IT202100019748A1 - Improved paint station, paint system including such a paint station, and method of painting. - Google Patents

Description

Improved paint station, paint system including such a paint station, and method of painting

The present invention relates to an improved painting station, a painting plant including such a painting station and painting method.

Field of invention

Pi? in detail, the invention relates to a painting station and a related plant of the above type, designed and manufactured in particular to allow online control of the thickness of the painting of pieces or products, such as tiles, panels and the like, so as to control the thickness of the applied layer of paint.

In the following, the description will be? aimed at the painting of panels and similar pieces, but ? it is clear how the same should not be considered limited to this specific use.

Known technique

How?? It is well known that there are currently painting plants for painting panels, majolica and the like. These plants include painting stations for applying layers of paint on the articles, and in particular on their upper surface.

Normally the painting of pieces takes place by means of one or more? frequently, more painting operations. In other words, the painting of the piece takes place with the overlapping of several? layers of paint on top of each other.

It often happens that process errors can occur, such as too little paint or too much paint applied.

To detect these errors, a manual control by an operator is currently required, which often takes place at the end of the batch and/or at the change of processing. This involves a first disadvantage for which if the quantity? of paint is wrong often it is necessary to discard the pieces. Another drawback? linked to the fact that, not having a continuous control of the applied paint thickness, but a sample check, c?? the risk of wasting several hours of work. Therefore, sometimes, to avoid the risk of many panels produced, ? It is possible to arrange the panels with a second processing cycle, but this action must be done manually. In some cases, it is also necessary to carry out checks on some specific points of the painting, the so-called "spot" check.

These problems cannot be solved by means of known painting systems, which are rather rigid for the control of the painted pieces, both at the end of the painting operations and during the same.

It is evident that this procedure is onerous in economic terms, since very often the products that may not be painted correctly must be discarded. Furthermore, if a major paint error or problem is not detected quickly, there is the potential for an entire batch of parts to be scrapped or destroyed, or at best, reintroduced into the paint process.

Also, nowadays paint is often wasted, why? it is applied in excess, not being able to achieve precise and continuous control of the dosage.

Purpose of the invention

In the light of the above, it is, therefore, the object of the present invention to propose a painting station capable of promptly detecting any defects and allowing immediate adjustment of the painting parameters.

? It is also an object of the present invention to propose painting systems which can possibly correct the painting errors of one or more? any stations.

? It is also an object of the present invention to propose an operating method for painting systems, capable of correcting painting errors of one or more? any painting stations.

Object of the invention

Therefore, a specific object of the present invention is a painting station, for painting pieces, such as panels, majolica and the like, comprising a cabin having an inlet opening, for the entry of a piece to be worked according to a feed direction, and an outlet opening, through which the painted piece is extracted from the cabin, a unit? of painting, for the commanded application of paint on a surface of said piece, a detection sensor, configured to detect the thickness of the paint applied by said unit? of painting on a test surface, and a unit? control logic, in which said unit? control logic ? functionally connected to said detection sensor, to acquire the data detected relating to the thickness of the paint applied on said test surface by said unit? of painting.

Always according to the invention, said unit? control logic can? be connected functionally to the unit? of painting, so as to check the painting parameters according to the data relating to the thickness of the paint applied on said test surface.

Still according to the invention, said test surface can be the surface to be painted of said piece.

Advantageously according to the invention, said test surface can be placed on a plate, preferably made of metal.

Further according to the invention, said station can? understand a? unit? handling for handling the piece to be painted inside said cabin, and said test surface can? be arranged on said handling means.

Preferably according to the invention, said unit? of handling pu? comprise a pair of driving rollers, and a conveyor belt moved in rotation by said pair of rollers, and said test surface can? be placed on said conveyor belt.

Always according to the invention, said station can? understand: a plurality? test surfaces, having an orientation transversal to the direction of advancement of the piece; and/or a continuous test surface oriented in the direction and in the feed direction a of the piece; and/or the test surface ? discontinuous, preferably consisting of a plurality? of rectangles, forming a discontinuous strip oriented in the direction of advancement of the piece.

Still according to the invention, said station can? comprising means for cleaning the surface of the conveyor belt from the paint applied for the paint thickness measurement test, comprising a doctor blade, capable of interfering with the surface of the conveyor belt, so as to scrape the paint arranged thereon and collect it, a rubber block, arranged on said doctor blade, intended to interfere on the surface of said conveyor belt.

Advantageously according to the invention, said detection sensor can be selected from one of the following types: infrared radiation; to magnetic detectors; eddy current; ultrasound; optical; a weight sensor; or based on destructive techniques.

Further according to the invention, said detection sensor can be installed inside the cabin.

Preferably according to the invention, said detection sensor can be installed outside said cabin, arranged in correspondence with said outlet opening.

