29.09.2011

Robot-supported packing of flexible infusion bags

Simple handling infusion bag are not an easy and stable alternative to infusion solutions in Glasflaschen. The flexibility of such bags requires however with packing a substantial know-how in process technique ï¿½ in particular with high throughput. Fresenius Kabi has a particularly adapted packaging installation in the employment for this problem. The employment of robots and image processing secures thereby highest productivity. The Fresenius Kabi Germany GmbH, Friedberg, is a subsidiary company of the Fresenius Kabi group. At the location Friedberg produces the enterprise infusion solutions in different packaging means, e.g. Glasflaschen or bags. A large chance sees the enterprise in its Freeflex bag for infusion solutions, which is to be handled free by PVC and flat steel bar exibel. Recently finished line placed and a fully automatic working is to manufacture in the future several thousand units of these bags per hour. The plant consists of empty bag manufacturing, filling, sterilisation and manufacturing. The process begins with the welding of a two-layered foil to a bag. Stations follow to filling, Begasen and Konnektieren of the bag. The connectors serve the infusion solution for the withdrawal and/or for the addition of medicines into the bag. In the connection the bags are welded in a Umverpackungsstation into a further foil situation. Thereupon they arrive over a volume system into the sterilisation range. To the withdrawal from autoclaves it goes again over a volume system into manufacturing. For the recognition of the bags a line camera over the volume is installed at the beginning of manufacturing. Individual camera recognizes all bags and distributes it with the help of a logistics software on the robots ï¿½ Adept Scaras of the type Cobra s800. ï¿½ recognizing the transparent bag was a challenge ï¿½, like that Dipl. - engineer Michael Frieï¿½, leading planning engineer with the Errichter of the plant, Erhardt + abbott automatic control engineering GmbH, cake, which had responsibility also for the installation of the robotics and for the software. ï¿½ we solved the task, by detecting the connectors at the bags. ï¿½ one of the connectors there is white, gave it here at the beginning of problems with the recognizability. A further problem arose as a result of the fact that the bags did not lie positionexactly on the volume. The system must not thus only recognize the bags, but determine for the robots also the ideal grab point. Fast robots ï¿½ short SignallaufzeitenDie Adept Scaras in each case a certain number of bags in a cardboard placing. They get all bags not already before the grab procedure assigned, but each robot makes a demand for a new grab instruction in the moment, in which it is free, against the image processing system, which thereupon to the robot sends item data. This approach requires short signal running times. The entire plant is interlaced in addition over professional bus and Ethernet, a Siemens-S-7-SPS forms the master. If a robot should fail, the arriving bag on the remaining three are distributed, and which knows fourth robots is waited. The robots are equipped in addition with protection circles from each other separated. ï¿½ if we only with three robots work, seize the remaining devices still between 95 and 97 per cent of the bags. The remainder manually packed ï¿½, so Dipl. - engineer Axel Kretschmann, responsible for the range manufacturing in the complete system. However the other three Scaras to the load limit would be demanded when switching a robot off. Until the fine vote fit, it already occurred that a robot stepped out because of overloading. Each cardboard stands on a balance, which communicates to the robot with a certain weight that he is to load the cardboard not further. ï¿½ we selected this solution, since we produce differently heavy bags. We have for it nine different programs for the selection ï¿½, report Kretschmann. The cardboards are delivered as punching hurry and put up in a special station. Following filling and weighing go double-railed. The filled cardboards become a courseï¿½ provide united, lengthwise and at the front side printed on as well as at the front side labeled and with an enclosing note. A camera, labeling and the enclosing note a bar code reader examines the front side print. After locking the cardboards arrive at the palletization challenge grip arm technology apart from the recognition of the bags and determining the ideal grab point by the logistics software turned out the development of a suitable grab system as a challenge. ï¿½ it needed a long development time, until we had a grab system so far that it really carries the bag forward ï¿½, so Kretschmann. A coworker worked altogether a half year alone on the construction of the Saugers. ï¿½ we had some manufacturers of grab systems with us in the house, those the bags to attempts also into their company took ï¿½, remember Kretschmann. An offerer would have created it nearly to develop a functioning grip arm. ï¿½ we used these first even in production. In the course of the time the grip arm worked however ever more unreliably, and also the cutting behavior became with increasing temperature of the bags worse and worse. In the final result we had to fall back to our own know-how. ï¿½ a large challenge was also correct arranging of the Sauger and the control of the grip arms. ï¿½ we have here in the work a high-quality compressed air. Normally we work therefore with vaccum pumps. In the case of our