EP1507891A1

EP1507891A1 - Method and device for the plasma treatment of work pieces

Info

Publication number: EP1507891A1
Application number: EP03732225A
Authority: EP
Inventors: Michael Litzenberg; Frank Lewin; Hartwig Müller; Klaus Vogel; Gregor Arnold; Stephan Behle; Andreas LÜTTRINGHAUS-HENKEL; Matthias Bicker; Jürgen Klein
Original assignee: SIG Technology AG
Current assignee: SIG Combibloc Services AG
Priority date: 2002-05-24
Filing date: 2003-05-09
Publication date: 2005-02-23
Also published as: WO2003100126A1; AU2003239757A1

Abstract

The invention relates to a method and a device which are used for plasma treatment of work pieces. Said work pieces are inserted into an at least partially evacuatable chamber of a treatment station and the work pieces (5) are positioned inside the treatment station by retaining elements (42). At least two retaining elements of a common carrier (41) are positioned in relation to each other in the region of the treatment station.

Description

Method and device for plasma treatment of

workpieces

The invention relates to a method for plasma treatment of workpieces, in which the workpieces are inserted into an at least partially evacuable plasma chamber of a treatment station and in which the workpieces are positioned within the treatment station by holding elements.

The invention further relates to a device for plasma treatment of workpieces, which has at least one evacuable plasma chamber for receiving the workpieces and in which the plasma chamber is arranged in the region of a treatment station, and in which the plasma chamber from a chamber bottom, a chamber lid and a side - Chen chamber wall is limited and has at least one holding element for positioning the workpieces.

Such methods and devices are used, for example, to provide plastics with surface coatings. In particular, such methods and devices are also already known for coating inner or outer surfaces of containers which are intended for packaging liquids. Devices for plasma sterilization are also known.

PCT-WO 95/22413 describes a plasma chamber for internally coating PET bottles. The bottles to be coated are lifted into a plasma chamber by a movable base and connected to an adapter in the area of a bottle mouth. The bottle interior can be evacuated through the adapter. In addition, a hollow lance is inserted through the adapter into the interior of the bottles to supply process gas. The plasma is ignited using a microwave.

From this publication it is also known to arrange a plurality of plasma chambers on a rotating wheel. This supports a high production rate of bottles per unit of time.

In EP-OS 10 10 773 a feed device is explained in order to evacuate a bottle interior and to supply it with process gas. PCT-WO 01/31680 describes a plasma chamber into which the bottles are introduced from a movable lid which was previously connected to a mouth area of the bottles. PCT-WO 00/58631 also already shows the arrangement of plasma stations on a rotating wheel and, for such an arrangement, describes a group assignment of vacuum pumps and plasma stations in order to support a favorable evacuation of the chambers and the interior of the bottles. In addition, the coating of several containers in a common plasma station or a common cavity is mentioned.

Another arrangement for carrying out an internal coating of bottles is described in PCT-WO 99/17334. In particular, an arrangement of a microwave generator above the plasma chamber and a vacuum and operating medium feed through a floor of the plasma chamber are described here.

In the vast majority of known methods, container layers made of silicon oxides with the general chemical formula SiO _x are used to improve the barrier properties of the thermoplastic material. In addition, portions of carbon, hydrogen and nitrogen can also be contained in the barrier layers produced in this way. Such barrier layers prevent penetration of oxygen into the packaged liquids and escape of carbon dioxide in the case of liquids containing CO ₂ .

The previously known methods and devices are not yet sufficiently suitable to be used for mass production, in which both a low coating price per workpiece and a high production speed must be achieved. The object of the present invention is therefore to provide a method of the type mentioned in the introduction in such a way that a quantitative production output is increased with good product quality.

This object is achieved in that at least two holding elements are positioned relative to one another in the area of the treatment station by a common carrier.

Another object of the present invention is to construct a device of the type mentioned in the introduction in such a way that, with a compact structure, high production output and good product quality are supported.

This object is achieved in that at least two holding elements are held by a common carrier in the area of the plasma station.

The joint positioning of the holding elements from a common carrier in the area of the treatment station makes it possible to support an increased production output for each treatment station. In particular, insertion of the workpieces to be processed into the treatment station and removal of the finished workpieces from the treatment station are supported. The common carrier for the holding elements supports an exactly reproducible positioning of the containers within the plasma station as well as the implementation of input and output processes with little expenditure of time and high reliability. In order to support the rapid execution of transfer processes, it is proposed that at least two holding elements be moved together with the carrier in a direction offset by a movement that is at least temporarily carried out by the carrier during the execution of a treatment process.

Simultaneous treatment of a large number of workpieces with a compact construction of the treatment device is supported in that at least two holding elements are moved together with the support offset relative to one another transversely to the direction of a movement which is at least temporarily carried out by the support during the execution of a treatment process.

When coating hollow workpieces, which are arranged with their mouths facing downward, it proves to be advantageous that a cavity of the plasma station is evacuated through the chamber floor.

A simple implementation in terms of device technology is also supported in that process gas is supplied through the chamber floor.

A quick and uniform distribution of the process gas in an interior of the workpieces can be achieved in that the process gas is fed through a lance into the interior of the workpieces.

Simultaneous insertion and removal of a large number of workpieces in the treatment station or from the treatment station is made possible in that the carrier is positioned relative to the treatment station. in particular, it is contemplated that the carrier, loaded with at least one workpiece, is inserted into the treatment station.

In order to shorten transfer times, it also proves advantageous that the carrier, loaded with at least one workpiece, is removed from the treatment station.

