阅读说明：本技术 用于以涂覆剂涂覆构件的涂敷设备 (Coating device for coating a component with a coating agent ) 是由 G.伯尔纳 于 2018-04-27 设计创作，主要内容包括：本发明涉及一种用于以涂覆剂涂覆构件的涂敷设备(1),其包括带有多个喷嘴(3)的压力头(2),从喷嘴可排出涂覆剂,其中,在每个单个喷嘴(3)处安装有喷嘴阀(4),其可打开阀打开时间长度以便将涂覆剂从相应的喷嘴(3)排出,且其中,每个喷嘴阀(4)相应关联有喷嘴阀供给管路(5),其在其排出口(6)处将涂覆剂输送给相应的喷嘴阀(4),该涂敷设备鉴于以下目的,将开头所提及的类型的涂敷设备改进成使得在涂覆过程期间在涂敷设备的多个平行布置的喷嘴处相应产生涂覆剂的尽可能可复制的且可预见的排出量,其特征在于,每个喷嘴阀供给管路(5)具有进入口(7),其可关闭或可闭锁成使得在喷嘴阀供给管路(5)内部封闭地可容纳有涂覆剂的限定配给的量或限定配给的体积。(The invention relates to a coating device (1) for coating components with a coating agent, comprising a pressure head (2) having a plurality of nozzles (3) from which the coating agent can be discharged, wherein a nozzle valve (4) is mounted at each individual nozzle (3) which can open a valve for a length of time in order to discharge the coating agent from the respective nozzle (3), and wherein a nozzle valve supply line (5) is associated with each nozzle valve (4) which delivers the coating agent to the respective nozzle valve (4) at its discharge opening (6), which coating device is improved in such a way that a maximally reproducible and predictable discharge amount of coating agent results in each case at a plurality of nozzles arranged in parallel of the coating device during a coating process, characterized in that each nozzle valve supply line (5) has an inlet opening (7), it can be closed or can be closed in such a way that a defined dispensed quantity or a defined dispensed volume of the coating agent can be accommodated in a closed manner inside the nozzle valve supply line (5).)

1. A coating device (1) for coating a component with a coating agent, comprising a pressure head (2) with a plurality of nozzles (3) from which the coating agent can be discharged, wherein at each individual nozzle (3) a nozzle valve (4) is mounted which is capable of opening a valve for a length of time in order to discharge the coating agent from the respective nozzle (3), and wherein each nozzle valve (4) is associated with a nozzle valve supply line (5), which delivers the coating agent at its outlet opening (6) to the respective nozzle valve (4), characterized in that each nozzle valve feed line (5) has an inlet opening (7), it can be closed or can be closed in such a way that a defined dosed quantity or a defined dosed volume of coating agent can be accommodated in the nozzle valve supply line (5) in a closed manner.

2. Coating device according to claim 1, characterized in that the coating agent is under pressure in the nozzle valve supply line (5), which increases the volume of the interior of the nozzle valve supply line (5) which is not under pressure or is under ambient pressure by an expansion volume, wherein the coating agent can be discharged through the nozzle (3) in the event of a pressure reduction by opening the nozzle valve (4), and wherein the discharged volume of the coating agent corresponds to the expansion volume.

3. A coating apparatus according to claim 2, wherein the nozzle valve (4) is openable during a valve opening time which is greater than a discharge time of the coating agent which is required in order to reduce the pressure in the interior of the nozzle valve supply line (5) to ambient pressure and discharge the expanding volume of coating agent.

4. A coating apparatus according to any one of the preceding claims, wherein a filling valve (8) is associated with the inlet opening (7), which in the open state enables the penetration of coating agent into the nozzle valve supply line (5) and in the closed state prevents the penetration of coating agent into the nozzle valve supply line (5).

5. Coating apparatus according to any one of the preceding claims, characterized in that the nozzle valve supply line (5) is designed to be elastically and/or reversibly deformable and/or reversibly volumetrically changeable.

6. A coating device according to any one of the preceding claims, wherein the nozzle valve supply line (5) is configured as a hose or a pipe.

7. A coating device according to any one of the preceding claims, wherein the nozzle valve supply line (5) is configured as a hose or tube composed of plastic.

