, it is possible to use the pressure increase and flow rate to determine a viscosity index that is proportional to the actual viscosity of the melt in the cavity.

[0005] To this end, U.S. Patent No. 5,999,623 discloses a method for determining the viscosity index of a melt in an injection molding tool. A pressure sensor and a temperature sensor are positioned within the cavity. The pressure sensor is positioned proximate the melt inlet into the cavity, and the temperature sensor is positioned at the end of the cavity's flow path. During filling of the cavity with melt, the pressure sensor measures the internal mold pressure, and the temperature sensor measures the temperature of the cavity wall. Shear stress is determined from the pressure increase from the empty cavity's internal mold pressure to the pressure at the time the melt reaches the temperature sensor and generates a temperature signal indicating that the cavity is filled with melt up to the temperature sensor's location. Flow rate is determined from the time difference between the time the pressure sensor measures the onset of the internal mold pressure increase and the time the temperature sensor measures the onset of the temperature increase at the end of the flow path. The viscosity index can then be calculated from the ratio of shear stress to flow rate. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2009040077 Summary of the Invention [Problem to be solved by the invention]

[0007] It is a first object of the present invention to improve the method known from US Pat. No. 5,629,999 for determining the viscosity index of a melt in an injection molding tool. It is a further object of the present invention to provide an apparatus which allows for a cost-effective determination of the viscosity index of a melt in an injection molding tool. [Means for solving the problem]

[0008] At least one of these objects is achieved by the features of the independent claims.

[0009] The present invention provides a method for determining a viscosity index of a melt in an injection molding tool, the method comprising: the injection molding tool including at least one cavity into which a melt is injected to fill the cavity; the injection molding tool including a pressure sensor unit disposed in the cavity, the pressure sensor unit measuring an internal mold pressure of the melt in the cavity and generating sensor data for the measured internal mold pressure; the injection molding tool including at least one evaluation unit configured to evaluate the sensor data, the evaluation comprising: determining when the sign of the first derivative of the sensor data starts to change from zero to positive; determining a fill time point at which the sign of the second derivative of the sensor data changes from zero to positive; calculating the pressure rise between the internal mold pressure at the time of filling and the internal mold pressure at the start; calculating a viscosity index from the pressure rise and the time difference between the filling time and the start time; The present invention relates to a method characterized by:

[0010] The present invention also provides an apparatus for determining a viscosity index of a melt in an injection molding tool, the apparatus further comprising, in addition to the injection molding tool, a pressure sensor unit and at least one evaluation unit, wherein the injection molding tool includes at least one cavity into which a melt can be injected, the cavity being capable of being filled with the injected melt, the pressure sensor unit being disposed in the cavity and measuring an internal mold pressure of the injected melt in the cavity and generating sensor data for the measured internal mold pressure, and the evaluation unit being configured to evaluate the sensor data, the evaluation including: an evaluation unit determining a start time point at which the sign of the first derivative of the sensor data changes from zero to positive; an evaluation unit determines a filling time point at which the sign of the second derivative of the sensor data changes from zero to positive; an evaluation unit calculating a pressure rise between the internal mold pressure at the time of filling and the internal mold pressure at the start; The evaluation unit calculates the viscosity index from the pressure increase and the time difference between the filling time and the start time. The present invention relates to an apparatus characterized by:

[0011] Applicant has surprisingly discovered that, in contrast to the teachings of US Patent No. 5,929,999, the viscosity index of the melt in the cavity can be determined using only one pressure sensor and no temperature sensor, making viscosity index determination cost-effective.

[0012] The invention is based on the discovery that the behavior of melt flow in a cavity satisfies the Hagen-Poiseuille law. Therefore, the increase in melt pressure during cavity filling is proportional to the product of viscosity and volumetric flow. Therefore, at the time of filling, the viscosity of the melt is proportional to the product of the pressure rise and the time lag of the flow path. This allows for a simple and fast determination of the viscosity index.

[0013] Further embodiments of the subject matter of the invention are set forth in the dependent claims.

