Coating method and coating system with improved dead-space filling
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- DUERR SYST AG
- Filing Date
- 2026-01-01
- Publication Date
- 2026-08-06
Smart Images
Figure EP2026050001_06082026_PF_FP_ABST
Abstract
Description
[0001] DESCRIPTION
[0002] Coating process and coating system with improved dead space filling
[0003] Technical field of
[0004]
[0005] The invention relates to a coating method for coating a component (e.g., a motor vehicle body component) with a coating agent (e.g., paint). The invention further comprises a coating system (e.g., a paint shop) for carrying out the coating method according to the invention.
[0006]
[0007] In modern paint shops for painting vehicle body components with paint, rotary atomizers are usually used as application devices, which are guided by multi-axis painting robots according to a predetermined painting program and apply the paint (filler, base coat, top coat and finally clear coat) to the vehicle body components via a rotating bell plate.
[0008] The dosage of the lacquer to be applied is usually achieved by a gear metering pump, which delivers the lacquer to the rotary atomizer. The lacquer is released within the rotary atomizer by a main needle valve located just upstream of the paint nozzle, such as that known from WO 2011 / 018169 Al. The rotary atomizer can also be equipped with several main needle valves, each releasing or shutting off the lacquer flow through a branch of the lacquer supply line, allowing different lacquers to be supplied via the parallel branches of the lacquer supply line and the two main needle valves.
[0009] The volume of the line between the main needle valve and the paint nozzle forms a dead space that cannot be flushed when the main needle valve is closed. However, this dead space between the main needle valve and the paint nozzle must be flushed during a color change to prevent paint carryover (contamination with paint from the old color). For this purpose, the rotary atomizer is inserted by the painting robot into a cleaning device ("cleaner"), as known, for example, from DE 102004061322 Al, DE 102010052698 Al and DE 10 2006 039 641 Al. In the cleaning device, the rotary atomizer is then flushed with cleaning agent with the main needle valve open to remove the old paint from the paint supply line and, in particular, from the dead space between the main needle valve and the paint nozzle.During this rinsing process, the residues of the old paint and the rinsing agent are also blown out of the dead space volume of the rotary atomizer with compressed air, so that the dead space volume is then empty.
[0010] After such a rinsing process in the cleaning device, the rotary atomizer is then filled with the new paint, a process known as primer. This primer fills the upstream flow volume of the rotary atomizer before the main needle valve. It also fills the dead space between the main needle valve and the paint nozzle. This prevents defects and undercoating during subsequent painting operations. Undercoating would occur if the dead space were not filled at the start of a painting process, meaning that no paint would be dispensed at the desired start point until the dead space was filled.
[0011] In the current state of the art, this application of the rotary atomizer takes place inside the cleaning unit to prevent contamination within the paint booth. Thus, when changing colors, the rotary atomizer is inserted into the cleaning unit, where the color change is then carried out by rinsing and blowing out the rotary atomizer, followed by the application of the new color. However, this established method of application within the cleaning unit has several disadvantages, which are briefly described below.
[0012] Firstly, pressing down the rotary atomizer inside the cleaning device takes a relatively long time, as a separate timer program is required.
[0013] Secondly, pressing down the rotary atomizer within the cleaning device leads to paint loss because the amount of paint applied is usually not precisely optimized for the dead space volume of the rotary atomizer. As a result, an excess of the applied paint escapes through the nozzle of the rotary atomizer. In practice, this often leads to overfilling of the dead space volume; that is, more paint is applied than is necessary to fill it. Consequently, some of the applied paint escapes through the nozzle of the rotary atomizer into the cleaning device, causing paint loss. This excess paint does not reach the vehicle body component being painted but must be disposed of, for example, by washing it out or collecting it in a container.The pressing down of the rotary atomizer within the cleaning device is therefore also referred to as a "waste shot" because, during the pressing ("shot"), the excess part of the pressed-down paint must be disposed of as waste ("waste").
[0014] Another problem with conventional coating application in a cleaning unit is that the coated paint, which is contained within the dead space, can dry out during the period between coating in the cleaning unit and the start of the actual coating process. This can cause problems even during normal operation without any malfunctions, as the rotary atomizer must first move from the cleaning unit to the starting point ("spray point") of the programmed coating path after coating, which takes a certain amount of time. The risk of the coated paint drying out is particularly high if a system malfunction causes a waiting period. The drying of the coated paint in the dead space usually leads to a coating failure.
[0015] Furthermore, it should be noted that rotary atomizers usually have an electrostatic paint charge to increase application efficiency and prevent disruptive overspray. This means that the paint to be applied is electrostatically charged, while the vehicle body components being painted are electrically grounded. However, when pressing the rotary atomizer into the cleaning device, this electrostatic paint charge must be deactivated, as otherwise electrical arcing could occur within the cleaning device. Due to the absence of the otherwise present electrostatic paint charge, pressing the rotary atomizer into the cleaning device can lead to contamination of the external surfaces of the rotary atomizer or the bell plate, resulting in subsequent painting defects.
[0016] Furthermore, when pressing down a rotary atomizer within a cleaning device, unfavorable painting parameters ("brush parameters") are often used, which can also contribute to the disruptive contamination of the external surfaces of the rotary atomizer or the bell plate. For the prior art, reference should also be made to US 4785760 A and DE 101 15463 Al.
[0017]
[0018] The invention is therefore based on the objective of improving the pressing action of an application device (e.g. rotary atomizer) and avoiding, as far as possible, the disadvantages of conventional pressing action in a cleaning device described above.
[0019] This problem is solved by a coating process according to the invention as defined in the main claim and a corresponding coating system.
[0020] The coating process according to the invention is preferably a painting process for coating motor vehicle body components. However, the invention is not limited to paint or motor vehicle body components with regard to the type of coating material or the type of components to be coated. For example, the coating material can also be a so-called high-viscosity thick substance, such as adhesives, waxes (e.g., preservative wax), sealants, or insulating materials, to name just a few. Furthermore, components other than motor vehicle body components can also be coated within the scope of the invention.
[0021] In the coating process according to the invention, an application device (e.g., a rotary atomizer) is used, which dispenses the coating material to be applied (e.g., paint) via a nozzle. In the preferred embodiment of the invention, the application device is a rotary atomizer. However, the invention is not limited to rotary atomizers with regard to the type of application device, but can also be implemented with other types of application devices, such as air atomizers, to name just one example. In the case of a rotary atomizer as the application device, the aforementioned nozzle is the paint nozzle of the rotary atomizer (see WO 2011 / 018169 Al), which opens into a rotating bell-shaped disc that then atomizes the paint and sprays it off at an annularly circumferential spray edge.
[0022] Furthermore, in the coating process according to the invention, the application device has a coating agent supply line to direct the coating agent (e.g., paint) to the nozzle (e.g., the paint nozzle of the rotary atomizer). This coating agent supply line contains a controllable main valve that either shuts off or releases the flow of coating agent to the nozzle. Between the main valve and the nozzle, there is thus a dead space in the coating agent supply line, which must be filled with the new paint during a color change and also during a short rinse (i.e., without a color change via a color changer), as described above in relation to the prior art. It should be noted that the main valve is preferably located in the application device and thus close to the nozzle, which allows for a small dead space between the main valve and the nozzle.
