EP3942090A1

EP3942090A1 - Apparatus and method for vacuum coating surfaces of objects

Info

Publication number: EP3942090A1
Application number: EP20711162.6A
Authority: EP
Inventors: Michael Herbort; Jan LENGEFELD; Patrick HEIDEMANN
Original assignee: KHS GmbH
Current assignee: KHS GmbH
Priority date: 2019-03-21
Filing date: 2020-03-13
Publication date: 2022-01-26
Also published as: DE102019107237A1; WO2020187715A1; US20220154340A1; CN113966410A

Abstract

The invention relates to an apparatus (1) for coating surfaces of objects by means of a gas separation method under a vacuum provided by a vacuum system, said apparatus having process chambers (12), including at least one treatment chamber for receiving the objects to be coated and at least one additional process chamber (12), connected to the at least one treatment chamber, for conducting gases to be separated and/or discharging portions of unseparated partial gas quantities, wherein a measuring unit (14) for detecting the coating thickness on a surface or on portions of the surface of the process chambers (12) is arranged in at least one additional process chamber (12), wherein the measuring unit (14) is connectable to a control and evaluation unit (30). The invention additionally relates to a method for monitoring surfaces in conduction paths of an apparatus (1) for coating surfaces of objects according to an apparatus (1) according to the invention, wherein the measuring unit (14) detects actual data of the coating thickness on a surface of the at least one additional process chamber (12) as a measurement value and said actual data are forwarded to an evaluation device in which said actual data are compared with target data.

Description

Device and method for vacuum coating of surfaces of

Objects

The present invention relates to an apparatus for coating

Surfaces of objects under vacuum provided by a vacuum system by means of a gas separation process, having process spaces, including a treatment chamber for receiving the objects to be coated, in particular the inner surfaces of hollow bodies, such as

Beverage containers, and process rooms connected to the treatment chamber for providing gases / gas mixtures to be separated. The invention also relates to a corresponding method for monitoring

Coating devices and especially their inner gas space / pipeline surfaces.

As a gas separation process for the coating device come

for example PVD, CVD, PCVD into consideration.

Not all reactive components are in the coating process in the

Coating chamber and implemented on the surface to be coated of the objects intended for the coating. This activated

Residual gas mixture unintentionally coats inside the vacuum system

Components of the coating device, such as pumps, pipes, flappers, etc. The degree of unwanted coating depends on the

Surface geometry and the shape of the container (bottle) of the object to be coated and the recipe used.

So far, maintenance intervals in which the surfaces of the components and process rooms of the coating device are cleaned have been canceled

Based on empirical values, without taking into account the actual contamination caused by unwanted coating. In case of doubt, a prediction is not possible and the system must be serviced and cleaned very early on or operated until it comes to an unexpected standstill.

This is a major disadvantage and uncertainty factor, particularly in coating systems with strongly or frequently changing recipes for gas mixtures. There is therefore a need to determine the need for maintenance associated with the removal of unwanted coatings

Coating devices of the type mentioned without the need to deactivate and inspect the entire device.

An object of the present invention is therefore to provide a

To create coating device of the type mentioned, which the

Determination of the need for maintenance of the coating device associated with the removal of unwanted coatings guaranteed without the need to deactivate the entire device.

According to the invention, this object is achieved by the features of the independent claims. Advantageous refinements are given in the subclaims.

Accordingly, the invention provides a device for coating surfaces of objects under a vacuum provided by a vacuum system by means of a gas separation process, having process rooms, including at least one treatment chamber for receiving the objects to be coated and at least one further process room connected to the at least one treatment chamber for passage

of gases to be separated and / or discharge of portions of unseparated gas subsets. In at least one further process room, a measuring unit for detecting the coating thickness is arranged on a surface or on sections of the surface of the process rooms, the measuring unit being connectable to a control and evaluation unit. The control and evaluation unit is preferably set up to determine the need and / or the point in time to clean the surfaces of the at least one further process space or the treatment chamber by removing unwanted coating. The control and evaluation unit is particularly preferably set up to evaluate an ACTUAL occupancy rate or course of an ACTUAL occupancy rate, in particular against a TARGET occupancy rate or TARGET course of an occupancy rate.