A continuous execution of transfer processes is supported in that the carrier carries out a rotational movement at least temporarily relative to the treatment station.

Simple kinematics when carrying out transfer operations can be achieved in that the carrier is equipped with workpieces to be treated by a rotating transfer element.

When using path-type transfer devices, it proves to be advantageous that the transfer element is moved at the same speed as the carrier at least at the time of transfer of a workpiece to the carrier.

To support controllable ignition of the plasma, it is proposed that microwaves generated in the region of the chamber lid be introduced into the cavity by at least one microwave generator.

A typical application is that workpieces made of a thermoplastic are treated.

In particular, it is thought that interiors of the workpieces are treated. An extensive area of application is opened up by treating containers as workpieces.

In particular, it is thought that beverage bottles are treated as workpieces.

A high production rate with great reliability and high product quality can be achieved in that the at least one plasma station is transferred from a rotating plasma wheel from an input position to an output position.

An increase in production capacity with only a slightly increased expenditure on equipment can be achieved by providing several cavities from one plasma station.

The use of conventional transfer wheels for carrying out transfer processes, even in plasma stations for the treatment of several workpieces, is made possible in that the treatment station is positioned by a plasma wheel which is moved in a clocked manner.

A typical application is defined in that a plasma coating is carried out as the plasma treatment.

In particular, it is contemplated that the plasma treatment is carried out using a low pressure plasma.

When coating plastic workpieces, it proves advantageous that plasma polymerization is carried out. Good surface adhesion is supported by the fact that at least some organic substances are deposited by the plasma.

Particularly advantageous usage properties for workpieces for packaging food can be achieved in that at least some inorganic substances are deposited by the plasma.

In the treatment of packaging, particular consideration is given to the fact that the plasma deposits a substance to improve the barrier properties of the workpieces.

To support a high quality of use, it is proposed that an adhesion promoter is additionally deposited to improve the adherence of the substance to surfaces of the workpieces.

High productivity can be supported by treating at least two workpieces simultaneously in a common cavity.

Another area of application is that plasma sterilization is carried out as the plasma treatment.

It is also contemplated that a surface activation of the workpieces is carried out as a plasma treatment.

To derive the finished workpieces, it is proposed that finished workpieces be removed at least one unloading station is used from the area of the carrier.

The workpieces to be treated are fed in that at least one loading station is used to feed workpieces to be machined into the area of the carrier.

Very short transfer times can be achieved in that the loading station is designed to feed workpieces to be machined to a carrier separate from the plasma wheel.

Low weights to be transferred when carrying out the transfer processes can be achieved in that at least one carrier is arranged in the area of each plasma station.

A simple implementation of the transfer operations is supported in that at least two holding elements are arranged along a circumference of the carrier.

For the supply of workpieces to carriers rotating together with a plasma wheel, it proves to be advantageous that an input path is provided for the transfer of workpieces to be treated to the carriers.

A kinematically simple implementation of the transfer processes is supported in that the input path runs centrally to a center point of the plasma wheel.

Locally changeable transfer points can be realized in that the input path is arranged in the area of a transfer element. Simple kinematic boundary conditions when carrying out the transfer operations are provided in that a speed of movement of the transfer element is adapted to a speed of movement of the carrier carried by the plasma wheel.

In order to derive finished workpieces, it is proposed that an output section be provided for removing workpieces to be treated from the supports.

Even when the workpieces are unloaded, it proves to be advantageous that the output path runs centrally to a center of the plasma wheel.

In addition, it is also intended for the unloading process that the output path is arranged in the area of a transfer element.

A convenient material flow during unloading can be achieved in that the transfer element is driven in a rotating manner.

Optimal utilization of the process angle is achieved by arranging the loading station on the one hand and the unloading station on the other hand at two cycle positions with a stationary plasma wheel.

In a clocked mode of operation, a simple constructive implementation is achieved in that the loading station is designed as a loading wheel. In a clocked mode of operation, in particular, it is also contemplated that the unloading station is designed as an unloading wheel.

An advantageous kinematics in transfer operations is achieved in that the wheels have a peripheral speed corresponding to a transport speed of the carrier in the area of its current transfer area.

Another mode of operation is defined by the fact that at least two rotations of the plasma wheel are provided for the period between an input of the workpieces into the plasma station and an output of the workpieces.

A material flow at a substantially constant height can be achieved in that the plasma station is guided so that it can be positioned at least partially in the direction of the carrier.

Another embodiment variant is that the carrier is guided so that it can be positioned vertically into the plasma chamber from above.

Finally, it is also contemplated that the carrier is guided so that it can be positioned in the vertical direction from below into the plasma chamber.

Exemplary embodiments of the invention are shown schematically in the drawings. Show it:

1 is a schematic diagram of a plurality of plasma chambers which are arranged on a rotating plasma wheel. net and in which the plasma wheel is coupled with input and output wheels.