[0023] The term "pressing" used in the context of the invention means that the coating material supply line in the application device (e.g., rotary atomizer) is filled with the new coating material (e.g., paint), both upstream before the main valve and downstream after the main valve in the dead space volume between the main valve and the nozzle. The term "pressing" used in the context of the invention thus also includes at least partial filling of the dead space volume between the main valve and the nozzle.
[0024] After pressing the application device (e.g. rotary atomizer) with the new coating material (e.g. paint) onto the surface, the actual coating process takes place, whereby the application device with its paint impact point is moved along a programmed coating path starting at a starting point ("injection point") and the coating material (e.g. paint) is applied through the nozzle to the component (e.g. automotive body component).
[0025] The invention is characterized by an improvement in the application device's pressure application. The application device is pressed down to fill the dead space volume while its ink impact point moves towards the starting point ("injection point") of the predetermined coating path, or is already located at the starting point of the predetermined coating path. Thus, the pressure application process is integrated into the actual coating process within the scope of the invention.
[0026] Firstly, this integration of the pressing process into the actual coating process is advantageous because it reduces the time required for pressing compared to the known pressing process in a cleaning device.
[0027] On the other hand, there is hardly any risk of the applied coating material drying out, since the processes of pressing and coating follow each other in quick succession, so that there is not enough time between the two processes (pressing and coating) for the applied coating material to dry.
[0028] A further advantage of the pressing process according to the invention is that there is no risk of electrical arcing, since the pressing process does not have to take place inside the cleaning device, meaning that the electrostatic charging of the coating agent does not need to be switched off during the pressing process. Therefore, the electrostatic charging of the coating agent can be switched on during the pressing process, which prevents any escaping coating agent from depositing on the outside of the application device and thus contaminating it.
[0029] Furthermore, the rotary atomizer can be operated with the same coating parameters (“brush parameters”) during the pressing process according to the invention as during the actual coating process, which also prevents the escaping coating material from accumulating on the outside of the application device due to unfavorable coating parameters and thus contaminating the application device.
[0030] In a preferred embodiment of the invention, the application device is pressed onto the starting point ("injection point") of the coating web a short time before the actual coating process begins. For example, the time interval between the end of the pressing and the start of the coating process can be at most 10 s, 5 s, 2 s, or 1 s. This is advantageous because the short time interval between the end of the pressing and the start of the coating process is then insufficient for the applied coating material to dry.
[0031] Furthermore, it should be noted that the application device is preferably pressed down at a small distance from the starting point ("injection point") of the predetermined coating line. Therefore, during pressing, the application device, with its point of contact with the coating, is preferably located at a small distance of no more than 1 m, 50 cm, 25 cm, 10 cm, or 5 cm from the starting point of the predetermined coating line.
[0032] According to the invention, the application device is preferably pressed down both at a short time interval and at a short spatial distance from the start of the actual coating at the "injection point".
[0033] In the preferred embodiment of the invention, the application device (e.g., rotary atomizer) is cleaned before coating and also before pressing down. A cleaning device, such as those known from DE 102004061322 Al, DE 102010 052698 Al, or DE 102006039641 Al, can be used for this purpose. This cleaning of the application device is carried out particularly during a color change or during so-called short rinses, independent of a color change. A painting robot can insert a rotary atomizer into the cleaning device for cleaning. Firstly, the rotary atomizer can be sprayed externally with cleaning agent within the cleaning device to perform external cleaning. Secondly, the rotary atomizer can be rinsed internally with cleaning agent within the cleaning device to flush out paint residues from the atomizer. Finally, paint and cleaning agent residues can be removed from the cleaning device using compressed air (e.g., from a pressure washer).Pulsed air is blown out of the rotary atomizer. It should be noted that the application device is preferably not pressed onto the new coating material within the cleaning device, as is known from the prior art. Instead, the application device (e.g., rotary atomizer) is withdrawn from the cleaning device and moved towards the starting point ("injection point") of the programmed coating path, where the pressing then takes place. Thus, the cleaning and pressing processes are preferably spatially and temporally separated within the scope of the invention.
[0034] The pressing action of the application device (e.g., rotary atomizer) according to the invention is not necessarily linked to a color change. Rather, regular short rinsing of the application device is advisable during operation, regardless of a color change. During this rinsing, the application device is cleaned in the cleaning unit, and the dead space is completely emptied. The pressing action according to the invention can also be performed after this short rinsing process.
[0035] As mentioned above, the invention allows the pressing process to be integrated into the coating process. Therefore, the main valve of the application device can remain open during the transition from pressing to coating. This means that the coating process follows the pressing process immediately and without any intermediate pause.
[0036] Furthermore, it should be noted that the pressing process should preferably be designed such that the dead space volume in the application device is completely filled with the coating material precisely at the programmed start of the application, without overfilling or underfilling. The duration of the pressing process and the coating material flow rate during pressing are therefore preferably dimensioned so that the complete filling of the dead space volume in the application device is just finished as precisely as possible at the programmed start of the application. Thus, during pressing, overfilling or underfilling of the dead space volume by more than 10%, 5%, 2%, or 1% of the dead space volume is preferably prevented.
[0037] Furthermore, it should be mentioned that the coating material to be applied is preferably conveyed to the nozzle of the application device by a coating material pump. The coating material pump is preferably arranged upstream of the application device (e.g., rotary atomizer) and is therefore not integrated into the application device. However, it is also possible, in principle, to integrate the coating material pump into the application device.
[0038] Furthermore, it should be mentioned that the coating agent pump is preferably a metering pump (e.g. gear metering pump) in which the flow rate is essentially independent of the pressure conditions at the inlet and outlet of the metering pump.
[0039] In this context, it should also be mentioned that several coating agent pumps (e.g. gear pumps) may be provided, which convey different coating agents through separate branches of the coating agent supply line.
[0040] The coating process according to the invention preferably comprises the following steps:
[0041] • Determining the dead space volume of the application device between the main valve and the nozzle,
[0042] • Determining a delay time of the main valve and the coating agent pump between a start signal to open the main valve and to start the coating agent pump and the subsequent delayed exit of the coating agent from the nozzle,
[0043] • Specification of a coating agent delivery flow rate for pressing down the application device, in particular a maximum possible coating agent delivery flow rate of the coating agent pump,
[0044] • Programming a time for the desired application start, • Calculating a lead time for opening the main valve before the desired application start time to fill the dead space volume of the application device, where the lead time is calculated from the following values:
[0045] o the dead space volume of the application device,
[0046] the delay time of the main valve and the coating agent pump and the specified coating agent delivery flow for pressing down the application device, and
[0047] • Opening the main valve at a time delayed by the holding time before the programmed time for the desired application start, in order to press the application device and fill the dead space volume with the coating material before the desired application start time.
