DE102011018704A1 - Apparatus and method for coating rotating surfaces - Google Patents

Abstract

Coating surfaces with free jets is associated with overspray and requires a complex movement of several individual nozzles. In order to carry out the coating more easily, the coating nozzles are arranged on a common carrier, surrounded by a suction device running around the edge. Heat sources installed on the carrier compensate for the heat loss that occurs during the coating process. The invention presented in various designs and modifications is particularly suitable for coating flat, rotating objects with a particle-laden atmospheric plasma.

Description

Apparatus and method for coating surfaces in which a particle-laden plasma gas stream strikes a rotating substrate and the gas stream deflected from the substrate passes into suction devices.

According to the state of the art, the coating of substrates is carried out in many applications. The substrates are often round and substantially flat or formed in relation to the flat dimensions with a low height profile. The products produced or refined there are many, as the following example but not limiting list: CDs, DVDs, optical glasses, optical reflectors, medical implants, wafers, plates, heat sink or power semiconductors.

The surfaces are painted to produce thicker layers or printed to achieve lower layer thicknesses, vapor deposited for extremely thin layers or deposited on the surface in vacuum processes from the plasma or gas phase. The advantage of the plasma coating process in vacuum is the production of material combinations in thin layers which can not be produced by vapor deposition, printing or painting or other equivalent processes.

For the transition region, coating with atmospheric plasma has generally been developed. In this case, a plasma state is generated in a gas stream by electrical discharges, the particles are admixed and thereby excited. The particulate mass flow thus mixed is set constant and can only be switched off in the sense of controllability. A connection is only possible with interruption, since the plasma can be ignited only after a finite time.

The particle-laden plasma gas stream exits through a nozzle and flows as an impact flow against the surface to be coated. The finely divided in the plasma gas stream of particles of metal, ceramics or other materials are so highly excited that adhesion to surfaces as in the plasma coating process in a vacuum is possible, with layer thicknesses such as vapor deposition, printing, painting or galvanic coatings achieved become.

The particle-laden atmospheric plasma gas stream nozzles used for the coating are very small in the ratio of the nozzle transverse area to the coating surface of the substrate. A relative movement of the nozzle to the surface is therefore used to sweep the surface, for example, in a line. For simple, rectangular surfaces, this process is simple and efficiently solved even with multiple nozzles.

The particle-laden atmospheric plasma gas stream has an exit temperature from the plasma nozzle of 50 ° C to 100 ° C in the applications. Thus, the method is suitable to coat heat-sensitive substrates such as plastic films very gently.

The disadvantages of the prior art are significant. The particles contained in the plasma gas stream are not completely deposited on the surface, but are carried out as overspray with the outflowing gas stream from the coating zone. This leads to contamination of the surrounding machine components and usually to frequent cleaning intervals, as a result, to reduce productivity and thus to increase production costs.

The coating of round substrates has so far been unsatisfactorily resolved, since in line-by-line scanning each line has to be individually adjusted in length in order to avoid the disadvantage of a time-consuming overrun of the regions outside the substrate surface and the associated overspray.

The coating time for large surfaces is reduced by the use of multiple nozzles, which increases the driving effort and / or an unproductive sweeping over outside surfaces is accepted. The acquisition of complex control systems or the acceptance of extended coating times more expensive both the production costs.

A problem associated with the coating is the treatment of hot substrates. The uniform rapid heating is a prerequisite for a short cycle time in the production process. The required heating is therefore part of the coating task.

Treating hot substrates with an atmospheric plasma gas stream results in convective cooling, similar to convective heating on cold substrates. In both cases, a temperature of the substrate is possible, which are carried out flat for homogenization. The strong local cooling caused by the cold plasma nozzle in the case of hot substrates can only be compensated unsatisfactorily and leads to material stresses which, depending on the material of the substrate (glass, ceramic or other), result in its destruction. In addition to the loss due to waste, there is an additional loss due to loss of production to remedy the fault.

The inventors have set themselves the task of improving the coating of round substrates with particle-laden atmospheric plasma gas stream, with the focus on avoiding the overspray. Associated with this they have set themselves the task of guiding nozzles optimized in this way without complex activation as a group over the substrate in minimal time.

At the same time, they have set themselves the task of enabling the treatment of hot temperature-sensitive products with a cold plasma gas stream, without at the same time generating an unacceptable cooling. However, the latter sub-task is less common and at the same time solved in a form that can be applied not only to coating but generally to atmospheric plasma.

The solution to the problem is sometimes surprisingly simple. In order to minimize the overspray, the flow guidance is optimized by special extraction points. For this purpose, two embodiments are presented. To shorten the coating time, several nozzles are used on a common carrier. The carrier is moved over the rotating substrate so that all nozzles without reduction constantly make the coating with nominal throughput. This achieves the lowest possible coating time with nozzles given in terms of application quantity and geometry. In a further developed embodiment, it is coated simultaneously with all the nozzles, with the area in the center being coated by only one nozzle.

To shorten the cycle time in production, the preheating for hot substrates has been integrated into the task, and solved with a special heat radiator in an upstream preheating or heating process. The cooled during the coating by the plasma gas stream locations are heated with heat radiators. This compensates for the convective loss of energy.

The solution is therefore that the plasma gas stream exits as an atmospheric plasma gas stream from a plurality of arranged on a common carrier nozzles, the deflected gas stream is sucked locally at each nozzle and together at the edge of the carrier, and the carrier at a constant distance to Substrate controlled over its entire surface moves. In addition, heat radiation sources on the support heat the substrate. Furthermore, the plasma gas flow is hindered by an introduced secondary gas flow and deflected more strongly into the suction.

Substrate and plasma gas flow move in the coating relative to each other. The disclosed invention is also applicable to other single or divided coating mass flows, such as wide density and viscosity range fluids, with or without dispersed solid or liquid particles.

The invention offers many advantages.

The direct extraction of the particle-laden atmospheric plasma gas stream or free jet emerging at each plasma nozzle directly leads to a strong reduction in the spread of the particle-laden effluent, and thus directly to the reduced overspray. This effect has also been found for an alternative flow guide in which the exiting particle-laden atmospheric plasma gas stream or free jet is surrounded by a purge gas, and which is sucked off at the edge of the carrier.

