Pools, pallets, and productivity

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by Kip Hanson

Automation is the key to competitiveness

Anyone who’s ever reviewed a job report or analyzed time cards has probably wondered: what the heck are they doing out there? That’s because production rates and setup times are frequently a guessing game even in well-organized shops, with customer delivery dates predicated on tooling and material availability, operator efficiency, programmer experience, and a host of other variables that often lead to bad parts and missed promises. It’s only by removing these variables that production consistency can be achieved. Computerized equipment may have taken manufacturers out of the crank-turning 70s, but the human element is still the great unknown, one that often leaves expensive CNC machines sitting idle while the operator eats a sandwich or chats with his neighbour.

A KUKA machine tending robot in a Nakamura-Tome machining cell.Breaking the rules
Enter automated part handling. Robots don’t take breaks. They never stop to complain, and they seldom gossip. Yet many manufacturers persist in the preconception that robotics and other forms of automation are only for high part volumes. And while that may once have been true, today’s technology puts that notion in the same department as Tom Sawyer and Huckleberry Finn: pure fiction.

“Automation offers the biggest benefit when you’re doing small batches and many different part numbers.” That’s the viewpoint of Vince D’Alessio, executive vice president at machine tool distributor Elliott-Matsuura Canada Inc., Oakville, ON, who says automation is used increasingly in shops large and small, but remains a path that shops should tread carefully. “Every year we implement more and more systems. And while the advantages of automation are clear, it’s important to become knowledgeable in every aspect of the technology before making a purchase, so as to avoid an expensive mistake. For example, people talk about flexible automation systems, or FMS, as the end game of manufacturing. But for some of these folks, FMS is more of a buzzword than it is a solution, and can easily become a costly exercise.”

D’Alessio does promote FMS and other high end systems, given the right circumstances, but says shops can frequently spend far less to get an equivalent bang for the buck. Shopping for the correct solution is a case of first understanding many factors, such as types of jobs, annual volumes, cycle times, product mix, and equipment budget, and it’s only by analyzing these parameters that the right blend of CNC, operator, and automation can be determined.

“You don’t have to spend a ton of money to achieve what’s needed,” he says. “Getting a full blown FMS running can easily take months, perhaps a year to become completely operational, where installing a few palletized machines geared towards a handful of jobs is far simpler and much less expensive. It all depends on what’s most efficient for the mix of work. Unfortunately, there are still plenty of companies that don’t realize how much automation can be used to benefit them, to make them more productive at the lowest possible cost.”

The new generation Matsuura five axis machining cell can handle up to 320 tools, 49 pallets and has turning capability.The road to FMS
Jeff Estes, director of Partners in THINC Technology Centers for machine tool builder Okuma America Corp., Charlotte, NC, agrees. “It’s a great time to be in manufacturing and machining. There are so many options available now compared to even ten years ago, and such good technology, that I truly believe you can cost effectively make one piece of anything using either a robot or an FMS. It’s just a question of doing your homework first, and investing in the proper equipment.”

For those whose homework leads them to an FMS solution, Estes says there are several things to consider. Since the primary goal of many automation endeavors is lights-out machining, tool life management and integrated metrology are key features. “To run unattended, it’s necessary to develop a closed loop system. This not only means monitoring tool life, but dealing with unexpected wear or breakage of the tool.” To accomplish this, parts are typically measured via machine-resident probing or integrated inspection systems, and appropriate wear compensation values sent to the machine controller. When tool wear gets beyond a certain preset threshold, the cell controller brings up a redundant tool or—worst case—calls a human to deal with the problem. This makes it feasible to operate multiple shifts or even entire weekends with no one in attendance.

A Fastems machining cell.Of course, there’s some low tech involved as well. Estes recommends super-sizing the lubrication and cutting fluid reservoirs, so as to avoid thousands of dollars in lost production over something as simple as a low oil alarm, and making sure there are redundant tool stations available. Some machine builders accomplish this with large capacity tool carousels, but a growing trend with FMS builders is the use of a centralized tooling module, or matrix. Instead of equipping each machining centre with hundreds of tools and toolholders, a robot is used to transport tools to and from a shared location, which stores all of the tools necessary for an entire group of machines.

Have your robot call my robot
One company offering such systems is Ohio-based engineered solutions provider Fastems LLC. Regional sales manager John Ross says the company’s Central Tool Storage System, or CTS, will even bring cutting tools back to the crib for servicing. “The robot will come and get four or five tools at a time and distribute them to whatever machines need them, and return other tools for sharpening or replacement as necessary. It’s a great solution for shops with multiple machines that can share the same tooling.”

