Suction cup monitoring: WITTMANN robots now look ahead
12.07.2017
The WITTMANN Group focuses on more than just constantly presenting new appliances. WITTMANN also continuously and actively improves its models already established on the market.
One result of this relentless drive for innovation has now manifested itself in the form of a new wear monitoring function in the vacuum system, which significantly simplifies the scheduling of maintenance work. This monitoring function is now available for all W8 servo robots.
WITTMANN W843 pro robot
It is generally known that small causes can have great effects. Wear on gripper systems can be named as an example of this truism from automatic plastic parts manufacturing. This applies in particular to systems using a vacuum for removing and fastening injection-molded parts. Wear occurs due to the constantly alternating strain on vacuum suction cups during the parts removal cycle. Moreover, leakages may develop at the connection points of vacuum hoses. A consequence of such processes may be that the robot’s gripper is no longer able to grip and remove the plastic part correctly. In such cases, the robot will normally discontinue its relevant sequence for safety reasons. For inside the mold space, there is a definite risk that the mold may close on a part which has not been removed, which could lead to extremely costly damage to the mold. The loss of a part outside the mold space will also lead to a process standstill in most applications, since the lost plastic part may obstruct downstream parts depositing and cause damage to the gripper as well.
So when such a fault occurs, the robot sequence is usually discontinued, with the inevitable consequence of a machine standstill. In other words, the failure of one component with an acquisition value of just one euro causes much higher costs for the ensuing machine standstill, which may well be in the three-digit range. To prevent this type of failure, WITTMANN robots from the W8 series are equipped from now on with an adjustable wear monitoring function for the suction cups.
Schematic diagram of the suction cup monitoring function and the R8 robot control system with the relevant screen display.
WITTMANN robots with an R8 control system can be flexibly programmed by the operator and adjusted to each specific situation concerning their response to parts loss. Previously, the WITTMANN R8 robot control system already allowed operators to set the vacuum level on the TeachBox for every individual suction circuit and to save these settings as a part of the process sequence. The individual feedback on possibly isolated cases of insufficient vacuum levels then enables the operator to set the optimal parameters for the specific surface structures of plastic parts. This makes it possible to respond to parts loss in a very specific way. The new vacuum analysis function now provides an additional advance warning system. Should the vacuum levels continue to deteriorate – which could be an indicator of increasing wear – a warning signal to that effect will be issued. The robot, however, can continue to operate until an actual part loss occurs, or ideally until early remedial action in the automatic system, which would prevent an unplanned machine standstill. WITTMANN W8 robots permit the support of eight vacuum hoses as standard, of which each one can be configured separately. The individual vacuum levels are imported via an analog measuring input and analyzed for the early warning system. The threshold values for early warning can be set by the operator. This function is included as a standard feature in the functionality of the R8 control system.
“Willingness to innovate manifests itself not least by giving due attention to sometimes very specific minor details of automatic production. We want to support our customers in coping even with small everyday problems”, says Martin Stammhammer, International Sales Manager Robots and Automation Systems of the WITTMANN Group. “Continuous maintenance is a task you can’t get around. Here, we strive to make planning easy for users and help them to prevent unplanned downtimes.”
info.de@wittmann-group.com
www.wittmann-group.com