Application device and associated calibration method

Abstract

The invention relates to an application device for applying an application agent (e.g. sealant) to a component (e.g. a motor vehicle body component), comprising a nozzle applicator having a plurality of nozzles (2, 3) for dispensing the application agent through the nozzles (2, 3) and a plurality of control valves (6, 7) for controlling the dispensing of the application agent through the respective nozzles (2, 3), wherein a control valve (6, 7) is associated with each of the individual nozzles (2, 3), and comprising a valve controller (11) for controlling the control valves (6, 7) of the nozzle applicator (1) by way of control signals (s1, s2), wherein the individual control valves (6, 7) react to the control signals (s1, s2) with different switching delays on account of their component variation, and the valve controller (11) at least partially compensates for the switching delays of the control valves (6, 7) in each case by means of a valve-specific temporal offset of the control signals (s1, s2). According to the invention, the valve controller (11) determines the temporal offset for the individual control signals (s1, s2) of the control valves (6, 7) in a calibration method by means of comparative measurements on the individual control valves (6, 7) without measuring the applied application agent on the component. The invention also relates to a calibration method for such an application device.

Description

[0001] DESCRIPTION

[0002] Application device and associated calibration procedure

[0003] Technical field of the invention

[0004] The invention relates to an application device for applying an application agent to a component, in particular for applying a sealant to a motor vehicle body component. Furthermore, the invention relates to a calibration method for compensating for valve-specific differences in the switching delays of control valves of a nozzle applicator with multiple nozzles for applying an application agent to a component.

[0005] Background of the invention

[0006] In modern paint shops for automotive body components, corrosion protection measures are applied in addition to the actual paint application. For example, sealant is applied to flanged seams to prevent moisture from penetrating the seam and thus prevent corrosion. Nozzle applicators, also known as droplet applicators, are used to apply the sealant. These nozzle applicators typically have five nozzles arranged side-by-side in a row, each individually controlled by a valve. The individual control valves are activated by signals at a specific frequency to apply the appropriate number of droplets.

[0007] The problem here is that the control valves, due to their component control, react to the control signals with different switching delays, resulting in varying sizes of the dispensed sealant droplets. In the prior art, these differing switching delays of the individual control valves are compensated for by a valve-specific time offset of the control signals. Thus, if a particular control valve reacts to its corresponding control signal with a relatively large switching delay, the corresponding control signal is advanced by the valve-specific time offset so that the control valve opens as simultaneously as possible with the other control valves. In the prior art, the individual valve-specific time offsets for compensating the different switching delays of the control valves are determined during injection tests with the respective applicator.The nozzle applicator applies drops of sealant onto a spray plate, and the size of each drop is then measured. Based on the size of these drops, the timing offset for each control valve is determined. This process of determining the timing offsets for the control signals can be repeated iteratively until the drops on the spray plate are all the same size.

[0008] A disadvantage of this well-known method for determining the time offset for the individual control valves is, firstly, the relatively large effort required to carry out the injection tests.

[0009] Another disadvantage is that adjusting the time offsets depending on the observed size of the drops on the spray plate requires a technical understanding of the underlying principles and can therefore only be carried out by appropriately trained operating personnel.

[0010] Furthermore, adjusting the time offset for the individual control signals during injection molding trials usually requires several iterative loops until the correct offsets are found.

[0011] Finally, it is also a disadvantage that the time offsets have to be recalculated after every change to the control, which leads to a great deal of effort.

[0012] For the general technical background of the invention, reference should also be made to EP 3 171 998 Bl, DE 10 2009 001 532 Al and EP 2485889 Bl. However, these patent publications concern completely different technical fields.

[0013] Description of the invention

[0014] The invention is therefore based on the objective of improving the determination of the temporal offsets of the control signals. This objective is achieved by an application device according to the invention or by a corresponding calibration method according to the independent claims.

[0015] The application device according to the invention serves to apply an application agent to a component. In a preferred embodiment of the invention, the application agent is a sealant, while the coated component is a motor vehicle body component. However, the invention is not limited to these examples with regard to the type of application agent or the type of coated component.