The arrangement of multiple nozzles on a common carrier is advantageous in many ways. For the first and most obvious, only one element needs to be moved instead of many individual nozzles. Secondly, by a suitable combination of nozzle number, arrangement and particle mass flow per nozzle, a targeted and complete coating in a single operation is made possible without coating nozzles covering areas outside the area to be coated. Third, the common arrangement leads to a superposition of the outflows of the individual nozzles and concentration of the sources of harmful overspray. Fourth, a circulating around the wearer suction proves to be more Gas is sucked as flows below the carrier through nozzles, also to keep the working space of the coating system is very useful.

As a consequence, gas is sucked under the carrier from the remaining coating space and directed into the circulating suction. Therefore, the outflows of the individual nozzles are reliably detected and can no longer flow laterally out of the carrier as an overspray. A suitable contour on the edge of the substrate to be coated supports this effect.

The main problem with all coating processes is the homogeneous layer thickness. This is guaranteed by this solution without overspray and at the same time in no time. A minimum coating time is given by the continuous use of all nozzles on the carrier.

Another positive effect of the common carrier is the ability to use IR LEDs as heat radiators. These compensate for the local heat loss of the substrate by the convective cooling of the plasma jet by an equally local radiation heating.

The basic preheating of hot substrates whose temperature is an essential factor in the subsequent coating process is achieved with a simple line source in a cost-effective and surprisingly simple design. Particularly advantageous is the similar design of the heating surfaces over the product.

The coating of the centers of rotating substrates is problematic, even if several elements are used on a support. An advanced solution is therefore the coating of the center with a circular nozzle, while all other nozzles coat the outside area. By this simple solution, furthermore, all the nozzles are continuously coated, and the goal of the minimized coating time is achieved by an equivalent means.

The sum of the effects significantly reduces the coating time to alternative prior art methods. Waiting times through reheating are eliminated, so that in total productivity is significantly increased by these measures.

The invention will be explained with reference to figures and descriptions of exemplary embodiments.

1 coating plant

2 Carrier with nozzles and suction - example for panning

3 Cross sections of the carrier 2

4 Diagram procedure

5 Carrier with different suction

6 Translation of a carrier with 3 nozzles

7 Translation of a carrier with 6 nozzles

8th Translation of a carrier with 4 nozzles

9 Carrier, embodiment with 4 plasma nozzles in different positions

10 Coating with 4 nozzles and swiveling carrier

11 Coating with 4 nozzles and pivoting and rotating support

12 coating profiles

13 Carrier with nozzles, version with annular purge gas nozzle

14 Coating with circular nozzle in the middle

15 preheating

16 Diagram procedure, variation

Description of exemplary embodiments

1 shows a coating system 1 in a first inventive embodiment. In a workroom 2 There is a substrate holder 3 , the substrate to be coated 4 and the carrier 5 with its leadership 6 , In the workroom 2 are one or more exhausts 7 attached in suitable places. During the coating process, the substrate rotates 4 , The direction of rotation 8th is given here by way of example. The opposite direction of rotation as well as direction reversal of rotation during the coating process are also claimed.

Furthermore, one or more air inlet openings 9 purposefully attached. Part of this supply air is provided by the carrier 5 captured and discharged as a suction gas stream. The other part of this supply air enters the suction 7 ,

Through the leadership 6 or other suitable means, not shown, become the carrier 5 the plasma gas supplied with the particles already dispersed therein and that of the carrier 5 collected exhaust gas streams discharged. The leadership 6 is designed so that the carrier 5 for the homogeneous coating of the substrate 4 required movement such as panning, rotation, translation or a combination of these performs.

2 describes in three different embodiments, the carrier 5 in a view from below (after 1 ), from the direction of the substrate 4 (not shown). 3 shows these embodiments as a side view and partly as an outbreak in the direction of the arrows along the dashed line in the illustrations after 2 ,

In 2a and 3a a first embodiment is shown. It consists of the carrier 5 with several (three exemplified here) plasma nozzles 10 each with a circumferential first suction 11 and a peripheral at the edge of the carrier second suction 12 , The plasma gas flow 13 flows out of the plasma nozzles as a free jet 10 , hits the substrate 4 , is deflected there and is from the arranged around each nozzle suction 11 partially recorded and withdrawn. A part of the outflowing free jet flows in the coating room 14 between carriers 5 and substrate 4 to the edge of the carrier in the there circumferentially arranged suction 12 , The suction 12 is designed so that a larger volume flow is sucked off than from the plasma gas stream 13 in the coating room 14 is registered. Therefore, gas flows from the Zuluftöffnungen 9 from the workroom 2 the coating plant 1 under the edge 15 of the carrier 5 and is there by the circulating around the carrier suction 12 recorded and dissipated together. Due to this special flow guidance, no particle-laden gas flow enters the working space 2 the coating plant 1 one. This is thus protected from harmful deposits that cause maintenance.

2 B and 3b show the carrier 5 to 2a in a further advantageous embodiment. To the plasma nozzles 10 around is a ring of (fourteen in this example) purge gas nozzles 16 arranged. The number and location of the purge gas nozzles 16 are like the number of plasma nozzles 10 matched to the coating task. The advantage of this arrangement is the additional support of the flow deflection of the particle-laden plasma gas stream 13 , At the same time as this additional influx of gas is the suction of the suction around the nozzles around 11 and around the wearer 12 strengthened. The effect is amazing, in the all-round suction 12 recorded amount of particle-laden plasma gas stream is significantly reduced. The benefit is the reduction of the particulate area in the coating room 14 , This has an effect on switching on and off of the gas flows as well as on the movement of the carrier 5 positive.

In 2c the application is presented in another very useful form. In the purge gas nozzles 16 are radiation sources 17 , here heat radiator, in particular IR LEDs, used. These heat radiation sources have a power of 0.1 watts to 20 watts, preferably 1 watts to 10 watts. The radiation energy thus applied to the substrate compensates for the convective heat loss by the cold atmospheric plasma in the case of hot substrates.

For the Absaugvolumenstrommengen advantageous values have been found when the suction 11 . 12 around the nozzles and the carrier a multiple, in particular two to four times, of the supplied plasma and secondary gas flow 13 . 16 capture and dissipate, and especially if the suction 11 around the nozzles about 1.05 times dissipates.

