Lights-Out Machining Requires 'Dimming the Lights'

Lights-out machining requires organization, preparation and automation, and readying workpieces, cutting tools and CNC programs for long, unattended operation. A shop must devote its workforce to preparing its machining resources for maximum productivity. Using your manned shift to prepare for your unmanned operations is a good strategy. One shop calls this “dimming the lights.”

Using your day shift to stabilize the process so it’s running smoothly before you leave for the night is the best way to ensure producing as many good parts as possible. Have the day shift monitor tool wear, monitor when offsets need to be made and benchmark when tool changes need to be made before the lights-out shift begins.

Not only is it critical to choose the most productive machines for your lights-out processes, but material and parts are prime selection criteria, as well. Chip control is critical, so material and cutting tools must perform predictably. Complex workpiece geometries work well for lights-out operations because of the long cycle times they require. Generally, parts with overall tolerances of ±0.0003 inch or less need some operator involvement over a production run to chart any accuracy drift that has occurred.

Selecting the most intuitive software is another way to get the most out of lights-out machining. Homeyer Tool and Die Company uses a system that watches the company’s lathe to see what part program is running and will automatically run the proper feeder program. The system also sends error codes to an off-site operator for easy fixes. Technical support via an Internet connection is available: An operator can take control of the feeder to fix issues and add upgrades from his desk. The software will even watch the lathe and send an email to an operator if the lathe shuts down.

Often, some creativity and ingenuity is in order to find the best processes for a lights-out operation. For example, Otto Engineering prepared itself for lights-out machining by implementing the idea of an automated parts catcher with four baskets for its multi-spindle machines. The machine-mounted parts manipulator places the finished part in the chute, and it is then deposited on a conveyor belt. One of four gates are opened by the machine’s controller directing the parts into a basket designated for that job. Another shop uses robotic loaders for lights-out hours.

Don’t forget that successful lights-out machining is labor free. The percent of margin increase from making parts labor free should offset any premium paid to ensure a reliable, consistent and quality run.

To read more lights-out machining tips and success stories, visit Take the Highland Road, Connecting the Technologies, and A Company’s Road to Lights-Out.