[0014] In the following, the invention will be explained in more detail by way of example with reference to the following figures: [Brief explanation of the drawings]

[0015] [Figure 1] 1 shows a schematic representation of a part of an apparatus V comprising an injection molding machine 1 for producing a product W. [Figure 2] 2 shows a graphical representation of sensor data XD (ti, i=1...n) obtained during the production of a product W by the injection molding machine 1 according to FIG. 1. [Figure 3] 3 shows an enlarged view of a portion of the graphical representation of the sensor data XD (ti, i=1...n) according to FIG. 2. DETAILED DESCRIPTION OF THE INVENTION

[0016] Like numbers refer to like objects throughout the figures.

[0017] FIG. 1 shows diagrammatically part of an apparatus V for determining the viscosity η of a melt M in at least one injection molding tool 11 .

[0018] The injection molding tool 11 is a component of a commercially available injection molding machine 1 known to those skilled in the art for producing at least one product W.

[0019] Injection molding is a cyclical process in which an injection molding machine 1 produces a product W in repeated cycles over time. Each cycle includes an injection phase I, a holding pressure phase II, and a cooling phase III. A cycle may last several seconds.

[0020] The components of the injection molding machine 1 are at least one injection unit 10, which includes a screw 10.1 and a nozzle 10.2. The material is liquefied by the screw 10.1 to form a melt M, which moves towards the nozzle 10.2. The melt M may be composed of plastic, metal, ceramics, etc.

[0021] The injection molding tool 11 comprises at least one cavity 11.1. In the injection stage I, the melt M is injected into the cavity 11.1 through the nozzle 10.2. The melt in the cavity 11.1 is hotter than the material. The melt M flows along a flow path in the cavity 11.1 and fills the cavity 11.1. An increase in pressure occurs. The melt M assumes the shape of the cavity 11.1. In the holding pressure stage II, the melt M in the cavity 11.1 is compressed, and additional melt M is supplied to compensate for the possible volumetric shrinkage. In the cooling stage III, the melt M cools in the cavity 110. The cooled melt M forms the product W. Finally, the product W is removed from the cavity 11.1.

[0022] A component of the injection molding machine 1 is at least one control unit 12. The control unit 12 controls the following machine setting variables S: · Measured speed of screw 10.1, injection speed of the melt M, the temperature of the melt M, Filling time t II The apparatus is configured to control the production of the product W by at least one of For this purpose, the control unit 12 is connected to the injection unit 10 and the injection molding tool 11 by signal lines, and controls the injection unit 10 and the injection molding tool 11 via the signal lines using the machine setting variable S. The control unit 12 generates machine setting data SD for the machine setting variable S. The machine setting data SD is digital data.

[0023] A component of the injection molding tool 11 is a pressure sensor unit 13 for each cavity 11.1. The pressure sensor unit 13 is disposed in the cavity 11.1. The pressure sensor unit 13 is configured to measure the internal mold pressure P of the melt M in the cavity 11.1. The pressure sensor unit may include a piezoelectric pressure sensor, a piezoresistive pressure sensor, a strain gauge, or the like.

[0024] The pressure sensor unit 13 preferably includes a piezoelectric pressure sensor that generates electric polarization charges under the action of the internal mold pressure P. The amount of generated electric polarization charges is proportional to the magnitude of the internal mold pressure P. Typically, the piezoelectric pressure sensor measures the internal mold pressure P with a measurement accuracy of 1%. Furthermore, the piezoelectric pressure sensor typically measures the internal mold pressure P with a time resolution of 0.01 Hz or less. The pressure sensor unit 13 generates sensor data XD(t i The sensor data index i may include an amplifier portion of the piezoelectric pressure sensor for amplifying the electric polarization charge to provide a time t i , i=1...n, the individual sensor data XD(t i ), and the sensor data number n indicates the sensor data XD(t i ) indicates the number of sensor data XD(t i ) at time t i, i=1...n, which follow each other in time and are preferably spaced apart in time from each other. i ) is digital data. Therefore, typically, in a cycle lasting t=10 seconds, the piezoelectric pressure sensor measures the internal mold pressure P at least 1000 times, and obtains at least 1000 pieces of sensor data XD(t i ) time sequence.

