When a manufacturer considers whether adding an automated machining cell−including robotics−to his shop is a good idea, he first needs to figure out what the payoff would be.
“There are many reasons somebody would put robotics into a production system,” said Joe Gemma, chief regional officer for North America at Kuka Robotics. “It could be for yield consistency, quality improvement, the skilled labor shortage, mass customization … ”
Mass customization, a term and practice used in smart manufacturing, means the production system is programmed to turn out variations of a part.
Gemma uses two examples.
Baca Systems in Auburn Hills, MI, uses a Kuka robot in its Robo SawJet cells to cut custom granite and quartz countertops.
“Every single job those systems produce is different,” Gemma said. “Software helps go from the kitchen design to instructions for the robot.”
In the automotive industry, a robot in an automated cell may have to drill several different configurations of holes in front bumpers to accommodate various numbers of sensors, lights and headlight washers.
“That mass customization drives the need for flexibility,” he said. “Otherwise, the manufacturer could have 20 or more different molding machines” for the different styles of bumpers.
The automotive example could be extended further—the benefits of automation and robotics still apply—to a job shop, where the production system would routinely produce different products; say custom cell phone covers, then key fobs, then bottle openers.
“There, it depends on how truly automated the environment is,” Gemma said.
There are other factors at play with automated machining cells, including maximizing a spindle’s operation, as Fastems’ RoboFMS promises to do.
Can you afford not to automate?
Factory automation company Fastems’ RoboFMS uses a six-axis Fanuc robot and “zero-point” workpiece fixture plates vs. a conventional rail-guided vehicle and machine pallets. By doing so, the system provides the flexibility and reach to automate machine tools that normally could not be automated, such as a five-axis vertical spindle.
“Mainly because that particular machine does not have a pallet changer, and if you don’t have a pallet changer on a machine, you have to stand in front of the machine to be able to do the program prove-outs” because that’s where the human-machine interface is, said Robert Humphreys, Fastems’ international sales manager.
The robot’s extended reach means that a factory can set the user interface a distance away from the system, creating a safe zone for the operator.
“So the man can stand in front of the machine to do whatever he needs to do, come out from in front of the machine, put the machine into automatic and the robot can then automatically load and unload the machine,” he said.
The zero-point fixture plates provide not only a secure, accurate location for the work piece but also a common adaptor for different machines and accurate to within microns. That means a shop can do five-axis, four-axis, vertical or other machining with the same fixture plate.
“So you can interface more processes and different types of machines with this form of automation and tooling,” Humphreys said. “If your process has to go from a four-axis to five-axis to a turning machine or VTL [vertical turning lathe] and then finish, in a normal situation machine pallets are not compatible with each other within those machine groups, and therefore not possible to automate.”
The bottom line is the RoboFMS maximizes a spindle’s operation, he said, with the goal to get as many hours out of a spindle as possible.
“If you buy a machine tool that costs you a million bucks, if you can get your machine tool to run 85–90% spindle use, you’re getting the maximum out of the machine,” he said.
Humphreys estimates that in a traditional machine shop, one that’s constantly changing over jobs with use of a pallet-changing machine, getting 40–50% spindle use would be a lucky situation.
“And if you’ve got no pallet changer, you might be getting 20%, 25%,” he said. “So by automating you are effectively getting more hours out of your machine tool, and hours equals money.”
The Fastems’ FMS not only maximizes the time a spindle is running, it minimizes labor costs because one or two operators can run a whole cell of integrated machine tools, Humphreys pointed out.
“People look at it and say $1 million, I could buy another machine for that,” he said. “Yes, true, but if you’ve got two machines in a system you could achieve four machines’ worth of output.
“And everybody’s saying skilled men, skilled operators are getting hard to find.”
When talking with customers, Humphreys focuses not on whether they can afford to automate but whether they can afford to not automate.
“If you don’t automate, your business could be dead in five to 10 years because you can’t get the skilled labor,” he said. “Or the skilled labor you get gets poached by the job shop down the road that pays a dollar an hour more and you’re constantly in flux.”
Automation generates more earning hours, more output with less operators, therefore you can pay premium wages to keep the best operators and still be profitable, Humphreys said. “Staying competitive is key to survival.”
Adding value to the shop floor
Swiss company ABB, the first global industrial robotics company to open a manufacturing plant in North America, also promises increased spindle use with the FlexMT, an engineered system designed to load and unload machine tools using vision-guided robotics. It’s meant for both small-batch and high-volume production.
“ABB’s standard cells are designed to be used in machine-tending applications and can also be used incorporated into assembly applications for part feeding,” said Mike Wolff, application engineer for robotic machine tending at ABB in Houston. “The systems are quick and easy to install, feature a friendly human/machine interface, and are suited for the full variety of machining applications and industries.”
ABB said the FlexMT increases spindle use by up to 60% over manual machine tending.
