ATI Industrial Automation (United States) - The primary objective of a foundry is to liquefy and form metal into shapes called castings. The environment is hot and the work is very physical and dangerous due to the hazardous materials. It’s no surprise foundry jobs are difficult to staff.
Above all else, Nidec Minster, a renowned press and automation equipment supplier, values their foundry workers and the critical role they play. Recently, Nidec Minster embarked on a manufacturing process improvement to make employee’s jobs safer and easier. Using ATI’s Multi-Axis Force/Torque (F/T) Sensors and a servo grinding spindle, the Nidec Minster integration team developed a remote-controlled robotic grinding process that gets the work done quicker and eliminates many safety hazards for workers.
Chipping and grinding processes are a necessary part of foundry work, and in many cases are done by hand. The manual process is backbreaking due to the ergonomics of handling the grinding equipment and the wear and tear on the body from the vibration of those tools.
Nidec Minster is a leading developer of vertically-integrated material forming solutions for a variety of industries. Their portfolio includes foundry operations, product development, manufacturing and solution integration. This holistic perspective gives Nidec Minster a deep appreciation for refining internal operations. They believe that people are a company’s most valuable resource and always look to create safer and more efficient processes that elevate their employees. At the same time, their focus on continuous improvement compels them to search for solutions that are adaptable and fluid to the constant changes in demand.
Nidec Minster identified a few key factors of their foundry operation that created serious safety concerns and developed a plan to streamline those issues in a new process. The first red flag was the material; in this plant the castings are made from ductile iron. The debris from the material removal processes can accumulate and combust. Second, castings can weigh up to 25,000 lbs and create ergonomic challenges in fixturing the parts and manually grinding the features. The various features to be processed are also large and require powerful grinding tools for heavy duty material removal. Lastly, production occurs in small but distinct batches. Material removal requirements vary from one batch to another and rely on operator experience to execute the right cut.
Before the upgrade, Nidec Minster ran a fully manual chipping and grinding process with foundry workers using handheld grinders – some weighing up to 20 lbs, for eight hour shifts, every day. Many employees finished their work day without feeling in their hands and arose each morning to chronic soreness and fatigue in their arms and shoulder. The foundry experienced rapid turnover with many employees sustaining short and long term injuries resulting from the back-breaking work.
The new system, ExoGrind, utilizes a robot to bring the process to the part which eliminates the need for complicated work-holding and safeguards employees against potential injuries from the grinding equipment. ExoGrind still integrates the operators into the process through remote operation; they can control the depth of each cut via force and torque feedback from the ATI sensor.
Using a military-grade wireless controller, the operator guides the robot and grinding process, adjusting the contact force with the touch of a button. ATI’s Omega191 Force/Torque sensor system provides the feedback for the operator’s haptic control system, allowing them to feel the force of the grinding spindle on the part. They can choose from a variety of grinding wheels to attack each feature with the optimal tool. During a cut, they can feel the part profile change as material is removed, enabling a direct translation of their experience with the manual process.
The Omega191 F/T Sensor includes a 190 mm diameter transducer and an electronics interface with cables for connection to the robot. The F/T transducer is mounted between the robot wrist and the grinding spindle. The electronics interface resolves the strain gage signals into forces and torques for use by the control system. As the mechanical loads applied to the sensor change throughout the process, the electronic interface translates electrical signals into more useful force and torque information that is transmitted instantly to the operator through haptic feedback from the controller.
The Omega191 sensor is rugged and accurate, effectively measuring the sizable contact forces from the grind and providing a method of process control and refinement. The monolithic transducer body features high levels of overload protection, which is critical for managing potential moment loads of a heavy grinding process, while silicon strain gages within the transducer body ensure accurate force sensing.
Electronic interface options for ATI Force/Torque sensors include DAQ, Ethernet, EtherCAT, serial, wireless, and many more. All electronic interfaces enable lightning fast communication between the sensor, controls, and robot. The sensor produces force feedback the operator can feel with their own hands and gives them the ability to make adjustments to the grinding spindle in real time.
The results of this system upgrade speak for themselves. Nidec Minster has achieved increased efficiency and process quality and estimates savings of $50,000 yearly in reduced scrap. ExoGrind can remove a greater amount of material with each pass than the manual operation which reduces processing time by about 32% per part. Due to increased incoming part quality, the downstream chipping and grinding tasks have been consolidated as well. Most importantly, ExoGrind eliminates safety concerns, which results in healthier, happier employees and reduced turnover.
Since many of the foundry employees play video games in their free time, using the controller was fun and easy, and ultimately accelerated their proficiency with the new system. Nidec Minster reports that even without any programming experience, ExoGrind operators were grinding successfully within 20 minutes. The lead operator for the grinding cell says he will never go back to manual operation. Using the remote controlled ExoGrind system, he can leverage the years of expertise he’s earned and do a job he actually enjoys.
Nidec Minster prioritized employee wellness in their process upgrade and achieved an outcome that eliminates safety hazards and increases employee engagement. The operators at Nidec Minster give the new system high praise. Not only do they feel safer, but they also feel more integrated into their work. The technique and expertise from their manual work translates directly to the ExoGrind system and the remote controller brings an element of familiarity.