[0048] Regarding the coating agent flow rate, it should be noted that in practice this rarely corresponds to the maximum possible flow rate of the coating agent pump. For example, if three different coating agent pumps are available, the maximum flow rate of the weakest pump can be used. Furthermore, the initial application of the coating agent may already be complete before the pump reaches its maximum flow rate, in which case a lower, arbitrary value is chosen.
[0049] Instead of the aforementioned term of a lead time, one could also speak of a lead time, compensation time, time shift, advancement period or a negative latency time within the scope of the invention.
[0050] The aforementioned determination of the dead space volume in the application device can be easily carried out experimentally by measuring the amount of coating material delivered between the opening of the main valve and the point where the coating material exits the nozzle, after a purging process and purging of the dead space. This amount of coating material then corresponds to the dead space volume in the application device and can be determined experimentally for various types and configurations of application devices. The determined values for the dead space volume can then be stored in a table and read out during operation.
[0051] The aforementioned determination of the delay time of the main valve and the coating agent pump can also be carried out in advance through tests. During these tests, the dead space volume can first be completely filled with the coating agent. Then, with the dead space volume completely filled, a so-called "pee spray" can be applied; that is, with a rotary atomizer as the application device, a coating strip is applied without the bell plate mounted. The time at which the coating agent exits the nozzle after opening the main valve and starting the coating agent pump can then be easily determined, from which the delay time can be derived. The delay time for different types of application devices and different configurations of these devices can be determined through these preliminary tests.The determined delay time values can then be stored in a table and read out during operation.
[0052] The aforementioned predetermined coating agent flow rate for the initial application can be the flow rate programmed for the start of coating at the injection point. Preferably, however, the aforementioned predetermined coating agent flow rate for the initial application is the maximum possible flow rate that the coating agent pump can deliver. This is advantageous to ensure that the dead space volume is filled as quickly as possible during the initial application. However, it is also fundamentally possible within the scope of the invention for the initial application to be carried out with a lower coating agent flow rate.
[0053] The aforementioned calculation of the holding time required to open the main valve before the programmed start of the application can then be carried out according to the following formula:
[0054]
[0055] with
[0056] At: Holding time required to press down the dead space volume of the application device,
[0057] Tver Z : Delay time of the main valve of the application device and the coating agent pump.
[0058] T L ade: Filling time required to fill the dead space volume after opening the main valve and starting the gear metering pump. The holding time required for pressing therefore consists of two time periods, namely firstly the delay time T Ve rz from main valve and coating agent pump and secondly from the actual filling time T La de-
[0059] The filling time T required to fill the dead space volume La de can be calculated using the following formula:
[0060]
[0061] >
[0062] with
[0063] Vtot: Dead space volume of the application device,
[0064] T La d e : Filling time required to fill the dead space volume V to t is required after opening the main valve and starting the gear metering pump.
[0065] It should be noted that the flow rate of the coating compound is generally not constant during the pressing process. While it has already been mentioned that pressing should preferably be carried out with the maximum possible coating compound flow rate that the coating compound pump can provide to ensure the fastest possible pressing, this flow rate is not immediately available after the pump is switched on, nor does it drop to zero immediately after the pump is switched off. Rather, the coating compound pump typically has an acceleration and deceleration ramp; that is, the pump reacts to being switched on and off with a time delay.The formula mentioned above for calculating the filling time therefore preferably also takes into account the actual values of the coating agent flow rate during the pressing process. The acceleration and deceleration ramps of the coating agent pump are thus preferably measured experimentally and stored in the control unit. Alternatively, however, it is also possible to model the acceleration and deceleration ramps of the coating agent pump, which allows for a simpler calculation.
[0066] The preceding section described a variant of the invention, including formulas, in which the coating agent flow rate is predetermined during application and the holding time required for application is determined accordingly. However, the invention also allows for the reverse: a specific holding time can be predetermined, and the required coating agent flow rate can be determined accordingly. Furthermore, it should be noted that the invention is not limited to use with application devices (e.g., rotary atomizers) that have only a single main valve. Rather, the invention also allows for the application device to have multiple main valves, each controlling the coating agent flow through its own coating agent supply line.For example, the application device can contain two, three, or four main valves, each controlling a coating agent flow in a branch of the coating agent supply line. The coating agent supply lines are joined downstream of the main valves, so that the combined section of the coating agent supply line forms the dead space volume that needs to be filled. The coating agent supply line of the application device can therefore split into two or more branches at the inlet, each containing a main valve.
[0067] It has already been mentioned that the coating agent pump is preferably a metering pump, in which the coating agent flow rate is essentially independent of the pressure conditions at the inlet and outlet of the metering pump. For example, a gear metering pump can be used as the metering pump.
[0068] Furthermore, it should be mentioned that the pressing process within the scope of the invention can be carried out very quickly. For example, the pressing can take place within a short time span of only 2 s, 1 s, 500 ms, 250 ms, 100 ms, 50 ms, 25 ms, 10 ms or 5 ms.
[0069] The main valve is preferably a main needle valve with a movable valve needle which, depending on the valve position, opens or closes a valve seat and thereby releases or closes the flow of the coating material accordingly. However, the invention is not limited to needle valves with regard to the design of the main valve, but can also be implemented with other valve types in principle.
[0070] The terms "main valve" and "main needle valve" used in the context of the invention mean that no further valve is arranged downstream of the main valve or main needle valve. The main valve or main needle valve is therefore to be distinguished from other valves that are arranged in the upstream region of the coating material supply line. By definition, the main valve is thus the last valve before the nozzle in the direction of flow.
[0071] As mentioned above, pressing down the application device should be done with the highest possible coating material flow rate to fill the dead space in the application device as quickly as possible. For example, the maximum possible coating material flow rate provided by the coating material pump (e.g., gear pump) can be used to press down the application device. This maximum possible coating material flow rate could be at least 100 ml / min, 200 ml / min, 400 ml / min, or 600 ml / min.
[0072] Furthermore, it should be generally mentioned that the application device is preferably pressed down to fill the dead space volume automatically and programmatically before coating.
[0073] Furthermore, it should be mentioned that the application device is preferably pressed down according to the invention during a color change. First, the application of the coating material with the old color is completed, after which the application device is cleaned. During cleaning, residues of the old coating material are removed from the application device by rinsing it with a cleaning agent and blowing it out with compressed air. Then, the application device is pressed down with the coating material of the new color according to the invention. Therefore, the following steps are preferably carried out sequentially during a color change:
[0074] • Finish the application with the old color,
[0075] • Insertion of the application device into the cleaning device by the application robot, • Rinsing of the old paint from the application device by introducing rinsing agent into the application device, with the application device located inside the cleaning device, • Blowing out of any remaining old paint and rinsing agent from the application device by introducing compressed air into the application device, with the application device located inside the cleaning device,
[0076] • Moving the application device out of the cleaning device and towards the injection point using the application robot, and
[0077] • Press the application device with the new color against the injection point or during the movement towards it.