application with a great many sow gladly so however a high moved mass at the grab head results. Due to the short cycle times we have so naturally a problem with the retaining strength. We have ourselves in the long run decided for a solution with venturis ï¿½, summarize Kretschmann. ï¿½ beginning we made also attempts with mechanical grab systems, which led however to a damage of the bag. After the drug law we must guarantee however that the grip arm does not damage the bag. ï¿½ as also the construction of the Sauger did not become so simple. It was valid to find a Sauger which can seize these flexible bags at all, so that the connection from the Sauger to the bag does not tear off also with high transverse forces, which arise during acceleration. Making more difficult it was added here still that the flexibility of the bag with rising temperature increases. ï¿½ after sterilizing the bag has a temperature from 50 to 70 ï¿½C, which still makes the grab procedure ï¿½, so to Kretschmann more difficult. For process-safe seizing each Sauger is ï¿½ and it is altogether per grip arm ï¿½ equipped with its own vacuum supply fourteen Sauger. Even if with several sow gladly no connection comes, the others continue working unimpaired. Simple controlconcept to serving the plant gives it a starting and a stop switch. If errors should arise when starting or during the enterprise, the operator can acknowledge these with the activate button. For example if an operator was to maintenance work at the robot and in his position shifted this, the position monitoring responds. If the operator starts the plant, then he must acknowledge this error only by repeated pressing of the activate button, and the plant starts error free. 99 per cent of all errors can be repaired in such a way. If error should arise, which is so high from the priority the fact that they cannot be acknowledged with these keys can help still switching of the system on and off. Even if the operator does not get ahead here, the error can be usually located over remote maintenance of the system. ï¿½ into the plant remote maintenance is inserted, also functioned ï¿½, so to Kretschmann. ï¿½ one cannot maintain that by far from each plant. ï¿½ with remote maintenance the possibility exists of waiting all users of the system: SPS, each individual robot, image processing system and control surfaces. For remote maintenance ISDN routing is integrated in the switchgear cabinet. Each participant has a Ethernet connection to the ISDN routs and lets themselves from the office of the accumulation judge out be waited in such a way, in routs itself in-selected. Frieï¿½ can make Parametrierungen as responsible persons of the plant also, e.g. Seizing and placing positions change. In addition it uses the plant software Explorob, which represents all components completely. All parameters of the four Adept Scaras such as speeds, procedure heights and GET eighth points are with this softwareï¿½ to adjust. Also error and operating messages in the detail can be looked at. The software is appropriate not anwenderspezifi sch to adapt but over a user interface for different robot types and controls. To variable program ï¿½ we had robots of different manufacturers in testing. The characteristics of the Adept devices ï¿½ durability and speed, volume pursuit as well as the camera system ï¿½ have us in the long run convinced ï¿½, so Kretschmann. A further advantage of the machines is that the complete energy supply for the grip arm is integrated in the robot. No cables or hoses are more at the bionic arm. The Adept control has the large advantage that programmers have here all possibilities. It is not deposited a firm code in the control, but a flexibly parametrierbare software. This is called for example for volume pursuit the fact that itself the robot simply thereupon lets supervise, whether he is still in the operating window. The programmer could write here by modules without problems a program, which runs on all four robots. Since there is already a plant of this kind with Fresenius Kabi, there were no large problems in the conception phase and with the installation. The challenge was to a large extent logistic nature, concerned thus the distribution of the bags on the individual robots. ï¿½ distributing several thousand bags in the hour let itself simulate before only with difficulty ï¿½, so Frieï¿½. ï¿½ some vote work was necessary here, until we had the problem in the grasp. ï¿½ a challenge was it to achieve the high availability from over 99,8 per cent to. ï¿½ one reaches 95 per cent fast ï¿½, thus Frieï¿½. ï¿½ from 95 per cent to 99,8 per cent to come, is however a giant step, which is possible with sophisticated tests and much experience only. ï¿½ ï¿½ 99 per cent of availability is theoretically still a good value ï¿½, supplements Kretschmann. ï¿½ with several thousand bags in the hour would then still be in our application however some, which were not finally seized. ï¿½ Kretschmann about committee: ï¿½ if the robots a bag do not seize, pack the operators these by hand. Committee does not result in this case. This happens only, if a robot seizes the bag and these incorrectly packed. Here we lie however with a rate of under 0,1 per cent. ï¿½ to the amortization of the plant it does not need large computations, white Kretschmann: ï¿½ we drive the range sterilisation and manufacturing with two coworkers. Without automation a substantially higher number of coworkers would be necessary with three-shift operation. ï¿½

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