Always according to the invention, said unit? of painting can? be a paint sprayer, wherein said paint sprayer comprises an electric pump, connected to said unit? control logic, and at least one nozzle for spraying the paint, in which said unit? control logic ? configured to drive said electric pump so as to increase and decrease the paint sprayed from said nozzle of said paint sprayer.

Still according to the invention, said unit? of painting can? be of the type roller, in which the unit? of roller painting comprises a roller, for the application of paint, and a pneumatic actuator connected to said unit? control logic and coupled to said roller, to adjust the contact pressure of said roller with the piece to be painted, and in which said unit? control logic ? configured to drive said pneumatic actuator so as to increase and decrease the paint applied by said roller onto said piece to be painted.

Further according to the invention, said station can? include a signaling device for the user in case a different paint thickness from the desired one is detected, capable of emitting an acoustic, luminous, written signal, on a mobile device or mobile support, such as a tablet, vibration, wearable.

A further object of the present invention is a painting plant, for painting and processing pieces, such as panels, majolica and the like, comprising at least one painting station as defined above, an inlet transport device arranged so as to feed the pieces to be painted and introduce them into said painting station through said inlet opening, an output conveyor device, arranged so as to pick up the painted pieces leaving from said painting station through said outlet opening, conveying said painted pieces into a direction of advancement, and at least one further transport device, arranged at said outlet opening of said painting station, in which said unit? control logic of said painting station ? functionally connected to said further conveyor belt, and in which, following painting by means of said unit? of painting, said detection sensor measures the thickness of the paint applied by said unit? of painting, such that, in the event that said thickness was above or below a threshold, said unit? central control activates said further conveyor belt so as to pick up said piece.

Still according to the invention, said plant can include a connected piece magazine called infeed conveyor belt.

Still according to the invention, said plant can comprising at least one further station for processing said painted piece outgoing from said painting station.

Advantageously according to the invention, said plant can include at least a first further painting station functionally connected to said unit? central control of said painting station, so that said unit? central control can adjust the painting parameters of said first painting station.

Furthermore, according to the invention, said plant can include a waste warehouse, and said additional conveyor belt can? be a deviation conveyor belt, connected to said reject warehouse.

Preferably according to the invention, said further conveyor belt can be a re-work conveyor belt, which connects said outlet opening to the entrance of said cabin, in which said unit? control logic picks up the painted piece in said painting station in the event that it is not painted sufficiently following the detection carried out by means of said detection sensor, bringing it back inside said painting station by means of said re-working belt to carry out a new painting by means of this unit? of painting.

Still according to the invention, said plant can include an abrasion or sanding station, and said further conveyor belt can? be a rework conveyor belt, connecting said outlet opening to said abrading or polishing station, wherein said unit? control logic picks up the painted piece in said painting station if it is excessively painted following the detection carried out by means of said detection sensor, returning it to said abrasion or smoothing station by means of said re-working belt.

The subject of the present invention is also a painting method comprising the steps of: carrying out the painting of a piece by means of a unit? of painting); detecting the thickness of the paint applied to said piece by means of a detection sensor; and adjust one or more? parameters to carry out a subsequent painting.

Still according to the invention, said parameters for carrying out a subsequent painting can comprise the regulation of the power supply of an electric pump of a paint sprayer and/or the regulation of the power supply of a pneumatic actuator of a roller paint applicator.

Still according to the invention, said step for detecting the thickness of the paint can take place by means of a detection sensor selected from one of the following types: infrared radiation; to magnetic detectors; eddy current; ultrasound; based on the measurement of the difference in thickness before and after the painting from the said unit? of painting; a weight sensor; based on destructive techniques; or based on distance measurements.

Advantageously according to the invention, said method can understand the step of repeating the step of carrying out the painting of a painted piece using said unit? of painting, in the event that the thickness of the applied paint as detected in the paint thickness detection phase was insufficient.

Further according to the invention, said method can understand the phase of discarding the piece painted by said unit? of painting, in the event that defects are detected in said phase of detecting the thickness of the paint.

Brief description of the figures

This invention will come now described for illustrative but not limiting purposes, according to its preferred embodiments, with particular reference to the figures of the attached drawings, in which:

figure 1 shows a schematic plan view of a painting station according to the present invention;

Figure 2 shows a schematic side view of a painting station according to Figure 1;

Figure 3 shows a schematic side view of the painting station according to Figure 2 in the stage of spraying the paint onto a panel or piece;

Figure 4 shows a schematic side view of the painting station according to Figure 2 in the phase of detecting the thickness of the paint deposited on the panel or piece;

figure 5 shows a schematic side view of the painting station according to figure 2 in the panel outfeed phase from the station itself;

figure 6 shows a second embodiment of the painting station according to the present invention;

Figure 7 shows cleaning means of a conveyor belt of the painting station according to Figure 6;

figure 8 shows a third embodiment of the painting station according to the present invention;

figure 9 shows a fourth embodiment of the painting station according to the present invention;

figure 10 shows a first embodiment of a painting plant;

Figure 11 shows a second embodiment of a painting plant;

Figure 12 shows a third embodiment of a painting plant;

Figure 13 shows a fourth embodiment of a painting plant;

Figure 14 shows a fifth embodiment of a painting plant; And

Figure 15 shows a sixth embodiment of a painting plant.

