Pushing the Envelope with Pallets and Robots

The range and requirements of flexible machining cells are increasing

As automated manufacturing processes continue to evolve from "nice to have" to "must have" in the wake of issues such as skilled worker shortages, flexible manufacturing system configurations continue to emerge in new and exciting forms.

Clearly, the COVID-19 pandemic spurred manufacturers to accelerate the addition of robots to pallet systems. But that's not the only intriguing turn the FMS has taken of late.

"Flexible manufacturing systems can mean very different things today than it did in yesteryear," explained Automation Manager Zach Spencer of Methods Machine Tools based in Sudbury, Mass. "In the past, everyone was used to pallet-exchanging systems to achieve maximum flexibility with their machines. These pallet pools allowed customers to mount various workholding on various pallets and run their machines unattended.

"Today, flexible automation can take many forms. This can be anywhere from palletized machines, robots moving pallets around—like our Plus-K and Plus-K60 automation systems—to more complex but still easy-to-use systems like flexible vision systems to set up parts."

For those new to the automation game, Spencer said to start simply.

"We typically recommend starting with a smaller and less-complicated system to get their feet wet with automation—get comfortable with it before making a huge leap. For us, this smaller or smarter type of system can mean tending one machine versus many, and doing one batch run instead of doing a lot of various types of workpieces at once."

Being that the pallet automation business is "the heart" of Fastems, the Finnish company is at the forefront of emerging automation trends. The pandemic has hastened the addition of robots to load and unload parts into FMS setups, said Mika Laitinen, solution sales director at Fastems.

Other ancillary operations are increasingly being added within the same systems, added Christopher Rezny, Central U.S. regional manager for Fastems. For instance, whether a part is turned or gets machined, it has to be washed. Additionally, parts must be checked—either singly or after a run of perhaps 100. Deburring and automatic fixture loading operations can also be performed, and connectivity to automatic guided vehicle (AGV) systems keeps materials flowing into the operation.

Originally designed for horizontal machining centers. the Fastems FPC (for flexible pallet container) system, can be expanded to service up to four machine tools.

"For the first time, at least in Finland, this engine block will be loaded and unloaded automatically in this type of machine tool using AGVs," as the system was built without a stacker crane. The AGV moves the machining pallet from location to location for washing, inspection, deburring and finishing. "We have also have sub-assembly tasks to perform certain final machining operations. And we have storage. So, we have the all the same elements as we would have on the traditional stacker crane-based FMS, but now everything is on one level" because of the component weight.

Using AGVs instead of a crane is ideal in a situation like this, Laitinen continued, given that the machining time is quite long—several hours—so there is no issue using the slower loading and unloading vehicle for the pallet change.

Whether pallet systems are linear or rotary, with single or multiple-machine setup, the flavors of FMS run the gamut.

At DMG Mori, its LPP, or linear pallet pool, and its more-basic RPS, or rotary pallet system, find homes in multiple configurations.

For an LPP, "the typical sweet spot for a job shop is 24 to 36 pallets and two or three machines and two load stations," said John McDonald, general manager for development at DMG MORI's manufacturing facility in Davis, Calif. "You’ve got material flow in and out of the load stations, work queued up in the pallet pool system, and the machines are working away day and night."

Meanwhile, the RPS is "a single-machine, single-pallet system," McDonald continued. "There are typically five pallets in it, and we go all the way up to 21 pallets. These are great for, again, queueing work. You don't have as much part mix, or you combine it with some sort of quick-change fixturing such that you can change up your work setup."Ultimately, the right FMS for a given shop is the one that optimizes unattended run time. It's all about getting more spindle hours in the day and more "walkaway" time to let employees perform other tasks, he said.

The other job of the FMS, of course, is to get more work in the door. "I have customers knocking on my door, saying, ‘Here's a job to bid on, there's a job to bid on.’ What I see weighing on most peoples’ minds is, ‘Can I really implement this thing?’ Our private technology tours and education-based events show these customers how these tools actually work together to achieve that unattended run time."

