Higher output and boosted productivity are two of the biggest reasons in justifying the use of automation. These goals can be carried out into injection molding and extrusion automation through Milacron’s proprietary Mosaic + control system, connected and providing the transfer of information back and forth to auxiliary equipment. Milacron provides automation cells that make production faster, robust and more reliable, while reducing the workload for the operator through innovative concepts and project scopes unique to the industry.
There are numerous opportunities and advantages to setting up a full work cell with specialized jobs for robotics including in-mold decoration/labeling, dispensing and sealing, machine tending, palletizing, insert loading, and part transfer over molding applications, among many other tasks that can be achieved. The ability to manage the work cell from a single point location through the Milacron Mosaic + Control provides a reduction of operator setup time, ease of cell operation, and a reduction in the possibility of human error, as robotic programs can be saved with mold files on the Mosaic + Control to ensure that both mold file and robotics program match the process being run at any given time.
Robot Selection
When choosing a robot, the application criteria of the molding process, downstream automation requirements or the specific part cavitation / orientation being produced will influence the robot reach and robot payload capability in order to properly size the robot. The reach and payload are indicators of robot size, but it is necessary to acknowledge the center of gravity and moment of inertia at different points of robotic movement in and out of a molding machine to validate the exact model required for any specific application. Considering the unique process forces and torques of the robot arm and how they occur at different points might be required, like insert loading, assembly force or part removal force, along with end of arm tooling movements can all be determining factors in verifying the correct robot model for the job at hand. Cycle time can also be a powerful factor, along with the accuracy and movement requirements of the robotic arm, along with End of Arm Tooling Rigidity that is needed for the process operations in your work cell. Machining holes or performing assembly may involve a greater level of accuracy than just picking a part out of a mold. Robot selection is a key step for success of the system, so requesting help of a robotics system design expert can help to ensure that the robot chosen is optimally designed for your specific needs.
After the robot selection and reach verification, the end-of-arm tooling should be evaluated. Determine how the part can be held—with either a vacuum or mechanical gripper, or a combination of both. In addition, sprues may need to be gripped and set in a granulator opening, a separate tray or simply dropped into a bin within the work cell. A significant factor in end-of-arm tooling is depends upon your mold and the complexity of the part, the part location in the mold, cavitation of the parts being produced, how the parts are ejected, the geometry of the parts, core sequences and inserts for loading into the part prior to molding are all details needed to verify end of arm tooling is optimally designed for your application.
If placing inserts in the mold to be over molded in the body of the part, the method of insert evaluation and decision on whether to automatically or manually feed the inserts, to an insert loading fixture for presentation to the robot is important for understanding cell design, overall floor space requirements and cycle time of the cell. Proper feeding of the inserts can dramatically reduce cycle time of the cell operation. By analyzing how inserts will be picked by the robot and placed into the mold either A Side or B Side, and determining which side of the mold finished parts are to be picked from, then end of arm tooling decisions on gripper circuits, types of grippers and vacuum cups can be designed to automate applications within the machine work cell that may have been solely manual operations previously.
Operator Engagement and Safety
As injection molding and extrusion work cells grow larger, so do the safety issues associated with running them. While virtually all plastic manufacturers follow the appropriate safety regulations in the design and development of the machinery, including shielding, guarding, safety shutoffs and “lock out – tag out” (LOTO) protocols, many are omitting some additional needs that come from high base or even larger tonnage machines.
Cell safety is a consideration that should be prominent through the entire design process. Important considerations are fencing to protect operators from the robotic system, along with placement of hard stops, which prohibit the robot from traveling outside of the allocated area.
As new emerging technologies are developed, Milacron will continue to grow our solutions, technology and service offerings with new equipment, practices, and techniques; without hesitating to modify or change with emerging technologies that promise to enhance these processes and bring the best to our customers.
Ron Gulbransen
Technical Product Manager, Auxiliaries