[0016] In accordance with the prior art described above, the application device according to the invention also has a nozzle applicator with several nozzles for applying the application agent through the nozzles. Each of the nozzles is associated with a control valve that controls the material dispensing through the corresponding nozzle.

[0017] Furthermore, the application device according to the invention, in accordance with the prior art described above, features a valve control system that actuates the control valves of the nozzle applicator with control signals. Due to component variations, the individual control valves react to the control signals with different switching delays, as already explained in the prior art. In the application device according to the invention, these different switching delays of the individual control valves are at least partially compensated by valve-specific time offsets of the control signals, as already described in the prior art.

[0018] The invention is distinguished by its unique method of determining the temporal offsets for the control signals. Specifically, the temporal offsets of the control signals for compensating for the different switching delays of the control valves are determined not by complex spraying tests on a spray plate, but rather through a calibration process involving comparative measurements on the individual control valves without measuring the applied material on the component (e.g., the spray plate). The invention thus eliminates the need for the complex spraying tests required to determine the valve-specific temporal offsets of the control signals.

[0019] The application device according to the invention preferably comprises at least one sensor (e.g., pressure sensor, flow rate sensor) that measures an application parameter, which allows the individual valve-specific switching delays of the control valves to be taken into account. In the calibration process, the valve control then determines the time offset for the individual control signals as a function of the application parameters measured by the sensor during the comparative measurements.

[0020] The invention essentially comprises three different variants for determining the time offsets for the control signals to compensate for the individual switching delay of the control valves. These three variants of the invention are described below in succession.

[0021] In a first embodiment of the invention, the sensor is a pressure sensor that measures the material pressure of the application medium. The application medium is preferably conveyed from a metering pump to the nozzle applicator via a common supply line. The pressure sensor then preferably measures the material pressure in the common supply line at the inlet of the nozzle applicator. The valve control then performs comparative measurements at the individual control valves, separately for each control valve and sequentially, in order to determine the individual switching delays of each control valve.In each comparative measurement, the valve control system activates the respective control valve with the same control signal as in the other comparative measurements. The application medium is also supplied to the nozzle applicator with the same flow rate in each comparative measurement, ensuring that the material pressure measurement is influenced as little as possible only by the different switching delays of the control valves. The valve control system then sets the time offset for the individual control signals based on the deviations between the material pressures measured for each control valve during the comparative measurements. The material pressures measured for each control valve during the comparative measurements thus serve as an indicator of the individual switching delay of each control valve.

[0022] When calibrating with a defined delivery rate for a defined time, the slopes of the pressure curves of the individual control valves (e.g., needle valves) are preferably compared. Due to the continuous switching—i.e., opening and closing—of the control valves (e.g., needle valves) at specific frequencies, only a certain quantity can be dispensed. If the metering system, which delivers the medium to the nozzle applicator, delivers a higher quantity than a control valve (e.g., needle valve) allows through continuous switching, the pressure in the system / at the nozzle applicator will steadily increase. This is because the delivery flow set by the metering system is slowed down by the interruptions of the control valve (e.g., needle valve). In conventional systems that operate with a constant application rate (i.e.,When one or more needles are opened at the beginning of a seam and closed at the end, it can be observed that stable pressure conditions are established after a certain time. With the conventional method, the slope of the pressure curve then reaches zero after a certain period. This would not be the case with the described continuous switching method, and the curve would rise throughout the entire discharge period. This calibration method is designed to exploit precisely this behavior. If a control valve (e.g., a needle valve) switches with a delay, it exhibits a different ratio between the duration the needle is closed and the duration it is open compared to the other control valves. Therefore, during the calibration process, the individual control valves are actuated sequentially with the same switching curve.The open-to-close ratio can be derived from the pressure curve relative to the pressure curves of the other control valves. Any difference in the pressure curves should be adjusted using an offset. This shifts the open-to-close ratio. If the pressure rise is the same for all control valves—within a certain tolerance—the application result will also be the same. After the initial evaluation of the pressure curves, the application system should automatically set offsets and repeat the process. After a further evaluation, offsets are again applied to the valve switching times if the pressure curves differ.