2 shows an arrangement similar to FIG. 1, in which the plasma station is each equipped with two plasma chambers,

3 is a perspective view of a plasma wheel with a plurality of plasma chambers,

4 is a perspective view of a plasma station with a cavity,

5 shows a front view of the device according to FIG. 4 with the plasma chamber closed,

6 shows a cross section along section line VI-VI in FIG. 5,

7 shows a representation corresponding to FIG. 5 with the plasma chamber open,

8 is a vertical section along section line VIII-VIII in Fig. 7,

9 is an enlarged view of the plasma chamber with the bottle to be coated according to FIG. 6,

10 is a perspective view of a support ring of a plasma wheel, on which a plurality of carriers for positioning several holding elements for bottle-shaped workpieces are arranged, 11 shows a schematic representation of a plasma wheel, in which fully equipped carriers for the workpieces are inserted into the plasma wheel and are removed from the plasma wheel together with the treated workpieces after the treatment process has been carried out,

Fig. 12 shows a modified embodiment compared to Fig. 11, in which on the. Plasma wheel rotatably mounted carriers are arranged, which cooperate with loading and unloading lines, which are arranged outside the plasma wheel,

13 shows a further modified embodiment in which a pulsed operation of the plasma wheel and a pulsed operation of input wheels and output wheels is provided,

Fig. 14 shows a plan view of a holding element for a single workpiece,

15 is a perspective view of a holding element according to FIGS. 14 and

FIG. 16 shows the holding element according to FIG. 15 with a bottle-shaped workpiece held.

1 shows a plasma module (1), which is provided with a rotating plasma wheel (2). A plurality of plasma stations (3) are arranged along a circumference of the plasma wheel (2). The plasma stations (3) are provided with cavities (4) or plasma chambers (17) for receiving workpieces (5) to be treated. To explain the basic design principle is shown in Fig. 1 only one workpiece (5) per plasma station (3) is shown. The feeds and discharges of the workpieces also only schematically show the handling of individual workpieces (5). In fact, at least two workpieces (5) are assigned to each plasma station (3).

The workpieces (5) to be treated are fed to the plasma module (1) in the area of an input (6) in accordance with the simplification of the illustration and are forwarded via a separating wheel (7) to a transfer wheel (8) which is equipped with positionable support arms (9). Is provided. The support arms (9) are arranged such that they can be pivoted relative to a base (10) of the transfer wheel (8), so that the distance between the workpieces (5) can be changed relative to one another. As a result, the workpieces (5) are transferred from the transfer wheel (8) to an input wheel (11) with a greater distance between the workpieces (5) relative to one another relative to the separating wheel (7). The input wheel

(11) transfers the workpieces (5) to be treated to the plasma wheel (2). After the treatment has been carried out, the treated workpieces (5) are removed from an output wheel

(12) removed from the area of the plasma wheel (2) and transferred into the area of an output section (13).

In the embodiment according to FIG. 2, the plasma stations (3) are each shown with two cavities (4) or plasma chambers (17) to further clarify the design principle. As a result, two workpieces (5) can be treated simultaneously. Basically, it is possible to make the cavities (4) completely separate from one another, but in principle it is also possible to delimit only partial areas from one another in a common cavity space such that an optimal coating of all workpieces (5) is ensured. In particular is here thought to delimit the partial cavities from each other at least by separate microwave coupling.

Fig. 3 shows a perspective view of a plasma module (1) with a partially constructed plasma wheel (2). To simplify matters, only one workpiece (5) is shown here for each plasma station (3). The plasma stations (3) are arranged on a support ring (14) which is designed as part of a rotary connection and is mounted in the area of a machine base (15). The plasma stations (3) each have a station frame (16) which holds plasma chambers (17). The plasma chambers (17) have cylindrical chamber walls (18) and microwave generators (19).

A rotary distributor (20) is arranged in a center of the plasma wheel (2), via which the plasma stations (3) are supplied with operating resources and energy. Ring lines (21) in particular can be used for the distribution of operating resources.

The workpieces (5) to be treated are shown below the cylindrical chamber walls (18). Lower parts of the plasma chambers (17) are not shown for the sake of simplicity.

Fig. 4 shows a plasma station (3) in perspective. To simplify matters, only one workpiece (5) is shown here for each plasma station (3). It can be seen that the station frame (16) is provided with guide rods (23) on which a slide (24) is guided to hold the cylindrical chamber wall (18). Fig. 4 shows the carriage (24) with chamber wall (18) in a raised state so that the workpiece (5) is released.

The microwave generator (19) is arranged in the upper region of the plasma station (3). The microwave generator (19) is connected via a deflection (25) and an adapter (26) to a coupling channel (27) which opens into the plasma chamber (17). Basically, the microwave generator (19) can be coupled both directly in the area of the chamber lid (31) and via a spacer element to the chamber lid (31) with a predeterminable distance to the chamber lid (31) and thus in a larger surrounding area of the chamber lid (31). to be ordered. The adapter (26) has the function of a transition element and the coupling channel (27) is designed as a coaxial conductor. A quartz glass window is arranged in the region of a junction of the coupling channel (27) in the chamber cover (31). The deflection (25) is designed as a waveguide.

The workpiece (5) is positioned in the area of a sealing element (28) which is arranged in the area of a chamber base (29). The chamber base (29) is designed as part of a chamber base (30). To facilitate adjustment, it is possible to fix the chamber base (30) in the area of the guide rods (23). Another variant is to attach the chamber base (30) directly to the station frame (16). With such an arrangement, it is also possible, for example, to design the guide rods (23) in two parts in the vertical direction.

FIG. 5 shows a simplified front view of the plasma station (3) according to FIG. 3 in a closed state of the plasma chamber (17). Here too, only one workpiece (5) is shown for simplicity. The carriage (24) with the cylindrical chamber wall (18) is lowered compared to the positioning in Fig. 4, so that the chamber wall (18) has moved against the chamber bottom (29). The plasma coating can be carried out in this positioning state.

FIG. 6 shows the arrangement according to FIG. 5 in a vertical sectional view. It can be seen in particular that the coupling channel (27) opens into a chamber cover (31) which has a laterally projecting flange (32). A seal (33) is arranged in the area of the flange (32) and is acted upon by an inner flange (34) of the chamber wall (18). In a lowered state of the chamber wall (18), the chamber wall (18) is thereby sealed relative to the chamber cover (31). Another seal (35) is arranged in a lower region of the chamber wall (18) in order to ensure a seal relative to the chamber bottom (29) here too.

