Metalcasting operations face several significant challenges, including a persistent labor shortage, stringent safety requirements, and demanding working conditions that often deter new workers.
Simultaneously, the global manufacturing landscape shows an accelerating trend toward automation, propelled by manufacturers’ need for increased efficiency, consistency, and operating cost savings. This shift is extending into traditionally labor-intensive sectors like foundries, where automated solutions for applications like grinding are emerging now as critical technology to address these pressing issues, and offering the potential to enhance productivity and results, improve worker safety, and alleviate the strain of manual processes.
Benefits of automated grinding
Automating grinding processes in a foundry presents several significant benefits for the operation, and addresses important challenges faced by the industry, including:
Improved worker safety: Grinding is a physically demanding and potentially hazardous task, exposing workers to dust, heat, noise, vibrations and flying debris. Automating the grinding process mitigates the safety concerns associated with manual grinding, significantly reducing the risk of injuries such as carpal tunnel syndrome, or other safety issues that can result from operator fatigue. Reducing these safety risks can also help facilities address labor shortages and challenges with worker retention in these dirty and hot environments.
Enhanced efficiency and productivity: Robotic grinding systems operate continuously using higher grind pressures, without breaks or fatigue, leading to higher production rates and more uniform product quality. This eliminates the variability associated with manual grinding, when fatigue and human error can affect results. Automation can result in more parts produced per shift, and thus also help to address labor shortages as operations produce more with fewer workers.
Reduced costs: While automation for material removal and grinding requires substantial up-front investment it generates cost savings in multiple areas, resulting in relatively short returns on investments. Automation provides the potential for reduced labor costs (if the work can be completed with fewer people), lower media consumption, and improved quality, all of which factor into overall unit costs.
A robotic work cell can also use software to assess abrasive media life: the software determines how much service life remains for an abrasive to ensure each one is used to its maximum value, helping reduce media costs and extend media life three to four times compared to manual operations.
Improved quality: The use of robotics generates precise and repeatable grinding operations. This leads to improved dimensional accuracy and surface finish, reducing the need for rework and improving overall product quality.
Implementing foundry automation
There are numerous foundry grinding applications that are well-suited for automation, including gate removal, edge radiusing, defect removal, and skeleton cut off. However, there are several considerations for plant managers and operators to keep in mind before implementing automation for material removal.
First, recognize that in many cases automated grinding and material removal may not achieve 100% of the finish requirements. A robotic grinding cell typically will accomplish 80% or more of the material removal necessary. The remaining material removal would then be completed manually or in a machining operation. But the capability of robotic cells to get the finishing process to that point will cut down significantly on the necessary manual or CNC time — savings that may still make automation a worthy investment.
It's important to fully identify the desired grinding process results before implementing automation. This will dictate which cell capabilities and equipment are required. Otherwise, the cell could be implemented with components that have the wrong horsepower, wrong spindle speeds, or even wrong abrasive media.
Another critical point is to not simply duplicate an established manual grinding process, as the robot is faster, more accurate, and capable of generating higher grinding pressures, which allows for the use of much more aggressive and longer-lasting (harder) grinding media than manual processes.
Working with a robotic integrator that can provide expert consultation and analysis is the best way to develop an appropriate automation solution. It’s important to look for a partner with robotic programmers who are experienced at material-removal applications, not just general robotic applications.
You should also work with abrasive specialists who understand foundry grinding processes. Because implementation of automation may impact the entire process, including both upstream and/or downstream operations, partnering with experienced material-removal experts is critical.
Automation saves time for aerospace manufacturer
Recently, a manufacturer of aerospace engine components was struggling to efficiently grind the inner diameter of titanium rings. The rings are small, with inside diameters of 2.5 to 6.5 inches, making it difficult for operators to reach into them for grinding. Operators also had to flip the rings end for end during the grinding process, considerably increasing safety issues and time needed to execute the process.
The manufacturer wanted to evaluate how automation with more aggressive media might improve this grinding process. The plant has used automation for other applications, involving utilized coated abrasive belts, but the rings would represent their first automated process using organic-bonded abrasives, similar to what was in use for the manual grinding processes.
To develop a solution for this manufacturer, Weiler Abrasives worked with Acme Manufacturing, a robotic systems integrator and machine tool builder that specializes in robotic material-removal processes, such as grinding, polishing, buffing, deburring, and cut-off. Weiler and Acme have a long history of collaborating on many successful projects for end users.
“This automation project was for a very specific application; our team went through rigorous testing to determine the correct finishing approach. That’s one reason why it’s so important to work with a partner who has experience in automating material removal,” according to John McGrane, Acme Manufacturing’s director of marketing communications. “Weiler worked very closely with us to determine the abrasive needs to help achieve the results we needed for this end user.”
After testing and confirmation of the media types and operating parameters required, a new robotic grinding cell was designed and built by Acme. It can manipulate the part, pick up a tool and automatically change the media as needed. The interior diameter of each ring may have unique variations; the system uses the abrasives to grind away imperfections and remove potential cracks before the part is sent for further processing.
The robotic cell has two different work-holding locations to accommodate different sized parts. It also dresses the media each time, ensuring that it has new grain exposed for maximum sharpness to provide a repeatable finish.
Weiler experts recommended the media required for this project and provided technical support regarding factors like angle of approach, pressure required, and the RPM used. Because this aerospace application uses high-strength alloy materials, it required some initial media testing to determine the best operating parameters for this specific application.
Those parameters determined the required spindle RPM and horsepower. Weiler bonded abrasives used on the robotic cell include snagging wheels, plugs, and Type 11 cups. And Weiler was on-site for the cell’s initial start-up to assist with any process refinements that may have been needed, as this was the first time the user had automated this specific grinding process.
The aerospace manufacturer was able to reduce the grinding cycle time from about 30 minutes for the manual process to 7 to 18 minutes, depending on part size for the automated process.
“Automation can save significant time, and this user was very satisfied with the results,” McGrane recalled.
One area where end users may expect significant improvement with automation is the extension of abrasive media life, because a robotic cell can manage media life and notify operators when a change is needed.
“The robot can be a lot more efficient with an abrasive compared to a human operator. It’s really using the full life of an abrasive,” according to McGrane. “We say the media life is typically three to four times longer.”
Automation offers a multitude of benefits for foundry grinding applications, including enhanced worker safety, improved efficiency and productivity, reduced costs, and improved quality. By mitigating safety risks, increasing production rates, ensuring consistent quality, and optimizing abrasive usage, automated grinding cells can address critical challenges faced by the foundry industry.