[0023] In a second embodiment of the invention, the sensor is not a pressure sensor, but a flow rate sensor that measures the flow rate of the application medium to the nozzle applicator. Here, too, the valve control performs comparative measurements at the individual control valves, with these comparative measurements being carried out separately for each control valve and sequentially. During each comparative measurement, the valve control applies the same control signal to the individual control valves, and each control valve is supplied with the same material pressure of the application medium as in the other comparative measurements, so that the different flow rates are influenced, as far as possible, only by the different switching delays of the individual control valves.In each comparative measurement, the flow rate through the respective control valve is measured by the flow rate sensor. The valve control then determines the time offset for the individual control signals of the control valves depending on the flow rate measured for each control valve during the comparative measurements. The flow rates measured for each control valve during these comparative measurements thus serve as an indicator of the individual switching delay of each control valve. In this second embodiment of the invention, material is also dispensed sequentially for a defined time using each control valve. However, in this case, a defined pressure is regulated / maintained by the metering system. After each step, the amount of material dispensed within the set time is recorded. These values ​​are then compared.If the dispensed quantity from one control valve differs from the others, the ratio between "open" and "closed" must be adjusted for that control valve. If all values ​​differ, the control valve with the middle measured material quantity is used as the reference. For a nozzle applicator with five nozzles and corresponding five control valves, this would mean that two control valves would have to be adjusted so that the offset reduces the actuation time, and the actuation time of the other two control valves would have to be increased. The advantage of this embodiment of the invention is that there is no risk of generating excessive pressure in the system during calibration, thus avoiding the need to abort the calibration process.

[0024] In a third embodiment of the invention, the sensor is a pressure sensor that measures the material pressure of the application medium, for example, in the common supply line at the inlet of the nozzle applicator. Here, too, the valve control system performs comparative measurements at the individual control valves, separately for each valve and sequentially, in order to determine the individual switching delays of the control valves. During the individual comparative measurements, the control valves are actuated with the same control signals and subjected to the same material pressure, which is regulated by a pressure regulator to a predetermined setpoint. The control deviation between the predetermined setpoint of the material pressure and an actual material pressure measured by the pressure sensor is then determined.The valve control then determines the time offset for the individual control signals based on the control deviations measured during comparative measurements for the individual control valves. The control deviations measured during these comparative measurements thus serve as an indicator of the individual switching delay of each control valve.

[0025] This third embodiment of the invention is comparable to the second embodiment. Here, dynamic pressure control is preferably implemented using a variable-speed (P) controller with tolerances and a slow response time for the set pressure. However, instead of comparing the delivered quantities, the resulting pressure differences are compared. This utilizes the property that the higher the delivery rate, the greater the difference between the set pressure and the resulting pressure. The difference between the resulting pressure curves is less than 1 bar. If a control valve switches with a delay, the dynamic pressure is higher for this control valve than for a control valve that switches readily. The ratio between "open" and "closed" is not the same.

[0026] The individual control valves are preferably needle valves with a movable valve needle which, depending on its position, opens or closes a valve seat, thereby enabling or blocking the application of the application agent through the associated nozzle. However, the invention is not limited to such needle valves with regard to the design of the control valves, but can also be implemented with other valve types.

[0027] It should also be mentioned that the control valves are preferably electrically driven, for example by a piezo actuator or a magnetic actuator, to name just two examples.

[0028] Furthermore, it should be noted that the individual nozzles of the nozzle applicator preferably have a common material supply line, and the sensor is arranged in this common material supply line, for example, between the nozzle applicator and a metering pump that supplies the nozzle applicator with the application agent. However, within the scope of the invention, it is also possible, in principle, for the sensor to be integrated into the nozzle applicator.