[0078] In addition to the coating method described above, the invention also claims protection for a coating system (e.g., a painting system) according to the invention, which carries out the coating method according to the invention. For this purpose, the coating system according to the invention initially comprises an application device (e.g., a rotary atomizer) with a nozzle for dispensing the coating agent, a coating agent supply line for supplying the coating agent to the nozzle, and a controllable main valve in the coating agent supply line for releasing or shutting off the flow of coating agent through the coating agent supply line to the nozzle, such that the coating agent supply line contains a dead space volume between the main valve and the nozzle.
[0079] Furthermore, the coating system according to the invention has a multi-axis coating robot for moving the application device. Preferably, the multi-axis coating robot is a painting robot with serial robot kinematics, such painting robots being known from the prior art (see WO 2009 / 115201 A2, WO 2010 / 025827 Al).
[0080] Furthermore, the coating system according to the invention has a coating agent pump (e.g. gear metering pump) for conveying the coating agent to the nozzle of the application device.
[0081] Furthermore, the coating system according to the invention comprises a control unit for the program-controlled operation of the coating robot, the coating agent pump, and the application device. The control is program-controlled according to a predefined coating program, which, for example, defines a coating path to be followed from the point of contact of the rotary atomizer. The control unit therefore preferably includes a control computer with a program memory in which a control program is stored. When the stored control program is executed, the coating system then carries out the coating process according to the invention, as described above.
[0082] Furthermore, it should be mentioned that the control unit does not necessarily have to be a single component located centrally. Rather, the invention also allows for the possibility that the control unit consists of several decentralized control modules, each performing specific control tasks.
[0083] The coating system according to the invention is characterized in that the control unit controls the coating robot, the coating agent pump (e.g., gear metering pump), and the main valve in the application device during operation in such a way that the coating system carries out the coating process according to the invention as described above. For this purpose, the control unit contains a correspondingly adapted control program.
[0084] Furthermore, the coating system according to the invention preferably also includes a cleaning device for cleaning the application device, wherein the control unit also controls the cleaning device in a program-controlled manner. Such cleaning devices are known, for example, from DE 10 2004061322 Al, DE 102010052698 Al and DE 102006039641 Al.
[0085] Furthermore, the coating system according to the invention can also include electrostatic charging of the coating material (e.g., paint) to electrostatically charge the coating material. The electrostatic charging of the coating material can be controlled by the control unit and remain switched on during the application process, since the application process does not take place in the cleaning device. The electrostatic charging of the coating material can, for example, provide for external charging via external electrodes or contact charging (direct charging) within the application device, as is known per se from the prior art.
[0086] When a rotary atomizer is used as an application device, it is usually driven by a compressed air turbine, which is typically located within the rotary atomizer. Such a compressed air turbine is known, for example, from DE 102015000551 Al, WO 2011 / 120619 Al, or DE 20321605 Ul. This compressed air turbine is supplied with compressed air, and the compressed air supply is also driven by the aforementioned control device. Thus, the control device can, for example, control drive air to drive the rotary atomizer and brake air to decelerate the rotary atomizer, as is known from the prior art.
[0087] Other advantageous embodiments of the invention are characterized in the dependent claims or are explained in more detail below with reference to the figures and a description of the preferred embodiment of the invention.
[0088] Brief description of the drawings
[0089] Figure 1 shows a simplified schematic representation of a painting system according to the invention for painting motor vehicle body components. Figure 2 shows a schematic representation of a rotary atomizer for painting the motor vehicle body components in the painting system according to Figure 1.
[0090] Figure 3 shows a flowchart to illustrate the painting process according to the invention.
[0091] Figure 4 shows a flowchart to illustrate the calculation of the lead time when pressing down the rotary atomizer.
[0092] Figure 5 shows a time diagram to illustrate the successive processes (rinsing, pressing, painting) during short rinsing, i.e., when a color changer, a color channel for connecting the color changer and / or a dosing pump are not also rinsed.
[0093] Figure 6 shows the time course of the paint flow and paint pressure when pressing down the rotary atomizer.
[0094] Figure 7 shows a modification of Figure 5 with the successive processes (rinsing, pressing, varnishing) during a color change.
[0095] Detailed description of the drawings
[0096] The following section describes first the schematic representation of a painting system according to the invention shown in Figure 1, which is used for painting motor vehicle body components.
[0097] The application of the lacquer is carried out in the conventional manner by means of a rotary atomizer 1, which is shown in detail in Figure 2 and is described in more detail below.
[0098] The rotary atomizer 1 is moved program-controlled by a multi-axis painting robot 2 with serial robot kinematics over the surface of the motor vehicle body components to be painted, as is known in the prior art (see WO 2009 / 115201 A2, WO 2010 / 025827 Al).
[0099] The movement of the rotary atomizer 1 across the surface of the vehicle body components to be painted is controlled by a control unit 3, which directs the painting robot 2 according to a predefined painting program. For example, the painting program specifies a painting path along which the paint impact point of the rotary atomizer 1 is to move across the surface of the vehicle body components to be painted. The programming of the painting path is also referred to as "teaching" in the relevant technical terminology. The painting path is typically defined by a sequence of points that are to be traversed sequentially by the paint impact point of the rotary atomizer 1. For each point in the painting path, the spatial position of the paint impact point and the spatial orientation of the rotary atomizer 1 at that point are specified during the programming ("teaching").In addition, the control unit 3 also specifies the path speed at which the painting robot 2 moves the rotary atomizer 1 along the painting path.
[0100] The control unit 3 also controls two main needle valves 4 and 5, which either release or block the flow of lacquer in the rotary atomizer 1, as will be described in detail later. The two main needle valves 4 and 5 enable so-called A / B operation, in which lacquer A and lacquer B are applied alternately.
[0101] Furthermore, the control unit 3 controls two gear metering pumps 6, which deliver the lacquer A or B to be applied to the rotary atomizer 1. The control unit 3 specifies the rotational speed of the gear metering pumps 6, which in turn determines the flow rate of lacquer A or B that is delivered by the gear metering pump 6 to the rotary atomizer 1.
[0102] Furthermore, the paint system includes a cleaning device 7 for cleaning the rotary atomizer 1. Such cleaning devices 7 are known from the prior art and are described, for example, in DE 102004061322 A1, DE 102010052698 A1, and DE 102006039641 A1. To clean the rotary atomizer 1, the paint robot 2 inserts the rotary atomizer 1 into the cleaning device 7, where it is then cleaned. Firstly, the rotary atomizer 1 is sprayed externally with cleaning fluid to clean its outer surfaces. Secondly, the rotary atomizer 1 is internally rinsed with cleaning fluid within the cleaning device 7 to remove the paint from the rotary atomizer 1, allowing a different colored paint to be applied subsequently.After rinsing the old paint from the rotary atomizer 1, any remaining old paint and rinsing agent are blown out of the rotary atomizer 1 using compressed air, as is known from the prior art. Furthermore, the painting system according to the invention also has an electrostatic paint charging system 8 ("ESTA") for electrostatically charging the applied paint. The applied paint is thus electrostatically charged while the vehicle body components to be painted are electrically grounded, so that the paint sprayed from the rotary atomizer 1 is deposited mainly on the vehicle body components to be painted due to electrostatic attraction, thereby achieving a high transfer efficiency with correspondingly little overspray.
