And now it's downside up!

The procedure for producing the hypodermic needles is quickly outlined: one end of the cannulas is overmolded with plastic in an injection molding device, resulting in the hypodermic needles. The injection molding process is followed by a comprehensive cleaning and testing routine to ensure that the needles meet the high requirements for cleanliness and functionality in later medical applications.

What's special about this application is the handling of the tiny cannulas and needles, since their inside diameter can be as narrow as 0.3 mm. In addition, the delicate parts already have a beveled tip, which must not be damaged under any circumstances and must be positioned precisely. This is because the orientation of the bevel must match the intended orientation of the applicator in order to ensure safe use of the applicator and precise administration of the medication later on.

In order for the robots being used to exactly grip these small parts and then put them down again, IMSTec relies on the iMS system from ITG. It consists of an electronic system, including calibration software, for each robot, as well as a touch probe that can be mounted alternately in appropriately prepared holders within the range of each robot for calibration.

The calibration process is then extremely simple: The robot grips a defined teaching object and brings it to the touch probe. The calibration software controls this process fully automatically; the person using the machine doesn't need to know anything about robotics. The tool center point of the gripper can now be ascertained exactly from the values determined and the design data of the teaching body.

Of course it's not enough for just the motions of the robot to be highly precise: the needle removal stations and transfer stations must also be calibrated exactly. And so the TS 150 touch probe from HEIDENHAIN is used in an almost familiar manner: it is attached to the robot arm by a special holder and measures the trays on which the needles are placed during the production process and after their completion.

The customers of the needle production systems are not the only ones who benefit from the higher accuracy of the robots. IMSTec itself also profits greatly from the ITG solution with the HEIDENHAIN TS 150, even already while constructing the facility. That's because the tactile system works smoothly wherever the robot can reach it, even in hidden corners, which makes it much easier to design such facilities. IMSTec also uses the calibration process repeatedly during the construction phase of the facilities, such as when modifying the design of the workpiece carriers. However, the initial calibration after the production unit has been set up at the customer's site is crucial, since it is then a matter of achieving the required accuracy in the series production of several million needles per year.

The customer can use the calibration tool at any time. This can be in the course of regular maintenance or if deviations occur during operation; which can happen at any time, as high-precision grippers react very sensitively to even the smallest changes or slight contact. Since the robot is calibrated fully automatically after starting the corresponding routines, the original accuracy of the system can be restored at any time without any expert know-how.