6, the chamber wall (18) encloses the cavity (4), so that both an interior of the cavity (4) and interior spaces of the workpieces (5) can be evacuated. To support a supply of process gas, hollow lances (36) are arranged in the area of the chamber base (30) and can be moved into the interior of the workpieces (5). The lances (36) are positioned by a lance slide (37) which can be positioned along the guide rods (23). A process gas channel (38) runs inside the lance slide (37) and, in the raised position shown in FIG. 6, is coupled to a gas connection (39) of the chamber base (30). This arrangement avoids hose-like connecting elements on the lance slide (37). FIGS. 7 and 8 show the arrangement according to FIGS. 5 and 6 in a raised state of the chamber wall (18). In this position of the chamber wall (18), it is possible to remove the treated workpieces (5) from the area of the plasma station (3) without any problems and to insert new workpieces (5) to be treated. As an alternative to the positioning of the chamber wall (18) shown in the drawings in an open state of the plasma chamber (17) achieved by displacement upwards, it is also possible to carry out the opening process by displacing a structurally modified sleeve-shaped chamber wall in the vertical direction downwards.

In the exemplary embodiment shown, the coupling channel (27) has a cylindrical design and is arranged essentially coaxially with the chamber wall (18).

FIG. 9 shows the vertical section according to FIG. 6 in an enlarged partial illustration in the vicinity of the chamber wall (18). In particular, the overlap of the inner flange (34) of the chamber wall (18) over the flange (32) of the chamber cover (31) and the holding of the workpieces (5) by the sealing elements (28). In addition, it can be seen that the lance (36) is guided through a recess (40) in the sealing element (28).

Fig. 10 shows a support ring (14) of a further embodiment of the plasma wheel (2). A plurality of supports (41) are arranged on the support ring (14), each of which positions holding elements (42) for the workpieces (5). In the embodiment shown, the carriers (41) are essentially circularly limited and six holding elements (42) are arranged in the vicinity of a circumference of the carriers (41). The holding elements (42) are designed for positioning bottle-shaped workpieces (5), the Workpieces (5) are each arranged with mouth openings in the vertical direction downwards.

The carriers (41) with the holding elements (42) and the workpieces (5) can be used in differently designed plasma stations (3). For example, it is possible to equip the plasma station (3) with only one plasma chamber (17) and to insert all workpieces (5) together into this plasma chamber (17). It is also conceivable to subdivide a corresponding common plasma chamber (17) into individual cavities (4) or separate plasma chambers (17) in the area of the plasma station (3) for each of the workpieces (5) or for subgroups of the supports (41) positioned workpieces (5).

11 shows a schematic representation of a plasma wheel (2) with a plurality of carriers (41). The carriers (41) are completely loaded with the workpieces (5) to be treated in the area of a loading station (43) and a carrier (41) equipped with the workpieces (5) is transferred to the plasma wheel (2). After completion of the treatment process and a corresponding rotational movement of the plasma wheel (2), the carrier (41) equipped with the workpieces (5) is removed from the plasma wheel (2) and transferred to the area of an unloading station (44).

After the finished workpieces (5) have been removed, the carrier (41) can again be loaded with workpieces (5) in the area of the loading station (43) and transferred back to the plasma wheel (2). In particular, in such an embodiment it is contemplated to use at least one carrier (41) more than can be arranged simultaneously in the region of the plasma wheel (2). As a result, immediately after a carrier (41) to be unloaded has been removed, a carrier fully equipped with workpieces (5) can be transferred back to the plasma wheel (2). With regard to the material flow of the workpieces (5), different variants are conceivable. For example, it is possible to always convey the workpieces (5) on an essentially horizontal transport path. Both loading of the carriers (41) in the area of the loading station

(43), machining of the workpieces (5) in the area of the plasma wheel (2) and unloading of the carriers (41) in the area of the unloading station (44) would be carried out at an essentially constant height level. However, it is also possible, for example on the plasma wheel (2), in the area of the loading station (43) and / or in the area of the unloading station (44), lifting movements of the carrier

(41), the carrier (41) with the workpieces (5) or also without the workpieces (5) being positioned in an upward or downward direction. Such a procedure is particularly advantageous if the support (41) is to be lifted into the plasma chamber (17) or lowered into the plasma chamber (17) together with the workpieces (5) to be machined.

FIG. 12 shows an embodiment modified from the representation in FIG. 11. The carriers (41) are arranged stationary in the area of the plasma wheel (2) and rotatably supported relative to the plasma wheel (2) by means of rotary bearings (45). In particular, it is contemplated to mount the carriers (41) in the region of the plasma wheel (42) in such a way that rotational movements can be carried out.

As in the embodiment in FIG. 11, in the embodiment in accordance with FIG. 12, in particular, it is thought that the plasma wheel (2) carries out a continuous rotational movement with a constant rotational speed. To support such an operating mode, the loading station (43) is formed from a transfer element (46) and a loading wheel (47). In the illustrated Embodiment, the workpieces (5) to be machined reach the area of the loading wheel (47) via an input path (48) and are transferred from there to the transfer element

(46) handed over.

