METHOD OF TRANSPORTING PRODUCTS IN A MANUFACTURING PROCESS

Abstract: Method for transporting disc-shaped, circular or essentially circular products from a manufacturing process to and through another process comprising at least one process stage which is executed in to all intents and purposes dust-free conditions under vacuum. The invention is characterized in that the products (37) from the first-mentioned process are placed in a magazine (2; 3; 4) with a to all intents and purposes dust-free atmosphere. Once a pre-determined number of products (37) has been received, the magazine (2; 3; 4) is sealed, evacuated and transported to vacuum process equipment (1) in which the aforementioned process stage is executed. The magazine (2) is connected to the latter and is opened under vacuum, whereupon the products (37) are removed from the magazine (2), one by one, and are conveyed inside the equipment (1) via a process zone (16) into a second, originally empty magazine (3) connected to the equipment. Once the pre-determined number of products (37) has been received, the second magazine is closed, with the vacuum maintained, and is disconnected from the vacuum process equipment (1).

Description: Method of transporting products in a manufacturing process The present invention relates to a method for transporting disc— —shaped, circular or essentially circular products from one process to and through a second process consisting of at least one process stage which is executed under to all intents and purposes dust—free conditions under vacuum. The invention also relates to a system which operates in the manner to which the invention relates. In conjunction with the manufacture of products of a kind which require dust—free manufacturing and/or finishing stages in a vacuum, it has previously been necessary to perform these stages in a so—called super—clean room, in other words extremely strict cleanliness requirements are imposed on the staff and equipment involved in manufacture. Amongst other things, the staff is required to wear special protective clothing, which is both uncomfortable and expensive, the latter being attributable to the fact that such clothing is of a disposable nature or requires special cleaning which can be performed by only a few laundries. The equipment, which in many cases is extensive, calLs for large, clean rooms which are expensive not only to build, but also to operate. The object of the present invention is to propose a method for simplifying and cheapening the manufacture of the products referred to by way of introduction, which is made possible in that the products from the first process are transported inside a magazine containing a to all intents and purposes dust—free atmosphere, in that the magazine, once a pre— etermined number of products has been received therein, is closed, evacuated and transported to a vaccum process equipment in which the aforementioned process stage is executed, in that the magazine is connected to said equipment and is opened under vacuum, in that the products are removed from the magazine one by one and are transported inside the equipment via a process zone and into a second, originally empty magazine connected to the equipment, and in that said magazine, once the pre—determined number of products has been received therein, is closed and, with the vacuum being maintained, is disconnected from the vacuum process equipment. In order to maintain a high degree of cleanliness, both ' inside the magazine and when handling the products, the following procedure -jn accordance with one characteristic feature of the invention is adopted in conjunction with the last—mentioned magazine once it has been disconnected from the vacuum process equipment. Either it is connected under vacuum to a second item of vacuum process equipment, or it is filled with a to all intents and purposes dust—free atmosphere and is transported to further treatment stages or is emptied of its products. In accordance with a second special characteristic feature of. the invention the products are stacked one on top of the other on being introduced into the magazine, and in conjunction with the stacking operation a separating layer consisting of a magnetizable or permanently magnetic body is placed between each product, and a magnetically operating lifting and transport device which interacts with the body belonging to the product in question is utilized in conjunction with the removal of the products from the magazine and with their transport into the vacuum process equipment, whereby particularly effective and gentle handling of the products is achieved. The rapid and efficient flow of products through the vacuum process equipment is achieved in accordance with a.further special characteristic feature of the invention in that the magazine is connected to the vacuum process equipment at the input station via a lock chamber which communicates with the vacuum process equipment and is capable of being separated from it, inside which lock chamber atmospheric pressure is present at the time of connection of the magazine, in