8. Coating device according to one of the preceding claims, characterized in that the pressure head (2) is connected to a central coating agent supply line (9) which is connected or connectable to all filling valves (8) in a fluid-conducting manner.

9. A coating device according to claim 8, wherein the central coating agent supply line (9) is connected to a pressure regulating unit (10).

10. A coating device according to claim 9, wherein said pressure regulating unit (10) is connected to an air pressure control unit (11).

11. Assembly comprising a coating device (1) according to any one of the preceding claims and a robot at which the coating device (1) is accommodated.

12. Assembly according to claim 11, characterized in that the robot has a robot arm which is pivotable and/or movable about a plurality of axes and/or the application device (1) is accommodated at a tool center point of the robot arm of the robot.

Technical Field

The invention relates to a coating device (applicationger ä t) for coating components with a coating agent (Beschichtungsmittel) according to the preamble of claim 1, comprising a pressure head (Druckkopf) having a plurality of nozzles from which the coating agent can be discharged, wherein a nozzle valve is fitted at each individual nozzle, which can open the valve for as long as the valve opening time in order to discharge the coating agent from the respective nozzle, and wherein a nozzle valve supply line (DuesenventilLeitung) is associated with each nozzle valve in each case, which supplies the coating agent to the respective nozzle valve at its discharge.

Background

Against this background, document DE 102017101937.5 discloses a coating device having a plurality of nozzles arranged in parallel for discharging (ausbringen) the coating agent. A nozzle valve is associated with each nozzle. When a drop or volume of coating agent should leave the respective nozzle, the respective nozzle valve is opened. The nozzle valve is opened during a defined valve opening time. The nozzle valve is closed again after the valve opening time.

The coating agent can be fed into the coating device by means of a pump (in particular a gear pump) via a central coating agent feed line and distributed there uniformly to the nozzles. In this case, a pressure builds up in the application device, which acts on the nozzle valve when the latter is closed. When the nozzle valve is opened, the pressure can be reduced at the nozzle with the volume of coating agent discharged.

Despite the uniform discharge force acting on all nozzles, different discharge volumes of coating agent and thus different drop sizes occur at different nozzles during the same uniform valve opening time.

In assemblies with a plurality of nozzles arranged in parallel, it is problematic that small differences in nozzle diameter, nozzle length, or additional differences in nozzle geometry or nozzle properties can already lead to inconsistent discharge volumes at different nozzles.

This can be associated with the fact that some coating agents exhibit a pressure-dependent viscosity, i.e. are thixotropic. Associated with this is the problem that the dispensed volume of coating agent at the nozzle (Dosierung) cannot be easily adjusted. If an unforeseen hydrodynamic effect occurs, for example due to differences in nozzle geometry, more or less coating agent will be discharged during the valve opening time than is desired.

However, even if the coating agent exhibits a viscosity that is largely independent of pressure, differences in nozzle geometry and nozzle characteristics can lead to inconsistent or unpredictable discharge volumes of coating agent at different nozzles.

Disclosure of Invention

The object of the present invention is therefore to improve a coating installation of the type mentioned at the outset such that a discharge of coating agent (austritsmenge) which is as reproducible and predictable as possible is produced in each case during the coating process at a plurality of nozzles of the coating installation arranged in parallel.

This object is achieved by the features of claim 1.

According to the invention, each nozzle valve supply line has an inlet opening which can be closed or can be closed in such a way that a defined dispensed quantity or a defined dispensed volume of the coating agent can be accommodated in a closed manner in the nozzle valve supply line.

According to the invention, it is firstly recognized that each nozzle must be considered individually in view of the coating agent to be discharged and the characteristics of the nozzle. It is then recognized that this can be achieved in a particularly simple manner if a defined dosed quantity of coating agent is accommodated in a separate manner in the respective nozzle valve supply line and the nozzle valve supply line functions as a reservoir. Such a reservoir can emit a clearly defined volume of coating agent depending on the pressure prevailing therein, as long as the outlet opening is in fluid connection with the nozzle guide. The pressure ratio in each individual system (which comprises the nozzle valve and the associated nozzle valve supply line) can be used according to the invention to produce reproducible and predictable discharge of coating agent from the respective nozzle. According to the invention, reproducible and predictable volumes of coating agent can be discharged from the nozzle, i.e. essentially independently of its technical properties. Thus, a stable production method is achieved.

