WO2018109307A1

WO2018109307A1 - Paint applicator comprising multiple cups

Info

Publication number: WO2018109307A1
Application number: PCT/FR2017/053360
Authority: WO
Inventors: Sophie Vidal
Original assignee: Compagnie Plastic Omnium
Priority date: 2016-12-14
Filing date: 2017-12-04
Publication date: 2018-06-21
Also published as: FR3059918A1

Abstract

The invention relates to a bowl-type paint applicator (2) comprising multiple spray cups (6, 8, 10), each cup having a different diameter (D1, D2, D3) to the other cups.

Description

Paint applicator with several cups

The invention relates to the field of paint applicators, more particularly bowl type paint applicators.

The car body parts are painted in cabins designed for this purpose. Generally, the painting process consists of the successive application of three different coatings on the part. A first coating, called primary, has the function of promoting the attachment to the part of the second coating. A second coating, called base, has the function of giving color to the room. Finally, a third coating, called varnish, has a function of holding and protecting the base. The pieces to be painted circulate in the painting booth in front of different paint stations, such as "painter robots", to receive the primary, then the base and finally the varnish. It can also be fixed spray stations, the piece being moved in front of the sprayer.

In the following description, the term paint corresponds to at least one of these three coatings.

The bodywork parts have portions having more or less large surfaces. For example, a bumper may have solid portions for which the surface to be painted is important, and grids for which the surface to be painted is relatively small.

In order not to waste paint, it is necessary to set up a device and / or a method to obtain a good coefficient of transfer of the paint on the part. The transfer coefficient is the amount of paint deposited on the part compared to the amount of paint sprayed from a sprayer. In other words, it is necessary to make sure to deposit on the piece the maximum of spray paint.

One current solution is to equip the paint booth with several sprayers, often two in each layer of coating (primer, base and varnish). These can be sprayers mounted on robotic and articulated arms, arms programmed to follow a precise trajectory at a given speed depending on the parts and areas to be painted. They may also be sprayers mounted on a stationary spray station, the part being moved in front of the sprayer.

These sprayers comprise at their end a bowl-shaped applicator. Each bowl has at its free end a paint spray cup. The cup is rotated and paint is injected at the base of the cup. The paint is plated on the wall of the cup due to the centrifugal force and is divided into droplets by the shape of the cup and its rotation. The droplets are then projected to the room to be painted from the cup. The spray of paint can be focused by jets of air projected around the cup. These jets of air take the form of a skirt surrounding the cup and are called "skirt tunes". These jets of air are projected from the end of the applicator all around the cup to conform the spray paint and atomize the paint.

Each sprayer includes a cup of different diameter and is intended to paint different surfaces. Large surfaces are painted with a large-diameter sprayer, and thinner surfaces are painted with a small-diameter sprayer to minimize paint loss.

However, and given the industrial rates to be respected, a room can not stay too long in front of a sprayer. In order to be able to respect these rates, it is frequent that an area is painted by a sprayer equipped with a cup not adapted for this zone. This is the case of small areas painted by a sprayer equipped with a large diameter cup. This practice results in a low transfer coefficient, reflecting a significant loss of paint. Sometimes a part must be painted by a single robot while it has surfaces of various sizes which also leads to a significant loss of paint.

An object of the invention is to eliminate, or at least to significantly limit, all or part of the aforementioned drawbacks, by providing a painting device to obtain a significant transfer coefficient while maintaining an optimal paint rate.

For this purpose, the invention relates to a bolus-type paint applicator comprising a plurality of spray cups each having a different diameter of the other cups.

Thus, a sprayer, for example a robotic arm or a fixed spray station, equipped with such an applicator will be able, during the time during which a piece is in front of him, to alternate from one cup to another in order to paint each zone. a body part with the cup adapted in the time allotted to it. This improves the transfer coefficient while maintaining a high paint rate. In addition, in the case of a painter robot, the latter will be able to adopt a specific path depending on the cup in action and therefore the area to be painted. In the case of a fixed spray station, the latter will be able to alternate between different cups depending on the area of the room facing him. We then have a transfer coefficient greater than a sprayer having only one cup and painting areas of fine and wide surfaces with the same cup. It is also possible to reduce the number of sprayers per cabin because the same sprayer can paint large and thin surfaces, which results in a saving of time (due to the decrease or even the disappearance of the transfer time between two paint stations) and maintenance (less sprayers). The use of such applicators could also make it possible to develop a painting sequence allowing a saving of time and thus an acceleration of paint rate.

The applicator according to the invention may optionally comprise one or more of the following characteristics:

the cups are nested one inside the other concentrically; the applicator comprises three cups, a first cup having a diameter selected from values between 25 and 35 mm, a second cup having a diameter chosen from values between 45 and 55 mm and a third cup having a diameter chosen from among values between 65 and 75 mm; each cup is connected to a pipe adapted to feed the cup in paint, each pipe being equipped with a valve adapted to allow control of the contribution of paint to the cup;

the applicator comprises at least one skirt air diffusion channel;

the applicator comprises a plurality of skirt air diffusion channels, each of the channels is adapted to orient the spray paint by only a portion of the cups, and;

- the air of skirt is negatively charged.