that the lock chamber is evacuated once the magazine has been connected to it in an air—tight fashion, and in that the separation between the lock chamber and the vacuum process equipment and the closure of the magazine are removed once a vacuum has been created inside the lock chamber, whereupon the products are removed from the magazine one by one and are transported with a stepped rotary motion through the process zone to the output station at which, in a fashion similar to the input station, the products are fed into the originally empty magazine, and at which station the magazine is disconnected in largely the reverse sequence in relation to its connection. A system for the transport of disc—shaped, circular or essentially circular products from a machine which discharges them one by one to and through at least one item of vacuum process equipment so arranged as to execute in a process zone at least one process stage under to all intents and purposes dust— ree conditions and under vacuum in the manner to which the invention relates, is characterized in that the system comprises a source of a to all intents and purposes dust—free atmosphere; a source of a vacuum; and a number of magazines, each so arranged as to receive and to issue a pre— etermined number of products and to be connected respectively to an input station and an output station of the aforementioned vacuum process equipment, in which the products are removed one by one from a magazine connected to the input station, are transported via at least one process zone in which the process stage is executed, and are finally conveyed to and into a magazine connected to the output station. An important prerequisite for the correct function of the method and system in accordance with the invention is the aforementioned magazine, which, in accordance with another special characteristic feature, consists of a long holder having an opening at its upper end which is capable of being closed by a vacuum—tight cover and having a connecting pipe stub which is capable of being closed by means of a valve so arranged as to be connected to the vacuum source or to the source of a to all intents and purposes dust—free atmosphere, inside which container devices are arranged for the automatic stacking of the aforementioned products on or alongside one another when these are introduced into the magazine container and for the automatic issue of the products one at a time. In conjunction with vacuum processes the products are often extremely susceptible to scratching and other similar stresses. Damage of- this kind can be avoided in accordance with a special characteristic feature of the invention to the effect that a second container intended for separating layers communicates with the aforementioned container, inside which second container devices are arranged for the automatic introduction of a separating layer between each product in connection with the stacking of these in the first—mentioned container. A second important prerequisite for the correct function of the method and system in accordance with the invention is that the equipment should comprise a vacuum chamber which has input/output stations and at least one process zone, in conjunction with which the aforementioned stations and the process zone are situated at a mutually identical distance from one another on an imaginary circle, and a lock chamber for each input/output station intended for the connection of a magazine, which lock chamber communicates with the vacuum chamber and is capable of being separated from it by means of a valve, which lock chambers are so arranged as to be placed under atmospheric pressure during connection and disconnection of a magazine to the respective chambers, and as to be placed under vacuum in conjunction with the introduction and the removal of products into and from the respective magazines, and that a rotating disc is so arranged inside the vacuum chamber and concentrically with the aforementioned circle as to be caused to rotate in steps, and in so doing to transport the products from the input station via the process zone to the output station. In order to achieve the highest possible degree of efficiency, the aforementioned input and output stations of the finishing treatment machine are interchangeable. The invention is described below in greater detail with reference to the accompanying drawing, of which Fig. 1 is an angled view from above showing a perspective view from the side of an illustrative embodiment of an item of vacuum process equipment which operates in the manner to which the invention relates. Fig. 2 is a plan view from the side and partially in section of the equipment in accordance with Fig. 1. Fig. 3 is a plan view from directly above of the equipment illustrated in the preceding Figures. Fig. 4 presents in the form of a flow chart with schematic cross—sections through parts of the equipment the way in which products are transported in. the manner to which the invention ' relates. Notwithstanding the fact that these products consist of discs of the "Compact Disc" type