Preferably, the coating agent is under pressure in the nozzle valve supply line, which increases the volume of the interior of the nozzle valve supply line, which is not under pressure or is at ambient or atmospheric pressure, by an expansion volume, wherein the coating agent can be discharged through the nozzle by opening the nozzle valve with a reduced pressure, and wherein the discharged volume of the coating agent corresponds to the expansion volume. This ensures that the droplets or droplets of coating agent always have the same volume, i.e. the expansion volume.

According to an advantageous embodiment of the invention, the nozzle valve is opened during a valve opening time (which is greater than the discharge time of the coating agent) which is required in order to reduce the pressure in the interior of the nozzle valve supply line to ambient or atmospheric pressure and to discharge the expanding volume of coating agent. The complete discharge of the entire expansion volume is ensured by a suitable choice of the valve opening time.

According to an advantageous embodiment of the invention, a filling valve (Bef ü llungsventil) is associated with the inlet opening, which in the open state enables the coating agent to penetrate into the nozzle valve supply line and in the closed state prevents the coating agent from penetrating into the nozzle valve supply line, whereby a uniform pressure or a pressure which is suitable for the nozzle valve and the nozzle valve associated therewith can be established in each nozzle valve supply line by means of a valve control unit (which can individually actuate each filling valve).

According to a further advantageous embodiment of the invention, the nozzle valve supply line is designed to be elastically and/or reversibly deformable and/or reversibly changeable in volume. The nozzle valve supply line can thereby be expanded in view of its internal and/or external diameter and can have an expansion volume as an additional volume. It is also conceivable to lengthen the nozzle valve supply line. The material properties of the respective nozzle valve supply lines determine the pressure ratio within them. The pressure or overpressure in the interior of the nozzle valve supply line when the respective nozzle valve is opened is reduced reproducibly due to the reversibility of its shape property (Formverhalten). This ensures that the same volume of coating agent, i.e. the expansion volume or additional volume, is always discharged from the associated nozzle, even if this nozzle differs from the other nozzles in terms of its diameter or other properties.

According to a further advantageous embodiment of the invention, the nozzle valve supply line is designed as a hose (Schlauch) or a pipe (Rohr). The hose or pipe can be easily machined. In addition, the pressure-induced shape change and thus the expansion volume of a cylindrical hose or pipe can be determined computationally relatively easily.

According to a further advantageous embodiment of the invention, the nozzle valve supply line is designed as a hose or a pipe made of plastic. The plastic exhibits less hysteresis properties and assumes its original shape (Ausgangsform) quite accurately after the pressure is reduced. Preferably, the nozzle valve supply line is made of an elastomeric plastic.

In this context, it is also conceivable to produce the nozzle valve supply line from metal if the metal exhibits suitable restoring properties into the original shape after the pressure has been reduced.

According to a further advantageous embodiment of the invention, the pressure head is connected to a central coating agent supply line (which is connected or connectable to all filling valves in a fluid-conducting manner). The coating agent can thus be centrally delivered from the Reservoir (Reservoir) up to the filling valve, wherein the valve control unit controls which filling valve is opened for establishing the appropriate pressure in the nozzle valve supply line and thus for dispensing.

Preferably, all filling valves are opened simultaneously and the same pressure is built up in all nozzle valve supply lines. If all nozzle valve supply lines are configured identically, the receiving capacity of all nozzle valve supply lines is increased by the same expansion volume or additional volume. All nozzles arranged in parallel can thus discharge equally large drops of coating agent.

According to a further advantageous embodiment of the invention, the central coating agent supply line is connected to a pressure regulating unit. It can thereby easily be adjusted that each nozzle valve supply line is loaded with the same pressure, i.e. when the valve control unit opens all filling valves simultaneously.