According to the invention there is also provided a paint spraying device, preferably a robotic arm, comprising an applicator according to the invention.

According to the invention there is also provided a method of spraying paint using an applicator according to the invention.

The paint spraying method using an applicator according to the invention may optionally include one or more of the following features:

paint is sprayed successively on a piece using different cups of the applicator;

a first surface of a part is painted with a first cup and a second surface with a width different from the first surface by means of a second cup of a diameter different from that of the first cup;

a trajectory of a robotic arm carrying the applicator is adapted according to a surface to be painted by at least one cup of the applicator, and;

which all the cups spray paint at the same time.

We will now present an embodiment of the invention in support of the appended figures, which are provided by way of examples and are not of any character in which:

- Figure 1 is a perspective view of a paint applicator according to the invention;

- Figures 2 and 3 are partial sectional views of a paint applicator according to the invention.

Referring now to Figure 1 which shows an example of paint applicator 2 type bowl, comprising a plurality of spray cups each having a different diameter of the other cups. Such an applicator is intended to be mounted on a sprayer (not shown).

According to the example of Figure 1, the paint applicator 2 comprises a main body 4 and three cups 6, 8 and 10 of different diameters. The cups are naturally arranged at the end of the bowl opposite the robotic arm or the spray station and are fixed to each other. The cup 6 is of small diameter and will be designated by the term "small cup", the cup 8 is of medium diameter and will be designated by the term "medium cup" and the cup 10 is of large diameter and will be designated by the term "large cup". The cups are three in number here but their number could be lower or higher.

The three cups are nested one inside the other in a concentric manner, they therefore share the same axis of rotation A. In this example, the small cup 6 has a diameter D1 of 30 mm, the average cup 8 has a diameter D2 of 50 mm and the large cup 10 to a diameter D3 of 70 mm. The three cups have a different flare. Each cup may have a shape capable of allowing fragmentation of the paint injected into droplets. Each cup may comprise on the contour of its opening a set of filaments (not shown) on which the droplets will circulate before being released as a spray towards the piece to be painted.

The applicator comprises at its end on which the cups are mounted, that is to say at the base of the cups, a flat surface 12 comprising a set of orifices 13. This set is capable of creating an air flow to focus the spray paint spray from the cups. These orifices have different orientations to more or less focus the spray paint, as will be shown later.

It may also be oriented nozzles to focus the spray paint. The surface

12 is flat but can adopt any other form to improve the focus of the spray paint.

Figures 2 and 3 are partial sectional views of the applicator to better understand its internal structure. The cups 6, 8 and 10 are respectively supplied with paint by pipes 14, 16 and 18 passing through the applicator. The pipe 14 feeds the small cup 6 in paint, the pipe 16 feeds the average cup 8 in paint and the pipe 18 supplies the large cup 10 in paint. These three pipes are put in place in an always immobile product injection block located centrally in the applicator and at the base of the cups. Each pipe may be equipped with a valve (not shown) to control the passage of paint through the pipes. The pipes may have as a source of paint a single tank or several different tanks. In the case of a single tank, it is possible that only one pipe is connected to the tank, the pipe being subdivided into as many branches as there are cups once the pipe has arrived at the end of the applicator near the cups. The paint routing mechanism is identical to that used in the prior art and will not be detailed here.

A turbine block 22 is located around the product injection block. This turbine unit comprises a rotor and is able to rotate the cups. The rotation of the cups is identical to that used in the prior art and will not be detailed here.

The set of orifices 13, able to create a flow of air making it possible to focus the spray paint sprayed from the cups, is connected to air diffusion channels 24 and 26. These channels 24 and 26 are included in FIG. an air supply unit 28. This power supply carries the flat surface 12 of the applicator. The channels 24 and 26, by supplying air to the set of orifices 13, allow the projection of air from the flat portion 12 of the applicator, in order to focus the spray paint sprayed from the cups. These channels open onto the flat surface 12, at the level of the orifices 13. In the case of FIG. 2, the first air channel 24 allows the projection of a first air stream 32 adapted to the small dish 6 and to the average cup 8 (that is to say able to focus a paint spray emitted from these cups), and the second channel 26 allows the projection of a second air flow 34 adapted to the large cup 10. In in other words, these channels 24 and 26 will lead to orifices 13 oriented differently to create air skirts of different diameters and adapted to different cups. In the example illustrated, the number of skirt and cup air distribution channels is different. It can however be identical. It is also conceivable that the air flow or flows are negatively charged. As the paint is also negatively charged at the outlet of the cup (s), the interaction between the air and the paint makes it possible to focus the spray paint better. In addition, the negative charge of the paint is maintained to the piece to be painted, which is neutral. This increases the transfer coefficient of the paint on the piece. The skirt air supply unit 28 also comprises at its interface with the large diameter cup an air channel 30 which is important for rotation and which can also be used to provide anti-pressure.