In the present case, any interior space of the device is to apply as a process space, which is at least temporarily with a vacuum during normal operation

is acted upon and in which the gas to be separated is passed. The actual process space is therefore particularly preferred

Treatment chamber, in which at least one object can be coated, and the vacuum lines connected to it, which are connected to one or more Vacuum pumps are connected to set the necessary process pressure (vacuum) and / or to pass gases.

The surfaces of objects to be coated are preferably inner surfaces of hollow bodies, such as, for example, containers, in particular bottles, preferably plastic bottles. The device is particularly preferably designed to coat the inner walls of bottles, in particular PET bottles.

A gas deposition process is, for example, a PVD (Physical Vapor Deposition), a CVD (Chemical Vapor Deposition) or a PCVD (Plasma (assisted) Chemical Vapor Deposition) process. These procedures are carried out under vacuum.

The gases that can be provided in the connected process rooms can be gases or gas mixtures. Here, gases are gases from a chemical

Compound or a chemical element understood. Gas mixtures are gases made up of at least two different chemical elements or chemical compounds. A vapor phase is also used synonymously as gas

unless something different is expressly mentioned. Gas mixtures are also preferred, homogeneous mixtures of substances.

The deposition rate is preferably measured while the process is running and thus allows predictions about the degree of contamination of individual components without opening the vacuum system.

Furthermore, the present invention ensures long-term in-line measurement of unwanted coating. This enables a meaningful prediction of the maintenance intervals of process pumps, flutters (control flaps),

Vacuum piping, etc. guaranteed. As a result, the remaining runtime (until maintenance) can be permanently compared with the planned runtime and, if necessary, even currently unnecessary maintenance activities can be identified and skipped or delayed.

Finally, the inventive monitoring of the deposition rate of the undesired deposition increases the efficiency of the coating device, since the achievement of the maximum tolerable stress state can be predicted. This also ensures that there are unplanned outages

can be avoided. Provision is advantageously made for the measuring unit to be arranged in an area of the further process rooms that is accessible without having to open the entire vacuum system of the coating device.

A device is preferably provided in which the measuring unit is in a bypass, in a separable space or line section, in a

Vacuum line of the vacuum system, is arranged in a supply line to the treatment chamber or in a discharge line from the treatment chamber.

This location at which the measuring unit is arranged can preferably be shut off so that the measuring unit or the sensor element can be exchanged during operation. This is preferably achieved by means of valves at both ends or both sides and suitable opening / removal measures, which ensure that the entire vacuum system does not have to be opened.

Other locations of the coating system suitable for this purpose can be considered, as long as it is preferably ensured that the

Measuring unit is accessible there without the entire vacuum system of the

Having to open the coating device.

The measuring unit used according to the invention preferably comprises a coating thickness detection element which has a sensor section and the sensor section has a strain gauge and / or

Includes resistance measuring strips and / or capacitive sensor measuring strips and / or magnetic induction measuring strips. All sensors of different types are preferably suitable for this element, in particular if they are miniaturized to such an extent that they can be used at suitable locations or areas of the coating device without requiring a large amount of space. These preferably include sensors for measuring the layer thicknesses of non-metallic coatings on a metallic substrate according to the magneto-inductive principle and sensors that use the eddy current principle for measuring isolating

Use layers on non-ferrous metals (coating on a metallic substrate). Coating thickness sensors or detection elements that can be implemented in strip form, such as, for example, are particularly suitable here

Strain gauges, resistance measuring strips, capacitive sensor measuring strips and / or magnetic induction measuring strips. The measuring unit is particularly preferred a gravimetric measuring unit, ie a measuring unit which takes into account the weight difference of the deposit, in particular on the sensor of the measuring unit.