in the drawing and in the rest of the description, in respect of which the designation compact disc is used below, it is obvious that the invention should not be regarded as being restricted to that particular type of product alone, but is capable of being modified within the scope of the idea of invention to include other disc—shaped, circular or to all intents and purposes circular products, such as silicon discs for use in the manufacture of integrated circuits. The present invention is based on an idea of invention which, unlike the previously customary procedure associated with processes which call for an extremely clean environment, namely to cause largely the entire operation to be performed in a super—clean room, instead ensures that a clean environment is present at all times in the immediate vicinity of the products. This is achieved in accordance with the invention in that the products, whenever they are situated outside the actual process equipment, are placed in magazines inside which a to all intents and purposes dust—free environment is maintained. Thus, with regard to the cleanliness of the environment outside the magazines and the process equipment, the only requirements which must be imposed are those which apply to the installation of control and regulation equipment, for example. The designation 1 is used in the drawing generally in respect of vacuum process equipment, and the designations 2, 3, and 4 in respect of magazines which are capable of being connected to the equipment, each of which magazines consists of two communicating containers 6, 7 arranged on wheeled frames 5 and having vacuum—tight closing lids 8 and 9. The construction and function, of the magazines is described below. The vacuum process equipment 1, inside which the compact discs are given a reflective coating of aluminium, consists of a vacuum chamber 10, which is supported on a frame 11, and in the embodiment illustrated in the drawing has three input/output stations 12, 13 and 14 for the connection of the magazines 2—4, a vacuum pump 15 and a process zone 16. The control, measurement and regulation equipment which is necessary for the execution of the vacuum process is housed inside two cabinets 17a, 17b. Each of the input/output stations 12—14 has a lock chamber 18, 19 and 20 which communicates with the vacuum chamber 10, which lock chambers can be separated from the chamber 10 by means of a valve 21, 22 and 23, and a vacuum pump 24, 25 and 26 by means of which a vacuum can be created inside the lock chambers. Each lock chamber exhibits an outward— and downward—facing opening which is executed in such a way that a magazine can be connected to it in a vacuum—tight fashion. Inside each lock chamber 18—20 organs 27 are also so arranged as automatically to remove and replace the cover 8 of a magazine which has been connected to the respective chamber, as explained in more detail below in connection with the flow chart in accordance with Fig. 4. It is characteristic of the invention that an item of vacuum process equipment has the input/output stations 12—14 and the process zone 16 situated at equal distances around the circumference of an imaginary circle, at the centre of which a rotating disc 28 is so mounted as to permit the transport of compact discs from an input station, via the vacuum process zone 16 and to an output station. The rotating disc is so arranged as to be caused to rotate by a stepping motor 29 situated outside the chamber 10, which motor provides rotational steps of 90° in the embodiment illustrated in the drawing. A considerable advantage of the transport being effected as rotary motion is that this gives rise to relatively few abrasive particles compared with a linear motion, which could jeopardize the process. Devices 30, 31 which interact with the rotating disc 28 are situated on the rotating disc with the same separation and at the same distance from the centre -of the aforementioned circle as in the input/output stations and the process zone, said devices serving the purpose of lifting compact discs one by one from an input station and transporting the compact discs through the stepped rotation of the rotating disc via the process zone and to an output station. The rotating disc may, as shown in Fig. 3, for example, consist of arms arranged in the form of a star, to the free, outer ends of which the aforementioned lifting devices are attached. These are mutually identical, and in the present embodiment intended for the handling of compact discs are so arranged as to operate electro— agnetical ly, as described in. conjunction with Fig. 4. As has already been mentioned, a magazine in accordance with the invention consists of two long containers 6, 7, which are arranged in an upright fashion on the wheeled frame 5 and which are executed at the top with an opening which is capable of being closed in a vacuum— ight fashion with the covers 8 and 9. The containers are enclosed by a common casing with handles 36. A pre—determined number of compact discs can be introduced into the container 6, and the container 7 is so arranged