Here are the key points to keep in mind if you’re setting up unattended machining operations on the metalworking plant floor.
A manufacturing concept that’s gaining in popularity as more factories and plants incorporate automation into their processes, unattended or “lights-out” operations let companies set up metalworking jobs and allow them to run for hours with less human supervision than traditional approaches.
At a simple level, unattended machining could mean setting up multiple parts in a machine so that it's able to run independently for several hours. A more complex scenario would include an advanced pallet-changing process that can be set up to run unattended for days. When the machining process is completed, it will switch out automatically to the next pallet——because there will always be another pallet standing by outside of the machining area. While a simple set-up of two pallets can be used on a standard machine, if a modular configuration is used, up to hundreds of pallets can enter the workflow and operate with little or no human intervention.
What Is "Lights-Out" or Unattended Machining?
In a machining environment, lights-out refers to adding multi-pallet systems or other equipment to a machining center to make it possible for that machine to run without human operators. According to Fabricating & Metalworking, a shop can typically produce five, 10, 12 or more unrelated workpieces in one continuous run without operator intervention.
In some cases, the job may also involve the use of robotics, particularly if many of the workpieces have short cycle times, but for most jobs it's not essential.
“While the amount of work that can be produced varies, a good rule of thumb is that a two-pallet system can run unattended for three hours; an eight-pallet system can run for eight to twelve hours; and a 40-pallet system can run from Friday night to Monday morning,” the publication points out. “That's a lot of work that wasn't being performed before.”
Here’s How It Works
Grainger Metalworking Specialist Justin Hagerty says unattended machining operations have become an attractive choice in a business world where skilled labor is becoming increasingly difficult to find and retain. “Right now, every shop that I visit is looking for workers who are willing and able to run its machines,” says Hagerty.
Hagerty says Grainger helps companies overcome this issue by incorporating different policies and procedures into their machining workflows. It also installs automated options that allow parts to be switched out without operator intervention. The ultimate goal is minimal operator intervention and a machine that can be kept running 24 hours a day—as opposed to a typical 10-hour shift.
“These unattended operations can be set up in the morning to run all day, all night,” says Hagerty, “or even for a couple of days in a row.
The Advantages of Lights-Out
By automating the metalworking process, companies can effectively speed up their operations, meet customer deadlines, lower their operating costs, and allocate human labor to more complex tasks.
“It’s tough to find workers with high-end skills,” Product Development Solutions points out in "Top Advantages of Lights Out Manufacturing." “Often an operator, trained to set up machines, can be stretched too thin. In a ‘lights out’ factory, that operator can set up multiple runs, while another machine is already running. Now, these employees can spend more time doing what they do best instead of unskilled tasks like loading and unloading.”
Along with improved production timetables, unattended machining operations also provide high levels of visibility over metalworking processes—something that’s not always attainable using traditional manufacturing methods. “Companies can monitor the lights-out processes in real-time,” says Hagerty, “and literally know when machine #1 is operating at 70% efficiency, or when the tool on machine #3 is broken and in need of attention.”
Available on mobile apps, this level of machine monitoring helps companies keep their operations running smoothly, enables quick intervention when there’s a problem and ultimately saves metalworking shops both time and money.
It's Not Just “Set It and Forget It”
When establishing and using unattended operations, metalworking shops need to realize that the processes themselves won’t run on their own. There will still be a need for human intervention, with the ultimate goal being to streamline the manufacturing process by reducing the number of times that an operator has to physically “touch” the raw materials, end product or the machine itself.
Hagerty says companies that start small by, say, incorporating a lights-out approach into a single aspect of their manufacturing processes, tend to see the best results from their efforts. “Not all companies are going to be able to manage long-term, ongoing unattended operations,” says Hagerty, “but nearly all of them can incorporate lights-out into cycles that last a few minutes or even a few hours.”
In a typical machine shop environment, for example, a company can put one vice on a machine that can handle one or two parts at a time on its own, in an automated fashion. Once that process is running smoothly, that machine shop can add five or six more vises onto the machine and create a process whereby multiple parts can be machined at once. “At that point, the whole line can run unattended,” says Hagerty, “thus allowing the operation to get ahead of its daily production numbers without the need for additional labor or equipment.”
First Steps to Success
To companies that want to establish their own unattended machining operations and reap some or all of its rewards, Hagerty says to start with your dominant tooling. A broken drill, for example, would typically require operator removal of the tool, checking for holder damage, removing the drill, cleaning the holder, replacing the drill and then reestablishing the length of the new tool in the CNC control. Even the company that doesn’t have an unattended operation can increase its uptime by having preset redundant tooling on-hand, ready for replacement.
“An operator should be able to grab that tool, load it, hit the cycle settings, and get the machine back up and running again quickly,” says Hagerty. “These switchovers can take time, so any redundant tooling, parts, or fixture that you can have on-hand are a good first step to an easy transition into the unattended operation mindset.”
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