The method in its basic form is in 4 shown in detail. With a device, as in 2a described by way of example, the process steps 20 ... 29 and 37 ... 41 performed, wherein the method step 30 optional can be included. The additional funds in 2 B lead the process steps 31 . 34 ... 36 out. The extension after 2c is through the process steps 32 . 33 displayed.

The carrier 5 is moved 20 and at the same time moves the sites of action 10 . 11 . 17 . 16 . 12 the process steps 24 . 27 . 33 . 34 . 36 . 40 and also influences the sites of action of the process steps 26 . 29 ,

The substrate is moved with its surface 28 and heated depending on production conditions 30 , The plasma gas is supplied 21 , a plasma is generated 22 and the particles mixed 23 , Tertiary gas is supplied in the working space of the coating plant 37 and only partially sucked out there again 41 ,

According to the invention, the free jet (s) are directed onto the surface 24 , the flow deflected 25 , thereby limited by the special flow guidance 26 and sucked off 27 , The special flow guidance is due to the flow of the tertiary gas to the edge of the carrier 38 , Divert there 29 and vacuuming 40 given.

By directing the free jet (s) onto the surface 24 this is coated 29 , The required homogeneity of the coating is determined by the movement of the surface 28 and the movement of the wearer 20 achieved on the size and location of the or the free jets 24 are coordinated.

In the further embodiment of the invention secondary gas is supplied by the carrier 31 and directed to the surface in several free-rays 34 , This flow is thereby diverted 35 and sucked off 36 , passing through the special flow deflections 25 . 39 limits the particle-laden flow 26 ,

In the third embodiment of the invention, one or more radiation sources are included. These are surrounded by secondary gas and thus protected against contamination and overheating 32 and heat the surface with radiation 33 ,

Further manifestations of the method are in 16 shown.

In 5 be several types of the carrier 5 to 2c disclosed. In particular, the suction 11 . 12 are changing to show that the shape is not just down to the one execution 2 is limited. In 5a . 5b . 5c is a carrier together 5 shown with three or four plasma jets 10 , and ten, fifteen or twelve surrounding purge gas nozzles 16 with internal radiation sources 17 ,

In 5a is the circulating suction 12 closed at the edge. The suction around the plasma nozzles is due to an areal distribution of fourteen large suction holes 50 realized. This flat shape is advantageous especially for large volume flows.

In 5b a carrier is shown in an alternative embodiment. The suction 51 around the wearer is not completely closed, but open to the edge, with another suction 52 reduces the gap. To the plasma nozzles 10 around is the suction 11 arranged.

5c shows a further variation according to the invention with a peripheral not closed peripheral suction 51 , The eighteen flat suction systems 50 are around the four plasma jets 10 arranged around. The shape of the suction openings 50 is not limited to the illustrated regular and symmetrical shape. Each convenient shape and arrangement is included, in particular, curved assemblies that do not have a rectilinear course of the plasma jets 10 consequences.

6 , shows an example of an advantageous arrangement and the independently claimed method of moving the nozzles over the substrate with the shortest coating time. In 6a is the carrier 5 above the substrate 4 shown. To simplify the explanation, the representation from below (after 1 ), the substrate 4 however for orientation with marked. On the substrate 4 becomes the coating surface 55 coated, which by an outer edge 57 and an inner edge 56 is limited. The carrier 5 contains a circumferential suction 12 , three plasma jets 10 with ambient exhaust 11 of which a plasma nozzle 58 on the inner edge 56 and two plasma jets 59 on the outer edge 57 are arranged.

The carrier 5 does not protrude over the substrate 4 out. The carrier will now be linear in the translational direction shown 60 moves until the inner nozzle 58 the outer edge 57 and the outer nozzles 59 the inner edge 56 achieved. The identical nozzles coat with the same coating performance. The coating time 62 is of the radius 61 depending on which the inner nozzle is located in each case. To the outside, the coating time decreases 62 linearly. This connection is in 6b shown. Above the normalized radius 61 is the normalized coating time 62 the inner plasma nozzle 58 applied. In 6c is the resulting coating amount 63 over the radius 61 shown. Since the circumference increases linearly with the radius, the result for the present case is that the radius is outside 57 twice as large as the radius inside 56 , a constant coating thickness.

It is thus shown that all the nozzles are in use over the entire coating time, which leads to a minimum of the coating duration, as well as the carrier 5 with no plasma nozzle out of the coating area, which leads to the additional avoidance of overspray.

In 7 is another carrier with more plasma jets in the same way as in 6a shown. The inner edge of the coating surface 56 is smaller, and inside are two plasma nozzles 58 appropriate. Again, the carrier drives 5 just over the substrate. The targeted control of the residence time for each radius and occasionally by switching off individual plasma nozzles a fastest possible intensive coating is achieved without the carrier 5 over the substrate 4 also runs.

Another use case is in 8th shown. On the carrier 5 are in plasma jets 10 with associated suction 11 , Secondary gas nozzles 16 and a circumferential suction 12 appropriate. The inner plasma nozzle 58 is the focus at the beginning. The carrier moves along the direction of movement 60 over the outer edge 57 the coating surface 55 and possibly even the substrate 4 out. In this example, the orientation of the plasma jets 10 to each other and to the edge 57 each with the same distance (pitch) executed.

With the start of the process all nozzles are turned on, and the carrier 5 is set in motion. It now increases its residence time along the path of movement of the carrier according to 8b at. If the outer nozzle 59 the edge of the coating surface 57 has reached, this is turned off. Because at this time the inner nozzle 58 has reached the starting point of the adjacent nozzle, is offset by this clever regulation, the continuously increasing increase in size. With a constant residence time, the carrier now moves out of the coating area 55 out. Each time you reach the edge 57 become the nozzles 10 switched off. In the 8c are the switching states (on / off) of all nozzles according to the assignment 65 . 66 illustrated over the path of movement of the carrier. The resulting coating amount with assignment 67 . 68 for the individual nozzles is in 8d shown.

In 9a -D is the carrier 5 to 5b shown in different tilted working positions. It can be seen that the entire coating area 55 is covered. The four plasma nozzles 10 however, not all start exactly on the outer edge 57 the coating surface 55 but are a bit offset. This results from the special geometric design of the kinematics (position of the nozzles, fulcrums and or four-way movements of the carrier).