as to accommodate a corresponding number of separating layers 34 (see Fig. 4) for the compact discs, which are e-xtremely susceptible to damage at this stage of manufacture and must not be allowed to come into contact with one another under any circumstances. Present inside the containers 6 and 7 are mutually synchronized devices for the automatic input and output of compact discs respectively into and out of the container 6, and for the automatic transfer of separating layers from the container 7 to the container 6 and vice versa. The aforementioned devices can be executed in many different ways within the scope of the invention and operate in. the following fashion. When the container 6 is empty, the container 7 is full of separating layers. At the same rate as compact discs are automatically introduced into the container 6, separating layers are transferred from the container 7 to the container 6 and are placed under the respective compact disc. When the pre—determined number of discs has been introduced into the container 6, this will be full of discs and separating layers, whereas the container 7 will be empty. In the embodiment of the present invention intended for the manufacture of compact discs, the separating layer 34 consists of a body 35 made of a magnetizable or permanently magnetic material, in conjunction with which the lifting and transport devices 30, 31 of the rotating disc 28 are so arranged as to attract and repel the aforementioned bodies 35 for the purpose of lifting the compact discs from a magazine and of releasing them down into a second magazine. With reference to Fig. 4, use will now be made of the lay—out drawings A—G to describe the method in accordance with the invention for transporting products, in this case compact discs, from a manufacturing process and through a finishing process. In an initial position the container 6 is empty, and the container 7 is full of separating layers 34. The communicating containers 6, 7 are evacuated, and the covers 8 and 9 close the vacuum—tight openings of the containers. The magazine is connected via a pipe stub 38 with a valve 39 arranged therein to a filter 40, through which dust—free air can flow into the magazine containers when the valve 39 is opened. Lay—out drawing A is used to illustrate how compact discs 37 are introduced into the container 6 after the valve 39 has been opened so that atmospheric pressure has been achieved inside the containers 6, 7 and it has thus become possible to remove the cover 8. The discs arrive from a previous manufacturing process which is not shown in the drawing. In this particular case this pressing of the discs means that they are simultaneously provided on one side with an information—carrying pattern, which is to be given a reflective surface in the vacuum process, and which is finally to be covered with lacquer in another finishing process. The introduction of the discs 37 into the container 6 takes place automatically, and in a similar automatic fashion separating layers 34 are taken from the container 7 and a re placed under the respective compact disc 37. When a pre—determined number of discs 37 has been introduced into the container 6, the container is closed by means of the cover 8, the filter 40 is disconnected, and the magazine is connected via the pipe stub 38 to a vacuum pump 41. The container 7 has now been emptied of separating layers; see lay—out drawing B in Fig. 4. Once a vacuum has been achieved inside the magazine, the valve 39 is closed and the vacuum pump is disconnected from the pipe stub 38. The magazine is rolled with the help of the wheeled frame 5 to the vacuum process equipment 1, inside which the vacuum process is executed continuously; see lay—out drawing C. This means that compact discs with separating layers are transported in a stepped fashion by the rotating disc 28 from a magazine attached to an input station, via the process zone 16, where the information— —carrying pattern cf the compact discs is coated with a thin layer of aluminium, and to a magazine attached to an output station. As has already been mentioned, there is no difference between the input and output stations, which are interchangeable. The function of the control equipment positioned in the cabinets 17a, 17b is to determine which particular station, under given conditions, is to be the input or output station. Let us now assume that the magazine in question is the one which is referred to in the other drawings by the designation 2, and which is accordingly to be connected to the input/output station 12. The way in which this is achieved is for the magazine to be raised up so that its upper part is caused to be connected in a vacuum-tight fashion to the lock chamber 18, inside which atmospheric pressure is now present. The valve 21 between the chamber 18 and the chamber 10 is closed. Since a vacuum is present inside the containers 6, 7, the cover 8 cannot be removed. In order to make this possible, the vacuum pump 24 is started up, and once a vacuum has been created inside the lock chamber 18, i.e. once identical pressure is