In the embodiment shown, the transfer element (46) has a circumferential transfer element (49), which can be implemented in a chain-like manner, for example. The loading wheel (47) initially transfers the workpieces (5) to be machined to the transfer element (49) in the area of a transfer position (50). Expediently the loading wheel

(47) and the transfer element (49) in the area of the transfer position (50) moved in the same direction and at the same peripheral speed in order to be able to carry out the transfer process continuously.

For the transfer of the workpieces (5) from the transfer element (49) to the carrier (41), a transfer path (51) is provided, which essentially has a curvature corresponding to the movement path of a part of the carrier (2) facing away from a center point (52) of the plasma wheel (2). 41) runs. This takes into account the fact that there is no fixed transfer position between the carrier (41) and the transfer element (49), but that the transfer position changes due to the rotation of the plasma wheel (2).

With a sufficiently fast rotational movement of the carrier (41) and a corresponding rotational speed of the transfer element (49), a relatively short dimensioning of the transfer path (51) can be carried out and a relatively short period of time can thus be implemented for the transfer process.

After completion of the treatment process of the workpieces (5) and a corresponding rotational movement of the plasma wheel (2) the carrier (41) reaches the area of a transfer element (53) which, together with an unloading wheel (54), forms the unloading station (44). Similar to the transfer element (46), the transfer element (53) also has. Transfer element (55), which can be chain-like, for example, and driven in rotation. The transfer of the coated workpieces (5) from the carrier (41) to the transfer element (55) and from the transfer element (55) to the unloading wheel (54) and from this to an output path (56) is carried out in a manner analogous to that for the input, only in reverse Sequence of the transfer processes to be carried out. A transfer section (57) of the transfer element (55) also runs with a curvature corresponding to the transfer section (51) of the transfer element (49).

FIG. 13 shows a variant in which the plasma wheel (2) is operated in cycles. This enables direct loading of the carriers (41) using the loading wheel (47) and direct unloading of the carriers (41) using the unloading wheel (54), since there are fixed input and output positions. In all embodiments, as an alternative to the loading wheels (47) and unloading wheels (54) shown, other rotating transfer elements (49, 55) that are moved back and forth alternately can also be used. However, the wheels shown have advantages both in terms of mechanical stability and in terms of the exact reproducibility of the movements carried out.

14 shows the holding element (42) for positioning a workpiece (5) (not shown) within the plasma chamber (17). The holding element (42) is designed like pliers and has two pivotably mounted holding arms (58, 59). The holding arms (58, 59) can be pivoted relative to axes of rotation (60, 61). To ensure automatic see fixation of the workpiece (5) by the holding element (42), the holding arms (58, 59) of springs (62, 63) are pressed into a respective holding position. The use of leg springs (62, 63) is preferred.

The holding element (42) is arranged above the carrier (41), so that after lifting the chamber wall (18) there is lateral accessibility of the holding element (42). The workpiece (5) can hereby be transferred from a positioning element to the holding element (42) without a lifting movement of the workpiece (5) in the direction of a longitudinal axis (64) of the cavity.

In Fig. 14 it can be seen in particular that a clamping space (65) for receiving the workpiece (5) is arranged between the holding arms (58, 59). The holding arms (58, 59) protrude into the clamping space (65) with fixing projections (66, 67). In addition, the holding arms (58, 59) have locking webs (68, 69) which face away from the fixing projections (66, 67) and which are arranged in one by locking elements (70, 71) which can preferably be positioned together with the chamber wall (18) Locking position can be fixed.

To further support and fix the workpiece (5), the holding element (42) has a stop element (72). The stop element (72) limits maximum insertion of the workpiece (5) into the clamping space (65). In the locking position, the workpiece (5) is pressed against the stop element (72) by the fixing projections (66, 67). The stop element (72) and the fixing projections (66, 67) are thereby arranged at approximately the same height level. 14 additionally shows the sealing element (28) and the lance (36) at a lower height level than the holding element (42) due to the selected viewing direction with respect to the plane of the drawing.

FIG. 15 shows the holding element (42) according to FIG. 14 in a perspective illustration and without depicting the locking elements (70, 71). It can be seen in particular that the holding element (42) has a base plate (73) from which the holding arms (58, 59) and the further components are carried. The base plate (73) can be mounted in the area of the carrier (41) via spacer elements (74, 75) and connecting elements (76, 77).

15 also shows that the fixing projections (66, 67) are each provided with insertion bevels (78) and outlet bevels (79). When the workpieces (5) are inserted into the clamping space (65), the workpiece (5) first comes into contact with the insertion bevels (78) and presses the holding arms (58, 59) apart against the forces of the springs (62, 63). After the workpiece (5) has been completely inserted into the clamping space (65), the holding arms (58, 59) automatically return to the locking position due to the forces of the springs (62, 63) and press the workpiece (5) against the stop element (72 ). The workpiece (5) is thereby fixed within the plasma chamber (17).

After completion of the treatment of the workpiece (5), the workpiece (5) is gripped by a transfer element and pulled against the outlet bevels (79). The outlet bevel (79) is preferably curved and is designed with a curvature course corresponding to an outer contour of the workpiece (5) in the contact area. The holding arms (58, 59) are thereby brought apart and release the workpiece (5). In particular, it is contemplated to provide the transfer element with controlled tong arms. The controlled pliers arms enable the workpieces (5) to be gripped actively and support the application of compressive and tensile forces to the insertion bevels (78) and the outlet bevels (79). In particular, it is contemplated that the controlled pliers of the transfer elements act on the workpiece (5) at an essentially same height level as the holding arms (58, 59) or at a somewhat lower or higher level. As a result, the introduction of tilting forces into the workpiece (5) is avoided or greatly reduced.