[0025] A component of the device V is at least one evaluation unit 14. The evaluation unit 14 comprises at least one data processor 14.1, at least one data memory 14.2, at least one output unit 14.3 and at least one input unit 14.4. At least one computer program CP is stored in the data memory 14.2 and can be loaded into the data processor 14.1. The evaluation unit 14 is connected to the control unit 12 and the pressure sensor unit 13 by signal lines. The evaluation unit 14 receives machine setting data MS generated by the control unit 12 via the signal lines and sensor data XD(t i ) is received.

[0026] By means of a computer program CP loaded into the data processor 14.1, the evaluation unit 14 calculates the sensor data XD(t i , i=1...n) into the data processor 14.1 and calculate the loaded sensor data XD(t i ) by means of a computer program CP loaded into the data processor 14.1, the evaluation unit 14 analyzes the sensor data XD(t i , i=1...n) into the data processor 14.1, and the loaded sensor data XD(t i ) is configured to evaluate

[0027] The sensor data XD(t i The result of the evaluation of the sensor data XD(t i ) is a graph of the sensor data XD(t i, i=1...n) can be expressed as a mathematical function. i ) is the function Y(t i ) can be plotted as a graph. The coordinate system includes an ordinate and an abscissa. The ordinate is the measured internal mold pressure p, and the abscissa is the sensor data XD(t i ) is generated at time t i , i=1...n. The function Y(t i ) graph is the mold internal pressure curve Y(t i ) is also called.

[0028] Sensor data XD(t i ) can be displayed on the output unit 14.3. Preferably, the output unit 14.3 also provides the operator of the injection molding machine 1 with a graphical representation of the sensor data XD(t) displayed on a screen. i This is a screen where you can see a graphical representation of the

[0029] Figure 2 shows the sensor data XD(t i ) is shown as a graph of the sensor data XD(t i ) shows the time progression from injection stage I to cooling stage III. Injection stage I: Initial internal mold pressure P ini At the beginning of the injection phase I, due to the position of the pressure sensor part 13 in the cavity 11.1, the initial internal mold pressure P ini The change in the internal mold pressure curve Y(t i ) shape remains flat. The cavity 11.1 is filled with additional melt M, and in a short period of time the internal mold pressure curve Y(t i ) is the initial internal mold pressure P ini Maximum internal mold pressure P max At the time t when the cavity 11.1 is completely filled with the melt M, II is the filling time t II Injection Phase I ends and holding pressure Phase II begins. During the holding pressure phase II, the melt M is compressed within the cavity 11.1. The injection device 10 applies a holding pressure to the melt M in the cavity 11.1 through the nozzle 10.2 during the holding pressure phase II. Furthermore, the more melt M flows into the cavity 11.1, the more the melt M compensates for the contraction of the cooled melt M. The internal mold pressure curve Y(t i ) first rises sharply and then falls again. The melt M solidifies in the cavity 11.1. The holding pressure phase II begins at the time t III At time t III is the time when the melt M in the area of the nozzle 10.2 of the injection device 10 has solidified to the extent that no more melt M can flow into the cavity 11.1, i.e., the time when the cavity 11.1 is sealed. III Cooling Phase III begins. In cooling stage III, the melt M cools further within the cavity 110. The internal mold pressure curve Y(t i ) continues to decrease. Cooling stage III begins at time t n and the finished product W is removed from the cavity 11.1.

[0030] FIG. 3 shows the sensor data XD(t i ) that covers the entire injection phase I and the beginning of the holding pressure phase II.

[0031] As a mathematical function, the sensor data XD(t i ) can be mathematically differentiated. i ) is the result of analyzing the sensor data XD(t i ) is the differential of the internal mold pressure curve Y(t i ) provides information about the gradient, curvature, etc. of the sensor data XD(t i ) at least the first derivative XD'(t i ) is calculated from the sensor data XD(t i ) at least the second derivative XD”(t i ) is calculated.

[0032] First derivative XD'(t i , i=1...n) is the internal mold pressure curve Y(t i , i=1...n) starts to rise. i And the first derivative XD'(t i ) changes its sign from zero (=0) to positive (>0). Then, at the start of injection phase I, t i The internal mold pressure curve Y(t i ) is flat. The internal mold pressure curve Y(t i ) is substantially monotonically increasing, i.e., the internal mold pressure curve Y(t i ) is approximately constant.