In a further exemplary embodiment, the measuring unit comprises a carrier and closure section and a sensor section, the sensor section being able to be combined and releasably connected to the carrier and closure section in a non-destructive manner. The sensor section is preferably designed to be pluggable. This makes it possible to remove the sensor section for evaluation alone and to replace it with a new one without having to exchange the entire measuring unit.

In a further exemplary embodiment, the sensor section has a measuring tongue and an interface section via which the connection to the carrier and closure section can be established. So it is possible when removing the

Sensor section only need to remove an interface section connected to the measuring tongue and no further elements of the measuring unit.

In a further exemplary embodiment, a device is provided in which the measuring unit has a transponder with which data and / or signals from the control and evaluation unit can be transmitted wirelessly to a receiving station. Such a transponder can preferably be a radio transmitter or be based on RFID technology.

In a further exemplary embodiment, a device is provided in which the measuring unit projects into a pipeline of the vacuum system. The measurement in a pipe of the vacuum system becomes a critical part of the

Coating device monitored.

A measuring unit is particularly advantageous, which comprises a carrier for the preferably strip-shaped coating thickness detection element, which is attached to a vacuum feedthrough, wherein the vacuum feedthrough can be connected to a flange tube which opens into a bore in the wall of the at least one further process space, and wherein the coating thickness detection element comes to lie in the area of the bore.

The object of the present invention is also achieved by a method for monitoring surfaces in conduction paths of an inventive

Device for coating surfaces of objects, in which the measuring unit is used as a measured value for actual data of the coating thickness on a surface of the at least one further process room and these ACTUAL data are passed on to an evaluation device in which these ACTUAL data are compared with TARGET data.

The measuring unit records actual data as measured values depending on the sensor used. These measured values allow a conclusion about the

Coating thickness in the area in which the measuring unit is used and thus the adjacent lines or process rooms.

The TARGET data are preferably specified and correspond to the measured values or the coating thicknesses derived from them. The TARGET data can preferably be specified and can preferably also be adapted. A

Adjustment can be preferred depending on the selected recipes,

Downtimes, operating times or empirical values from parallel operated

Measurement units, either in the same device or in a device operated in parallel, take place.

The evaluation unit preferably comprises a comparator with which the ACTUAL data and the TARGET data are compared with one another. The ACTUAL data preferably also include a time stamp, so that a gradient over time can be determined from the number of ACTUAL data determined. This can be used to forecast future coating scenarios.

The comparison of the ACTUAL data with the TARGET data is preferably carried out continuously or sequentially. To measure the coating thickness in running systems, it may be sufficient to carry out a daily comparison. The interval in which the comparison takes place is preferably predetermined as a function of the gradient of the ACTUAL data determined in the past. It is thus possible to make a comparison in three days with a freshly cleaned device, while a narrower interval is specified for a gradient that makes it possible to reach the target data soon.

The comparison of the ACTUAL data with the TARGET data is particularly preferably carried out continuously and is transferred wirelessly to an evaluation unit and continuously evaluated there. The development of the ACTUAL data over time in correlation with the data driven on the device is particularly preferred

Coating processes brought. This makes it possible to identify particularly critical processes in which a higher gradient of the actual data occurs than in other procedures. Taking into account the coating processes to be carried out on the device in the future, these findings can be used for a

Forecast of the coating thickness can be used.

In the case of predetermined constellations, when comparing the ACTUAL data with the TARGET data, a signal is preferably generated with which a message, in particular an error message or a warning message, is generated. This constellation can preferably be freely defined and selected for predetermined coating thicknesses such as 80% of the maximum achievable coating thickness before cleaning for a warning message or at 95% for an error message.

Maintenance and / or shutdown times are preferably predicted and preferably also reported as a function of the gradient of the measured value over time.