[0029] Furthermore, it should be mentioned that the nozzle applicator preferably has more than two, five, ten, 20 or even more than 50 nozzles, wherein the nozzles in the nozzle applicator can be arranged in a straight line, in particular equidistantly.

[0030] The control signals for controlling the control valves of the nozzle applicator are preferably switching curves that alternate between on-times with the control valve open and off-times with the control valve closed, wherein the control signals can have a switching frequency of at least 1 Hz, 2 Hz, 5 Hz, 10 Hz, 20 Hz, 50 Hz, 100 Hz or 200 Hz.

[0031] Furthermore, it should be noted that the nozzle applicator is preferably a droplet applicator that dispenses droplets of the application agent. However, within the scope of the invention, it is also possible for the nozzle applicator to dispense continuous jets of the application agent from the individual nozzles, which are aligned in the direction of the jet. In addition to the application device according to the invention described above, the invention also includes a calibration method for compensating for switching delays of the control valves of the nozzle applicator. The individual process steps of the calibration method according to the invention are already described in the preceding description of the operation of the application device according to the invention, so a separate description of the individual process steps is unnecessary.

[0032] In addition, it should be mentioned that the comparative measurements on the control valves and the calculation of the time offset for the individual control signals are preferably repeated iteratively until the different switching delays of the control valves are compensated by the time offsets down to residual differences of at most 500 ps, ​​250 ps, ​​100 ps, ​​50 ps, ​​40 ps, ​​25 ps or 10 ps.

[0033] Other advantageous embodiments of the invention are characterized in the dependent claims or are explained in more detail below together with the description of the preferred embodiments of the invention with reference to the figures.

[0034] Brief description of the drawings

[0035] Figure 1A shows a simplified schematic representation of an application device according to the first variant of the invention.

[0036] Figure 1B shows a flowchart to explain the calibration method according to the first variant of the invention.

[0037] Figure 2A shows a simplified schematic representation of an application device according to the second variant of the invention.

[0038] Figure 2B shows a flowchart to explain the calibration method according to the second variant of the invention.

[0039] Figure 3 shows a flowchart to explain the calibration method according to the third variant of the invention.

[0040] Figure 4 shows a diagram illustrating the needle stroke of various needle valves as a function of time.

[0041] Detailed information

[0042] The first variant of the invention, which is shown in Figures 1A and 1B, will now be described.

[0043] Figure 1A shows an application device according to the invention with a nozzle applicator 1 having several nozzles 2, 3 for each dispensing a droplet jet 4, 5 of a sealant. For the sake of simplicity, only the two nozzles 2, 3 of the nozzle applicator 1 are shown in the drawing to facilitate understanding of the invention. In practice, however, the nozzle applicator 1 typically has additional nozzles besides the nozzles 2, 3.

[0044] Furthermore, the nozzle applicator 1 has an associated control valve 6, 7 for each of the nozzles 2, 3, which controls the material discharge through the associated nozzle 2, 3.

[0045] The sealant to be applied is supplied to the nozzle applicator 1 by a metering pump 8 via a common supply line 9.

[0046] In the common supply line 9, a pressure sensor 10 is arranged between the metering pump 8 and the nozzle applicator 1, which measures a material pressure p in the common supply line 9 and reports it to a control unit 11 with a valve control.

[0047] The control unit 11 controls the two control valves 6, 7 with associated control signals sl, s2. In addition, the control unit 11 also controls the metering pump 8 and specifies a flow rate Q with which the metering pump 8 delivers the sealant to be applied to the nozzle applicator 1.

[0048] As explained in the introduction regarding the state of the art, the control valves 6 and 7 react to the control signals sl and s2 with different switching delays due to unavoidable component control. The control unit 11 therefore determines suitable time offsets for the control signals sl and s2 in order to compensate as effectively as possible for the individual, valve-specific switching delays of the control valves 6 and 7. These time offsets are determined within the framework of a calibration procedure, which is described below with reference to the flowchart in Figure 1B. The calibration procedure involves a comparative measurement S1 on the first control valve.