In the various figures, similar parts will be indicated with the same reference numbers.

Detailed description

With reference to figures 1 and 2, a painting station 1 can be observed, an infeed conveyor belt 21, moved by rollers 211 arranged parallel to each other and transversely with respect to the direction of advance A, and an outfeed conveyor belt 22, moved by respective rollers 221, also arranged parallel to each other and transversely with respect to the feed direction A.

The painting station 1 comprises a booth 11, a detection sensor 12 and a unit? painting 13.

The booth 11 has an inlet opening 111, arranged in correspondence with the inlet belt 21, through which the piece to be painted P is introduced and moved along the direction A, and an outlet opening 112, through which the painted piece is extracted from the painting station 1 and conveyed by the outgoing conveyor belt 22.

The painting station 1 comprises, disposed inside the cabin 11, a unit? painting 13, which in the case in question ? a paint sprayer 13, for spraying or nebulizing the paint on the piece P while it is being moved inside the booth 11. In this case, the paint sprayer 13 comprises one or more? nozzles through which ? It is possible to spray the paint to be applied on the upper surface Ps of the piece to be painted P.

In other embodiments, the spray system may also include robots, so you can have one or more? fixed nozzles, or one or more? nozzles moved (inside the cabin 11), automatically.

As you can see, the paint sprayer 13 ? arranged, with respect to the feed direction A of the piece P, upstream of the detection sensor 12.

In other embodiments, the unit? of painting 12 pu? be of different types. For example, the unit? of painting 13 pu? be of the roller type, i.e. it provides pneumatic moving parts for one or more? rolls on which? applied the paint, which are then placed in contact with the upper surface of the workpiece P, while the same ? moved in feed direction A.

In other embodiments the? unit? of painting 13 pu? also be of the type for icing application.

Furthermore, still inside the painting station, is it expected a unit? movement 14, in turn comprising a pair of rollers 141 and 142, which move a belt 143 in rotation according to the arrow B, to allow the movement of the piece P inside the cabin 11 always in the forward direction A.

The thickness detection sensor 12 has the purpose of detecting the quantity? of paint applied by the unit? sprayer 10, which, in the embodiment in question, comprise, as mentioned, a paint sprayer 13.

The detection sensor 12 ? able to measure the thickness of the paint V applied by the unit? painting 13.

Said detection sensor 12 can? be made according to different technologies. In a preferred embodiment the detection sensor 12 ? infrared radiation, which ? capable of measuring any layer of coating or paint V on any substrate, regardless of the material used. Furthermore, the infrared radiation detection sensor 12 ? also able to accurately detect the thickness of the paint, even fresh, i.e. just applied.

The infrared radiation thickness detection sensor 12 operates by detecting the infrared radiation emitted by the painted upper surface Ps of the piece P. In particular, at the beginning the detection sensor 12 emits a radiation which locally heats the material (the the size of the spot is variable, as is the shape of the heating pulse) and then the infrared radiation emitted by the previously heated surface is detected. The detection sensor 12 works since? the cooling profile (which is inferred from the infrared radiation emitted) ? characteristic of the substrate and the thickness of the applied paint.

In some embodiments, the radiated stimulus light can be pulsed or modulated by a step signal, with a variable duty-cycle according to the needs? and the composition of the paint applied by the paint sprayer on the surface of the piece P. Furthermore, by varying the duty-cycle, and carrying out different measurements, ? It is possible to detect various information about the application of the paint V on the surface Ps of the piece P.

Normally, for the correct operation of the detection sensor 12 of the thickness ? generally it is necessary to carry out a calibration operation on a known piece (that is a piece P or panel worked and painted correctly) of which the thickness of the paint is precisely known, so? to carry out measurement calibrations. Typically, the calibration is on one, preferably two or more? measuring points, averaging the results obtained and calculating the deviation, for greater precision.

In some embodiments the calibration takes place according to the following procedure:

- characterizing the thermal response of the substrate; - also characterizing the thermal emission curve of the coating (which can be deduced from the infrared radiation emitted after heating).

The characterization of the coating is done by considering two limit situations: small thickness and large thickness (which obviously must be known). In practice, it is necessary to carry out the calibration of the system upstream for each paint used, cos? to acquire the cooling curve at two known thicknesses and with these data the cooling for each thickness is interpolated.

After calibration, the system can? be put online and ? ready to measure.

In other embodiments? It is possible to make a detection sensor 12 based on magnetic detectors, which allow the measurement of non-magnetic layers or coatings on a ferrous substrate.