[0103] Furthermore, control unit 3 also controls other components of the paint shop, such as the cabin air conditioning of a paint booth and a linear conveyor that transports the vehicle body components to be coated through the paint shop. These other components of the paint shop are not shown for the sake of simplicity.
[0104] The following describes the schematic representation of the rotary atomizer 1 shown in Figure 2, which is largely of conventional design.
[0105] The rotary atomizer 1 has a bell-shaped disc 9 as its spraying element, which rotates around a rotational axis 10 during operation and is driven by a compressed air turbine (the compressed air turbine is not shown for simplicity). Such compressed air turbines are known, for example, from WO 2011 / 120619 Al and DE102015000551A1.
[0106] The paint to be applied is dispensed from a paint nozzle 11 through a nozzle opening 12 centrally into the bell-shaped container 9. The paint exiting the nozzle opening 12 of the paint nozzle 11 axially and centrally first encounters a distributor disc located at the front of the bell-shaped container 9, which deflects the paint radially outwards. The paint then flows over an overflow surface at the front of the bell-shaped container 9 to an annular spray edge 13, where it is sprayed off, as is known from the prior art (see WO 2011 / 018169 Al). The spray pattern of the paint is indicated in the drawing by arrows emanating from the spray edge 13 of the bell-shaped container 9. For the sake of simplicity, the distributor disc and the overflow surface of the bell-shaped container 9 mentioned above are not shown in the drawing.
[0107] The two main needle valves 4 and 5 mentioned above are housed in a casing 14 of the rotary atomizer 1 and are each designed as needle valves. Each main needle valve 4 and 5 has a movable valve needle 15 or 16, respectively, which can be moved in the direction of the double arrow to selectively open or close the respective main needle valve 4 or 5. The mechanical actuation of the two main needle valves 4 and 5 is pneumatic, but other actuation methods (e.g., electromagnetic) are also possible. The drawing shows main needle valve 4 in a closed position, in which the flow of lacquer A is blocked by main needle valve 4. The other main needle valve 5, on the other hand, is shown in an open position, in which the flow of lacquer B is enabled.
[0108] The paint is supplied to the nozzle opening 12 in the paint nozzle 11 via a paint supply line 17, which branches upstream of the paint nozzle 11 into two lines 18, 19 on the one hand and 20, 21 on the other. The main needle valve 4 controls the flow of paint A through the two lines 18, 19 into the common paint supply line 17. The other main needle valve 5, on the other hand, controls the flow of paint B through the two lines 20, 21 into the common paint supply line 17.
[0109] Furthermore, the rotary atomizer 1 has a rinsing liquid supply line 22 through which rinsing liquid can be supplied to rinse the rotary atomizer 1. Within the rotary atomizer 1, the rinsing liquid supply line 22 branches into three lines 23, 24, and 25. Lines 23 and 24 open into lines 18 and 20, respectively, of the paint supply line 17, thus enabling the rinsing of old paint from lines 18 and 20 of the common paint supply line 17. The third line 25 of the rinsing liquid supply line 22, on the other hand, leads to the paint nozzle 11 and opens at a nozzle opening 26 to rinse the inside of the bell-shaped plate 9.
[0110] The following describes how a color change from paint B (e.g. red paint) to the differently colored paint A (e.g. green paint) takes place.
[0111] The paint B is first conveyed via the branch lines 20, 21 and the common paint supply line 17 to the paint nozzle 11 and then sprayed off the bell plate 9. The main needle valve 5 is open, while the other main needle valve 4 is closed, as shown in Figure 2.
[0112] For a color change, the main needle valve 5 is first closed by pressing the valve needle 16 of the main needle valve 5 into its valve seat, thus shutting off the flow of paint B. Then, cleaning agent is introduced into the rotary atomizer 1 via the cleaning agent supply line 22 to flush the line branches 18, 20, and the common paint supply line 17. The cleaning agent is then flushed out through the nozzle opening 12 of the paint nozzle 11. Additionally, the cleaning agent is also routed through the line branch 25 into the paint nozzle 11, where it exits through the nozzle opening 26 to flush the bell plate 9. After this flushing process, compressed air can be introduced to blow out any remaining cleaning agent and old paint from the rotary atomizer 1.
[0113] It should be mentioned that the two line branches 18, 20 and the common lacquer supply line 17 downstream of the two main needle valves 4, 5 together form a dead space volume V to The dead space is formed after the rinsing process and the blowing out of the remaining cleaning agent and old paint. Before a new painting process with the new paint A, this dead space volume must first be filled with the new paint A, a process also known as priming. For this purpose, the main needle valve 4 is opened, whereupon the new paint A can flow through the branch lines 18, 19 into the common paint supply line 17 to fill the dead space volume Vtot with the new paint A.
[0114] Firstly, it should be noted that the filling of the dead space volume Vtot described above does not take place in the cleaning device 7, as is the case in the prior art described at the beginning. Rather, the filling and filling of the dead space volume Vtot takes place in the rotary atomizer 1 immediately before the start of the actual painting process. This means that the rotary atomizer 1 is moved by the painting robot 2 to the previously programmed starting point ("spray point") of the painting path and filled there or in the immediate vicinity of this starting point. This is advantageous because the filling can be carried out much faster than with the conventional filling process in the cleaning device 7.
[0115] Furthermore, the pressing action can be performed with the same painting parameters (“brush parameters”) and with the electrostatic paint charging 8 switched on. This is advantageous because it prevents paint that escapes during pressing from accumulating on the outside of the rotary atomizer 1 and contaminating it.
[0116] A further advantage of pressing the rotary atomizer 1 near the programmed starting point ("spray point") of the paint line is that only a short time elapses between the end of the pressing and the start of the painting, so that the pressed-on paint cannot dry in the rotary atomizer 1. Furthermore, it should also be mentioned that the amount of pressed-on paint within the scope of the invention is limited to the dead space volume V. to t can be optimized. This means that exactly as much lacquer is used for pressing as the dead space volume V. tot is large. On the one hand, this ensures that the dead space volume V is large. to t is completely filled with paint. On the other hand, overfilling of the dead space volume V is prevented. to t with the disruptive consequence of paint escaping from the nozzle opening 12.
[0117] The following describes the flowchart according to Figure 3, which illustrates the painting process according to the invention.
[0118] In a first step, S1, a paint path is programmed along which the paint impact point of the rotary atomizer 1 is to be guided across the surface of the vehicle body components. The paint path begins at a starting point on the surface of the vehicle body component, which is also referred to as the injection point. The programming of the paint path is known from the prior art and is also referred to as "teaching." Typically, path points are defined on the surface of the vehicle body component, which are to be traversed sequentially by the paint impact point of the rotary atomizer 1. For each path point, the spatial coordinates of the path point and the spatial orientation of the rotary atomizer 1 at that point are programmed.
