Case Studies Of Industrial Robots

Robots in action can be found everywhere. Robot Manufacturers give examples of robot applications in different industries.

Wittmann, Austria - IFR-Partner

Swiss precision in the clean room

The Forteq Healthcare Company is producing their parts in the clean room.The production of an inhalator for the controlled dosing of pharmaceuticals treating respiratory diseases is a very typical example from the product portfolio of the Forteq Healthcare Company. This product's single components are manufactured highly automated in the clean room. Afterwards the parts are completed to ready-for-sale units on fully automated assembly lines.

The systems are producing precision parts, amongst other things cog wheels of 0.02 grams that are used in the inhalator's counting mechanism. This mechanism allows for overseeing the fill level of the inhalator. The counting mechanism being absolutely correct at indicating the fill-level is of prime importance, when the patient's health is depending on the exactly regulated and continuous inhalation of the active ingredient.

The counting mechanisms for inhalators are consisting of ten single components, including cog wheels and an inspection window.The inhalator is made of ten parts, of which nine are molded by using hot runner systems. Five of these are produced in six production cells. The automation machinery is coming from WITTMANN Kunststofftechnik in Kaltbrunn/Switzerland.

Because of the small weight of the single parts, it is not possible to switch off the non-conform cavities of the multi-cavity molds - therefore the removal of the whole shot is imperative. The robot is processing the good/bad-signal and afterwards orderly placing the parts (16 to 32 pieces per shot, depending on the mold) for the subsequent separation or drops them into the scrap channel.

A 32-fold vacuum gripper is removing the cog wheels weighing only 0.02 grams. The linear robot is maneuvering the vacuum gripper within an 8-seconds-cycle.When removing these highly sensitive parts, the gripper has to be positioned at the mold at a maximum tolerance of 0.2 mm by means of index pins. Only this is making sure that the sliders and ejector pins are not damaging the parts that still have a temperature of about 90°C. The rugged grippers are optimized in terms of weight to shorten the removal time as much as possible.

Thus literally Swiss precision work is necessary that is done by the gripper construction department of WITTMANN Kunststofftechnik in Kaltbrunn. Dr. Joachim Franke, Forteq Healthcare CEO states: "The quality and performance of the WITTMANN automation is one reason for our years lasting supplier loyalty."

Reliability and low maintenance

Forteq is a young company with a long tradition, having emerged from the former Mikron Plastic Technology. Besides the injection molding technology, clean room production is playing a key role in the medical field. The manufacturing of the products is happening consistently in the ISO 8 class clean room. Not only companies working in medical technology and diagnostics are to find amongst their customers. Predominantly technical plastics and polypropylene are processed in systems that are reaching cycle times of 4.4 seconds without the use of a robot, and 7.9 seconds with robot part removal.

To meet the highest quality standards, Forteq is starting a file for every new development as a part of the design and development process. They are monitoring the adherence of all regulations and standards, whereby the documentation of all modifications and considered alternatives - that have emerged during the development phase - is absolutely assured. Then they start production following cGMP guidelines. Forteq is conducting ISO 9001:2000 and ISO 13485:2003 quality management systems. This access was at the bottom of the decision to buy the actually existing production cells. To Dr. Franke and his team the reliability and low maintenance of temperature controllers, robots, and other peripheral units are of special importance.

Six WITTMANN robot systems of different technical states (and different years of construction) are forming the center point of the automation. However, they are featuring one thing in equal measure: Undisturbed operation seven days a week, 24 hours a day, week by week - only interrupted by necessary production cell and clean room maintenance.

The precision parts are assembled fully automatically.The realized cycle times meanwhile are partly going below the eight-seconds-boundary. Here the highly dynamic so-called W-Drives, which are a WITTMANN development, are top-performing. Nevertheless the part removal can last up to two seconds, due to the most precisely executed mold docking and the mandatory monitoring whether each single part has been removed from the mold or not. Walter Reinmann, Head of the Forteq Component Production, explains: "When molding such small parts, the mold protection of the injection molding machine is not really reacting reliably, and damage caused by a part that has not been removed from the mold can lead to immense costs. We rather accept the removal times being some tenths of a second longer, due to the bigger mass of the solid gripper system. But the bottom line is that we are sure to save a lot of money by getting an undisturbed continuous run and products that are meeting the specifications."

The robot is inserting the removed parts into separating devices from which they are carried via a piping system to the packing pouches. From there they are brought to the assembling machines without any further repacking or other handling. Sample parts for the quality control are requested either constantly and periodically via the robot's software, or they can be sorted out sporadically via a hand lever outside the safety guarding. Depositing of the parts is happening in special drawers which can be emptied at any time without disturbing the run of the production cell.

Short cycle times: Quick return on investment

The new robot types W721 CSS3 and W732 CSS3 are 3-axes servo-robots. Compared to their predecessors a significant cycle time reduction from 12.5 to 8 seconds was achieved - maintaining absolute identical reliability and precision of the units. Considering 48 weeks of operation a year, the return on investment is occurring in very short time.

Intelligent WITTMANN control

The WITTMANN R7.2 control is fit for teach-in programming. To meet special requirements, the list of commands can be completed. The display of errors or malfunctions as plain text is one of these special TeachBox functions. All sensors or control inputs that are reading certain positions of the mechanical elements can be real-time controlled via the software, and they can activate an alarm in case one signal is missing within a defined time frame. Displaying plain text is making sure that the operator can localize the defect without any delay. "If necessary, the displayed text can be entered by our operators themselves even in different languages. This is enormously facilitating the identification of problem areas. This as well is making a further contribution to increasing the equipment's availability", says Walter Reinmann.

And if it is possible - at a cycle time of e.g. 6 seconds and a production period of 48 weeks a year - to increase the number of working cycles per year up to nearly five million, an optimal programming is absolutely mandatory. Highest acceleration and speed are only applied, where they are necessary to keep the entire cycle as short as possible. This minimizes the abrasion of pneumatic tubes and energy chains, thus helping to reduce the contamination of the clean room. The following course is executed in an economic manner, which means that every movement is as short as possible and as slow as maintainable. The intelligent program architecture of the software is allowing to build such a program structure by just taking a few simple steps - and hence is one more argument for the use of linear robots in the clean room.

The optimal production of parts that are, in some respects, extremely delicate, requires a perfect "teamwork of men and machine". "In the long run, it is only possible to meet the very high requirements of the pharmaceutical and medical industry by reverting to a highly qualified team of experienced experts and selected efficient and reliable machinery", states Forteq Healthcare CEO Dr. Joachim Franke in conclusion.