Exchanging milling cutters

Before the cutters are transferred to the robotic cell, they are measured by an operator. The values are saved on a data chip attached to the cutter’s locating element. The operator then reads the cutter’s code into the database of the horizontal machining center. After this, he places the cutter in the loading chamber of the cell, whose rotating changing table can hold up to eight cutters. The robot recognizes which storage location is specified for the cutter based on the code. It then picks up the cutter and puts it in its place in the rack.

Whenever the machining center requires a different cutter, its controller sends the appropriate request to the robot controller. The KR 125 L100 then retrieves the cutter from the rack using its double gripper, and moves to a wait position. Once the safety door separating the robot from the machine has opened, the robot places the cutter in one of the milling spindles. In total, the system requires three different spindles, which vary with regard to their design and dimensions. The robot therefore has to exchange them using different methods. It inserts cutters into one of the spindles vertically upwards from below, and into the other two horizontally. If a cutter is damaged, the robot segregates it directly onto the changing table of the loading chamber.

• KUKA KR 125 L100 robot
• PC-based KUKA robot controller, including control panel with familiar Windows interface
• Hydraulic double gripper
• Robot programming
• Rack
• Changing table
• Safety facilities
• Commissioning

The complete horizontal machining center was supplied by Waldrich Coburg. The associated robotic cell was developed and manufactured by Demmeler Automatisierung und Roboter GmbH, from Heimertingen near Memmingen, Germany. Demmeler has been a KUKA system partner for many years.

High repeatability and process reliability

The robot provides a high degree of repeatability and process reliability, thus avoiding damage to the milling machine. Precision is so important because each cutter is equipped with a KSK 100 locating element, i.e. a hollow shank taper, which requires a particularly exact changing position.

Short cycle time

The cycle time of the robot is shorter than that of a conventional tool changer.

Extraordinary flexibility

The jointed-arm robot provides extraordinary flexibility which “normal” machines, by their very nature, cannot offer. Thus there is no problem adapting it to new tasks if the user should want to do so later, for example due to changed production conditions.