The mechanism for projecting skirt airs is identical to that used in the art previous and will not be detailed here.

However, it is interesting to note that the use of several cups of different diameters makes it possible to create several paint sprays of different diameters without having to use too much skirt air which can sometimes reduce the transfer coefficient because of the effects of rebound of the paint on the important air volumes created near the room.

In operation, a piece to be painted is conveyed in front of a sprayer. The turbine unit 22 rotates the cups around the axis A. A first cup is then supplied, adapted to the surface to be painted, via the pipe connecting this cup to a source of paint. This routing may be enabled by opening a valve at the pipe connecting the cup to a paint source.

The paint entering the rotating cup is plated on the wall of the latter because of the centrifugal force resulting from the rotation of the cup by the turbine unit. The paint spreads over the entire surface of the cup as it travels to the distal end of the cup. The droplets of paint arriving at the end of the cup travel along the filaments disposed on the contour of the distal end of the cup and are released to form a paint spray. This spray is focused via a skirt air adapted to the cup and follows a general direction parallel to the axis of rotation A.

In the case of a robotic arm, it will follow a programmed path to paint the surface of the room for which the cup is adapted.

Once the first painted surface, the paint supply of the first cup is stopped by closing the valve controlling the supply of paint through the supply pipe of the cup. The same activation mechanism is then repeated to paint a second surface different from the first, for example finer than the latter. Then activates another cup adapted to this second surface. The activation and operation mechanism is the same as for the first cup. The trajectory then followed by the robotic arm is adapted to the surface to be painted by the second cup to further improve the transfer coefficient.

This sequence of operation is limited to the successive activation of two cups, one cup at a time. However, it is possible for example:

- activate a third cup after the second;

- Activate the second cup without having stopped the power of the first;

- activate several cups together; or

- to activate all the cups together, in the case of a surface for which a large diameter cup is adapted, in order to increase the paint yield.

It is also possible to alternate between the cups as many times as necessary to paint a room to optimize the painting process. In the case of a part comprising two ends having large surfaces to be painted and a central portion comprising a surface to be painted finer. It is then possible to paint a first end with a first cup adapted to the surface to be painted, then to paint the central portion with a second cup of smaller diameter than the first cup and finally, to reuse the first cup to paint the second end.

The invention is not limited to the embodiments presented and other embodiments will become apparent to those skilled in the art.

Nomenclature

2: applicator

4: main body of the applicator

6: small cup

D1: diameter of the small cup

8: medium cup

D2: diameter of the middle cup

10: big cup

D3: diameter of the large cup

12: flat surface

13: holes

14: feed pipe of the small cup

16: Medium Cup Feeder Pipe 18: Large Cup Feeder Pipe 20: Injection Block Product

22: turbine block

24: the first skirt air projection channel 26: the second skirt air projection channel 28: the skirt air supply unit

30: anti-depression air channel

32: first airflow

34: second airflow

Claims

claims

1. Bowl type paint applicator (2), characterized in that it comprises a plurality of spray cups (6, 8, 10) each having a different diameter from the other cups.

2. Applicator (2) according to claim 1, wherein the cups (6, 8, 10) are nested one in the other concentrically.

3. Applicator (2) according to any one of the preceding claims comprising three cups (6, 8, 10), a first cup (6) having a diameter (D1) selected from values between 25 and 35 mm, a second cup (8) having a diameter (D2) selected from values between 45 and 55 mm and a third cup (10) having a diameter (D3) selected from values between 65 and 75 mm.

4. Applicator (2) according to any one of the preceding claims, wherein each cup (6, 8, 10) is connected to a pipe (14, 16, 18) adapted to feed the cup

(6, 8, 10) in painting, each pipe (14, 16, 18) being equipped with a valve adapted to allow the control of the contribution of paint to the cup (6, 8, 10).

5. Applicator (2) according to any one of the preceding claims comprising at least one channel (24, 26) skirt air diffusion (32, 34).

6. An applicator (2) according to claim 5 comprising a plurality of skirt air diffusion channels (24, 26) (32, 34), each of the channels (24, 26) is adapted to orient the spray paint by only a part cups (6, 8, 10).

An applicator (2) according to any one of claims 5 or 6, wherein the skirt air (32,34) is negatively charged.

A paint spraying device, preferably a robotic arm, comprising an applicator (2) according to any one of the preceding claims.

9. Paint spraying process using an applicator (2) according to any one of the preceding claims.

10. The method of claim 9 wherein successively spraying paint on a workpiece using different cups (6, 8, 10) of the applicator.

11. Spraying method according to any one of claims 9 or 10, wherein a first surface of a workpiece is painted with a first cup (6, 8, 10) and a second surface with a different width the first surface with a second cup (6, 8, 10) of a different diameter than the first cup.

12. A method of spraying according to any one of claims 9 to 11, wherein a trajectory of a robotic arm carrying the applicator (2) is adapted according to a surface to be painted by at least one cup (6, 8, 10) of the applicator.

13. Spraying process according to claim 9, wherein all the cups (6, 8, 10) spray paint at the same time.