[0033] Second derivative XD”(t i ) is the internal mold pressure curve Y(t i ) provides information about the curvature of the filling point t II So, the second derivative XD”(t II The sign of ) changes from zero (=0) to positive (>0). At the filling time t II The internal mold pressure curve Y(t i ) rises at the filling time t II The internal mold pressure curve Y(t i ) curves to the left. At the filling time t II Now, the cavity 11.1 is completely filled with melt M and the filling pressure P II is measured.

[0034] Here, the flow behavior of the melt M in the cavity 11.1 satisfies the Hagen-Poiseuille law: the pressure rise ΔP of the melt M during filling of the cavity 11.1 is proportional to the product of the viscosity η and the volumetric flow rate Q.

number

[0035] Viscosity index K η is the sensor data XD(t i ) can be mathematically determined by integrating the sensor data XD(t i The result of the evaluation of the sensor data XD(t i , i=1...n). The evaluation unit 14 calculates the integral of the filling time t II and the starting time t i The sensor data XD(t i ) definite integral I(t i ) is calculated.

number

[0036] Viscosity index K η is the definite integral I(t i ) is expressed graphically as the viscosity index K η In Figure 3, the internal mold pressure curve Y(t i , i=1...n) at the filling time t II and the starting time t i The area between the abscissa and INT is

[0037] By means of a computer program CP loaded into the data processor 14.1, the evaluation unit 14 calculates the sensor data XD(t i ) and evaluate the target viscosity index K η * Determine the target viscosity index K η *is proportional to the viscosity η at which the injection molding machine 1 produces a high-quality product, a so-called non-defective part. Whether a product W is non-defective can be evaluated by quality control, as indicated by at least one quality characteristic, such as a specified dimensional accuracy, the absence of parting lines, or casting defects (short shots). If the quality characteristic is not met, the part is considered defective.

[0038] Preferably, the target viscosity index K η * is determined in a test run during the setup of the injection molding machine 1 before the actual operation of the injection molding machine 1 begins. η * is stored in the data memory 14.2.

[0039] During operation of injection molding machine 1, viscosity index K η is determined for each cycle during the production of product W. It is determined in real time, i.e., before the next cycle in the time series begins, the viscosity index K of the current cycle is calculated. η The determination of the viscosity index K determined for the cycle is completed. η can be stored in the data memory 14.2.

[0040] By means of the computer program CP loaded into the data processor 14.1, the evaluation unit 14 calculates the target viscosity index K η * is loaded into the data processor 14.1 and the viscosity index K determined for the current cycle is η Loaded target viscosity index K η * The computer program CP loaded in the data processor 14.1 allows the evaluation unit 14 to compare the target viscosity index K η * is loaded into the data processor 14.1 and the viscosity index K determined for the current cycle is η Loaded target viscosity index K η * It is configured to compare with.

[0041] The viscosity index K determined for the current cycle η is the target viscosity index K η * If the comparison shows that the product W produced in the current cycle is a good product, the evaluation unit 14 generates a good product marking GM. The product W produced in the current cycle is marked as a good product by the good product marking GM. The good product marking GM can be stored in the data memory 14.2.

[0042] By comparison, the viscosity index K determined for the current cycle η Target viscosity index K η * If a predetermined deviation from BM is found, the product W produced in the current cycle is defective and the evaluation unit 14 generates a defective product marking BM. The product W produced in the current cycle is marked as defective by the defective product marking BM. The defective product marking BM can be stored in a data memory 14.2.

[0043] The data memory 14.2 stores injection molding expertise as specialized data KD. The specialized data KD is digital data. The viscosity index K determined for the current cycle η is the target viscosity index K η * If it is different from the viscosity index K determined in the current cycle, the evaluation unit 14 loads the specialized data KD into the data processor 14.1 by means of the computer program CP loaded into the data processor 14.1. η By means of the computer program CP loaded into the data processor 14.1, the evaluation unit 14 uses the loaded specialized data KD to generate corrective machine setting data CD for the viscosity index K determined in the current cycle. η The data processor 14.1 is configured to load the specialized data KD into itself and to use the loaded specialized data KD to generate corrective machine setting data CD for .