In another embodiment? Is it possible to use systems based on eddy currents as a detection sensor 12 of the thickness, so? to measure the non-conductive coating on a non-ferrous metal substrate.

In a further embodiment, the thickness detection sensor 12 is of the ultrasonic type, which allows the measurement of paint coatings on non-metallic substrates. Typically, this detection technology ? used for dry coatings, and avoids contact measurements.

In a further embodiment it is possible to use a direct measurement as detection sensor 12, measuring the difference in thickness between before and after painting. In practice, this would be a measure of distance. Distance measurements are needed because? allow you to measure the distance between the measuring tool and the panel before and after painting. Obviously, after painting, the thickness of the panel increases, so the distance from the instrument decreases, and therefore ? It is possible to calculate the thickness of the paint by difference.

In another embodiment, the detection sensor 12 is a weight sensor, detecting the difference in weight of the piece P before and after painting.

In other embodiments? It is possible to use 12 destructive techniques as a thickness detection sensor, in which after painting the paint is removed from a small portion of the finished piece, in order to measure the applied thickness. .

The detection sensor 12, in the embodiment under examination, is arranged inside the cabin 11. However, in other embodiments, as better explained below, said detection sensor 12 can? also be arranged outside the booth 11, so as to intercept and measure the thickness of the paint of the piece P leaving the booth 11. In this case, the detection of the thickness of the paint applied by the unit? of painting 13 takes place outside the cabin 11.

In addition, as better described below, ? It is possible to read the thickness of the paint not only on the piece P, as indicated above, but also on the conveyor belt 143 of the painting booth 11 (inside or outside said booth 11), giving the command to the sprayer to spray on the carpet of said conveyor belt 143 in a free space between the pieces for sample readings. In other words, the unit? varnishing unit 13 sprays the varnish onto the piece and at least partially onto the conveyor belt 143 at the same time, or directly onto the conveyor belt 143 only in a test area, so that the thickness of the correct varnish can subsequently be determined. ? otherwise? a system for recovering the paint for cleaning the conveyor belt 143 is provided.

In a further embodiment, metal plates can be provided directly on the conveyor belt 143 (not shown in the figures) in which ?continuously? the paint heads.

In another embodiment, the thickness and correct painting by the unit? The painting process 13 is performed by giving the command to apply paint on a specific sample substrate or test area, arranged inside the booth 11 or just at the exit. In particular, ? It is possible to arrange inside the cabin 11 a small metal plug (not shown in the figure) to be painted if necessary when it is necessary to carry out control tests, so? then to carry out the thickness measurement on this metal dowel. Also in this case means are provided for cleaning the metal plug to carry out the subsequent machining tests.

The advantage of measuring the thickness on the conveyor belt 143 or on another known substrate? that eliminates the need? having to characterize the painted substrates.

The painting station 1 also includes a unit? control logic 15, functionally connected both to the detection sensor 12 and to the unit? painting 13.

The unit control logic 15 ? equipped with programmable processing means, such as a microprocessor, a PLC and the like, possibly connected to a further unit? central control (do not show figure) of a possible plant in which the painting station 1 can? be integrated. Alternatively, the unit? control logic 15 pu? be integrated as a software module in a processor intended for controlling the entire system.

Furthermore, the unit? control logic 15 ? configured to control the amount? of paint dispensed by the unit? of painting 13. In particular, in the case in which l?unit? of painting 13 was a paint sprayer 13, the unit? control logic 15 would be configured to control the electrovalve or the electropump for dispensing the paint, so? to allow for control and management of the quantity? of paint V sprayed or nebulized on the piece P to be painted. Thus, unit? control logic 15 pu? adjust the thickness of the paint applied to the piece P.

Instead, in the event that the unit? of painting 13 was of the type roller, the?unit? control logic 15 would be configured to control the pneumatic actuator of the roller, so? to adjust the pressure with which the roller is applied to the upper surface Ps of the piece P to be painted. In this case, the unit? control logic 15 pu? also check the pressure between the applicator roller and the dosing roller, and the speed? rotation of the dosing roller.

The unit control logic 15 ? arranged in such a way as to acquire the information and data relating to the thickness of the paint V applied by the unit? of painting 13, detected by the detection sensor 12, cos? by disposing of the thickness of the paint applied to the piece P leaving the booth 11.

In this way, the unit? control logic 15 pu? possibly regulate through an appropriate feedback the quantity? of paint V that the unit? of painting 13 potr? apply to the subsequent P pieces to be painted.

The painting station 1 described above operates as follows.

As mentioned, various systems are envisaged for detecting and carrying out paint thickness tests. Will it be done in the following? reference to figures 3, 4 and 5 for detecting the thickness directly on the piece to be painted P, while in figures 6, 7, 8 and 9, the embodiments of detecting the thickness of the piece directly on the conveyor belt 143 will be described, i.e. on specific surfaces inside and outside the cabin 11.

