Mechatronic gripper handles plastic parts for medicines

Details: Released: 04.10.2013; Last updated: 10.10.2023; Hits: 15248

Truly large machines are needed to mass-produce comparably small pharmaceutical plastic parts. In the development and manufacture of a removal and palletizing device for the manufacture of injection molded parts, the manufacturing pharmaceutical company commissioning the contract stipulated that no compressed air should be used in the product-contacting area. The parallel grippers from Gimatic used at the machine-transport device interface offer a lot more features than just clean operation.

At Waldorf, when entering the production hall, the first impression is that there is a lot to do. The order books are full here and it is missing despite additional hall for two years again footprint to build the sometimes quite space-intensive machines. The second impression also inspires, because it is very clean in the halls in all the creating and doing. This is not least due to the fact that the specialist in high-speed automation for injection molding productions mainly builds machines for cleanroom production. The privately owned company, in which all shareholders are active, employs around 100 employees in Engen, Baden-Württemberg. Cycle times mostly between 2 and 12 s as well as the high number of cavities predestine the automation solutions for use in medical technology, pharmacy and food packaging.

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The machine manufacturer's business is almost two-fold: With a high level of vertical integration of up to 80%, it distributes up to 65% to mechanical solutions for medical and pharmaceutical technology and about 35% for food packaging. Fast sampling systems with the shortest possible intervention times, from the concept to the complete system, taking into account all the necessary certifications, are created here for cleanrooms all over the world. As a key supplier, trained employees carry out the certification in accordance with the GMP regulations in-house.

Compressed air remains outside

A current project with a manufacturing pharmaceutical company is a removal and palletizing device that is to be operated completely without compressed air in the product area. The unit is used for removing and palletizing plastic injection-moulded parts that will later dispense active ingredients from medicines. At the interface between the machine and the palletizing device, a small articulatedRobot with the parallel gripper MPPM 1606 from Gimatic that the 'good parts' are placed on the pallet, the parts to be checked are placed on the designated medical-typical QS tray and the bad ones are sorted out.

An eightfold gripper first fetches the products from the injection mold. The plastic part to be treated contains a small steel tube, which is introduced via a special procedure of the end customer. The delicate part must therefore be handled very carefully so that it is not damaged. The gripper receives a signal from the controller, where the respective part to be removed is to be stored. It is important that no committee comes into the range of good parts and ultimately all seats are occupied there.

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"We're talking about an eight-cavity mold with a cycle time of fifteen seconds," says Christian Boos, Technical Manager at Waldorf Technik GmbH & Co. KG, describing the system's key figures. This means that eight parts come out of the machine every 15 seconds. "Even if this is not a high-performance application, it represents a high-end application for the product itself. However, we also manufacture systems here that produce 64 parts every five seconds," says Boos. This value then forms the basis for the performance considerations of the facility and the other attachments.

The manager describes the customer's specifications: "Compressed air is a potential contamination factor and undesirable in cleanrooms. In addition, the product must be treated very gently, it is gripped from the inside and thus in the area where later the medium will be on the way. That's why we used an electric gripper with stainless steel jaws here. "The trend in medical facilities is in principle to exclude compressed air, to avoid particle emissions and system solutions are on the rise. "Previously, we only built systems with our components. In the meantime, we incorporate many specific components from suppliers, such as robots, cameras, or grippers. "

Constructive decision criteria

"The selection of the MPPM 1606 parallel gripper was a constructive decision due to the required product sensitivity, precision, cleanroom suitability and the other requirements that our customer made," says Boos. “Our grippers all work according to the plug & play principle. We have various patents that give us strong competitive advantages, ”says Johannes Lörcher, managing director of Gimatic GmbH in Bodelshausen.

The grapples are very light, very compact and can quickly weigh only half in comparison. Thanks to an innovative gripping force safety device, the gripper is only energized when it moves. Even in the de-energized state, he reliably holds his cargo. "The engine controller card developed by us shuts off the engine at a previously defined power consumption. This always happens when the gripper has seized and regardless of the absolute travel. The force is held by the integrated spring, the gear is self-locking, so that the gripper can not loosen itself, "Lörcher explains the functional principle of the gripping force safety device. The advantages over compressed air operated grippers are also not to be dismissed anyway. Among the already mentioned are still the control by only one line and the direct signal processing of the valve control.

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"In the first attempt, one thinks that a component like a gripper, which is offered on the market in significant variations, does not necessarily contribute to the overall success of such a complex machine," says Boos. "When looking at the quality of the parts to be manufactured, however, it quickly becomes clear that sensitivity is very important here, so that no damage to the handling of the sensitive plastic parts occurs." The MPPM 1606 offers quality advantages, production reliability and reject reduction for this application, especially pneumatic grippers can afford. Especially in medical technology, the specifications for avoiding product damage are very high and numbered zero.

Fallacy: Mechatronics more expensive than pneumatics

Most people think electric grippers are more expensive than pneumatic grippers. Christian Boos has his very own assumption: "One should not compare the unit price of the components, but should consider the total costs. In the case of pneumatic components, more parts have to be procured, the process up to installation is more complex and the installation itself requires more resources. All these costs must be added to the unit price. If you pass the thought on in terms of benefits and energy costs, you clearly see the advantages. "After the first use of a standard product from Gimatic, Waldorf was very satisfied with the new collaboration:" More will certainly follow, "concludes Boos.

Broadest program in view

At the Motek autumn trade fair, the K plastics trade fair and SPS IPC Drives, Lörcher is promising a real explosion of product presentations, including further versions of parallel and three-jaw grippers, new radial and angular grippers and rotary modules. Each series will be available in three sizes. All products are always clean room certified at the IPA Stuttgart

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Gimatic also presents indexing tables that cycle endlessly, an electric sprue gripper for the plastics industry and linear modules with integrated Linear motor. “If we look a little further into the future, our customers can look forward to gripping force regulation that we are currently developing. “It allows you to individually access two to three different gripping forces within a product line based on a signal,” the managing director says, making us curious about what’s to come.