present in the chamber 18 and in the container 6, the cover can be removed with the help of the previously mentioned device 27; see lay—out drawing D. The valve 21 is opened at a point not later than the time at which the container, from which the issue of components took place in the course of the procedure outlined above, is empty. This can be effected without problem, since a vacuum is present not only inside the vacuum chamber 10, but also inside the lock chamber 18 and the magazine 2. With the help of the previously mentioned input/output devices inside the magazine 2, the compact discs are fed into it together with their separating layers to a pre— —determined position relative to the lifting and transport devices 30, 31 of the rotating disc 28 (see lay—out drawing E), by means of which devices the discs are raised one by one and are transported by the rotating disc in steps of 90° to the process zone 16, through the process zone, and to the output station 13 to which the magazine 3 is connected. The compact discs 37, which at this point have been coated with aluminium, are now conveyed together with their separating layers 34, automatically one at a time in a similar fashion to the output stage, but in the reverse sequence; see the right—hand half of lay—out drawing C. When the magazine 3 is full, the magazine 2 will be empty, and can now serve as a magazine for receiving compact discs arriving from the magazine 4, which has been connected to the vacuum chamber in the same way as described above in relation to magazine 2. The disconnection of the magazine 3 from the station 13 takes place largely in the reverse sequence to its connection. The valve 22 is first closed. The cover 8 is then positioned automatically by means of the device 27 above the opening of the container 6, and the valve 39 is opened so that dust—free air can enter the lock chamber 19 via the filter 40. Since atmospheric pressure is now present inside the lock chamber, the magazine 3 can be disconnected from it without difficulty; see lay—out drawing F. A vacuum is still present inside the magazine 3, which should accordingly be capable of being connected without difficulty to a second item of vacuum process equipment, or of being stored for a period of long or short duration, for example in order to achieve a uniform rate cf production. In the case illustrated in Fig. 4, the magazine 3 is now transported to a final finishing process, indicated by a block 42 n lay—out drawing G, which may involve the aluminium coatings of the compact discs being covered with a layer of lacquer, for example. In order to achieve the automatic, one—by—one issue of the discs, it is first necessary to remove the covers 8 and 9, which can only be achieved once atmospheric pressure is present inside the magazine. For this purpose the valve 39 is opened so that a dust—free atmosphere can flow in via the filter 40. As the discs are issued, the separating layers are returned to the container 7. Once the container 6 has been emptied, the container 7 will be full of separating layers and will be ready to be filled once more in accordance with lay—out drawing A.

Claims: 1 2 Patent Claims 1. A method for transporting disc—shaped, circular or essentially circular products from one process to and through another process comprising at Least one process stage which is executed in to all intents and purposes dust—free conditions under vacuum, c h a r a c t e r i z e d in that the products (37) from the first—mentioned process are placed in a magazine (2; 3; 4) with a to all intents and purposes dust—free atmosphere, in that the magazine (2; 3; 4) is sealed and evacuated once a pre—determined number of products (37) has been received and is transported to vacuum process equipment (1) in which the aforementioned process stage is executed, in that the magazine (2) is connected to .the latter and is opened under vacuum, in that the products (37) are removed from the magazine (2), one by one, and are conveyed inside the equipment (1) via a process zone (16) into a second, originally empty magazine (3) connected to the equipment, and in that the second magazine is closed, once the pre— etermined number of products (37) has been received, with the vacuum maintained, and is disconnected from the vacuum process equipment (1). 2. A method according to Patent Claim 1, c h a r a c t e r z e d in that the last— entioned magazine (2) which has been disconnected from the vacuum process equipment - (1) is either connected to a second item of vacuum process equipment under vacuum or is filled with a to all intents and purposes dust—free atmosphere and is conveyed to a further treatment stage (42) or is emptied of its products (37). 