Referring therefore now again to figure 2, as well as? to the figures 3, 4 and 5, you can? observe the operation of the painting station 1 according to the present invention in different phases.

In particular, normally a user U places the piece P to be painted on the incoming conveyor belt 21.

In the event that the painting station 1 was part of a painting or processing plant more? large, the piece P to be painted pu? be fed from a previous painting station or, in general, from a previous processing station of the piece P itself or from a piece magazine.

Subsequently, piece P enters painting station 1 and, when it passes under the unit? sprayer 13, or, in the embodiment in question, under the paint sprayer (see figure 3), the latter starts the painting operations, spraying the paint V, while the piece P is moved in the feed direction A from ?unit? handling 14.

After the painting operations, the detection sensor 12 measures the thickness of the paint V applied to the painted piece P at a specific point or in more than one point. points of the upper painted surface Ps, cos? to detect the thickness of the applied paint (see figure 4).

Subsequently, as shown in figure 5, the painted piece P, at least on the upper surface Ps (but possibly also in other parts) is extracted from the painting station 1, and in particular from the booth 11, transported moved by the outgoing conveyor belt 22 , always enlivened in the A direction.

In this way, the unit? control logic 15 pu? adjust the painting parameters of the unit? of painting 13, i.e. driving the solenoid valve or the electric pump to decrease or increase the paint to be sprayed, if you have a paint sprayer, i.e. decrease or increase the pressure of the roller on the surface of the piece P to be worked to increase or reduce the paint to be applied, the quantity? of dispensed paint, the pressure between the applicator roller and the dosing roller, etc..

Furthermore, the unit? control logic 15 pu? be connected to a signaling device (not shown in the figures) for the user in case a different paint thickness from the desired one is detected, capable of emitting an acoustic, luminous, written signal, on a mobile device or mobile support, such as a tablet, vibration , wearables.

With reference now, as mentioned, to figures 6, 7, 8 and 9, is the modality described? with which the thickness is detected directly on the conveyor belt 143 or in other points different from the piece P.

Pi? specifically, with reference to figure 6, it can be observed that the conveyor belt 143 has the test surfaces 16, having a transversal orientation to the feed direction A of the piece P.

As can be observed, when the unit? of varnishing 13 applies the varnish on the piece P, part of this varnish goes on the test surfaces 16. In this way, subsequently the thickness of the varnish can? be measured by the detection sensor 12.

To allow further tests, possibly on the same measurement area 16, the painting station 1 comprises means for cleaning the surface of the conveyor belt 143 from the paint applied for the test. In particular, figure 7 shows an embodiment of such means for cleaning the surface of the conveyor belt 143 comprising a doctor blade 144, arranged near the of the roller 142, and capable of interfering with the surface of the conveyor belt 143, so as to scrape the paint disposed on it, and collect it in a collection tank (not shown in the figure) to be reused. Said means for cleaning the surface of the conveyor belt 143 can also comprise a rubber block 145, arranged on said doctor blade 144, which improves the cleaning of the surface of the conveyor belt 143.

With reference to figure 8, an alternative embodiment of a conveyor belt 143 is observed, in which the test surface 16 is continuous and oriented in the direction and in the feed direction a of the piece P.

With reference to figure 9, a further embodiment of a conveyor belt 143 can be observed, in which in this case the test surface 16? discontinuous, and constituted in particular by a plurality? of rectangles, forming a sort of discontinuous strip also oriented in the direction of advancement A of the piece P.

As mentioned above, then, ? It is possible to provide a specific area inside or outside the painting booth 11, not arranged on the conveyor belt 143, in which it can? be reported a plate 17 on which ? placed the test surface 16, as shown in figure 9. The unit? of painting 13 pu? carry out painting tests by means of the detection sensor 12, without carrying them out on the piece P or on the conveyor belt 143. Of course, as mentioned above, cleaning means can be provided for the test plate 17 which are not shown in the figure.

In said figure 9 the plate 17 which constitutes the test surface 16 ? disposed inside the painting booth 11, but pu? also be placed outside.

With reference now to figures 10, 11, 12, 13, 14 and 15, six distinct embodiments of a painting plant I can be observed, including the painting station 1 according to the present invention.

In particular, with reference to figure 10, the plant I1 comprises a supply magazine MP, in which pieces P to be painted are stored. The pieces P to be painted are fed by the conveyor belt 21 at the entrance to the painting station 1. The feeding of the pieces P takes place along the feed direction A at the entrance to the cabin 11 of the painting station 1. In the case in question the detection sensor 12 ? located inside cabin 11.