[0119] For a color change or for short rinsing, the rotary atomizer 1 is then inserted in a step S2 by the painting robot 2 into a cleaning device 7 ("Cleaner"), as is known, for example, from DE 102004061322 Al, DE 102010052698 Al, DE 102006039641 Al.
[0120] In cleaning device 7, the rotary atomizer 1 is sprayed externally with a cleaning fluid in step S3 to remove paint residue from its outer surfaces. Additionally, the rotary atomizer 1 is rinsed internally with a rinsing fluid to remove any remaining old paint residue. Finally, any remaining old paint and rinsing fluid are blown out of the rotary atomizer 1 with compressed air. At the end of this cleaning process, the dead space volume V to The t of the rotary atomizer 1 is therefore initially empty.
[0121] After the cleaning process in step S3, the rotary atomizer 1 is then moved out of the cleaning device 7 by the painting robot 2 in a step S4 and moved to the programmed starting point ("spray point") of the painting path.
[0122] Shortly before reaching the injection point, in step S5 the rotary atomizer 1 is pressed in order to reduce the dead space volume V. to The rotary atomizer 1 is filled with the new paint. For this purpose, the corresponding main needle valve 4 or 5 in the rotary atomizer 1 is opened for a lead time At before the intended start of painting at time t=t5. The gear metering pump 6 then increases its speed and the corresponding main needle valve 4 or 5 opens so that the paint is pressed into the dead space volume V. to The flow of paint can pass through the rotary atomizer 1. It should be noted that pressing the rotary atomizer 1 with a predetermined paint delivery flow Q...ma x is set to achieve the shortest possible pressing time. This typically corresponds to the maximum paint delivery rate that the gear metering pump 6 can provide. Alternatively, the specified paint delivery rate Qmax can also be chosen to be lower, for example, if the time required to fill the dead space volume Vtot is shorter than the time needed to accelerate the gear metering pump 6 to its maximum possible paint delivery rate.
[0123] At time t=t5, the dead space volume V to The rotary atomizer 1 is then completely filled with the new paint, and in step S6, the painting robot 2 begins to move the rotary atomizer 1 with its paint impact point along the programmed painting path, thereby applying the new paint. It should be noted that the painting process uses a paint flow Q. La ckier< Qmax is achieved.
[0124] The following describes the flowchart according to Figure 4, which explains the determination of the lead time At required for pressing and which has already been mentioned above.
[0125] In a first step S1, the dead space volume V is determined. to The speed t of the rotary atomizer 1 is determined. In practice, the value of the dead space volume V is used. to The dead space volume (Vtot) can be read from a table depending on the atomizer type. The values stored in the table can be determined for different atomizer types through testing. For example, the volume of paint that must be pumped before it exits the nozzle 11 of the rotary atomizer 1 after rinsing and emptying can be measured.
[0126] In a further step S2, the maximum paint flow rate Q is then determined. max is determined, which is the maximum amount that can be delivered by the gear metering pump 6. The application is then carried out with the maximum possible paint delivery flow Q. ma x is useful so that the pressing action can be performed as quickly as possible.
[0127] In a further step S3, the filling time T is then determined. La The amount determined is used to fill the dead space volume V to t is required. This refers to the time that must be pressed until the dead space volume V is reached. to t is completely filled with the lacquer. The filling time T is usually La in the range of milliseconds.
[0128] Furthermore, in step S4, the delay time Tverz of the gear metering pump 6 and the main needle valve 4 or 5 of the rotary atomizer 1 is measured. This ensures that the gear metering pump 6 does not immediately deliver the maximum paint flow rate Q after being switched on. maRather, the paint delivery flow Q increases after switching on according to an acceleration ramp, as shown in Figure 6. Similarly, the paint delivery flow Q does not immediately drop to zero after switching off the gear metering pump 6, but decreases according to a deceleration ramp, as also shown in Figure 6. The maximum paint delivery flow Q ma In this case, x corresponds to the performance limit of the gear metering pump 6. In addition, the main needle valve 4 or 5 of the rotary atomizer 1 may also have a delay time, which should also be taken into account.
[0129] In the next step S5, the lead time At for pressing down the rotary atomizer 1 is then calculated as follows:
[0130]
[0131] Figure 5 shows a schematic representation of the sequence of the various processes during the short rinse of the rotary atomizer 1, i.e., without a color change. During the period from t=t1 to t=t2, the bell-shaped plate 9 is first rinsed in the cleaning device 7. During the period from t=t3 to t=t5, the pressure is then applied, filling the dead space volume V. to The pressing period consists of the delay time TVERZ from t=t3 to t=t4 and the actual filling time TLADE from t=t4 to t=t5. The actual painting process then begins at time t=t5.
[0132] Figure 6 shows the time course of the paint delivery flow Q during the activation of the rotary atomizer 1. Thus, at time t=t3, the start signal for activation is given and the gear metering pump 6 accelerates according to an acceleration ramp until the paint delivery flow Q reaches its maximum value Q. max is reached. The speed of the gear metering pump 6 is then reduced again according to a braking ramp in order to reduce the paint delivery flow Q to a value Q=Qiaci. <ier abzusenken, der für den anschließenden Lackierprozess geeignet ist. Zum Zeitpunkt t=t5 ist dann das Totraumvolumen V to The dead space volume V in the rotary atomizer 1 is completely filled with the paint, and the painting process can begin simultaneously. The pressure applied to the rotary atomizer 1 is therefore controlled so that the pressure process continues until the dead space volume V is completely filled. to The painting process and the painting process follow each other immediately in time.
[0133] Finally, Figure 7 shows a modification of the time diagram according to Figure 5, so that to avoid repetition, reference is largely made to the above description.
[0134] It should be noted that a color change occurs, during which the color changer, the color channel, and the dosing pump must also be rinsed, which takes place between t=t1 and t=t2. Between t=t2 and t=t3, the bell plate 9 is then rinsed.
[0135] The period from t=t4 to t=t5 represents the delay time.
[0136] During the period from t=t5 to t=t6, the color changer, color channel and dosing pump are filled.
[0137] During the period from t=t6 to t=t7, the dead space volume V is then filled. to t-
[0138] Finally, at time t=t7, the actual painting process begins.
[0139] The invention is not limited to the preferred embodiment described above. Rather, the invention also includes variants and modifications that likewise utilize the inventive concept and therefore fall within the scope of protection. In particular, the invention also claims protection for the subject matter and the features of the dependent claims independently of the respective referenced claims and, in particular, also without the features of the main claim. For example, various definitions for the pressing action according to the invention have been described above, namely in temporal and spatial proximity to the so-called "injection point," outside the cleaning device, or immediately before the painting process. These definitions are also possible independently of one another. The invention thus comprises various aspects of the invention that enjoy independent protection. Advantages of the invention
[0140] The invention offers several advantages, which are briefly listed below:
[0141] In the invention, the application device (e.g. rotary atomizer) can be pressed down in temporal and spatial proximity to the actual start of application ("spray point"), so that less time is required for pressing down the application device than with the known method of pressing down the application device in a cleaning device.
