by Kip Hanson
From cells to systems, automated but flexible manufacturing is a game-changer for many companies. The question is how to achieve it?
No offense to the fine people who produce our cars and trucks, but automakers have it easy. When you’re machining crankshafts and cylinder heads by the gazillions, there’s little concern over the stuff that can make or break a job shop or other high-mix, low-volume manufacturer that face challenges like overly long machine setup times, improper tool selection and workpiece fixturing that’s far from flexible.
What matters most in the world of high-volume manufacturing—whether it’s car parts or candy bars—is a predictable process and the shortest cycle time possible. Oh, and parts that meet quality specifications don’t hurt either.
The right stuff
Granted, meeting these goals isn’t necessarily a slam dunk. It requires the right cutting tools, high-quality equipment, and a solid knowledge of manufacturing. But in many respects, shaving seconds off a machining cycle that will run for months or even years is considerably easier than eliminating hours of machine setup time each day or wasting time on a fixture that might never be used again. And it’s certainly much easier to automate a high-volume production line than it is a CNC lathe or machining centre that runs perhaps dozens of jobs each week.
And yet, machine shops large and small are learning that round-the-clock manufacturing—preferably unattended, for the most part—together with high overall equipment effectiveness (OEE) levels are becoming a key factor in successful business operations…and in many cases, business survival. The good news? Grabbing hold of both is not as difficult as one might think.
John Einberger, product line manager for machine tool builder Makino, notes that there are many ways to attack the problem. “On the higher-volume end of the spectrum, you’ll typically see some sort of cellular manufacturing approach, where you have robots loading and unloading material on standalone CNC machine tools,” he says. “A flexible manufacturing system (FMS), on the other hand, is an excellent solution for shops that do high-mix, relatively low-volume work, but is typically composed of horizontal machining centres and a linear pallet system. Sitting between these two solutions is our MMC-R product.”
Makino’s MMC-R automation system, he explains, utilizes a robot and a “mother fixture” to automate four and five-axis horizontal and vertical machining centres. This gives customers a great deal of flexibility in terms of workpiece size and configuration, as well as the types of machine tool they wish to use. “It’s a very powerful combination, one that’s really taking off in the structural aerospace and defense markets,” says Einberger.
David Walton, director of engineering operations at Makino, agrees, but recommends that shops work on their machining processes before exploring any forms of machine tool automation. “Without a stable process, any potential labour savings will quickly be consumed by the need for human intervention,” he says.
That means the use of high-quality, possibly material-specific cutting tools. It means rigid, accurate toolholders and workholding and an equally capable machine tool. And it means NC programs that have been thoroughly vetted before uploading to the machine control, preferably with some form of toolpath simulation software. “Once you have all those building blocks in place, you’ll open the door to levels of success that are otherwise unachievable,” adds Einberger.
Making beautiful music
Control of Makino’s MMC2 and MMC-R relies on MAS-A5, a system control software that schedules and synchronizes the FMS’s various parts much like the conductor of a symphony orchestra maintains perfect harmony. Chris Rezny, central regional manager at Fastems LLC, West Chester, Ohio, suggests that such cell control software comprises the heart and soul of any FMS—in the case of Fastems equipment, this is known as MMS, short for Manufacturing Management Software.
“MMS does more than shuttle pallets around and queue up jobs,” Rezny says. “It manages the tool and part data, NC programs, material availability, order dates and quantities—basically everything needed for automated production.”
MMS also shares information with the shop’s other software systems, including CAM, ERP, and TMS. This interoperability provides complete visibility while eliminating problems that might arise from outdated information or data entry errors. “Let’s say your customer calls with a drop-in order for parts,” says Rezny. “The system is smart enough to figure out where it can slot an emergency job, check that everything needed to make it is available, and provided none of its existing priorities gets violated, deliver the parts as promised.”
Rezny seconds the advice given by Makino’s Einberger and Walton, recommending that shops interested in automation start small, perhaps focusing on a single machine, product line, or family of parts. They should also plan ahead when installing any new machine tools by ensuring there will be enough room for a future robot or pallet system.
However they get started, Rezny says the most important thing is to do just that: get started. “Between our extensive hardware lineup and the MMS software that Fastems developed, we’re able to automate everything from a single CNC lathe to a cell containing a handful of machine tools and auxiliary equipment to an entire factory, regardless of the brand or vintage,” he says. “Manufacturers have 8,760 hours available to them each year. It’s our goal to get them productive for as many of those hours as possible.” SMT