On exiting the cabin 11, the exit conveyor belt 22 picks up the painted piece P and its path can be continue conveying the piece P itself towards a further varnishing station 4 and possibly, by means of the further transport belt 23 to another varnishing station 5, or it can? be diverted onto a deviation conveyor belt 24, leaving the normal painting route indicated with direction A, towards another direction, and in particular in the S direction, along the deviation conveyor belt 24, until it reaches a warehouse of waste indicated with the letter MS.

In other embodiments, the further varnishing stations 4 and 5 can consist of other units? of machining of the piece P, as a unit? possible cutting, abrasion or firing.

In a further embodiment, the unit? control logic 15 pu? also be connected to the other painting stations 4 and 5, similarly to painting station 1, so as to be able to control their painting.

In the I1 system, the unit? control logic 15 of the varnishing station 1 ? also capable of controlling the movement of the pieces P along the conveyor belts 22, 23 and 24. In this way, the unit? control logic 15 pu? eventually decide when to discard a piece P, for example why? not painted properly.

By means of the I1 system in figure 6, in the event that:

- a P piece to be painted coming from the MP warehouse was found to be defective as the unit? of painting 13 was not correctly calibrated; and - such that it was not possible to correct the painting error with an appropriate control of any further painting stations (or other processing, for example abrasion), such that too much or too little paint V had been deposited or sprayed on the surface Ps of the piece P;

then in that case the? unit? control logic 15, after having detected the defect, pu? activate the deviation conveyor belt 24, in order to eliminate the incorrectly painted piece P from the line and accumulate it in the waste magazine MS

Furthermore, at the same time, the unit? control logic 15 pu? also check the electric pump of the paint sprayer 13, for example, or in any case any other parameter aimed at regulating the operation of the unit? of painting 13, so as to increase or decrease the paint V to be applied on the subsequent piece P to be painted, possibly correcting the painting error.

Alternatively, if there are defects of a different nature, the unit? control logic 15 pu? interrupt the feeding of pieces P by stopping the infeed conveyor belt 21, possibly notifying the competent personnel so that? carry out the necessary revisions of the painting station 1.

Figure 11 shows a variant of the painting plant I1 of figure 6, in which in this plant I2 the thickness detection sensor 12 is? arranged outside the booth 11. In particular, in the embodiment shown, the detection sensor 12 of the painting station of the painting plant 12 is arranged in correspondence with the exit opening 112 of the cabin 11.

Does the painting plant I2 of figure 11 work? similar to the one shown in figure 10.

With reference to figure 12, a third embodiment of a painting plant 13 according to the present invention can be observed, in which ? a varnishing station is integrated 1.

In particular, also in this case the painting plant I comprises a piece magazine MP, which feeds the pieces to be painted by means of the painting station 1 in the feed direction A by means of an infeed conveyor belt 21.

The painting station 1 comprises a sensor 12 and the unit? central control 15. Furthermore, the painting station 1 can? also comprise a second inlet opening 113, fed by a re-working conveyor belt 25 connected to the outlet conveyor belt 22. Also in this case the painting plant 13 comprises a possible further painting station 4 connected, by means of the further conveyor belt 23, to a possible further varnishing station 5. Also said further varnishing stations 4 and 5 can be connected to the unit? control logic 15, so that the latter can regulate its operation.

Alternatively, said additional painting stations 4 and 5 may possibly be other workpiece processing stations.

Furthermore, also in this case, the unit? control logic 15, connected to sensor 12, ? configured to control the incoming conveyor belt 21, the outgoing conveyor belt 22 and the rework belt 25.

As in the previous embodiments, the workpieces P are removed, for example, from the workpiece magazine MP and fed in the feed direction A via the conveyor belt to the inlet 21 into the varnishing station 1.

In this painting station 1 each piece P is painted and the thickness of the paint applied is measured by means of the detection sensor 12. In the event that, for example, the thickness is not sufficient, as not enough paint V has been applied on the upper surface Ps of the piece P, the unit? control logic 15 pu? vary the feed direction A and route the incorrectly painted piece P in the direction of the arrow indicated by the letter R on the re-working conveyor belt 25, which brings the incorrectly painted piece P back to the entrance to the cabin 11 through the second entrance opening 113, or it enters directly from the main opening (depending on the path of the transport device).

In this way, the unit? control logic 15 pu? suitably adjust the paint sprayer 13, or check the units? painting stations 13 operating inside the booth 11, to carry out a new painting of the appropriate thickness such as to obtain the desired coating.

Subsequently, of course, the 12 sensor will measure? again the overall thickness of the paint V on the piece P just painted for the second time. In the event that the painting operation was satisfactory, piece P can? continue normally in direction A to undergo further painting or processing in the stations indicated with the reference numbers 4 and 5.

Of course, it is possible to have hybrid implants between the embodiments shown in figure 10 or in figure 11, with the one shown in figure 12.

Figure 13 shows a further embodiment of the painting system indicated with reference I4, an alternative to the system described in figure 12, in which in the painting booth 11 there is no a second inlet opening 113 is foreseen, but the rework belt 25 returns any piece P to be repainted directly to the inlet conveyor belt 21.