FIG. 16 shows the arrangement according to FIG. 15 after inserting a bottle-like workpiece (5) which is acted upon by the holding arms (58, 59) between a support ring (80) and a shoulder region (81). Holding such a bottle-like workpiece (5) in the neck region shown leads to a very stable fixation of the workpiece (5). The locking elements (70, 71) are also shown in FIG. 16. The locking elements (70, 71) are positioned together with the chamber wall (18). In the arrangement shown, the locking elements (70, 71) block a movement of the holding arms (58, 59), so that an uncontrolled opening of the holding element (42) is reliably prevented.

A typical treatment process is explained below using the example of a coating process and carried out in such a way that the workpieces (5) are first transported to the plasma wheel (2) using the loading station (43) and that the sleeve-like chamber wall (18) is inserted in a pushed-up state the workpieces (5) into the plasma station (3). After the insertion process has been completed, the chamber wall (18) is removed into its sealed positioning lowered and at the same time an evacuation of both the cavity (4) and the interior of the workpieces (5).

After the interior of the cavity (4) has been sufficiently evacuated, the lances (36) are moved into the interior of the workpieces (5) and, by moving the sealing elements (28), the interior of the workpieces (5) is sealed off from the interior of the cavity (5). 4) performed. It is also possible to move the lances (36) into the workpieces (5) synchronously with the beginning of the evacuation of the interior of the cavity. The pressure inside the workpieces (5) is then further reduced. In addition, the positioning movement of the lances (36) is at least partially already carried out parallel to the positioning of the chamber wall (18). After reaching a sufficiently low vacuum, process gas is introduced into the interior of the workpieces (5) and the plasma is ignited with the aid of the microwave generator (19). In particular, it is intended to use the plasma to deposit both an adhesion promoter and the actual barrier layer made of silicon oxides on the inner surfaces of the workpieces (5).

The adhesion promoter can be applied, for example, in a two-stage process as the first stage before the barrier layer is applied in the second stage, but it is also conceivable, in a continuous process, to use at least a part of the barrier layer facing the workpiece (5) as a gradient layer - To generate at least part of the adhesion promoter immediately. Such a gradient layer can easily be changed during the duration of an already ignited plasma by changing the composition of the product. Zeßgases are generated. Such a change in the composition of the process gas can be achieved abruptly by changing valve controls or continuously by changing the mixing ratio of components of the process gas. A typical structure of a gradient layer is such that a part of the gradient layer facing the workpiece (5) contains at least a predominant proportion of the adhesion promoter and at least a predominant part of the barrier material in a part of the gradient layer facing away from the workpiece (5). A transition of the respective components takes place continuously in at least part of the gradient layer in accordance with a predeterminable gradient curve.

The interior of the plasma chamber (17) and the interior of the workpieces (5) are first evacuated together to a pressure level of approximately 20 mbar to 50 mbar. The pressure in the interior of the workpieces (5) is then further reduced to approximately 0.1 mbar. A vacuum of about 0.3 mbar is maintained while the treatment process is being carried out.

After the coating process has been completed, the lances (36) are removed from the interior of the workpieces (5) and the plasma chamber (17) and the interior of the workpieces (5) are ventilated. After reaching the ambient pressure within the cavity (4), the chamber wall (18) is raised again in order to remove the coated workpieces (5) and to enter new workpieces (5) to be coated. To enable the workpieces (5) or the supports (41) to be positioned laterally, the sealing elements (28) are moved back into the chamber base (30) at least in regions. As an alternative to the interior coating of workpieces (5) explained above, exterior coatings, sterilizations or surface activations can also be carried out.

The chamber wall (18), the sealing elements (28) and / or the lances (36) can be positioned using different drive units. In principle, the use of pneumatic drives and / or electrical drives, in particular in one embodiment as a linear motor, is conceivable. In particular, however, it is envisaged to implement curve control to support exact movement coordination by rotating the plasma wheel (2). The curve control can be designed, for example, in such a way that control curves are arranged along a circumference of the plasma wheel (2), along which curve rollers are guided. The cam rollers are coupled to the components to be positioned.

According to a further embodiment which differs from the embodiments shown in the drawings, it is possible to use at least two carriers (41) per plasma station (3). For example, it is for a plasma station

(3) conceivable for the treatment of six workpieces (5), three workpieces (5) each by a common carrier

(41) to position and thus insert two carriers (41) per plasma station (3).

The supports (41) can be constructed in a manner dependent on the specified structural boundary conditions. For example, it is possible to design the carrier (41) like a plate and to provide it with suitable recesses, for example for the lances (36) and the sealing elements (28). It is also conceivable to construct the carrier (41) like a ring or to construct a to choose that starting from a central area outward-pointing spoke-like support segments are used.

In order to supply the necessary operating resources, in particular negative pressure and process gas, channel branches can be arranged in the area of the chamber base (30), which make it possible to supply several plasma chambers (17) or cavities (4) with common control valves.

The arrangement of several workpieces (5) in the area of a common plasma station (3) explained in the exemplary embodiments makes it possible, on the one hand, to achieve an increased production output. Another variant consists in treating different workpieces (5) simultaneously on a common machine. For example, it is possible to provide successive supports (41) with different workpieces (5) in the direction of movement and to insert them in appropriately adapted plasma stations (3). In the area of assigned input devices and output devices, the different workpieces (5) to be treated would then be fed alternately in groups and separated again from one another in the area of the output device. In principle, it is also possible to provide a correspondingly mixed arrangement of different workpieces (5) on a common carrier (41) if suitable input and output devices are provided. A user therefore does not need several machines to process different products or is relieved of complex machine conversions.