According to a further advantageous embodiment of the invention, the pressure regulating unit is connected to an air pressure control unit (luftdruckkontileinheit). This ensures that a pressure prevails in the nozzle valve supply line which, in a suitable manner, exceeds the ambient or atmospheric pressure (i.e. the air pressure), so that a reliable discharge of the coating agent is achieved.

According to a further advantageous embodiment of the invention, the assembly can comprise a robot, at which a coating device of the type described here is accommodated. Robots, in particular industrial robots, can be used in painting lines, in particular in the automotive industry.

According to a further advantageous embodiment of the invention, the robot has a robot arm which is pivotable and/or displaceable about a plurality of axes. Alternatively or additionally, the coating device is accommodated at a Tool Centre Point (TCP) of a robot arm of the robot. The coating device can thus be moved easily in all spatial directions and can be pivoted about a plurality of axes.

The coating apparatus described herein may also be used to carry out a method in which the coating agent is discharged under pressure from the nozzle until the pressure drops and is the same as the ambient pressure preferably the coating apparatus is applied to digital painting or for overspray (Ü berspr ü hen).

Drawings

In the drawings:

fig. 1 shows a schematic representation of an application device with a pressure head having 32 nozzles, which are arranged parallel to one another, wherein a nozzle valve and a filling valve are associated with each nozzle, and wherein a nozzle valve supply line in the form of a hose is arranged between each nozzle valve and each filling valve,

fig. 2 shows a schematic representation and a comparison of the time-dependent operation of the filling valve and the nozzle valve from top to bottom, wherein the course of the pressure and the coating agent storage in the hose is shown over time, and wherein the flow of coating agent or material through the nozzle is shown,

fig. 3 shows a cross-sectional view of the hose on the left, the inside of the hose having a first radius (radius, inside) in the pressureless and unloaded state, while on the right, the inside of the hose having a second radius (increased radius, inside) in the pressure-loaded and tensioned state,

fig. 4 shows a table in which the modulus of elasticity and the transverse elongation coefficient (querdehnnungszahl) of different materials, from which the hose described herein can be made,

fig. 5 shows a table in which the modulus of elasticity and the transverse elongation coefficient of the plastic are listed, wherein the hose form factor of different hoses with different radii on the outside and inside is calculated and measured,

fig. 6 shows a table in which the modulus of elasticity and the transverse elongation coefficient of the plastic are listed, wherein the hose shape factor of different hoses with different radii on the outside and inside is calculated, wherein the discharge time and the nozzle resistance for the coating agent are stated according to a rough estimate, and wherein the volume and the pressure of a single drop of coating agent are stated,

fig. 7 shows a table in which the modulus of elasticity and the lateral extension coefficient of the plastic are listed, wherein the hose shape factor of different hoses with different radii on the outside and inside is calculated, wherein the discharge time and the nozzle resistance for the coating agent are stated according to a rough estimate, and wherein the volume and the pressure of a single drop of coating agent are stated.

Detailed Description

Fig. 1 shows a coating device 1 for coating a component with a coating agent.

The coating device 1 comprises a pressure head 2 with a plurality of nozzles 3 arranged in parallel, from which the coating agent can be discharged, wherein at each individual nozzle 3 a nozzle valve 4 is mounted, which can open for a long time in order to discharge the coating agent from the respective nozzle 3.

Each nozzle valve 4 has associated with it a nozzle valve supply line 5 which delivers coating agent to the respective nozzle valve 4 at its outlet opening 6.

Each nozzle valve supply line 5 has an inlet opening 7 which can be closed or lockable in such a way that a defined dispensed quantity or a defined dispensed volume of the coating agent can be accommodated or held in a closed manner in the nozzle valve supply line 5.

The contained, defined dosing volume is at a pressure exceeding ambient or atmospheric pressure.

The coating agent in the nozzle valve supply line 5 is in this respect under pressure, which increases the volume of the interior of the nozzle valve supply line 5, which is not under pressure or is at ambient pressure, by the expansion volume.

The opening of the nozzle valve 4 allows the coating agent to be discharged through the nozzle 3 with a reduced pressure, the discharged volume of the coating agent corresponding to the expansion volume.