This design causes all plasma jets during the coating phase 10 on the carrier 5 are constant and in common use. Only in the last period of the coating, at most 20% of the coating time, more preferably at most 10%, and most preferably at most 5% of the coating time, are not all nozzles on the coating. In this way, a minimum of the coating time is achieved. And this with homogeneous layer thickness and avoidance of overspray.

The 10 illustrates the process of a coating by illustrating the movement of the carrier 5 over the rotating 8 coating surface 55 , Switched nozzles are shown as filled circles, switched off nozzles as circular rings. The trajectories of the nozzles during pivoting of the carrier are indicated by dashed lines, supplemented by the direction of movement along these tracks.

The carrier 5 is located in 10a in the initial position, all nozzles are active and panning begins. A nozzle sweeps the middle ( 10b ) until the outermost nozzle reaches the edge and is turned off ( 10c ). The pivoting movement 70 is continued until the reversal point ( 10d ). There all nozzles are switched off except for one.

This first pass has now yielded a primer coat of the coating surface which, however, is not uniformly constant with respect to the layer thickness. The second movement section now compensates for this in the reverse direction of movement 70 by using only one (or a few) nozzles, as in 10d and 10e shown. When the initial position is reached, all nozzles are switched off and the process is completed ( 10f ).

Interestingly, it has been shown that it is precisely the reversal of this process, ie first only one nozzle in use, then all leads to improved adhesion for certain combinations of materials. An inverse order as previously described is therefore also expressly claimed.

Under certain installation conditions, it may be necessary not to drive over the coating surface twice, but several times. This is expressly claimed.

A particularly preferred embodiment is in 11 shown. The carrier 5 is rotatable about a pivoting arm 71 stored. During the pivoting movement 70 over the coating surface 55 rotates 72 the carrier 5 around the swivel arm 71 , An example of this movement sequence is in the 11a -G shown. It can be seen that all areas of the coating surface, and also the middle, are swept over. The position of the fulcrum of the carrier, the location of the nozzles, the rotational speed profile 70 . 72 are set so that all nozzles remain in use continuously.

It is obvious that none of the nozzles leaves the area of the coating surface, so that the resulting coating time represents the mathematically achievable minimum.

In this embodiment, all three individually claimed inventive concept can be seen. First, the special support of the coating process by the IR and / or UV radiation in the plasma coating process, the second, the special design of the carrier with plasma nozzles, optional secondary gas nozzles and multiple suction and third, the minimized coating time by the continuous use of all nozzles ,

12 finally, illustrates the sequence for the coating amount distribution in a process in which all nozzles are in use simultaneously. As in 6c or 8d is the coating amount 63 over the radius 61 the coating surface shown. The patches are the coating amounts assigned to the individual nozzles. In contrast to 8d All surfaces are the same size. The different representations 12a and 12b make it clear that the distribution of coating power over the radius does not have to be linear ( 6c . 8d . 12a ), but according to the curvy circular paths of the nozzles can be very different ( 12b example).

This property can be used excellently to achieve effects in coatings that are otherwise difficult or impossible. Especially the combination of individual plasma nozzles in a coating process offers further possibilities.

13 describes a modified version in the 2 and 3 presented solution. In 13a is the carrier 5 in a view from below, from the direction of the substrate 4 (not shown).

13b shows this embodiment as a side view and partly as an escape in the direction of the arrows along the dashed line in the illustration 13a , This version with a purge gas nozzle 18 around the nozzles 10 around consists of the carrier 5 with several (here exemplarily four) plasma nozzles 10 each with a circulating purge gas nozzle 18 and one on the edge 15 of the carrier 5 revolving suction 12 , The plasma gas flow 13 flows out of the plasma nozzles as a free jet 10 is from the arranged around each nozzle purge gas 18 surrounded, meets the substrate 4 , is deflected there, and flows in the coating room 14 between carriers 5 and substrate 4 to the edge of the carrier in the there circumferentially arranged suction 12 , The suction 12 is designed so that a larger volume flow is sucked off than from the plasma gas stream 13 and purge gas 18 in the coating room 14 is registered. Therefore, gas flows from the supply air openings 9 from the working space 2 the coating plant 1 under the edge 15 of the carrier 5 and is there by the circulating around the carrier suction 12 recorded and dissipated together. Due to this special flow guidance, no particle-laden gas flow enters the working space 2 the coating plant 1 one. This is thus protected from harmful deposits that cause maintenance.

The advantage of this arrangement is the additional support of the flow deflection of the particle-laden plasma gas stream 13 through the purge gas 18 , The particular advantage of this arrangement is the controlled by the purge gas in each operating condition atmosphere of the plasma gas stream.

The benefit is in addition to the reduction of the particle-containing area in the coating room 14 an improvement of the safety concept of the coating chamber. Thus, with minimal gas consumption, penetration of ambient gas, in particular oxygen, into the plasma gas stream is hindered until the plasma has lost its reactivity. This applies to switching on and off operations of the gas streams as well as the movement of the carrier 5 , This arrangement has been found to be particularly suitable when not all and in particular only one of the installed nozzles is used.

Another embodiment of the invention is in 14 shown. A substrate 4 that with constant speed 82 rotates, is made from over moving coating nozzles 80 . 81 coated. All coating nozzles 80 . 81 are identical in their coating behavior and produce a similar coating. Of the coating nozzles is only from the nozzle 80 exemplified the way to the center. The other nozzles 81 (here in the example four) are just right on the edge 83 , the beginning and end of the coating process.

All coating nozzles 80 . 81 are arranged at the beginning of the process outside of the substrate in a start or parking position (not shown), start at the same time from there and return at the same time back there. As a result, all coating nozzles are always used during the entire coating process. This leads to the minimum possible coating time for the selected coating nozzle number. By direct starting and ends at the outer radius 84 of the substrate 4 In addition, the overspray is reduced to the minimum. In order to produce the layer thickness of the coating homogeneously and constantly over the radius, the total residence time of the coating nozzles drops on each radius from the outer edge 83 towards the center linearly proportional to zero.

