By equipping its automatic machining centers with automatic door openers, BorgWarner Emissions/Thermal Systems has improved productivity and controlled a source of repetitive motion injury.
At its Cadillac, MI plant, BorgWarner Emissions/Thermal Systems manufactures cooling systems and other components for heavy-duty commercial vehicles. Many of the products made there include castings that must be machined, and the company has a large contingent of CNC machining centers to perform these operations. The plant routinely operates three shifts, five or six days a week.
Opening the Doors
Typically, these machining centers have a sliding glass door that must be opened and closed manually to unload and reload the machine between cycles -- a procedure that led to problems with repetitive motion injuries for some employees.
"Some of our machines are fairly large, and when the operators are moving the door open and closed all day long, they had some problems with shoulder pain," explains Chris Stanley, facilities/maintenance environmental and safety manager. (ATD Door Opener has been installed on the Mori Seiki CL-25 shown here.)
In looking for a solution, he discovered that the some of the machines were designed to have automatic door openers as an option. "They were designed into the machine and hard to integrate once the machine was built," he says. "If it could be done, it would cost an extraordinary amount of money."
Instead, the company found an automatic opener that was designed for field retrofit on existing machinery. The ATD Automatic Door Opener, from A & A Manufacturing Co, Inc, New Berlin, WI, is easy to incorporate on a wide variety of machining centers with horizontal or vertical door orientations. It protects operators from both crushing and repetitive motion injuries and includes built-in safety features that continuously monitor torque and speed. (Once the operator pushes the button to open the door at the end of the cycle, he can concentrate on loading the next workpiece without incurring repetitive motion injuries.)
"About two years ago, I bought four of them to start with," says Stanley. "They worked out so well that we now have them on 14 machines. In the next few months, they will be on every machine."
The ATD door openers reverse automatically when they encounter an obstacle, preventing both injuries and downtime. "We've done the pencil test and it didn't break the pencil," Stanley notes. (After a workpiece is loaded, the operator, as shown, simply pushes a button to close the door and start the next cycle.)
The self-calibrating openers operate without adding limit switches, light curtains, pressure switches, or photo eyes. Their internal braking system engages in any stopped position. Fully electric, they require no shop air. A preprogrammed control module is easy to use.
Simple Solution -- Multiple Benefits
In operation, the machine cycles are automatic but controlled manually by the operator. "Once he loads the machine, the operator pushes a button to close the door and start the cycle," says Stanley.
"We have reduced repetitive shoulder injuries by at least half, if not more," he continues, citing reduction in injuries as a primary benefit. When the machine reaches the end of a cycle and the operator needs to change a part, he simply pushes a button on the machine's control panel, and the door opens. (With its cover removed, the ATD Door Opener's simple belt-driven design is visible.)
Opening the machine doors automatically has also helped speed up operations.
"It's faster than opening the door manually," Stanley points out, "and the speed can be increased or decreased depending on your needs. It's very flexible." He says programming them is simple, using a laptop computer.
"We installed them ourselves," he adds. "The bracket comes with the ATD, and the only modification was to weld it to the machine."
While all the door operators at BorgWarner are currently controlled manually, it is also possible to integrate them into the machine controls -- an option the company is looking into, according to Stanley.
