Lights-Out Machining Driving Success at Gray Manufacturing
Denver, NC – October 22, 2024 – Different religions and leadership philosophies live by the power of four. In a way, so does Gray Manufacturing Technologies.
Gray’s “power of four” could refer to the number of lights-out machines at the Compass Precision operating company. Behind its four Mikron units that can run unattended all hours of the day, Gray has taken tremendous strides in its growth over the past couple years.
“We’ve really dove into it hard the last two years, and we’ve gotten pretty good at how to order parts in the machine that makes the most sense to get the most throughput with minimal amount of input,” said Gray general manager Evan Grose. “It’s really changed things greatly for not just Gray and Compass in terms of getting more parts through and getting more dollars, but it’s given time back to the employees.”
“By perfecting their lights out capabilities, it has allowed Gray to take on programs that they would not have been able to do previously based on customer delivery demands and price sensitivity,” said Compass VP of Sales Jim Miller.
Two of Gray’s four Mikron machines are identical E700 units. Robotics is used in both to load the machines.
Gray also possesses a Mikron E500 and Mikron HSF600 unit. Both have the ability to use a 7-pallet change system to ensure the machine runs all night or all weekend.
This gives Gray the ability to either run large quantities of the same part number or small qualities of different part numbers. But that’s just the beginning of the advantages lights-out machining gives Gray.
With multiple pallets, all four Mikron machines can fulfill two or more different orders simultaneously. Running the machines lights out also means that the parts are completed with minimum labor.
“It’s free money. It doesn’t cost anything, and it keeps our machines going 24 hours a day as long as we have the work,” said Gray shop floor lead Chris Atkins.
Gray’s automation philosophy is similar to that of sister operating company Strom Manufacturing whose lights-out production skills were highlighted in a recent YouTube video (see below). The difference is that Strom uses 4-axis horizontal CNC mills while Gray has 5-axis vertical machining centers. Each address a different class of components.
“Like Strom, Gray’s lights-out automation capabilities bring it tremendous capabilities to serve customers better,” explained Compass CEO Gary Holcomb who led the effort to acquire Gray in early 2020. “We can offer shorter lead times by running at night, better quality because of extremely stable processes, and improved economies by stretching our labor costs over more production.”
With machining complete overnight, parts are ready for inspection when Gray opens in the early morning. Unattended machining can occur over the weekend as well. Chris said two of their Mikron units have run almost every weekend in 2024.
This has allowed Gray to increase its production without hiring a lot of new machinists. Thus, the operating company has become more profitable while keeping costs low to customers.
Because of lights-out machining, Gray doesn’t require its current employees to work long hours to help the company grow either. Weekend shifts are sometimes as short as 15 minutes, as machinists arrive at the shop at the end of cycle times to then commence the next cycle.
Customers don’t have to be concerned with any risks with unattended machining either. Gray’s machines have tool break detection and other safety nets. If a tool moves out of a certain parameter, the machine stops to ensure a significant mistake isn’t made on a part.
“We put in the leg work in the front end to make sure we set it up to catch as much as possible and stop the machine in the event something goes wrong,” Evan said. “But if everything goes right, we get it rolling and we leave and go home.
“When we come back 24 hours later, we’ve got product. If it’s Friday, then we come in on Monday, and there’s a large amount of parts ready for inspection.”
But Gray doesn’t just use automation to its advantage when no one is around. Gray can run lights-out during the day too, which allows machinists to do other work around the shop, such as maintenance. The company’s machinists will also often clean their work area and write additional programs after setting up unattended machinery.
In other cases, Gray machinists can run multiple machines at one time. Evan called that a “giant win.”
Lights-out machining sounds easy on paper. It relatively is once the machine is going. Gray uses lights-out to machine a lot of aluminum and titanium parts in the aerospace & defense and space industries.
But the Gray team has needed to be meticulous to make automation work best. For the lights-out machines to be most efficient, it’s best to load the unit with two parts that require the same tools. That requires grouping parts for different customers together based on tool capacity.
It’s also best to look ahead at a machine’s schedule and calculate when a cycle is going to end. That way, Gray can ensure an employee will be there at that time to restart the machine, so it is constantly running.
It’s an evolving process.
“We are very impressed by the efforts Evan and his team have put forth to squeeze out every last minute of spindle time possible. When it comes to productivity and efficiency, the easiest portion to achieve is the first 85%,” Compass COO Bill Canning said. “The last 15% is extremely challenging. That piece is mostly driven by the ‘guts’ of the organization.
“The team, their commitment to process, and willingness to think about things just a little bit differently is what pushes them over the top. With that, everyone wins.
Critics of the process will point to the fact that Gray isn’t necessarily supporting the American workforce by hiring new employees to help the company grow. Instead, the company is settling for free labor from unattended machining.
But without it, Gray wouldn’t be where it is today, and today, it’s a lot closer to adding more equipment to support growth and then additional machinists to support that equipment.
And again, the lights-out capabilities greatly improves the work environment for Gray’s current employees.
“We’re not trying to program people out of the loop. That’s not the idea,” Evan said. “We want to use the loop to make people’s lives better.”
Lights-out machining at Gray is doing that and then some, as the operating company continues to see significant growth.