The coating is carried out according to the following inventive description:
Except for a coating nozzles 80 all coating nozzles move 81 from the outer radius 84 inside to the radius 85 and back.

A coating nozzle 80 Performs a more complex movement to include the center within the radius 85 to coat. The movement is generally divided into a radial velocity component 88 . 89 . 90 . 91 and tangential components of motion 92 ,

For the way from the outer radius 84 to the inner radius 85 this is similar to the other, first mentioned coating nozzles 81 , Only faster, particularly preferably, the movement speed of the coating nozzle by the factor of the coating nozzle number is greater. The area of the radius 85 up to the radius 86 is a transitional area, within the radius 86 rotates the coating nozzle 80 , preferably counter to the direction of rotation 82 of the substrate 4 so that the tangential relative velocity 92 in between circular coating nozzle and rotating substrate 4 is constant. At the same time the circular coating nozzle moves 80 towards the center. This increases the angular frequency of the circular coating nozzle 80 , Before reaching the center, the radial direction of movement of the circular coating nozzle is reversed 80 in turn. As the angular frequency decreases, it moves to the radius 86 , The inside reversal point is chosen so that the coating is at the center of the substrate 4 no elevation or defect is formed, and so realized the aforementioned decrease in the residence time of the coating nozzle per radius to zero in the center.

For a uniform coating, this process has to be repeated several times within the radius 86 proven.

Another preferred variant is the starting and ending of the circular nozzle in the center. In this case, a preferred variant is a parking position with a greater distance to the substrate than during the coating process. Especially the coordinated combination of switching, lowering, circling and radial movement (as well as the end in with circles, radial movement, lifting and switching off) results in a particularly homogeneous coating in the center of the substrate.

This technical teaching is based on the finding that to produce a layer thickness in a coating with coating nozzles with a constant, non-controllable mass flow, the generated Layer thickness reciprocal proportional to the speed at the location of the coating between the coating nozzle 10 and substrate 4 is.

If a certain coating thickness can be achieved with one pass, this is associated with a certain speed. In that area 84 to 85 a multiple coating takes place through all the nozzles coating there.

Within the range 86 towards the center, however, only a single coating possible. The required relative speed between the coating nozzle and the substrate can only be produced by a circular movement of the coating nozzle with the frequency increasing towards the center.

The transition region of 85 to 86 is characterized in that the multiple coating is converted into a single coating. For this purpose, it is a preferred variant, the inner coating nozzle already off 85 to start with the circular motion.

To generate the circular motion, a device is presented in which the coating nozzle is arranged on a rotating carrier with eccentric guide. The rotation at the required frequency is performed by the wearer. The eccentric shifts the coating nozzle along the radius. A rotatably mounted feedthrough on the eccentric decouples the coating nozzle from rotations about its own longitudinal axis, so that the line feeds are only guided in a circular manner, but do not rotate. A device designed with these features allows precise coating of a substrate rotating at a constant frequency below it.

It is advantageous to carry out the circular movement of the nozzle counter to the direction of rotation of the substrate, since the relative speed is thus achieved with a lower circular movement frequency, as in the same direction rotation. The same direction rotation is also claimed as a special variant with.

The inventive idea is the combination of the residence time decreasing radially linear to the center and the minimum relative speed between the coating nozzle and the substrate surface. From this it is possible to produce many different derivatives by changing quantities which have previously been given a constant name, such as the coating mass flow rate or the frequency of the substrate, the specific embodiments of which are likewise claimed in devices.

In 15 the heating is solved in an inventive way. A rotating substrate with a diameter 83 , which is preferably between 40 mm and 1500 mm, and which is particularly preferably between 150 mm and 450 mm, is from a heat radiator arranged above 100 irradiated. The distance from the heat radiator to the surface of the substrate is h, and may be from the design distance H 101 differ.

The substrate to be warmed up is not limited in material. It can consist of both a highly conductive material such as metal and a thermal dielectric such as ceramics. It has been found that the inventive heat radiation source heats up equally efficiently.

The radiation surfaces of the heat radiator 100 are multi-part, with approximately the same radiant power density and the same temperatures and irradiated from the outer diameter 84 Beginning of the substrate, different width circular rings, up to the complete circle. The radiation surfaces are dimensioned in their length so that at a realized distance h of substrate 4 to heat radiator 100 of 1/3 H <= h <= 5/3 H the radiation leads to a homogeneous heating.

As a measure of homogeneity, the maximum temperature difference of the irradiated substrate surface is used. The resulting homogeneity is below 8 K, with a suitable distance setting even less than 3 K.

In a specific embodiment, the radiation intensity does not remain constant over the entire heating period, but is modulated. In the last part of the heating phase, the power of the radiant surfaces is reduced, thus achieving a homogeneity of less than 0.5 K. Further advantageous modulations of the radiation intensity are claimed, in particular pulsed drives with alternating frequency and / or amplitude.

For the design of linear radiation elements, the following formula has been verified from the test results and numerical simulation:

The length of each radiating element Li ( 103 . 104 . 105 . 106 ) is represented by its order number i, the total number of elements N, the substrate diameter D ( 83 ) and the design distance H ( 101 ) Are defined. The formula also applies to variations of the distance h ( 101 ) in operation within the specified limits.

The design for this heating method is a twin tube heater 102 with four different heating coil lengths 102 . 103 . 104 . 105 advantageous. There are different designs for this. The technically simplest solution (the sum of the Heizwendellängen per single tube is the same) is particularly stressed, and in particular only one-sided connection of the lines 108 , The outstanding advantage of this solution is that the heating coil is made of different lengths of a single source material. As a result, the radiation power due to production are very homogeneous, and the voltage drop in each individual tube identical. This guarantees a uniform radiant power for every single tube. The use of only one connection side for the passage of the leads 108 reduces the manufacturing effort again. The heat radiator is embodied without or preferably with an applied reflector layer on the twin tube radiator. Particularly preferably, the reflector layer is a gold finish.

Another design of the heat radiator consists of several line radiators of individual tubes with one or more radiating element per tube. Another group of different designs consists of several juxtaposed spotlights, such as infrared LEDs or fiber optic ends of a laser. Also obvious is the design as a surface radiator with the shape similar to a circle segment. These solutions with their versions are claimed.