Finally, with reference to figure 14, a variant of the painting system shown in figure 12 can be observed, in which in this painting system indicated with the reference I5, the detection sensor 12 is? disposed outside the cabin 11. In particular, the detection sensor 12 ? arranged substantially in correspondence with the outlet opening 112 of the booth 11.

The operation of the painting plant I5 of figure 14 ? similar to the one shown in figure 12.

Finally, figure 15 shows the I6 plant, which ? a variant of the painting system shown in figure 14, in which the reworking belt 25 returns the piece directly to the infeed belt 21 and not to the painting booth through the opening 113.

Advantages

An advantage of the present invention ? that of allowing retro-operated control of the painting carried out in a painting station.

A further advantage of the present invention is to allow for the reduction of waste from incorrectly painted pieces.

? Another advantage of the present invention is that of allowing real-time control and correction of the operation of the painting members, whether they are a roller or a paint sprayer.

A further advantage of the present invention ? to not apply excess paint, cos? to achieve material savings.

The present invention ? been described by way of illustration, but not limitation, according to your preferred embodiments, but ? it should be understood that variations and/or modifications may be made by experts in the art without thereby departing from the relative scope of protection, as defined by the attached claims.

Claims (26)

1. Painting station (1), for painting pieces (P), such as panels, majolica and the like, comprising a cabin (11) having an inlet opening (111), for the entry of a piece (P) to be worked according to a feed direction (A), and an outlet opening (112), through which the piece (P) painted is extracted from the cabin (11), a unit? paint (13), for the commanded application of paint (V) on a surface (Ps) of said piece (P), a detection sensor (12), configured to detect the thickness of the paint applied by said unit? of painting (13) on a test surface (Ps, 16), ed a unit? control logic (15), in which said unit? control logic (15) ? functionally connected to said detection sensor (12), to acquire the data detected relating to the thickness of the paint (V) applied on said test surface (Ps, 16, 17) by said unit? of painting (13). 2. Painting station (1) according to the previous claim, characterized in that said unit? control logic (15) ? connected functionally to the unit? of painting (13), so as to control the painting parameters according to the data relating to the thickness of the paint (V) applied on said test surface (Ps, 16). 3. Painting station (1) according to any one of the preceding claims, characterized in that said test surface (Ps) ? the surface to be painted of said piece (P). 4. Painting station (1) according to any one of the preceding claims, characterized in that said test surface (16) is? arranged on a plate (17), preferably made of metal. 5. Painting station (1) according to any one of the preceding claims, characterized from the fact of understanding a? unit? handling (14) for handling the piece (P) to be painted inside said cabin (11), and by the fact that said test surface (16) ? arranged on said movement means (14). 6. Coating station (1) according to the preceding claim, characterized by the fact that this unit? of handling (14) comprises a pair of driving rollers (141, 142), ed a conveyor belt (143) moved in rotation by said pair of rollers (141, 142), and by the fact that said test surface (16) ? arranged on said conveyor belt (143). 7. Painting station (1) according to any one of claims 5 or 6, characterized in that it comprises: - a plurality? test surfaces (16), having an orientation transverse to the feed direction (A) of the piece (P); and/or - a continuous test surface (16) oriented in the direction and in the feed direction (A) a of the piece (P); and/or - the test surface (16) ? discontinuous, preferably consisting of a plurality? of rectangles, forming a discontinuous strip oriented in the feed direction (A) of the piece (P). 8. Painting station (1) according to the preceding claim, characterized in that it comprises means for cleaning the surface of the conveyor belt (143) from the applied paint for the paint thickness measurement test, comprising a doctor blade (144), suitable to interfere with the surface of the conveyor belt (143), so as to scrape the paint arranged on it and collect it, a rubber plug (145), arranged on said doctor blade (144), intended to interfere on the surface of said belt transport (143). 9. Painting station (1) according to any one of the preceding claims, characterized in that said detection sensor (12) ? selected from one of the following types: - infrared radiation; - to magnetic detectors; - parasitic currents; - ultrasound; - optical; - with weight sensor; or - based on destructive techniques. 10. Painting station (1) according to any one of the preceding claims, characterized in that said detection sensor (12) ? installed inside said booth (11). 11. Painting station (1) according to any one of the preceding claims, characterized in that said detection sensor (12) ? installed outside said cabin (11), arranged in correspondence with said outlet opening (112). 12. Painting station (1) according to any one of the preceding claims, characterized in that said unit? of painting ? a paint sprayer (13), wherein said paint sprayer (13) comprises an electric pump, connected to said unit? control logic (15), ed at least one nozzle for spraying the paint (V), in which this unit? control logic (15) ? configured to drive said electric pump so as to increase and decrease the paint (V) sprayed from said nozzle of said paint sprayer (13). 