Endurance test for robots

TASK

Automation of a numerically controlled machining center

The demands made on robots tasked with the loading and unloading of machine tools are extremely exacting, as exemplified by the setup at commercial vehicle supplier Klubert + Schmidt. It was only with the arrival of a robust Stäubli robot that one of their machining centers could be automated in such a way as to make the process completely reliable.

Klubert + Schmidt GmbH produces exhaust flaps, EGR valves and back pressure valves for almost all commercial vehicle manufacturers of repute. The manufacture of these systems for high-performance in-engine brake action at the K+S site in Pottenstein north of Nuremberg is characterized by a high level of insourcing and the pursuit of top quality. It goes without saying that the production of the throttle valves, a central component of the engine brake, is also carried out in house on modern machining centers.

There are a number of variants, with diameters ranging from 27 to 130 millimeters. The valve flaps arrive as blanks and leave the machine as the finished item. Automation plays a key role here – if the robot comes to a standstill, so does the complete machining center.

SOLUTION

Complete processing in three-shift operation

Adjacent to the five-axis vertical milling machine, the manufacturer has installed a robot cell which not only handles the loading and unloading but also other jobs further down the line. The robot is question is a Stäubli six-axis TX90L. The extremely robust build of this industrial robot has ensured uninterrupted operation since installation.

To perform its loading and unloading duties, the Stäubli TX90L has to reach deep into the work area of the machining center, a maneuver that not only requires the robot to have a long range but also involves the risk of collision within such a confined space. This is where the compact design of the six-axis model really comes into its own.

But there is yet another aspect that is especially appreciated at Klubert + Schmidt. The machining center, where the Stäubli TX90L is now operating with utmost reliability, had experienced problems with the previous automation solution. Aggressive media, such as coolants, would regularly bring the robot built and supplied by a rival manufacturer to a standstill. Since the Stäubli machine has been in use, the automated processes have run smoothly and without interruption.

The inevitable contact with filings, swarf, cooling lubricants and other aggressive media creates insurmountable problems for many industrial robots. Any six-axis robots brought in to cope with these conditions must therefore be configured accordingly. Stäubli robots of the TX series score high marks in this respect, with their fully enclosed design and their elaborate wrist construction, which can be relied upon to prevent the ingress of dirt, dust, liquids and filings.

CUSTOMER USAGE

Reliable production to a high quality standard

The automation solution chosen has brought many advantages to this family-owned and family-run business. These include the reduction of non-productive time by means of rapid, fully automated loading and unloading of the machining center, the minimization of machine downtimes and the finishing to perfection performed by the Stäubli robot in parallel to the processing by the NC machine.

Thanks to robot automation, semi-autonomous operation of the plant can continue over a period of several hours. The Stäubli industrial robot has made the automation of the machining center at Klubert + Schmidt a reliable solution.