In 16 is the process which in the basic form in 4 is shown in detail, provided with further inventive features. This is the coating process 43 by a preheating process 42 optionally supplemented.

The description after 14 is in 43 pictured, and the description of the preheating after 15 in the process step 42 ,

For optional preheating 42 before the coating 43 becomes the surface of the substrate 4 moved relative to the heat radiation source 28 , The heat radiation source consists of several heat radiation surfaces, which are firstly designed as line emitters with different lengths, and secondly start at the edge of the substrate, and third aligned to the center of the substrate, with an arrangement of the heat radiation surfaces in pairs in each tube of a double-tube radiator is particularly preferred , This heat radiation source irradiated 44 the substrate 4 and thereby heats it to the temperature required for the following operation.

The coating process 43 is shown in a further form of the basic form. The process steps 20.1 and 28.1 are modifications that also with 20 and 28 can be exchanged. The remarks to 4 are therefore also associated with the exchanged process steps 20.1 and or 28.1 claimed.

With a device, as in 13 described by way of example, the process steps of the coating 43 carried out. The secondary gas flows directly around the outflow of the free jets 24 around, borders the flow and is at the same time deflected on the surface, and then enters the suction.

An extension of the procedure with radiation sources as in 4 is not shown, but is claimed with.

Another embodiment is the arrangement of the nozzles on multiple carriers 20.1 where one nozzle orbits the center of the coating surface while all other nozzles coat the outside. The circular movement 28.1 the inner nozzle is selected so that a certain minimum relative speed nozzle surface is not exceeded, wherein the substrate moves relative to the nozzles 28.1, preferably rotating.

The other examples are not described with figures.

In the coating according to the present invention, the direction of rotation is 8th claimed in both directions. In the embodiment shown above, that the carrier sweeps over the substrate radius twice, a reversal of direction is particularly advantageous, especially when the coating nozzles reach the center of the coating surface. Due to the controlled shutdown with the following restart in the other direction, results in a particularly homogeneous coating.

The use of purge gas nozzles 16 (or 18 ) has further advantages in the carrier 5 to 2 (respectively. 13 ). Is the purge gas tempered with suitable means before it from the purge gas nozzles 16 ( 18 ), this assists the coating process. This is particularly useful when a hot substrate 4 from the plasma gas stream 13 from the plasma nozzles 10 is cooled. The power requirements of the radiation sources 17 in the purge gas nozzles 16 reduce with it.

The design of the radiation sources 17 is not limited to heat radiation. Visible light is advantageous for process observation, and the use of UV for process control. The possibility of selectively conditioning the substrate which has just been coated with UV radiation opens up new application possibilities. Therefore, all wavelengths of electromagnetic radiation are expressly claimed.

In a likewise claimed according to the invention variant of the method, the secondary gas 31 only to protect the radiation sources 32 used. The flow guide and amount of gas flow is then designed so that the free jets on the surface 34 are negligible, causing the subsequent process steps 35 . 36 are equally negligible in their effect.

Another embodiment not shown relates to the movement of the carrier and the arrangement of the nozzles thereon. The trace of the nozzles on the substrate surface lies in the interior almost or completely on each other outwards, every trace of each nozzle is a spiral, which is more and more adjacent to the other. By this arrangement, a uniform coating is produced without crossing the tracks.

With regard to the execution of the first suction around the nozzles and a surface suction also mixed forms are possible, which are also claimed included in the inventive concept.

A variant with a wide range of applications is the treatment of temperature-sensitive material, which is heated by the plasma gas flow inadmissible. By suitable temperature, here cooling, the secondary gas from the purge gas nozzles, the substrate is cooled again immediately after coating. This arrangement is very efficient and is not claimed for use with atmospheric plasma but generally for all coating operations with particles dispersed in the gas stream.

Another useful application of the inventive concept is the use of the on a common carrier 5 arranged coating nozzles 10 with different coating materials in the coating nozzles. Usually, material is coated uniformly, a change of the production order requires a time and cost intensive retooling, which is thus avoided. In this special embodiment, at least one, preferably all nozzles are equipped with different coating particles and / or plasma gas, so that in each case only one nozzle is active during the coating. A carrier with two to six materially different nozzles is advantageous, carriers with 3 or 4 nozzles are particularly stressed. In the 5 The disclosed type is best suited for this purpose as a basic variant, and can be combined as needed with the other inventive solutions.

The disclosed invention, in its application, goes beyond the specific case of the plasma gas stream, and includes fluids having a wide density and viscosity range and with or without dispersed solid, liquid or gaseous particles. The coating mass flow thus defined is a fluid having a density of 0.01 kg / m ³ up to 5000 kg / m ³ . The process steps 21 to 23 after 4 and 16 are to summarize in this sense, and adapted to the fluid read. The coating mass flow occurs either from a single nozzle or from a group of nozzles.

The disclosed invention is also applicable to purposes other than the coating, especially when no particles are mixed. These applications are also claimed and used, for example, for activating, cleaning, sterilizing and generally treating surfaces.

By a suitable movement of the wearer 5 It is possible that this circles over a stationary substrate and thereby coated. The inversion is a standing or slowly moving substrate with nozzles moving above it. An application of the inventive idea to these designs is possible. This variation, in which the movement of the nozzle and substrate takes place relative to one another, is included in the claim for protection of all the above variations. The term rotating substrate is specifically intended to avoid by-pass solutions in this sense.

The application of the disclosed method and apparatus is not limited to substrates having a flat, flat and round geometry. Objects which are formed with respect to the flat dimensions with a low height profile, such as optical lenses or mirrors, printed circuits or printed circuit boards are also included in the scope.

In summary, an invention is disclosed which has several advantages in the use of atmospheric plasma. These arise when the plasma nozzles are arranged on a common carrier. On the one hand, the overspray is reduced because the flow is specifically directed into suction systems. This is achieved in addition to specially arranged suction also by other secondary air.

Another resulting advantage is the use of radiation sources such as IR LEDs. These are not only protected from contamination by the secondary flow, but also cooled. Radiation sources in a suitable form are used to preheat the substrate to accelerate the cycle time from the production process.