[0049] 6 and then a comparative measurement S2 is carried out on the second control valve 7.

[0050] During the first comparative measurement S1 at the control valve 6, the control unit 11 controls the metering pump 8 in one step Sl.l so that the sealant to be applied is conveyed to the nozzle applicator 1 with a flow rate Q that is as constant as possible.

[0051] In a second step S1.2, the control valve 6 is then controlled by the control unit 11 according to a predetermined control curve, whereby the control curve defines the opening and closing times of the control valve 6.

[0052] In step S1.3, the material pressure is then measured by the pressure sensor 10 when the first control valve 6 is activated and a first pressure curve is recorded.

[0053] In the second comparative measurement S2, the same steps are then performed for the second control valve.

[0054] 7 repeated.

[0055] During the evaluation in step S3, the pressure curves recorded during the comparative measurements are compared, and the time offsets for controlling the two control valves are determined depending on the comparison of the pressure curves.

[0056] To avoid misunderstandings, it should be noted that the comparative measurements Sl and S2 for the two control valves 6 and 7 are recorded separately and sequentially. During comparative measurement Sl on control valve 6, the other control valve 7 remains permanently closed. Similarly, during comparative measurement S2 on the other control valve 7, control valve 6 also remains closed.

[0057] The second embodiment of the invention, illustrated in Figures 2A and 2B, will now be described. The second embodiment partially corresponds to the first embodiment described above, so reference is made to the preceding description to avoid repetition, using the same reference numerals for corresponding details. A special feature of the second embodiment is that a flow sensor 12 is arranged in the common supply line 9 between the metering pump 8 and the nozzle applicator 1, instead of the pressure sensor 10. This flow sensor measures the flow rate Q of the sealant to be applied to the nozzle applicator 1.

[0058] A further special feature of the second embodiment of the invention is that the material pressure p in the common supply line 9 is regulated to a predetermined setpoint pson by a P-controller 13. For this purpose, the application device has a pressure sensor 14 which measures an actual value PIST of the material pressure in the common supply line 9 and forwards it to a subtractor 15, which calculates a control deviation Ap = pson - PIST between the predetermined setpoint pson and the measured actual value PIST and forwards it to the P-controller 13 so that the P-controller 13 can control the metering pump 8 in such a way that the control deviation Ap is compensated for, so that the material pressure in the common supply line 9 corresponds as closely as possible to the predetermined setpoint pson.

[0059] In this embodiment of the invention, the control unit 11 also performs a calibration procedure to determine a time offset for each of the individual control valves 6, 7, which compensates for the individual valve-specific switching delay of the respective control valve 6, 7. The individual process steps of the calibration procedure according to the invention are shown in Figure 2B.

[0060] The control unit performs 11 comparative measurements SI, S2 on the two control valves 6, 7.

[0061] In both comparative measurements, the sealant to be applied is conveyed to nozzle applicator 1 at a constant and regulated material pressure p. It should be noted that the specified material pressure p is the same in both comparative measurements SI and S2.

[0062] Furthermore, in the two comparison measurements SI, S2, the two control valves 6, 7 are each controlled with a predetermined control curve, whereby the control curves are identical in the two comparison measurements SI, S2.

[0063] In addition, during the two comparative measurements SI, S2 for the two control valves 6, 7, a measurement of the flow rate Q1 or Q2 is carried out and from this a determination of the material quantity VI or V2, which is applied during the control operation during the comparative measurements SI, S2.

[0064] During the evaluation in step S3, the two material quantities VI, V2 are compared in the two comparison measurements SI, S2 and the time offsets for the individual control valves 6, 7 are determined depending on the comparison.

[0065] Figure 3 shows a flowchart to illustrate the calibration procedure according to the third invention variant, wherein this third invention variant functions with the application device shown in Figure 2A.