[0044] The corrected machine setting data CD is the viscosity index K determined for the current cycle. η Target viscosity index K η * is used to correct for deviations from

[0045] The deviation is the viscosity index K η is the target viscosity index K η * If the value is too low compared to the value of the machine setting variable S, the corrective machine setting data CD is - reducing the metering speed of screw 10.1; Reducing the injection speed of the melt M; Reducing the temperature of the melt M, The filling time t from injection stage I to holding pressure II II To shorten Command at least one of the following:

[0046] However, the deviation is due to the viscosity index K η is the target viscosity index K η * If the correction machine setting data CD is too high compared to the machine setting variable S: Increasing the metering speed of the screw 10.1, Increasing the injection speed of the melt M; increasing the temperature of the melt M, Filling time t from injection stage I to holding pressure stage II II Delaying Command at least one of the following:

[0047] The corrected machine setting data CD is the viscosity index K determined for the current cycle. η The corrected machine setting data CD is an instruction to the control unit 12 on how to correct the deviation of the machine setting data CD. The corrected machine setting data CD is digital data. The control unit 12 receives the corrected machine setting data CD generated by the evaluation unit 14 via a signal line.

[0048] The control unit 12 calculates the viscosity index K determined for the current cycle.η For this purpose, the control unit 12 is configured to use the corrective machine setting data CD to correct deviations in the following corrective machine setting variables CS: - Corrected measuring speed of screw 10.1, Corrected injection speed of melt M, Corrected temperature of the melt M, Corrected filling time t from injection stage I to holding pressure stage II II Generate at least one of the following: The corrected machine setting variable CS is used to determine whether the immediately following cycle or any subsequent cycle will produce the corrected viscosity index K η Guaranteed to work with '.

[0049] The monitoring of the operation of the injection molding machine 1 is repeated for each injection molding cycle. Therefore, the evaluation unit 14 calculates the corrected viscosity index K determined for the immediately following cycle. η 'Target viscosity index K η * In case of a match or deviation, a step of generating a good product marking GM or a bad product marking BM and the viscosity index K determined in the current cycle are performed. η In this example, the generation of the corrected machine setting data CD described above is repeated. [Explanation of symbols]

[0050] 1 injection molding machine 10 Injection device 10.1 Screw 10.2 Nozzle 11 Injection molding tools 11.1 Cavity 12 Control Unit 13 Pressure sensor section 14 Evaluation Section 14.1 Data Processor 14.2 Data Memory 14.3 Output Section 14.4 Input section BM defective product marking CD correction machine setting data CP Computer Program CS Correction Machine Setting Variable ΔP Pressure increase ΔT time difference η Viscosity K η viscosity index K η 'Corrected viscosity index K η * Target viscosity index GM Good Product Marking i index of sensor data I. Injection stage II. Pressure holding stage III Cooling stage INT area I(t i ) definite integral KD Expertise M melt n Sensor data number P Internal mold pressure P ini Initial internal mold pressure P II Filling Pressure P max Maximum internal mold pressure S Machine setting variables SD Machine setting data t period t i time Start of t1 injection phase t i Starting point t II Filling time t III Sealing point t n End of cooling phase V device W Products XD(t i ) Sensor data XD'(t i ) first derivative XD”(t i ) second derivative Y(t i ) Internal mold pressure curve

Claims

1. The viscosity index (K) of the melt (M) in the injection molding tool (11) η 1. A method (11.1) for determining a mold pressure (P) of the melt (M) in the injection molding tool (11) comprising: a pressure sensor unit (13) arranged in the cavity (11.1); the pressure sensor unit (13) measuring an internal mold pressure (P) of the melt (M) in the cavity (11.1); and a sensor data (XD(t)) for the measured internal mold pressure (P). ｉ )), and the injection molding tool (11) generates the sensor data (XD(t ｉ )))), said evaluation comprising: The sensor data (XD(t ｉ )) the first derivative (XD'(t Ｉ The time when the sign of t changes from zero (=0) to positive (>0) Ｉ ) The sensor data (XD(t ｉ )) second derivative (XD"(t ＩＩ The time point at which the sign of the ＩＩ ) The filling time (t ＩＩ Internal mold pressure (P ＩＩ ) and the start time (t Ｉ Internal mold pressure (P ｉｎｉ ) calculating the pressure rise (ΔP) between The pressure rise (ΔP) and the filling time (t ＩＩ ) and the start time (t Ｉ ) and the viscosity index (K η ) and A method characterized by