13. Painting station (1) according to any one of the preceding claims, characterized in that said unit? of painting ? roller type, in which said unit? of roller painting comprises a roller, for the application of paint, and a pneumatic actuator connected to said unit? control logic (15) and coupled to said roller, to adjust the contact pressure of said roller with the piece (P) to be painted, and in which said unit? control logic (15) ? configured to pilot said pneumatic actuator so as to increase and decrease the paint (V) applied by said roller onto said piece (P) to be painted. 14. Coating station (1) according to any one of the preceding claims, characterized in that it comprises a signaling device for the user in case a different paint thickness from the desired one is detected, capable of emitting an acoustic, luminous, written, on mobile device or mobile medium, such as tablet, flip, wearable. 15. Painting plant (I1, I2, I3, I4, I5, I6), for painting and processing pieces (P), such as panels, majolica and the like, comprising at least one painting station (1) according to any of claims 1-13, an inlet transport device (21) arranged so as to feed the pieces (P) to be painted and introduce them into said painting station (1) through said inlet opening (111), an outlet conveyor device (22), arranged so as to pick up the painted pieces (P) coming out of said painting station (1) through said outlet opening (112), conveying said painted pieces (P) in one direction feed (A), and at least one further transport device (24, 25), arranged at said outlet opening (112) of said painting station (1), in which said unit? control logic (15) of said painting station (1) ? functionally connected to said further conveyor belt (24, 25), and in which, following the painting by means of said unit? of painting (13), said detection sensor (12) measures the thickness of the paint (V) applied by said unit? of painting (13), such that, in the event that said thickness was above or below a threshold, said unit? central control activates said further conveyor belt (24, 25) so as to pick up said piece (P). 16. Painting plant (I1, I2, I3, I4, I5, I6) according to the preceding claim, characterized in that it comprises a parts magazine (MP) connected to said infeed conveyor belt (21). 17. Painting plant (I1, I2, I3, I4, I5, I6) according to any one of claims 15 or 16, characterized in that it comprises at least one further processing station for said painted piece (P) leaving said station of painting (1). 18. Paint plant (I1, I2, I3, I4, I5, I6) according to the preceding claim, characterized in that it comprises at least a first further paint station (4) functionally connected to said unit? central control unit (15) of said painting station (1), so that said unit? central control unit (15) can regulate the painting parameters of said first painting station (4). 19. Plant (I1, I2) according to any one of claims 15-18, characterized by the fact that it includes a waste warehouse (MS), e by the fact that said additional conveyor belt ? a deviation conveyor belt (24), connected to said reject magazine (MS). 20. Plant (I3, I4, I5, I6) according to any one of claims 15-19, characterized by the fact that said additional conveyor belt ? a rework conveyor belt (25), which connects said outlet opening (112) to the entrance of said booth (11), in which said unit? control logic (15) picks up the piece (P) painted in said painting station (1) in the event that it is not sufficiently painted following the detection carried out by means of said detection sensor (122), bringing it back inside said station of painting (1) by means of said re-working belt (25) to carry out a new painting by means of said unit? of painting (13). 21. Plant (I3, I4, I5, I6) according to any one of claims 15-20, characterized by the fact that it includes an abrasion or sanding station, by the fact that said additional conveyor belt ? a rework conveyor belt (25), connecting said outlet opening (112) to said abrading or polishing station, in which said unit? control logic (15) picks up the piece (P) painted in said painting station (1) in the event that it is excessively painted following the detection carried out by means of said detection sensor (122), returning it to said abrasion or sanding station by means of said rework tape (25). 22. Painting method including the steps of: carry out the painting of a piece (P) using a unit? painting (13); detecting the thickness of the paint (V) applied to said piece (P) by means of a detection sensor (12); And adjust one or more? parameters to carry out a subsequent painting. 23. Painting method according to the preceding claim, characterized in that said parameters for carrying out a subsequent painting comprise the regulation of the power supply of an electric pump of a paint sprayer and/or the regulation of the power supply of a pneumatic actuator of a roller paint applicator. 24. Painting method according to any one of claims 22 or 23, characterized in that said paint thickness detection step takes place by means of a detection sensor (12) selected from one of the following types: - infrared radiation; - to magnetic detectors; - parasitic currents; - ultrasound; - based on the measurement of the difference in thickness before and after painting from the said unit? of painting; - with weight sensor; - based on destructive techniques; or - based on distance measurements. 25. Painting method according to any one of claims 22-24, characterized in that it comprises the step of repeating the step of carrying out the painting of a painted piece (P) by means of said unit? of paint (13), in the event that the thickness of the paint (V) applied as detected in the paint thickness detection phase was insufficient. 26. Painting method according to any one of claims 22-25, characterized in that it comprises the step of rejecting the painted piece (P) by means of said unit? of painting (13), in the event that defects are detected in said step of detecting the thickness of the paint (V).