[0142] Within the scope of the invention, the amount of coating material used for pressing can be optimized to the dead space volume of the application device, so that when pressing the application device, no coating material escapes from the application device via the nozzle and thus no coating material has to be discarded.
[0143] The pressing-on process according to the invention outside the cleaning device can be carried out with the same coating parameters ("brush parameters") as the actual painting and with an electrostatic paint charge switched on, so that there is hardly any contamination of the outer surfaces of the application device by the pressed-on paint.
[0144] Because of the temporal proximity of the pressing process according to the invention to the subsequent coating process, the pressed-on coating material can hardly dry out in the dead space volume.
[0145]
[0146] 1 rotary atomizer
[0147] 2 painting robots
[0148] 3 Control unit
[0149] 4 Main needle valve A of the rotary atomizer
[0150] 5 Main needle valve B of the rotary atomizer
[0151] 6 gear metering pumps A and B for conveying paints A and B respectively.
[0152] 7 Cleaning device for cleaning the rotary atomizer
[0153] 8 Electrostatic paint charging (“ESTA”)
[0154] 9 bell plates
[0155] 10 Rotation axis of the bell plate
[0156] 11 Paint nozzle in the rotary atomizer
[0157] 12. Nozzle opening of the paint nozzle
[0158] 13 Spray edge of the bell plate 14 Housing of the rotary atomizer
[0159] 15 Valve needle of the main needle valve A
[0160] 16 Main needle valve B
[0161] 17 Common paint supply line in the rotary atomizer
[0162] 18, 19 Branch lines of the paint supply through the main needle valve for paint A
[0163] 20, 21 Branch lines of the paint supply through the main needle valve for paint B
[0164] 22 Detergent supply line in the rotary atomizer for rinsing the rotary atomizer 23-25 Branch lines of the detergent supply line in the rotary atomizer
[0165] 26 Nozzle opening of the detergent supply line in the paint nozzle
[0166] p varnish printing
[0167] Q. Paint delivery flow of the gear metering pump
[0168] Qmax Maximum possible paint delivery rate of the gear metering pump when pressing down. Qiackier Paint delivery rate of the gear metering pump during painting.
[0169] At holding time for pressing down the dead space volume before the programmed start of painting
[0170] tl Start of the rinsing process of the rotary atomizer in the cleaning device
[0171] t2 End of the rinsing process of the rotary atomizer in the cleaning device
[0172] t3 Start of pressing down the rotary atomizer with opening of the main needle valve and starting of the gear metering pump
[0173] t4 Start of filling the dead space volume of the rotary atomizer
[0174] t5 Start of programmed painting start
[0175] T La The filling time for filling the dead space volume
[0176] Tverz delay time of gear metering pump and main needle valve
[0177] Total dead space volume between main needle valves and paint nozzle
Claims
REQUIREMENTS 1. Coating process for coating a component with a coating material, in particular for painting a motor vehicle body component with a paint, comprising the following steps: a) Providing an application device (1), in particular a rotary atomizer (1), with a) a nozzle (11, 12) for dispensing the coating material, a2) a coating agent supply line (17-21) for supplying the coating agent to the nozzle (11, 12), a3) a controllable main valve (4, 5) in the coating material supply line (17-21) for releasing or shutting off a coating material delivery flow (Q) through the coating material supply line (17-21) to the nozzle (11, 12), and a4) a dead space volume (V to t) in the coating agent supply line (17-21) between the main valve (4, 5) and the nozzle (11, 12), b) Pressing the application device (1) with the coating agent, whereby the main valve (4, 5) is open and the coating agent is supplied through the coating agent supply line (17-21) into the dead space volume (V) to t) is pumped downstream behind the main valve (4, 5) to reduce the dead space volume (V to t) to fill at least partially with the coating material, and c) Coating the component with the coating material after pressing the application device (1) onto the component with the coating material, wherein the application device (1) is moved with its color impact point starting at a starting point along a programmed coating path and applies the coating material to the component through the nozzle (11, 12), characterized by d) that pressing down the application device (1) to fill the dead space volume (V tot) occurs while the application device (1) is moving with its color impact point towards the starting point of the programmed coating path or is already at the starting point of the programmed coating path.
2. Coating method according to claim 1, characterized in that, a) that there is a short time period of at most 60 s, 30 s, 15 s, 10 s, 5 s or 2 s between the end of the pressing (t5) and the beginning of the coating (t5), and / or b) that the application device (1) is located at a small spatial distance of no more than 1 m, 50 cm, 25 cm, 10 cm or 5 cm from the starting point of the programmed coating path when pressing down.
3. Coating method according to one of the preceding claims, characterized by the following step: Cleaning the application device (1) in a cleaning device (7) before coating and also before pressing, so that the pressing of the application device (1) takes place outside the cleaning device (7).
4. Coating method according to one of the preceding claims, characterized in that the main valve (4, 5) of the application device (1) remains open between pressing down the application device (1) and the subsequent coating.
5. Coating method according to one of the preceding claims, characterized by a) that a time (t5) is specified as the start of application for the start of the coating at the starting point of the coating path, and b) that when the application device (1) is pressed down, the dead space volume (V tot) is completely filled with the coating material at exactly the specified time (t5) of the start of application, without overfilling the dead space volume (V) to t) and without underfilling the dead space volume (V to t).
6. Coating method according to one of the preceding claims, characterized by the following step: Conveying the coating material by means of a coating material pump (6) through the coating material supply line (17-21) to the nozzle (11, 12), in particular by means of a metering pump (6), in particular by means of a gear metering pump (6).
7. Coating method according to claim 6, characterized by the following steps: a) Determining the dead space volume (V to t) of the application device (1) between the main valve (4, 5) and the nozzle (11, 12), b) Determining a delay time (T Verz) of the main valve (4, 5) and the coating agent pump between a start signal to open the main valve (4, 5) and to start the coating agent pump (6) and the time-delayed subsequent exit of the coating agent from the nozzle (11, 12), c) Specification of a coating agent delivery flow (Q ma x) for pressing down the application device (1), in particular a maximum possible coating agent delivery flow (Qmax) of the coating agent pump (6), d) Programming a time (t5) for the desired application start, e) Calculating a lead time (At) for opening the main valve (4, 5) before the time (t5) of the desired application start to fill the dead space volume (V) to t) of the application device (1), wherein the holding time (At) is calculated from the following values: el) the dead space volume (V to t) of the application device (1), e2) the delay time (T Verz) of the main valve (4, 5) and the coating agent pump (6) and e3) the specified coating agent delivery flow rate (Qmax) for pressing down the application device (1), and f) Opening the main valve (4, 5) at a time (t3) delayed by the holding time (At) before the predetermined time (t5) for the desired application start, in order to press the application device (1) and the dead space volume (V to t) to fill with the coating material before the time (t5) of the desired start of application.