It is also contemplated to perform a functional grouping of pumps which are used to generate the required negative pressure can be used. For example, it is possible to use pumps of the same type and to alternately connect successive plasma stations (3) to the respective pumps in the direction of movement. As a result, the individual plasma station (3) remains connected to an associated pump for longer and switching times are saved. In the case of simultaneous treatment of differently shaped workpieces (5) or workpieces (5) with different sizes relative to one another, it is also possible to connect the respective plasma stations (3) or the associated plasma chambers (17) with different pumps, in order to connect them to the provide specific geometry of the workpiece (5) adapted to optimal process conditions. Successive plasma stations (3) can thereby be connected to different pumps in terms of circuitry.

Claims

P atent claims

1. Method for the plasma treatment of workpieces, in which the workpieces are inserted into at least one at least partially evacuable chamber of a treatment station and in which the workpieces are positioned within the treatment station by holding elements, characterized in that at least two holding elements (42) in the area of the treatment station can be positioned relative to one another by a common carrier (41).

2. The method according to claim 1, characterized in that at least two holding elements (42) are moved offset relative to one another together with the carrier (41) in the direction of a movement carried out at least temporarily by the carrier (41) during the implementation of a treatment process.

3. The method according to claim 1, characterized in that at least two holding elements (42) are moved together with the carrier (41) offset relative to one another transversely to the direction of a movement carried out at least temporarily by the carrier (41) during the implementation of a treatment process.

4. The method according to any one of claims 1 to 3, characterized in that a cavity (4) of the plasma station (3) is evacuated through the chamber floor (29).

5. Method according to one of claims 1 to 4, characterized in that process gas is supplied through the chamber bottom (29).

6. The method according to one of claims 1 to 5, characterized in that the process gas is supplied through lances (36) into the interior of the workpieces (5).

7. Method according to one of claims 1 to 6, characterized in that the carrier (41) is positioned relative to the treatment station.

8. The method according to one of claims 1 to 7, characterized in that the carrier (41) loaded with at least one workpiece (5) is inserted into the treatment station.

9. The method according to any one of claims 1 to 8, characterized in that the carrier (41) is removed from the treatment station loaded with at least one workpiece (5).

10. The method according to any one of claims 1 to 9, characterized in that the carrier (41) carries out a rotational movement at least temporarily relative to the treatment station.

11. The method according to any one of claims 1 to 10, characterized in that the carrier (41) is equipped with workpieces (5) to be treated by a rotating transfer element (49).

12. The method according to one of claims 1 to 11, characterized in that the transfer element (49) at least at the time of transfer of a workpiece (5) to the carrier (41) at the same speed as the carrier

(41) is moved.

13. Method according to one of claims 1 to 12, characterized in that microwaves generated by at least one microwave generator (19) are introduced into the cavity (4) in the area of the chamber lid (31).

1 . Method according to one of claims 1 to 13, characterized in that workpieces (5) made of a thermoplastic are treated.

15. The method according to any one of claims 1 to 14, characterized in that interior spaces of hollow body-like workpieces (5) are treated.

16. The method according to any one of claims 1 to 15, characterized in that containers are treated as workpieces (5).

17. The method according to any one of claims 1 to 16, characterized in that beverage bottles are treated as workpieces (5).

18. The method according to any one of claims 1 to 17, characterized in that the at least one plasma station (3) is transferred from an input positioning to an output positioning by a rotating plasma wheel (2).

19. The method according to any one of claims 1 to 18, characterized in that a plurality of cavities (4) are provided by a plasma station (3).

20. The method according to one of claims 1 to 19, characterized in that the treatment station is positioned by a clocked moving plasma wheel (2).

21. The method according to any one of claims 1 to 20, characterized in that a plasma coating is carried out as the plasma treatment.

22. The method according to any one of claims 1 to 21, characterized in that the plasma treatment is carried out using a low-pressure plasma.

23. The method according to any one of claims 1 to 22, characterized in that a plasma polymerization is carried out.

24. The method according to any one of claims 1 to 23, characterized in that at least some organic substances are deposited by the plasma.

25. The method according to any one of claims 1 to 23, characterized in that at least some inorganic substances are deposited by the plasma.

26.. Method according to one of claims 1 to 25, characterized in that a substance to improve the barrier properties of the workpieces (5) is deposited by the plasma.

27. The method according to claim 26, characterized in that an adhesion promoter is additionally deposited to improve adhesion of the substance to a surface of the workpieces (5).

28. The method according to any one of claims 1 to 27, characterized in that at least two workpieces (5) are treated simultaneously in a common cavity.

29. The method according to any one of claims 1 to 20, characterized in that plasma sterilization is carried out as plasma treatment.

30. The method according to any one of claims 1 to 20, characterized in that surface activation of the workpieces (5) is carried out as plasma treatment.

31. Device for the plasma treatment of workpieces, which has at least one evacuable plasma chamber for receiving the workpieces and in which the plasma chamber is arranged in the area of a treatment station, and in which the plasma chamber is delimited by a chamber floor, a chamber lid and a side chamber wall and holding elements for Positioning of the workpieces, characterized in that at least two holding elements (42) are held in the area of the plasma chamber (17) by a common carrier (41).

32. The device according to claim 31, characterized in that at least two holding elements (42) are arranged offset relative to one another in the direction of a movement orientation of the treatment station.

33. The device according to claim 31, characterized in that at least two holding elements (42) are arranged offset relative to one another transversely to the direction of movement orientation of the treatment station.