[0066] In this third embodiment of the invention, the control valves 6 and 7 are each supplied with the same material pressure p and controlled by the same control curve. During the two comparative measurements SI and S2, the control deviation Apl and Ap2, respectively, is measured, which is present at the P-controller 13 and must be compensated for by it. In the evaluation step S3, the two control deviations Apl and Ap2 are then compared, and the time offsets for compensating the individual valve-specific switching delay are then determined based on this comparison.

[0067] Figure 4 shows a diagram illustrating the different switching behavior of two needle valves. The x-axis represents the time during a switching operation, while the y-axis shows the needle stroke. The diagram shows that the needle valves react to their actuation at different speeds and exhibit a switching delay At. Needle valve 2 is therefore delayed relative to needle valve 1 by the switching delay At, which should be compensated for by a corresponding time offset.

[0068] Advantages of

[0069] The invention enables the automated compensation of differences in the switching behavior of multiple control valves (e.g., needle valves). The prior art's requirement for manually adjusting the timing offsets for individual control valves during injection molding trials is eliminated, thus saving time during commissioning, replacement, or maintenance of the system. Furthermore, the appearance of the applied seam is improved due to a more homogeneous droplet distribution. Reference numerals:

[0070] I Nozzle applicator

[0071] 1, 3 nozzles of the nozzle applicator

[0072] 4, 5 droplet jets

[0073] 6, 7 Control valves of the nozzle applicator

[0074] 8 Dosing pump

[0075] 9 Supply line

[0076] 10 pressure sensor

[0077] II Control unit with valve control

[0078] 12 Flow sensor

[0079] 13 P-controllers for pressure control

[0080] 14 Pressure sensor

[0081] 15 Subtractors sl, s2 Control signals for the control valves p Material pressure at the nozzle applicator

[0082] Q. Flow rate to the nozzle applicator

[0083] PIST Actual value of the sealant pressure at the nozzle applicator

[0084] Psou target value of the sealant pressure at the nozzle applicator

[0085] Ap pressure deviation

Claims

REQUIREMENTS 1. Application device for applying an application agent to a component, in particular for applying a sealant to a motor vehicle body component, comprising a) a nozzle applicator with a) several nozzles (2, 3) for dispensing the application agent through the nozzles (2, 3) and a2) several control valves (6, 7) for controlling the dispensing of the application agent through the respective nozzles (2, 3), wherein each nozzle (2, 3) is assigned a control valve (6, 7), and b) a valve control (11) for controlling the control valves (6, 7) of the nozzle applicator (1) with control signals (sl, s2), wherein b) the individual control valves (6, 7) react to the control signals (sl, s2) with different switching delays due to their component variations, and b2) the valve control (11) adjusts the switching delays of the control valves (6, 7) by a valve-specific time offset. the control signals (sl, s2) are at least partially compensated,characterized in that c) the valve control (11) determines the time offset for the individual control signals (s1, s2) of the control valves (6, 7) in a calibration procedure by comparative measurements on the individual control valves (6, 7) without measuring the applied application medium on the component.

2. Application device according to claim 1, characterized in that a) at least one sensor (10, 12, 14) is provided which measures an application parameter (p, Q), in particular a) a pressure sensor (10) for measuring the material pressure (p) or a2) a flow rate sensor (12) for measuring the flow rate (Q) of the application medium, and b) that the valve control (11) in the calibration procedure determines the offset for the individual control signals (s1, s2) depending on the application parameters that are measured by the sensor (10, 12, 14) during the comparative measurements, c) that the sensor (10, 12, 14) preferably in a common The supply line (9) to the nozzle applicator (1) measures.

3. Application device according to claim 2, characterized in that a) the sensor (10) is a pressure sensor (10) that measures the material pressure (p) of the application medium, preferably in the common supply line (9) to the nozzle applicator (1), b) the valve control (11) performs the comparative measurements on the individual control valves (6, 7) separately for each control valve (6, 7) and successively in order to determine the individual switching delays of the control valves (6, 7), c) the valve control (11) during the individual comparative measurements cl) controls the respective control valve (6, 7) with the same control signal (sl, s2) as during the other comparative measurements, c2) supplies the respective control valve (6, 7) with the same delivery flow (Q) of the application medium as during the other comparative measurements, and c3) measures the material pressure (p) via the pressure sensor (10).and d) that the valve control (11) determines the time offset for the individual control signals (sl, s2) depending on the deviations between the material pressures (p) measured in the comparative measurements.