Preference is given to measurements at several locations and in sections

Messages about maintenance and / or cleaning requirements are reported and / or a shutdown is forecast. By measuring at several locations in the device, it is possible to take into account the coating situation at several selected locations and to compare them with one another. In this way, a more precise picture of the coating situation is determined and individual (partially) defective measuring units or sensor elements are compensated and also identified by redundancy. In addition, the susceptibility to coatings on the

different locations and this difference can also be determined and used for the forecast.

The measuring unit, in particular the sensor section, is preferably removed from and outside the device for coating surfaces

Objects evaluated. Simply plugging in and unplugging the

Sensor element it is possible to change this and the loaded one

Read out sensor element externally. Particularly preferably, the old, loaded sensor element is then worked up so that it can be used again.

Further details and advantages of the invention will now be explained in more detail using an exemplary embodiment shown in the drawings. Show it:

1 shows a double coating chamber for containers as well as the supply and discharge vacuum and gas lines,

2 shows a sectional view of a pipe section of the coating device according to the invention, in which a measuring unit is arranged, and

3 shows a plan view of an embodiment of the measuring unit in the

Pipeline section of Fig. 2.

The coating device 1 shown in Fig. 1 shows a

Double coating chamber 6 for container 2 and supply and discharge vacuum and gas lines 7.1 to 7.6. In the downstream line 7.1 is a

Pipe section 10 shown in front of a vacuum pump 5, in which a

Measuring unit 14 is arranged.

This pipeline section 10 from FIG. 1 is shown again in greater detail in FIG. The pipeline section 10 of the device for coating surfaces of objects under a vacuum provided by a vacuum system by means of a gas separation process has a further process space 12 in the form of a pipeline with measuring stubs for receiving a measuring unit 14. In connection with this further process space 12 is a flap valve or flapper 9 (shown to the left of the further process space 12). The vacuum pump 5 connects on the other side (to the right of the further process space 12 - not shown here).

A measuring unit 14 communicating with its interior via a bore 13 is attached to a wall of the further process space 12 and is shown in greater detail in FIG. 3. This measuring unit 14 is preferably a gravimetric measuring unit. The measuring unit 14 is used for (preferably gravimetric) detection of the coating thickness on the surface of the process space 12 in the area of the bore 13. In a manner not shown in FIG To clean process rooms or parts thereof by removing unwanted coating. As can be seen from FIG. 3, the measuring unit 14 comprises a strip-shaped one

Coating thickness detecting element 15 in the form of a

Strain gauge, which has two sensor fields 16 and 17, the output signals of which are connected to the control and evaluation unit via two pairs of measuring lines 18 and 19. The strain gauge 15 is attached to a flat sheet metal element 20, which is held via a base plate 21 made of insulating material, which is fixed on an axially cut pipe end part 22 of a tubular support 23. The two pairs of measuring lines 16 and 17 pass through the tubular carrier 23 and are from this via a

Vacuum feed-through 24 led out.

As can be seen from FIG. 2, the measuring unit 14 is coupled to the further process room 12 via a flange tube 25 connected in a vacuum-tight manner to the wall of the further process room 12 so that its detection element 15 is in the area of the bore 13, but set back from the wall of the further process room 12 comes to rest, at this point the strength of a

to determine unwanted coating on the surface of the further process space 12.

By measuring the coating thickness, the condition of the

Vacuum components are monitored permanently or continuously (dynamically) during the ongoing maintenance interval. This means that the remaining runtime (until maintenance) can be permanently compared with the planned runtime and, if necessary, even currently unnecessary maintenance activities can be identified and skipped or delayed.

The efficiency of the systems is increased by the present invention, since the achievement of the maximum tolerable load condition can be predicted and thus unplanned failures can be avoided.