34. Device according to one of claims 31 to 33, characterized in that at least one vacuum channel is arranged in the chamber base (29) for evacuation of a cavity (4) of the plasma station (3).

35. Device according to one of claims 31 to 34, characterized in that at least one channel for supplying process gas is arranged in the chamber floor (29).

36. Device according to one of claims 31 to 35, characterized in that for supplying process gas into the interior of the workpieces (5), lances (36) are arranged so that they can be positioned relative to the chamber floor (29).

37. Device according to one of claims 31 to 36, characterized in that the carrier (41) is guided so that it can be positioned relative to the treatment station.

38. Device according to one of claims 31 to 37, characterized in that finished processing for removal Workpieces (5) from the area of the carrier (41) at least one unloading station (44) is used.

39. Device according to one of claims 31 to 38, characterized in that at least one loading station (43) is used to feed workpieces (5) to be processed into the area of the carrier (41).

40. Device according to one of claims 31 to 39, characterized in that the loading station (43) for feeding workpieces (5) to be processed to one of the plasma wheel

(2) separate carrier (41) is formed.

41. Device according to one of claims 31 to 40, characterized in that a transfer device is used for feeding carriers (41) loaded with workpieces (5) into the area of the treatment station.

42. Device according to one of claims 31 to 41, characterized in that a transfer station is used for removing carriers (41) with finished workpieces (5) from the area of the treatment station.

43. Device according to one of claims 31 to 42, characterized in that at least one microwave generator (19) is arranged in the area of the chamber lid (31).

44. Device according to one of claims 31 to 43, characterized in that the plasma station (3) for coating workpieces (5) is made of a thermoplastic.

45. Device according to one of claims 31 to 44, characterized in that the plasma station (3) is designed for coating container-like workpieces (5).

46. Device according to one of claims 31 to 45, characterized in that the plasma station (3) is designed for coating the interior of hollow body-like workpieces (5).

47. Device according to one of claims 31 to 46, characterized in that the plasma station (3) for coating workpieces designed in the form of beverage bottles

(5) is formed.

48. Device according to one of claims 31 to 47, characterized in that the at least one plasma station (3) is carried by a rotating plasma wheel (2).

49. Device according to one of claims 31 to 48, characterized in that several cavities (4) are arranged in the area of the plasma station (3).

50. Device according to one of claims 31 to 49, characterized in that a chamber wall (18) provided for providing at least two cavities (4) is arranged in a positionable manner.

51. Device according to one of claims 31 to 50, characterized in that at least one carrier (41) is arranged in the area of each plasma station (3).

52. Device according to one of claims 31 to 51, characterized in that the carrier (41) is rotatably mounted in the area of the plasma station (3).

53. Device according to one of claims 31 to 52, characterized in that at least two holding elements (42) are arranged along a circumference of the carrier (41).

54. Device according to one of claims 31 to 53, characterized in that an input path (48) is provided for transferring workpieces (5) to be treated to the carrier (41).

55. The device according to claim 54, characterized in that the input path (48) runs centrally to a center point (52) of the plasma wheel (2).

56. Device according to claim 54 or 55, characterized in that the input path (48) is arranged in the area of a transfer element (49).

57. Device according to one of claims 54 to 56, characterized in that the transfer element (49) is driven in a rotating manner.

58. Device according to one of claims 54 to 57, characterized in that a movement speed of the transfer element (49) is adapted to a movement speed of the carrier (41) carried by the plasma wheel (2).

59. Device according to one of claims 31 to 58, characterized in that an output section is provided for removing workpieces (5) to be treated from the carriers (41).

(56) is provided.

60. The device according to claim 59, characterized in that the output path (56) runs centrally to a center point (52) of the plasma wheel (2).

61. Device according to claim 59 or 60, characterized in that the output section (56) is arranged in the area of a transfer element (55).

62. Device according to one of claims 59 to 61, characterized in that the transfer element (55) is driven in a rotating manner.

63. Device according to one of claims 59 to 62, characterized in that a movement speed of the transfer element (55) is adapted to a movement speed of the carrier (41) carried by the plasma wheel (2).

64. Device according to one of claims 31 to 63, characterized in that the plasma wheel (2) is driven in cycles with phases of movement and phases of rest.

65. Device according to one of claims 31 to 64, characterized in that on the one hand the loading station (43) and on the other hand the unloading station (44) are arranged at two cycle positions with a stationary plasma wheel (2).

66. The device according to claim 65, characterized in that the loading station (43) is designed as a loading wheel (47).

67. The device according to claim 65, characterized in that the unloading station (44) is designed as an unloading wheel (54).

68. Device according to one of claims 65 to 67, characterized in that the wheels (47, 54) have a peripheral speed corresponding to a transport speed of the carrier (41) in the area of its current transfer area.

69. Device according to one of claims 31 to 68, characterized in that for the period between an input of the workpieces (5) into the plasma station (3) and an output of the workpieces (5) at least two rotations of the plasma wheel (2) are provided.

70. Device according to one of claims 31 to 69, characterized in that the plasma station (3) is guided at least partially in the direction of the carrier (41) so that it can be positioned.

71. Device according to one of claims 31 to 70, characterized in that the carrier (41) is guided so that it can be positioned in the vertical direction from above into the plasma chamber (17).

72. Device according to one of claims 31 to 70, characterized in that the carrier (41) is guided so that it can be positioned in the vertical direction from below into the plasma chamber (17).

73. Device according to one of claims 31 to 72, characterized in that in the area of a chamber base (30) of the plasma station (3) at least one branch for the supply of at least one resource provided by a resource source is arranged.