The third independent advantage is the special guidance of the carrier over the substrate. By the arrangements of nozzles and movements shown, the minimum coating time for these and other coating tasks is realized. Just the arrangement of several nozzles with different coating materials are wide degrees of freedom and motion sequences.

These inventive ideas already provide a great advantage individually and are claimed as well as individually and independently both as a method and as a device. The various combinations resulting from these inventions are also claimed as methods and apparatus.

Furthermore, the descriptions describe various applications and embodiments of the inventions with their advantages, which are hereby also included in the claimed scope.

LIST OF REFERENCE NUMBERS

1

coating plant

2

working space

3

substrate uptake

4

substratum

5

carrier

6

Guidance from the carrier

7

Extraction in the work area

8th

Rotation direction of the substrate

9

air intake opening

10

Plasma nozzle

11

Extraction around the plasma nozzle around

12

Extraction around the wearer

13

Plasma gas flow

14

coating room

15

Edge of the carrier 5

16

Purge gas nozzle

17

radiation source

18

Purge gas nozzle

20

Move carrier

21

Add plasma gas

22

Create plasma

23

Mix particles

24

Steer free jet on surface

25

Divert flow

26

Narrow the flow

27

Aspirate the flow

28

Move surface

29

Coat the surface

30

Heat substrate

31

Feed secondary gas

32

Protect radiation source

33

Heat surface with radiation

34

Steer free jet on surface

35

Divert flow

36

Aspirate the flow

37

Feed in tertiary gas

38

Lead to the edge of the carrier

39

Divert flow

40

Aspirate the flow

41

Aspirate the flow

42

preheat

43

coating

44

Irradiate substrate

50

Suction opening arranged around the plasma nozzle

51

Extraction around the edge of the support

52

Suction opening on the edge of the carrier

55

coating area

56

Inner edge of the coating surface

57

Outer edge of the coating surface

58

Plasma nozzle inside

59

Plasma nozzle outside

60

movement direction

61

Radius coordinate axis

62

coating time

63

coating amount

64

Function of plasma nozzles (on / off)

65

Function graph of the inner nozzle

66

Function graph of the outer nozzle

67

Coating amount of inner nozzle

68

Coating amount of outer nozzle

70

pan direction

71

Swivel arm for the wearer

72

Direction of rotation carrier

80

Coating nozzle for indoor use

81

Coating nozzle for outdoor use

82

Rotation of the substrate

83

Outer edge of the substrate, diameter D

84

outer radius

85

Inner coating radius of the nozzles 81

86

Radius inside area

87

Central area

88

Radial speed component

89

Radial speed component

90

Radial speed component

91

Radial speed component

92

tangential relative velocity

100

Radiant heaters

101

Distance heat radiator - substrate

102

Twin tube emitters

103

Heating coil 1, L1, i = 1

104

Heating coil 2, L2, i = 2

105

Heating coil 3, L3, i = 3

106

Heating coil 4, L4, i = 4

107

Contusion, one-sided conduction

108

lead

Claims (36)

Device for coating surfaces 1 consisting of a plasma gas stream with particles 13 a rotating substrate 4 and a suction 7 characterized in that the plasma gas stream 13 is formed as atmospheric plasma, the plasma gas stream 13 from one or more nozzles 10 emanates, and all nozzles 10 on a carrier 5 above the substrate 4 are arranged. Apparatus according to claim 1, characterized in that at least one and more preferably in each case around each nozzle 10 around a first suction 11 is attached, and to the carrier 5 around a second suction 12 is arranged. Device according to one of the preceding claims, characterized in that around at least one nozzle 10 around a Spülgasdüse 18 attached and around the carrier 5 around a suction 12 is arranged. Device according to one of the preceding claims, characterized in that per plasma nozzle 10 one or more radiation sources 17 preferably radiation heaters and in particular IR LEDs are arranged in the vicinity. Device according to one of the preceding claims, characterized in that the carrier 5 as a guide 6 for controlled movement parallel to and over the surface of the substrate 4 is formed and to produce a uniform coating thickness of at least one of the following means position of the nozzles 10 on the carrier 5 , Rotational frequency of the substrate 8th , Movement of the carrier 60 . 70 . 72 , Shut off the nozzles 64 controlled influenced. Device according to one of the preceding claims, characterized in that by in the carrier 5 contained purge gas nozzles 16 one or more gas streams in the coating room 14 be introduced and / or this purge gas flow around at least one radiation source 17 how IR LED or UV LED is guided. Device according to one of the preceding claims, characterized in that the plasma gas stream with particles 13 at least one and most preferably at each nozzle 10 is materially different, in particular by other dispersed particles, that in a preferred embodiment two to six, and more preferably four nozzles 10 on a carrier 5 are arranged and that for coating at least one and more preferably exactly one nozzle 10 is used. Apparatus for coating surfaces consisting of a plurality of coating mass streams which flow out of a plurality of nozzles, a substrate moving relative to the nozzles 4 and a suction 7 characterized in that the individual coating mass flows are the same, and each individual coating mass flow a fluid mass flow with a density of 0.01 kg / m ³ up to 5000 kg / m ³ or preferably a plasma gas stream with particles 13 in particular, which is designed as atmospheric plasma, and all nozzles 10 above the substrate 4 are arranged. Apparatus according to claim 8, characterized in that in each case around each nozzle 10 around a first suction 11 is arranged. Device according to one of the preceding claims 8 or 9, characterized in that around at least one nozzle 10 around a Spülgasdüse 18 attached and around the carrier 5 around a suction 12 is arranged. Device according to one of the preceding claims 8 to 10, characterized in that in each case the surface to be coated of the substrate is a flat geometry with low height profile and particularly preferably a flat surface. Device according to one of the preceding claims 8 to 11, characterized in that before the coating, the substrate surface is irradiated by a heat radiator containing a plurality of radiation surfaces, wherein the substrate rotates relative to the heat radiator. Device according to the preceding claim, characterized in that the heat radiator has a linear shape and is preferably designed as a double-tube radiator, the radiating surfaces are designed as heating coils of different lengths, each radiator tube start the heating coils outside and are interrupted at least once. Device according to the preceding claim, characterized in that the partial length Li of a heating coil i from the number N, the design distance H and the largest substrate diameter D according to the calculation rule