3. A method according to Patent Claim 1, c h a ra c t e r i z ed in that the magazine (2; 3; 4) is connected at the input station (12—14) to the vacuum equipment (1) via a lock chamber (18—20) which communicates with the latter and is capable of being separated from it, inside which chamber atmospheric pressure is present at the time of connection of the magazine (2; 3; 4), in that the lock chamber (18—20) is evacuated once the magazine has been connected to it in a leak—proof fashion, in that the separation (21—23) between the lock chamber (18—20) and the vacuum equipment (1) and the closure (8) of the magazine are removed once a vacuum has been created inside the lock chamber (18—20), whereupon the products are removed from the magazine (2; 3; 4 ) one by one and are transported in conjunction with a stepped rotary motion through the process zone (16) and to the output station at which, in a similar fashion to the input station, the products (37) are fed into the originally empty magazine, and at which station the magazine is disconnected in largely the reverse sequence relative to its connection. 4. A method according to Patent Claim 1, c h a r a c t e r i z e d in that the products (37) are stacked one on top of the other on being introduced into the magazine (2; 3; 4), in that a separating layer (34) consisting of a magnetizable or permanently magnetic body is placed between each product in conjunction with the stacking operation, and in that a agneticaLly operating lifting and transport device (30, 31) which interacts with the body belonging to the product in question is utilized in conjunction with the removal of the products (37) from the magazine (2; 3; 4) and with their transport into the vacuum process equipment (1). 5. A system for th,e transport of disc—shaped, circular or essentially circular products (37) from a machine which discharges them one by one to and through at least one item of vacuum process equipment (1) so arranged as to execute in a process zone at least one process stage under to all intents and purposes dust—free conditions and under vacuum, c h a r a c¬ t e r i z ed in that the system comprises: a source (40) of a to all intents and purposes dust—free atmosphere; a source (41) of a vacuum; a number of magazines (2; 3; 4), each so arranged as to receive and to issue a pre—determined number of products (37) and to be connected respectively to an input station and an output station (12—14) of the aforementioned vacuum process equipment (1), at which the products (37) are removed one by one from a magazine (2; 3; 4) connected to the input station (12—14), are transported via at least one process zone (16) in which the process stage is executed, and are finally conveyed to and into a magazine (2; 3; 4) connected to the output station (12—14). 6. A system according to Patent Claim 5, c h a r a c t e r i z ed in that the vacuum process equipment comprises a vacuum chamber (10) which has input/output stations (12—14) and at least one process zone (16), in conjunction with which the aforementioned stations (12—14) and the process zone (16) are situated at a mutually identical distance from one another on an imaginary circle, and a lock chamber (18—20) for each input/output station (12—14) intended -for the connection of a magazine (2; 3; 4), which lock chamber communicates with the vacuum chamber and is capable of being separated from it by means of a valve, which lock chambers are so arranged as to be placed under atmospheric pressure during connection and disconnection of a magazine (2; 3; 4) to the respective chambers (18—20), and as to be placed under vacuum in conjunction with the introduction and the removal of products (37) into and from the respective magazines (2; 3; 4), and in that a rotating disc (28) is so arranged inside the vacuum chamber and concentrically with the aforementioned circle as to be caused to rotate in steps and in so doing to transport the products (37) from the input station via the process zone (16) to the output station. 7. A system according to Patent Claim 5, c h a r a c t e r i z e d in that the aforementioned input and output stations (12—14) are interchangeable one with the other. 8. A system according to Patent Claim 5, c h a r a c t e r z e d in that the aforementioned magazine comprises a long holder (6) having an opening at its upper end which is capable of being closed by a vacuum—tight cover (8) and having a connecting pipe stub (38) which is capable of being closed by means of a valve (39) so arranged as to be connected to the vacuum source (41) or to the source (40) of a to all intents and purposes dust—free atmosphere, inside which container (6) devices are arranged for the automatic stacking of the aforementioned products (37) on or alongside one another when these are introduced into the magazine container (6) and for the automatic issue of the products (37) one at a time. 9. A system according to Patent Claim 8, c h a r a c t e r i z e d in that a second container (7) intended for separating layers (34) communicates with the aforementioned container (6), inside which second container devices are arranged for the automatic introduction of a separating layer (34) between each product (37) in connection with the stacking of these in the first—mentioned container (6).

Inventors: NORDLANDER JOHAN, NORDLANDER, JOHAN
Applicants: APPLIED VACUUM SCANDINAVIA AB
Application year: 1987
Main classification: B65G49
IPC codes: B65G49, C23C14, H01L21