First-time automation users PumpWorks, a Houston-based manufacturer of pumps for the oil/gas, water and chemicals industries, said in a case study the robot in the FlexMT was easy to program, and the system increased quality and throughput while reducing the cost per part.
“We’ve seen a huge value add with the FlexMT over the last year,” said Trey Maxwell, vice president. “It has brought our uptime on the machine from the mid-50s to the high 70s. Part production is up at least 50%, and we get more production in one cell.”
Maxwell said the FlexMT integrated directly to the company’s Mazak machining center.
“It’s a bolt-on product that talks the same language as our machining center, which allowed us to integrate the product into our existing manufacturing process very quickly.”
Wolff said the FlexMT works with all major machining systems and is compatible with horizontal and vertical lathes, machining centers, five-axis machines and grinders.
The FlexMT comes equipped with both an in-feed and out-feed conveyor. The modular system has six standard plug-and-play options, including two separate de-burring tools, a re-grip table, a needle marking unit, a turn station, and an air-cleaning box. Metrology equipment is an option.
Also recently developed by ABB are software programs and systems designed to make programming robotic machine tool cells easier.
The company recently introduced the PC-based RobotStudio Machine Tending PowerPac and the controller-based RobotWare Machine Tending software that together allow simulation, validation and optimization to be completed in the 3D virtual world and then transferred directly to the real world.
Everything from cycle times to post-processing capabilities to potential risks for collisions can be simulated virtually—before costly mistakes are made on the factory floor.
Standardizing for better communication
At Festo Corp., Nuzha Yakoob, senior product manager for electric automation, is rethinking how manufacturing is designed and embracing the concept of reconfigurable lines.
With reconfigurable lines, manufacturers assemble various vendors’ production cells that do specific tasks. The individual cells are standardized so they can communicate with each other and employ adaptive technologies that enable them to handle products of different sizes. These cells are less complex than current automated machines that are built around certain fixed products, which is a more expensive approach.
For example, a manufacturer with a configurable line can make the soft changes necessary on the fly to fill, label and cap different sizes of laundry detergent. Or he can make the soft changes necessary to have the same line handle jars of jelly and then catsup bottles.
Humphreys, of Fastems, offers another example that’s similar to Gemma’s customized auto bumpers:
You could have a line or cell that produces a cylinder head and you’re currently making model No. 4. Let’s say there’s a new model for better emissions, No. 5, to be sold only in California, where anti-pollution standards are tougher. You also need to make model No. 3, a legacy version, for spare parts. But you only make two No. 3 parts per month.
“All models are slightly different,” Humphreys said, “but are made with the same fixtures but different tooling, in the same run, and a 2D dot matrix on each part tells the system which model it’s working on at any one time.”
If the robot’s not equipped with machine vision to read the 2D dot matrix, the system could communicate to the robot’s controller which model it’s handling, Gemma said.
Configurable cells give a factory the freedom to build a line and then quickly change the number and/or sequence of the units depending on the need, Yakoob said. The line is scalable, so when demand drops a shop can rescale the line for changing production requirements.
“Efficiency is really key now,” she said. “It’s the target of all manufacturers.”
As more manufacturing returns to the United States, Yakoob said sees factories accepting reconfigurable cells as a means to achieve greater efficiency. She’s had discussions with companies that have already realized this is the way to go, including Procter & Gamble and Nike.
That’s not to say that reconfigurable lines are only useful to large manufacturers. Smaller lot sizes and mass customizations are also driving their use.
“It’s not so much the size or the capacity of production of an organization,” she said. “Where it’s not so appropriate would be an automotive manufacturer could not use the same reconfigurable line to build some gear boxes that are heavy and really dirty, and then redeploy the line to build circuit boards. You have to cluster the products in such a way that there are common processes, tool handling, loading and so on.”
The challenge to more widespread adoption, in addition to standardization that enables connectivity, is a decision-making tool for planning and scheduling tasks, Yakoob said.
“What’s been coming into the modern era is connectivity, or linking machines to a central intelligent controller,” said Humphreys.
Say a shop has three identical machines. When an order arrives, an operator uploads information about what’s needed and the due date. The controller determines what resources are available: One machine’s tools are at the end of their life cycle, so it sends the job to the two remaining machines.
“What you don’t want is a queue behind one machine and the other idle,” Humphreys said. “The idea is to keep the spindles turning.”
While not all shops can have three identical machines due to the expense, the ideal situation is to build some flexibility into your system with that kind of redundancy, he said.
Festo, which makes process control and factory automation solutions, is helping fill the need for a decision-making tool with its new Servo press kit, YJKP, for electrical press-fitting applications.
“It’s an automation cell with its own controller, therefore intelligent, and apps or routines are already programmed in for a multitude of different applications,” Yakoob said.
Although the YJKP is Festo’s first offering for making configurable lines a reality, she said the company plans to release more this year.