with a tolerance of + -10% H and preferably with a tolerance of + -5% H. Device according to one of the preceding claims 8 to 12, characterized in that a nozzle is arranged in a multi-part guide, the at least one first means for linear guidance of the nozzle from the substrate edge to the center of the substrate, a second means for circular guidance of the nozzle, a third means for decoupling the rotation of the circular guide on the nozzle and a fourth means for displacing the nozzle from the edge of the circular guide to the center of the circular motion of the guide and contains back. Device according to one of the preceding claims 8 to 12 and / or 15, characterized in that each nozzle 10 on a carrier 5 is arranged, the first, a suction 12 surrounds, and second, in the carrier 5 one or more radiation sources 17 preferably radiation heaters and in particular IR LEDs are arranged in the vicinity of the nozzle, and thirdly the carrier 5 Purge gas nozzle 16 contains one or more gas streams in the coating room 14 initiate, and / or fourth, the air flow in the carrier 5 the purge gas flow around at least one radiation source 17 how IR LED or UV LED is guided. Device according to one of the preceding claims 8 to 12, 15 and / or 16, characterized in that the plasma gas stream with particles 13 at least one and most preferably at each nozzle 10 is materially different, in particular by other dispersed particles, that in a preferred embodiment two to six, and more preferably four nozzles 10 on a carrier 5 are arranged and that for coating at least one and more preferably exactly one nozzle 10 is used. A method of coating surfaces with a particle-loaded plasma gas stream 24 on a rotating substrate 28 meets, the gas flow deflected from the substrate 25 gets into exhausts 26 , characterized in that the plasma gas stream 24 as an atmospheric plasma gas stream of several on a common carrier 5 arranged nozzles 10 exit. Method according to the preceding claim, characterized in that the deflected gas stream 25 locally at each nozzle 11 and together on the edge of the carrier 5 sucked 12 becomes. Method according to one of the preceding claims, characterized in that at least one nozzle, a purge gas stream 18 flows out, which flows to the particle-laden plasma gas stream preferably annular and more preferably concentric, and the deflected gas stream 25 . 35 together on the edge 12 of the carrier 5 is sucked off. Method according to one of the preceding claims, characterized in that heat radiation sources 17 on the carrier 5 the substrate 4 Warm up 33 , Method according to one of the preceding claims, characterized in that the carrier 5 at a constant distance from the substrate 4 controlled over its surface moves 20 and for producing a uniform layer thickness on the substrate one of the following means position of the nozzles 10 on the carrier 5 , Rotation frequency 8th of the substrate 4 , Movement of the carrier 60 . 70 . 72 , Shut off the nozzles 64 is changed during the coating time. Method according to one of the preceding claims, characterized in that a gas between the plasma gas stream and the edge of the carrier 5 is initiated 34 and / or flows around the radiation sources and thus protects against contamination and / or overheating 32 , Method according to one of the preceding claims, characterized in that the directed on the surface free jet 24 at least one and most preferably at each nozzle 10 material, in particular by admixing other particles 23 , and that in a preferred embodiment two to six and more preferably four nozzles 10 on a carrier 5 are arranged and that for coating at least one and more preferably exactly one nozzle 10 is used. Process for coating the surface of a substrate with one or more equal coating mass flows, characterized in that in each case as a coating mass flow, a fluid mass flow with a density of 0.01 kg / m ³ up to 5000 kg / m ³ or preferably a particle-loaded plasma gas stream 24 is used, and more preferably an atmospheric plasma gas stream with particles dispersed therein, the on a relative to the coating mass flow moving substrate 28 meets and coated, and the coating mass flow deflected from the substrate 25 gets into exhausts 26 , Method according to the preceding claim, characterized in that the substrate rotates. Method according to one of the preceding claims 25 or 26, characterized in that the substrate has a flat height profile and is particularly preferably flat. Method according to one of the preceding claims 25 or 27, characterized in that the nozzles 10 on a common carriers 5 are arranged. Method according to one of the preceding claims 25 to 28, characterized in that the deflected coating mass flow locally at each nozzle 11 and together on the edge 12 of the carrier 5 is sucked off. Method according to one of the preceding claims 25 to 29, characterized in that at least one nozzle, a purge gas stream 18 flows out, which flows to the particle-laden plasma gas stream preferably annular and more preferably concentric, and the deflected gas stream 25 . 35 together on the edge 12 of the carrier 5 is sucked off. Method according to one of the preceding claims 25 to 30, characterized in that in addition to at least one nozzle 10 at least one heat radiation source 17 on a carrier 5 is arranged and the substrate 4 heats 33 , Method according to the preceding claims 25 to 31, characterized in that a gas between the nozzles and the edge of the carrier 5 is initiated 34 and / or flows around the radiation sources and thus protects against contamination and / or overheating 32 , Method according to one of claims 25 to 32, characterized in that prior to the coating, a plurality of heat radiation surfaces irradiate the substrate, and these heat radiation surfaces are firstly designed as a line emitter with different lengths, and secondly start at the edge of the substrate, and thirdly aligned to the center of the substrate , wherein an arrangement of the heat radiation surfaces in pairs in each case a tube of a double-tube radiator is particularly preferred. Method according to one of the preceding claims 25 to 33, characterized in that the carrier 5 at a constant distance from the substrate 4 controlled over its surface moves 20 and for producing a uniform layer thickness on the substrate one of the following means position of the nozzles 10 on the carrier 5 , Rotation frequency 8th of the substrate 4 , Movement of the carrier 60 . 70 . 72 , Shut off the nozzles 64 is changed during the coating time. Method according to one of the preceding claims 25 to 33, characterized in that one of the nozzles circularly coated the inner region of the substrate and, firstly, the angular frequency increases toward the center and, secondly, particularly preferably the relative velocity of the nozzle to the substrate surface is constant, and the other nozzles the outer region coat by moving from the outer radius of the substrate inwards and backwards, and particularly preferably at the same time coat the same radius of the substrate. Method according to one of the preceding claims 25 to 35, characterized in that the directed on the surface free jet 24 at least one and most preferably at each nozzle 10 material, in particular by admixing other particles 23 , and that in a preferred embodiment two to six and more preferably four nozzles 10 on a carrier 5 are arranged and that for coating at least one and more preferably exactly one nozzle 10 is used.

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