Where high mix and low volume is the rule, Ross recommends one of Fastems’ container systems: out-of-the-box solutions meant for smaller customers looking to get into some form of automation. “The base container system accommodates up to three machines and between 4 to 12 pallets, depending on the size. This is expandable to three containers, for a total of nine machines on the same cell controller. All of the offsets, programs, tooling, basically everything needed to run dozens of jobs at a moment’s notice, is stored right there.”

Suburban Manufacturing increased efficiency of its Okuma HMCs by using flexible manufacturing systems with multiple load stations.Ross says he worked with one shop recently, the owner of which was skeptical about adding a Fastems FMS container to his Okuma horizontal machining centre. Within a few months, however, he was churning out “an unbelievable amount of work. The machine never stops making parts.” Ross says these results are typical, and shops can easily achieve 90 per cent or better spindle utilization with even a small FMS. “With two machines running two shifts, it’s not unusual to save $200,000 or more per year on labour costs alone. And since each job only has to be setup once, just think about all the extra production time that’s gained. It’s hard for a lot of shop people to wrap their minds around it, but once they have one in front of them, or visit someone who does, the light bulb goes on.”

So simple a caveman can do it
Ross says FMS operation is often no more difficult than training the shop’s top person and making him or her responsible for the system. From there it’s a matter of loading raw material in one end and taking finished parts out the other, something even unskilled labour is capable of doing. Still too difficult? Hire a robot.

Robots are used for everything from underwater exploration to orthopedic surgery, but in a manufacturing context, they are primarily tasked with welding, assembly, and machine tending. Edward Manera, account manager for KUKA Robotics Canada Ltd., Mississauga, ON, says he’s spoken to plenty of shops who’ve used robots for these tasks and more, and are usually happy with the ROI. To these people, Manera’s first statement is this: “most companies will help you get a good payback; we want to help you get the best payback using a more repeatable robot.”

According to Manera, repeatability makes the difference between performing only simple tasks and doing higher value work such as deburring, sorting, inspection, and even light machining. “Robots have changed a great deal over the years,” he says. “For example, many are now equipped with vision systems, so can identify features such as slots or holes and orientate parts accordingly. And today’s machines are much faster as well, able to carry heavy payloads even at an extended reach.” These capabilities mean manufacturers can utilize robots for an increasing number of complex tasks, Manera says.

As with any investment in automation, Manera says it’s important to know what you’re trying to accomplish before spending even a nickel on equipment. He recommends companies develop process maps, to define the bottlenecks and areas where ROI will be greatest, and then scope out how a robot will provide value. “Is it a quality issue? A shortage of manpower? Piece cost? Lack of organization? A problem well defined is already half solved, so take the time to document processes up front, focusing on the highest value solution instead of solving the wrong problem.”

The brains of the operation
Lastly, don’t forget the intelligence needed to drive all this hardware. Robots, pallet changers, and even automatic barfeeders would be worthless without the tools to control them. And with unattended manufacturing especially, software often spells the difference between success and failure. Fortunately, FMS and robotics providers offer software to drive their wares, most of which do an excellent job. But many of these are proprietary systems are designed to run that manufacturer’s brand of equipment specifically. For shops with a mix of machine tool types and brands, or who want to do their own integration, these systems are often limited.

Mike Rogers, director of automation and regional sales manager at Predator Software Inc., Beaverton, OR, says a good cell management system will deal with whatever curve balls get thrown its way. “If the machine loads up a new part during the night and our cell controller finds that somebody has misplaced the files needed for that job, it should be a simple error to resolve. The software has the intelligence to automatically abort that job, tell the machine to go home, unload the pallet, flag the job for human intervention the next morning, and move on to the next job in the queue.”

More difficult problems such as a machine axis overload or a broken tool should be treated as a more fatal error. In these cases, the machine can immediately be taken offline to prevent further damage. In either event, job scheduling plays a crucial role in efficient, predictable production. This means deciding between alternate machine tools, reprioritizing jobs based on changing conditions in the queue, and communicating with subsystems such as tool life management, metrology equipment, and even the shop’s ERP system.

Rogers says he’s seeing greater interest in automation from job shops and other low volume manufacturers. “Companies that were once turning out high-volume production parts each month are now being asked to produce much lower ‘Just-in-Time’ quantities of 5, 20, or 100 parts per order. And even on the repeat jobs, there’s little forecast: the two year contracts are gone, so a shop’s automation has to be flexible enough to adapt quickly to changing market conditions.” The number of companies going it alone on integration is also on the rise, he says, and even small shops with a few machines are tying them together with a robot or automated pallet loader. “There aren’t too many off-the-shelf solutions for these folks, especially if they’re dealing with disparate brands of equipment. But assuming the machine builder has at least given us remote control access, or has one of the standard protocols such as MTConnect, Okuma THINC, or Fanuc FOCAS, we should be able to talk to it.” SMT

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