List of reference symbols

1 coating device

2 bottle, hollow body

5 vacuum pump

6 double coating chamber for containers

7 inlet and outlet vacuum and gas lines

9 flap valve or flapper (control flap)

10 pipe section

12 further process room (e.g. pipe section with measuring nozzle)

13 hole

14 measuring unit

15 Coating thickness detection element

16 sensor field

17 sensor field

18 pairs of test leads

19 test lead pair

20 sheet metal element

21 base plate

22 pipe end piece

23 carriers

24 Vacuum feed-through

25 flange pipe

Claims

1. Device (1) for coating surfaces of objects under a vacuum provided by a vacuum system by means of a

Gas separation process, having

Process rooms (12),

including at least one treatment chamber for receiving the objects to be coated

and at least one further process space (12) connected to the at least one treatment chamber for the passage of gases to be separated and / or the discharge of portions of non-separated gas subsets,

characterized in that a measuring unit (14) for detecting the coating thickness on a surface or on sections of the surface of the process rooms (12) is arranged in at least one further process room (12), the measuring unit (14) being connectable to a control and evaluation unit .

2. Device (1) according to claim 1, characterized in that the

Measuring unit (14) comprises a coating thickness detection element (15) which has a sensor section and the sensor section has a

Includes strain gauges and / or resistance measuring strips and / or capacitive sensor measuring strips and / or magnetic induction measuring strips.

3. Device (1) according to claim 1 or 2, characterized in that the measuring unit (14) comprises a carrier and closure section and a sensor section, the sensor section being non-destructively connectable and releasable with the carrier and closure section.

4. Apparatus according to claim 3, characterized in that the

Sensor section has a measuring tongue and an interface section via which the connection to the carrier and closure section can be established.

5. Device according to one of the preceding claims, characterized

characterized in that the measuring unit (14) has a transponder with which data and / or signals from the control and evaluation unit can be transmitted wirelessly to a receiving station.

6. Device (1) according to one of the preceding claims, characterized in that the measuring unit (14) in a region of the at least one further process space (12) is arranged, which is accessible without having to open the entire vacuum system.

7. Device (1) according to one of the preceding claims, characterized in that the measuring unit (14) is arranged

- in a bypass,

- in a separable room or line section,

- in a vacuum line (7) of the vacuum system,

- in a supply line to the treatment chamber or

- in a derivation from the treatment chamber.

8. Device according to one of the preceding claims

characterized in that the measuring unit (14) protrudes into a pipeline of the vacuum system.

9. Device (1) according to one of claims 2 to 8, characterized in that the measuring unit (14) comprises a carrier (23) for the coating thickness detection element (15) which is attached to a vacuum feedthrough (24), wherein the Vacuum feed-through (24) can be connected to a flange tube (25) which opens into a bore (13) in the wall of the at least one further process space (12), and wherein the coating thickness detection element (15) can be arranged in the region of the bore (13) is.

10. A method for monitoring surfaces in conduction paths of a device (1) for coating surfaces of objects according to one of the preceding claims, in which the measuring unit (14) is used as a measured value as actual data of the coating thickness on a surface of the at least one further process space (12) and these ACTUAL data are passed on to an evaluation device in which these ACTUAL data are compared with TARGET data.

11. The method according to claim 10, in which the comparison of the actual data with the target data takes place continuously or sequentially.

12. The method according to claim 10 or 11, wherein at predetermined

Constellations when comparing the ACTUAL data with the TARGET data, a signal is generated with which a message, in particular an error message or a warning message, is generated.

13. The method according to any one of claims 10 to 12, characterized in that maintenance and / or switch-off times are forecast as a function of the gradient of the measured value over time.

14. The method according to any one of claims 10 to 13, characterized in that measurements are taken at several locations and reports on maintenance and / or cleaning requirements are reported in sections and / or shutdown is forecast.

15. The method according to any one of claims 10 to 14, characterized in that the measuring unit, in particular the sensor section, is removed and outside the device (1) for coating surfaces of

Objects is evaluated.