The Eyes Have It

An aluminum foundry takes a deeper look into the process of pouring molten metal, using eye-tracking technology to inform its safety practices and training methods

Some visions of the future lose sight of the present, focusing almost entirely on the potential for automation, robotics, and information technology to optimize performances and systems that are vulnerable to human inconsistency. Future manufacturing will be clean, quiet, and continuous, it is implied. No stress, no disruption.

But in the present, the work must continue. Automated pouring is no option for many foundries, due to the volumes or varieties of castings they produce, and this is equally true for molding, grinding, or finishing processes. But, advanced technology can describe more than robots, and by applying the right technology it may be possible to improve the performance and safety of human workers.

“Eye tracking” is a sensor technology that makes it possible to know where an individual’s eyes are fixed during a sequence or period of time. One of the pioneers of eye-tracking, Tobii AB, explains that the technology makes it possible to know where a subject’s eyes are focused, and determines an individual’s presence, attention, focus, drowsiness, consciousness, or other mental states. The data developed in this way can be used in product testing or consumer awareness/preference studies. More advanced development of the eye-tracking data can be used to control games or systems, as in virtual reality environments.

Earlier this year, a market-research study pointed to the automotive market as a growth sector for eye-tracking, to enhance vehicle safety by monitoring the operator’s focus.

Operators in one foundry are out in front of this trend. Tobii’s research division, Tobii Insight Pro, coordinated with H&H Castings in York, PA, casts complex aluminum components, from less than a pound up to 300 lb., in low- to high-volume runs. It relies on capable operators to fill its shell and no-bake molds.

According to Jacob Hammill, system manager at H&H Castings, the safety risks inherent to the pouring process have limited the foundry’s ability “to see first-hand what our employees experience … Eye tracking provided an interesting avenue for reducing accidents, improving performance, and cutting training time.”

He explained that the plant had defined some standard procedures for the pouring operation, mainly concerned with how to operate the equipment on the line. “Previously, we had new hires observe an experienced worker doing the pour from afar, to avoid getting hurt,” Hammill explained. “They really couldn’t get a precise look at the pouring process.”

In what is understood to be the first application of eye-tracking to a metalcasting process, Tobii Insight Pro monitored the eye movements of workers during pouring at H&H Castings, to bring new insight to optimal methods, to identify the causes of errors, and to identify new efficiencies in the process.

Mike Bartels, senior research director for Tobii Pro Insight, explained that a sample of six H&H Castings operators were recruited to demonstrate the flexibility and effectiveness of eye-tracking as a training tool under demanding and high-risk conditions.

“Each employee wore the Tobii Pro Glasses 2 eye-tracker as they went about their daily routine,” according to Bartels. “After a brief calibration, the eye tracker was turned on and the employee was asked to complete their work tasks, which included prepping the molten metal into the ladle, pouring it into the casting models, and removing the castings. 

“The eye trackers captured eye movements from their point of view with a dot visualizing precisely where they looked within their field of vision,” he explained. “The eye-tracking data was then exported for post analysis. The entire recording process took 15 to 30 minutes.”

The eye-tracking results were played back, “instant replay” style, for quick and actionable insights, and then deeper analysis was conducted using Tobii Pro Lab software.

Hammill reported that, with regard to worker safety, “the eye-tracking (results) showed how the intense concentration needed to do the job left our workers vulnerable to objects on the periphery of their vision.”

That led to a new determination to keep the workplace clear of obstructions and unnecessary clutter.

More than that, Hammill said results will provide significant new information for H&H Castings’ training program. “We now have a visual sketch of the ‘perfect pour’ that we can teach,” he noted. “We train a new employee in the melt department twice a month, on average, as it’s one of the most demanding, and consequently, the most volatile position in the factory. Average training time is one full week, but with these first-person eye tracking videos we project that it will save us two days per employee.

“Showing them the videos, we can both streamline training activities and communicate an array of detail about the intricacies of the job,” Hammill said. “Ideally this could save us 400 hours of training time per year in that department. “

He indicated that a significant discovery of the Tobii Pro Insight was “the rationale for even our more experienced operators making an occasional pouring mistake.

“Because they are so familiar with the pouring process,” Hammill explained, “they sometimes let their guard down and lessen their visual concentration.  We now know to hold a refresher course for this subset of employees, to ensure that the quality of their work remains above par.”

“One of the things that interested us about working with H&H Castings on this project is that – as far as we know – this is the first time that eye-tracking has been used to study attention in a metalcasting environment,” Bartels offered.

“If you were to talk to lot of these experts, they wouldn’t be able to precisely tell you what makes the perfect pour and why they might have over poured into a mold,” he continued. A lot of that is just intuitive behavior built up over the years through experience, and trial-and-error.  Through eye tracking we can get an exact outline of where they placed their attention, and how it impacted their work.” 

The value of this is that the best practices can be codified, and then standardized. “We can understand the process behind a job done well, and teach that to others,” according to Bartels. “For example, we identified the optimal positon people should hold their head when pouring.  This position ensures that one’s attention is not rapidly shifting between the ladle spout and the target of the pour, which was a common cause for mistakes.”

Also, the study established the importance of visual concentration throughout the sequence, from filling a ladle to pouring, to removing debris and cleaning the ladle. This is relevant to experienced workers as well as newer one.

“The possibility of attention strain led us to recommend to H&H that they give operators regularly timed breaks,” Bartels reported. “These breaks would likely improve both performance and safety.”

All of the results may be understood by other foundries too as a new point of reference in safety studies. “The marvelous thing about eye tracking is that instead of segregating vision from these other biometrics (e.g., audio disturbances, fatigue) we want to bring them together for a fuller, richer understanding of human behavior in all its nuisances.” 

Bartels indicated that, because H&H Castings represents a typical foundry, the discoveries there should prompt similar operations to consider the availability of new technology to improve worker safety and optimize training methods.

According to Jacob Hammill, H&H Castings will be following through on its own progress. “We hope to expand our training videos to other departments,” he reported, “things like making videos for fork-lift training, proper lifting, safe operations, etc. 

“Eventually, we’d like to incorporate the technology for more performance-based evaluations in areas like finishing,” he said, “which includes our grinders and saw operators, in the hope of increasing their efficiency.”  

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