2. The viscosity index (K η ) is the time of filling (t ＩＩ ) and the start time (t Ｉ ) and the sensor data (XD(t ｉ , i = 1...n)) ｉ 2. The method of claim 1, wherein the calculated value is calculated from

3. The sensor data (XD(t ｉ )) is a function in the coordinate system (Y(t ｉ )), the coordinate system includes an ordinate and an abscissa, where the ordinate represents the measured internal mold pressure (P) and the abscissa represents the generated sensor data (XD(t ｉ , i=1 . . . n)), The viscosity index (K η ) is the time of filling (t ＩＩ ) and the start time (t Ｉ ) and the function (Y(t ｉ 2. The method of claim 1, wherein the area (INT) is calculated as the area under the graph of

4. said injection molding tool (11) being a component of an injection molding machine (1) for producing at least one product (W); The evaluation unit (14) evaluates the sensor data (XD(t ｉ )) to determine a target viscosity index (K) that allows the injection molding machine (1) to produce a high-quality product (W), i.e., a good product. η ＊ 4. The method according to claim 1, further comprising determining a time period for which the time period is longer than the predetermined time period.

5. The production of the product (W) is a cyclical process in which the injection molding machine (1) repeatedly produces the product (W) in repeated cycles over time, and the evaluation unit (14) evaluates the viscosity index (K) determined for the current cycle. η ) to the target viscosity index (K η ＊ ) and is configured to compare The viscosity index (K) determined for the current cycle η ) is the target viscosity index (K η ＊ If the comparison indicates that the product (W) produced in the current cycle matches the product (W), then the product (W) produced in the current cycle is good and a good product marking (GM) is generated; The viscosity index (K) determined for the current cycle η ) is the target viscosity index (K η ＊ 5. The method of claim 4, wherein if the comparison indicates a deviation from the current cycle (W), the product (W) produced in the current cycle is defective and a defective marking (BM) is generated.

6. The viscosity index (K) determined for the current cycle η ) is the target viscosity index (K η ＊ If the comparison indicates that the viscosity index (K) determined in the current cycle deviates from the η 6. The method according to claim 5, wherein the specialization data (KD) are used to generate corrective machine setting data (CD) for the .

7. 7. The method according to claim 6, characterized in that the injection molding machine (1) comprises at least one control unit (12), which is configured to control the production of the product (W) by means of at least one machine setting variable and to correct deviations of the viscosity (η) determined for the current cycle according to the correcting machine setting data (CD) for the production of the product (W) by at least one correcting machine setting variable (CS).

8. The viscosity index (K) of the melt (M) in the injection molding tool (11) η ), which in addition to the injection molding tool (11) further comprises a pressure sensor unit (13) and at least one evaluation unit (14), The injection molding tool (11) includes at least one cavity (11.1), into which the melt (M) can be injected, and the cavity (11.1) can be filled with the injected melt (M). The pressure sensor unit (13) is disposed in the cavity (11.1) and measures an internal mold pressure (P) of the injected melt (M) in the cavity (11.1), and generates sensor data (XD(t)) for the measured internal mold pressure (P). ｉ )), and the evaluation unit (14) generates the sensor data (XD(t ｉ ) wherein said evaluation comprises: The sensor data (XD(t ｉ )) the first derivative (XD'(t Ｉ The time when the sign of t changes from zero (=0) to positive (>0) Ｉ ) is determined by the evaluation unit (14), The sensor data (XD(t ｉ , i=1 . . . n)) ＩＩ The time point at which the sign of the ＩＩ ) is determined by the evaluation unit (14), The filling time (t ＩＩ Internal mold pressure (P ＩＩ ) and the start time (t Ｉ Internal mold pressure (P ｉｎｉ The evaluation unit (14) calculates the pressure rise (ΔP) between the The pressure rise (ΔP) and the filling time (t ＩＩ ) and the start time (t Ｉ ) and the viscosity index (K η ) is calculated by the evaluation unit (14). The device (V) is characterized in that:

9. The evaluation unit (14) determines the filling time (t ＩＩ ) and the start time (t Ｉ ) and the sensor data (XD(t ｉ )) definite integral (I(t ｉ )) to the viscosity index (K η 9. The device (V) according to claim 8, characterized in that it calculates

10. The evaluation unit (14) evaluates the sensor data (XD(t ｉ )) as a function in the coordinate system (Y(t ｉ )), the coordinate system includes an ordinate and an abscissa, where the ordinate represents the measured internal mold pressure (P) and the abscissa represents the generated sensor data (XD(t ｉ , i=1 . . . n)), The evaluation unit (14) determines the filling time (t ＩＩ ) and the start time (t Ｉ ) and the function (Y(t ｉ The viscosity index (K) is calculated as the area (INT) under the graph of η 9. The device (V) according to claim 8, characterized in that it calculates

11. said injection molding tool (11) being a component of an injection molding machine (1) for producing at least one product (W); The evaluation unit (14) evaluates the sensor data (XD(t ｉ )) to determine a target viscosity index (K) that allows the injection molding machine (1) to produce a high-quality product (W), i.e., a good product. η ＊ 9. The device (V) according to claim 8, characterized in that it is adapted to determine the

12. The evaluation unit (14) calculates the viscosity index (K η ) to the target viscosity index (K η ＊ ) and is configured to compare The viscosity index (K) determined for the current cycle η ) is the target viscosity index (K η ＊ If the comparison indicates that the viscosity index (K) determined for the current cycle matches the viscosity index (K), the product (W) produced in the current cycle is a good product, and the evaluation unit (14) generates a good product marking (GM) and η ) is the target viscosity index (K η ＊ 12. The device (V) according to claim 11, characterized in that if the comparison indicates that the product (W) produced in the current cycle deviates from the standard deviation (D) of the product (W), the product (W) produced in the current cycle is defective and the evaluation unit (14) generates a defective marking (BM).

13. The viscosity index (K) determined for the current cycle η ) the target viscosity index (K η ＊ If the comparison indicates a predetermined deviation from the viscosity index (K) determined in the current cycle, the evaluation unit (14) η 13. Device (V) according to claim 12, characterized in that it uses the specialized data (KD) to generate corrective machine setting data (CD) for the

14. The deviation is the viscosity index K η is the target viscosity index K η ＊ , the corrected machine setting data (CD) is calculated based on the following machine setting variables (S): - reducing the metering speed of the screw (10.1); - reducing the injection speed of the melt (M); - reducing the temperature of the melt (M), The filling time (t) from the injection stage (I) to the holding pressure stage (II) ＩＩ ) to shorten or Alternatively, the deviation is η is the target viscosity index K η ＊ , the corrected machine setting data (CD) is calculated based on the following machine setting variables (S): Increasing the metering speed of the screw (10.1); Increasing the injection speed of the melt (M); - increasing the temperature of the melt (M); The filling time (t) from the injection stage (I) to the holding pressure stage (II) ＩＩ ) to delay 14. Device (V) according to claim 13, characterized in that it commands at least one of the following:

15. The injection molding machine (1) has the following machine setting variables (S): - the measured speed of said screw (10.1), - the injection speed of the melt (M); the temperature of the melt (M), The filling time (t) from the injection stage (I) to the holding pressure stage (II) ＩＩ ) and configured to control the production of said product (W) by at least one of the following corrective machine setting variables (CS): - corrected measured speed of said screw (10.1), - the corrected injection speed of the melt (M), the correction temperature of the melt (M), Corrected filling time (t) from injection stage (I) to holding pressure stage (II) ＩＩ ) the viscosity index (K) determined for the current cycle in accordance with instructions of the corrected machine setting data (CD) for the production of the product (W) by at least one of η 15. Device (V) according to claim 13 or 14, characterized in that it comprises at least one control (12) adapted to correct deviations of the

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