4. Application device according to claim 2, characterized in that a) the sensor (12) is a flow rate sensor (12) that measures the flow rate (Q) of the application medium, preferably in the common supply line (9) to the nozzle applicator (1), b) the valve control (11) performs the comparative measurements at the individual control valves (6, 7) separately for each control valve (6, 7) and successively in order to determine the individual switching delays of the control valves (6, 7), c) the valve control (11) during the individual comparative measurements cl) controls the respective control valve (6, 7) with the same control signal (s1, s2) as in the other comparative measurements and c2) supplies the respective control valve (6, 7) with the same material pressure (p) of the application medium as in the other comparative measurements and c3) thereby via the flow rate sensor (12) the flow rate (Q) through the respective control valve (6, 7) 7) measures,and d) that the valve control (11) determines the time offset for the individual control signals (sl, s2) depending on the deviations between the flow rates (Q) that occur during the, Comparative measurements will be taken.

5. Application device according to claim 2, characterized in that a) the sensor (14) is a pressure sensor (14) that measures the material pressure (p) of the application medium, preferably in the common supply line (9) to the nozzle applicator (1), b) the valve control (11) performs the comparative measurements on the individual control valves (6, 7) separately for each control valve (6, 7) and successively in order to determine the individual switching delays of the control valves (6, 7), c) the valve control (11) during the individual comparative measurements cl) controls the respective control valve (6, 7) with the same control signal (sl, s2) as during the other comparative measurements, and c2) regulates the material pressure (p) of the application medium to a predetermined setpoint value, in particular by means of a proportional (P) controller, and c3) determines the control deviation (Ap) between the predetermined setpoint value of the material pressure (p) and a Actual value of the material pressure (p),which is measured by the pressure sensor (14), and d) that the valve control (11) determines the time offset for the individual control signals (sl, s2) depending on the control deviations (Ap) determined in the comparative measurements.

6. Application device according to one of the preceding claims, characterized in that a) the individual control valves (6, 7) are each needle valves with a displaceable valve needle which, depending on its position, opens or closes a valve seat and thereby enables or blocks the application of the application agent through the associated nozzle, and / or b) that the control valves (6, 7) are electrically actuated, and / or c) that the individual nozzles (2, 3) of the nozzle applicator (1) have a common material supply line and the sensor is arranged in the common material supply line, and / or d) that the nozzle applicator has more than 2, 5, 10, 20 or 50 nozzles (2, 3), and / or e) that the nozzles (2, 3) in the nozzle applicator are arranged in a straight line, in particular equidistantly, and / or f) that the control signals are switching curves that alternately Switch-on times with open control valve (6,7) and have switch-off times with the control valve closed (6, 7), and / or g) that the control signals have a switching frequency of at least 1 Hz, 2 Hz, 5 Hz, 10 Hz, 20 Hz, 50 Hz, 100 Hz or 200 Hz, and / or h) that the nozzle applicator is a droplet applicator that dispenses droplets of the application agent.

7. Calibration method for compensating switching delays of control valves (6, 7) of a nozzle applicator (1) with multiple nozzles (2, 3) for applying an application agent to a component, in particular for applying a sealant to a motor vehicle body component, especially for an application device according to one of the preceding claims, a) conveying the application agent to the individual nozzles (2, 3) of the nozzle applicator (1), b) actuating the control valves (6, 7) of the application device with control signals (sl, s2), wherein the individual control valves (6, 7) react to the control signals (sl, s2) with different switching delays due to their component variation, c) determining the switching delays of the individual control valves (6, 7), d) setting a time offset individually for the individual control signals (sl, s2) to compensate for the individual switching delays of the individual control valves (6, 7). characterized bye) that the time offsets for the control signals (sl, s2) are determined by comparative measurements on the individual control valves (6, 7) without measuring the applied application medium on the component.

