Six-Axis Robots Coat, Handle Casting Molds

July 31, 2005
Two units for unloading, transport, handling, and spraying

Germany’s Druckguss Hoym GmbH supplies specialty aluminum and magnesium diecastings, as both small- and medium-sized parts, for automotive and electrical products customers around the world. But, a determination to improve quality and lower costs forced the operators to realize one of its diecasting cells needed to be automated.

The Druckguss Hoym operators determined fairly quickly they would need a sophisticated machine to unload the molding machines, transport and handle the molds and other materials, and to perform effective, complete mold spraying: The mold must be entirely covered with the release agent, or castings can stick in the mold. Only a six-axis robot would ensure total mold coverage.

The solution included two automation devices from KUKA Robotics Group, a KR 30 robot and a KR 60 K shelf-mounted system. The KR 30 uses a three-pronged gripper to take the blank metal from the machine’s hot casting mold. Because the robot always grips the casting on its sprue, it is able to handle a wide range of products. Then, the robot positions the casting in front of sensors to determine part presence and whether or not the part is complete. At that point the part is immersed in a cooling bath at a temperature of approximately 30°C. (The castings range in temperature from 300° to 350°C.) Rejects are placed on a conveyor to a separate container. Once the completed part is removed, the KR 30 places it in a trimming press.

As soon as the KR 30 robot receives a signal from the unloading inspection that the part is complete, the shelf-mounted KR 60 K applies a high-pressure spray of a water-soluble parting agent to the the diecasting machine mold, to ensure that the next casting is removed just as easily. This robot — installed on top of the machine to save space — executes a precise spray pattern, conserving consumption of the parting agent to manage costs.

According to Druckguss Hoym, the new automated casting cell has lowered its overall costs, improved working conditions, and allowed it to perform very fast product changes. The precision of the shelf-mounted robot has lowered the Hoym’s consumption costs and by instituting an automated cell it has reduced the man-power requirement to a single operator for two machines, further reducing the operating cost. Workers also find the conditions more amenable, as the manual labor once needed in the hot and dangerous setting filled with parting-agent vapors and metal fines.

Finally, the robotized cell is simple to operate and maintain. The KUKA units are PC controlled and managed from a control panel with a Windows-based interface, which makes adjustments quick and easy. For Druckguss Hoym, the automated casting cell reduced operating costs and improved efficiency on the production floor.