The nozzle valve 4 is opened during a valve opening time which is greater than the discharge time of the coating agent. This discharge time is required in order to reduce the pressure in the interior of the nozzle valve supply line 5 to ambient or atmospheric pressure and to discharge the expanding volume of coating agent.

A filling valve 8 is associated with the inlet opening 7, which in the open state enables the coating agent to penetrate into the nozzle valve supply line 5 and in the closed state prevents the coating agent from penetrating into the nozzle valve supply line 5.

The nozzle valve supply line 5 is designed to be elastically and reversibly deformable. The nozzle valve supply line 5 is configured as a hose. The nozzle valve supply line 5 is embodied as a hose made of plastic.

The pressure head 2 is connected to a central coating agent supply line 9 (which is connected or connectable to all filling valves 8 in a fluid-conducting manner). The central coating agent supply line 9 is connected to a pressure regulating unit 10. The pressure adjustment unit 10 is connected to an air pressure control unit 11.

The coating apparatus 1 can be accommodated at a robot, not shown. In particular, the robot may have a robot arm which is pivotable and movable about a plurality of axes, wherein the application device is accommodated at a tool center point of the robot arm.

Fig. 2 shows the mode of action of the coating installation 1 according to different temporal profiles. The uppermost graph shows that the filling valve 8 is opened and closed twice during a time interval of about 5 milliseconds (ms). That is, if the associated filling valve 8 in series is closed and a defined metered amount or a defined metered volume of coating agent is contained in the nozzle valve supply line 5 in a closed and pressurized manner before the nozzle valve 4 is opened, the associated nozzle valve 4 is opened once in the same time interval.

The third diagram, viewed from above in fig. 2, shows that if the nozzle valve 4 is closed and the filling valve 8 is opened, a pressure increase is achieved in the interior of the nozzle valve supply line 5. The pressure in the nozzle valve supply line 5 rises to a value preset by the pressure regulating unit 10. Due to this pressure, the nozzle valve supply line 5, which is embodied as a hose, is expanded. The volume of the hose that is not under pressure is increased by an expansion volume.

The expansion volume and thus the volume of coating agent which can be additionally accommodated under pressure in the hose depend on the preset pressure of the pressure regulating unit 10 and on the properties of the hose.

The filling time depends on the design of the valve, in particular on the resistance of the valve and the viscosity of the coating agent. The filling time should be long enough to account for the different viscosities.

The filling valve 8 is closed after the desired filling of the nozzle valve supply line 5 (including the filling of the edge region). Both valves 4, 8 are closed for a relatively short time.

When the nozzle valve 4 is then opened, the coating agent is discharged via the nozzle 3 until the pressure in the nozzle valve supply line 5 is equal to the ambient or atmospheric pressure. The dispensing of the coating agent takes place under approximately controlled pressure or force.

As can be appreciated from fig. 2, the discharge time is shorter than the valve opening time (during which the nozzle valve 4 is open). The discharge time depends on the design of the respective nozzle valve 4 and the viscosity of the coating agent. The expansion volume of the coating agent or lacquer discharged through the nozzle 3 does not depend on the viscosity of the coating agent or lacquer. Thus, dirt or abrasion effects and differences or fluctuations in viscosity have no or little effect on the drop volume or droplet volume.

The expansion volume of the coating agent discharged from the nozzle 3 can be determined according to fig. 3 and the following formula.

The following equation illustrates how the increase in the inner radius of the hose can be determined:

in this formula:

v the lateral extension coefficient (lateral contraction coefficient or poisson's ratio),

e, the modulus of elasticity of the rubber composition,

r_ithe inner radius of the inner tube is,

r_athe outer radius of the outer tube is,

△r_iincrease of inner radius due to increase of pressure

p_i The pressure on the inner surface of the nozzle valve supply line 5,

delta V expansion volume due to pressure increase and

C^*hose form factor at lower pressures.

The expansion volume (i.e. the increase in volume relative to the hose not under pressure) and thus the quantity of coating agent that can additionally be accommodated in the hose can be determined from the following formula. In addition, the hose form factor can be determined.

Tables listing material data and data determined by calculations or experiments are illustrated in fig. 4 to 7.

List of reference numerals

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