8. Coating method according to claim 7, characterized in that the holding time (At) required for pressing down the application device (1) is calculated according to the following formula: t ^Lade d" Ty erz with At: Lead time required to compress the dead space volume (V) to t) of the application device (1) is required, Tver Z: Delay time of the main valve (4, 5) of the application device (1) and the coating agent pump (6), T L ade: Filling time required to fill the dead space volume (V to t) is required after opening the main valve (4, 5) and starting the gear metering pump (6).
9. Coating method according to claim 8, characterized in that the calculation of the required filling time T La de according to the following formula: with Vtot: Dead space volume (V to t) of the application device (1), ade: Filling time required to fill the dead space volume (V to t) is required after opening the main valve (4, 5) and starting the gear metering pump (6), Q: Coating agent flow rate during filling of the dead space volume (V) to t) of the application device (1), t: Time during the filling of the dead space volume (V) tot) of the application device (1).
10. Coating method according to one of claims 6 to 9, characterized in that a) the application device (1) is pressed down with a larger coating agent delivery flow rate (Qmax) than the subsequent coating of the component in order to fill the dead space volume (Vtot) as quickly as possible, and / or b) that the application device (1) is pressed down with the maximum possible coating agent flow rate (Qmax) that the coating agent pump (6) can supply in order to reduce the dead space volume (V to t) to fill as quickly as possible.
11. Coating method according to one of claims 6 to 10, characterized in that a) the coating agent pump (6) has an acceleration ramp, such that the coating agent delivery flow rate (Q) increases according to the acceleration ramp when the coating agent pump (6) is switched on, b) that the coating agent pump (6) has a deceleration ramp such that the coating agent delivery flow rate (Q) decreases according to the deceleration ramp when the coating agent pump (6) is switched off, and c) that the calculation of the holding time (At) required for pressing is carried out depending on the acceleration ramp and / or the deceleration ramp of the coating agent pump (6).
12. Coating method according to one of claims 7 to 11, characterized by the following steps for determining the delay time (T Ve rz) of the main valve (4, 5) and the coating agent pump (6): a) Filling the dead space volume (V to t) of the application device (1) with the coating material, so that the dead space volume (V to t) preferably completely filled with the coating material, b) switching on the coating material pump (6) and opening the main valve (4, 5) of the application device (1), c) Determining the discharge of the coating material from the nozzle (11, 12) of the application device (1), and d) Determining the delay time (T Ve rz) of the main valve (4, 5) and the coating agent pump (6) as the time interval between switching on the coating agent pump (6) and opening the main valve (4, 5) and the subsequent delayed release of the coating agent from the nozzle (11, 12).
13. Coating method according to one of claims 6 to 12, characterized by the following steps for pressing down the application device (1): a) Specifying a particular coating agent delivery flow rate (Qmax) for pressing down the application device (1) and determining the required holding time (At) for filling the dead space volume (V) to t) depending on the specified coating agent delivery flow rate (Qmax), or b) Specification of a specific holding time (At) for filling the dead space volume (V)to t) and determining the required coating agent delivery rate (Q) depending on the specified holding time (At).
14. Coating method according to one of the preceding claims, characterized by a) that the coating agent supply line (17-21) of the application device (1) splits into at least two line branches (18-20) on the inlet side, b) that a main valve (4, 5) is arranged in each of the pipe branches (18-20) of the coating material supply line (17-21), and c) that the dead space volume (V to t) downstream behind the main valves (4, 5), d) that preferably a rinsing agent supply line (22-24) opens into each of the two line branches (18-20) of the coating agent supply line (17-21), preferably downstream behind the two main valves (4, 5).
15. Coating method according to any one of the preceding claims, characterized by a) that the coating agent pump (6) is a metering pump (6) in which the coating agent delivery flow rate (Q) is substantially independent of the pressure conditions at the inlet and outlet of the metering pump (6), and / or b) that the coating agent pump (6) is a gear metering pump (6), and / or c) that the application device (1) is pressed down until the dead space volume (Vtot) is completely filled within a pressing time of at most 2 s, 1 s, 500 ms, 250 ms, 100 ms, 50 ms, 25 ms, 10 ms or 5 ms, and / or d) that the main valve (4, 5) is a main needle valve (4, 5) and has a movable valve needle (15, 16) which, depending on its position, opens or closes a valve seat and thus also the coating agent flow rate (Q), and / or e) that no further valve is arranged in the coating agent supply line (17-21) downstream of the main valve (4, 5), and / or f) that the application device (1) is a rotary atomizer (1), and / or g) that the maximum possible coating agent delivery flow rate (Qmax) of the coating agent pump (6) used to press down the application device (1) is at least 100 ml / min, 200 ml / min, 400 ml / min or 600 ml / min, and / or h) that pressing down the application device (1) to fill the dead space volume (V to t) is carried out programmatically and automatically before coating, in particular in the case of a color change or after a short rinse of the application device (1), and / or i) that an electrostatic coating agent charging (8) is provided for electrostatic charging of the coating agent, wherein the electrostatic coating agent charging (8) is switched on during pressing, and / or j) that the application device (1) is rinsed before pressing, whereby the coating material is removed from the dead space volume (V to t) is rinsed out and preferably residues of the coating agent and the rinsing agent are removed with compressed air from the dead space volume (V to t) be blown out, and / or k) that the application device (1) is pressed down during a color change, and / or l) that the coating material is a varnish, and / or m) that the components to be coated are motor vehicle body components.
16. Coating system for coating a component with a coating material, in particular a painting system for painting a motor vehicle body component with a paint, comprising a) an application device (1), in particular a rotary atomizer (1), with al) a nozzle (11, 12) for dispensing the coating agent, a2) a coating material supply line (17-21) for supplying the coating material to the nozzle (11, 12) and a3) a controllable main valve (4, 5) in the coating material supply line (17-21) for releasing or shutting off the coating material flow (Q) through the coating material supply line (17-21) to the nozzle (11, 12), and a4) a dead space volume (V to t) in the coating agent supply line (17-21) between the main valve (4, 5) and the nozzle (11, 12), b) a multi-axis coating robot (2) for moving the application device (1), c) a coating agent pump (6) for conveying the coating agent to the nozzle (11, 12) of the application device (1), and d) a control device (3) for program-controlled control of the coating robot (2), the coating agent pump (6) and the main valve (4, 5) of the application device (1), characterized by e) that the control device (3) controls the coating robot (2), the coating medium pump (6) and the main valve (4, 5) of the application device (1) during operation such that the coating system performs the coating process according to one of the preceding claims.
17. Coating system according to claim 16, characterized by a) a cleaning device (7) for cleaning the application device (1), wherein the control unit (3) also controls the cleaning device (7) in a program-controlled manner, and / or b) an electrostatic coating agent charging (8) for electrostatically charging the applied coating agent, wherein the control device (3) also controls the electrostatic coating agent charging (8) in a program-controlled manner, and / or c) a compressed air turbine for driving the rotary atomizer (1) and a compressed air supply for the compressed air turbine, wherein the control device (3) also controls the compressed air supply in a program-controlled manner.