8. Calibration method according to claim 7, characterized in that a) an application parameter is measured by a sensor (10, 12, 14), in particular material pressure (p) and / or flow rate (Q) to the respective nozzle, and b) the time offsets for the individual control valves (6, 7) are determined as a function of the application parameters measured in the comparative measurements. c) the sensor (10, 12, 14) preferably measures the application parameter (p, Q) in a common supply line (9) to the nozzle applicator (1).

9. Calibration method according to claim 8, characterized in that a) the sensor (10) is a pressure sensor (10) that measures the material pressure (p) of the application medium, preferably in the common supply line (9) to the nozzle applicator (1), b) that the comparative measurements are carried out separately for the individual control valves (6, 7) and consecutively in order to determine the individual switching delays of the control valves (6, 7), c) that the valve control (11) during the individual comparative measurements cl) supplies the respective control valve (6, 7) with the same flow rate (Q) of the application medium as during the other comparative measurements, c2) controls the respective control valve (6, 7) with the same control signal (sl, s2) as during the other comparative measurements, and c3) measures the material pressure (p) at the respective control valve (6, 7) via the pressure sensor (10), and d) that the valve control (11) determines the time offset for the individual control signals (sl, s2) depending on the deviations between the material pressures (p) measured during the comparative measurements.

10. Calibration method according to claim 8, characterized in that a) pressure curves of the material pressure are measured in the comparative measurements, and b) the pressure curves measured in the comparative measurements are compared in order to determine the time offset for the individual control signals (s1, s2).

11. Calibration method according to claim 8, characterized in that a) the sensor (12) is a flow rate sensor (12) that measures the flow rate (Q) of the application medium, preferably in the common supply line (9) to the nozzle applicator (1), b) the comparative measurements are carried out separately for the individual control valves (6, 7) and sequentially in order to determine the individual switching delays of the control valves (6, 7), c) the valve control (11) during the individual comparative measurements cl) supplies the respective control valve (6, 7) with the same material pressure (p) of the application medium as during the other comparative measurements, c2) actuates the respective control valve (6, 7) with the same control signal (sl, s2) as during the other comparative measurements, and c3) measures the flow rate (Q) through the respective control valve (6, 7) via the flow rate sensor (12).and d) that the valve control (11) sets the time offset for the individual control signals (sl, s2) in, Determines the dependency on the deviations between the flow rates (Q) measured in the comparative measurements.

12. Calibration method according to claim 11, characterized in that a) the delivery quantities of the application agent are determined in each of the comparative measurements, and b) the delivery quantities are compared in the comparative measurements in order to determine the time offset for the individual control signals (sl, s2).

13. Calibration method according to claim 8, characterized in that a) the sensor (14) is a pressure sensor (14) that measures the material pressure (p) of the application medium, preferably in the common supply line (9) to the nozzle applicator (1), b) that the comparative measurements are carried out separately for the individual control valves (6, 7) and successively in order to determine the individual switching delays of the control valves (6, 7), c) that the valve control (11) in the individual comparative measurements cl) controls the respective control valve (6, 7) with the same control signal (sl, s2) as in the other comparative measurements and c2) regulates the material pressure (p) of the application medium to a predetermined setpoint value, in particular by means of a P-controller, and c3) determines the control deviation between the predetermined setpoint value of the material pressure (p) and an actual value of the material pressure (p) measured by the pressure sensor (14),d) that the valve control (11) sets the time offset for the individual control signals (sl, s2) depending on the control deviations measured in the comparative measurements.

14. Calibration method according to one of claims 7 to 13, characterized in that the comparative measurements on the control valves (6, 7) and the calculation of the time offset for the control signals are repeated iteratively until the different switching delays of the control valves (6, 7) are compensated by the time offsets to residual differences of at most 500 ps, ​​250 ps, ​​100 ps, ​​50 ps, ​​40 ps, ​​25 ps or 10 ps.

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