DMG Mori's LPS 4 software, launched in 2021, is the fourth generation of the company's automation system management software. With it, manufacturers can eliminate some of the material-management steps by connecting directly to an ERP. For instance, if a customer orders 500 blocks of 6061 aluminum to produce water pumps, McDonald explained, "once you’ve created that water pump job, your ERP system can drive the demand to the pallet pool system of what it's going to produce next. We’ve removed that manual link of someone entering data from the ERP into the LPS 4 software; we’ve closed that loop by connecting those two. Not all customers are ready to start using that level today—but some of the more productive shops do."

Illustrating just what its FMS can do, DMG Mori runs a one-meter LPP with three machines in its own machine shop, McDonald noted. "It has a part washing station, robot loading, hydraulic fixtures and material pallets in it. We’re machining the castings that we build our machines with here in our Davis factory. An operator loads the casting onto the material pallet. Nearly all these castings must be craned; they’re way too heavy for anyone to lift. They’re craned onto a pallet that looks like a forklift pallet. The part is placed on there, then goes into the pallet racks. The material pallet goes into the robot load itself, as well as the fixture pallet. So, the robot picks up the part and loads it on the fixture, then the part is secured with hydraulic work holding. And then the part goes into the machining center.

"Once that operation is finished, it goes into the parts washing; the part is cleaned to remove any chips or grit from taped holes. We have customers that have taken that even further, to where we’ve integrated measuring machines and laser marking cells. Also, some customers use the LPP in combination with our centralized tool management system—so, not just the work pieces but also the tools in the machine magazine are automatically changed. Typically, we’ll see OEMs implementing these kinds of cells."

Methods, too, is serving the evolution from simple pallet exchanging systems to robot-tended solutions with pallet management controls, Spencer said.

"One very successful system we have developed and deployed is our RoboDrill Plus-K system," Spencer explained. "This system utilizes a FANUC RoboDrill with a FANUC Robot to tend it. On the robot side of things, there is the ability to store up to 60 workpieces in the system at a time. This system has a pallet management function embedded within the machine control that allows the operator to set specific program numbers to the various 60 stations that parts can be stored. This flexible system also allows for extended tooling on the machine, which can be massively helpful when working on various types of parts in the 60 different work stations."

And, high-mix, low-volume production isn't off the table, Spencer added. In those cases, "we typically recommend a more rigid solution. With any automation or machine tool sale, we try to show the customer the ROI calculations for their shop to help approve the sale of the equipment. We do what we can to beat an 18- to 20-month ROI for the customer." The company's Plus-K system is tailor-made for high-mix/low-volume work, he added.

"We have had great success with the medical industry with flexible systems. I think a major reason for this is the need in the medical industry for a high-mix type of application. By this I mean that they can typically run small batches—up to maybe 10 parts at a time—before needing to make a different type of part. This lends itself perfectly to a more flexible solution that is extremely easy to change from one part number to the next."

For track-and-trace requirements, he continued, "we offer cell controllers that can assist customers in traceability of parts through systems. Cell controllers can monitor the uptime of equipment, alarm statuses and history, as well as machine usages. These systems typically have either QR code, barcode or RFID scanning capability that allows the operator to scan parts in and out of the cells when running production. This information is typically stored in a database local to the cell, where it can be copied onto a customer's server."

When laser cutting and welding enter the equation, an FMS takes on a slightly different definition, said Dominic Rickard, North America sales manager for Prima Power Laserdyne, based in Brooklyn Park, Minn.

"A flexible manufacturing system for 3D laser processing means providing a system that can support a wide variety of laser processes, i.e. laser welding, laser drilling and 3D laser cutting," Rickard explained. "The system needs to support the manufacturing needs and be adaptable for the future needs of the business."

That adaptability would include support for:

--Low volume today and higher volume in the future.

--A range of materials, from mild steel, stainless steel and aluminum to specialty materials. Switching from one assist gas to another via electronic and programmatic control is important.

--Quick changes from one manufacturing process to another—from welding to cutting to drilling and vice versa. For example, he said, "LASERDYNE systems can switch from 3D laser cutting to 3D welding in one to two minutes."

Furthermore, he advised, laser-based FMS must provide real-time parameter and process information to manufacturing/operation monitoring systems—and that information must also be recorded and stored for future reference and analysis.

"From our perspective, the size of the system or machine is independent of flexibility," Rickard said. "The size of the system is determined by the parts the customer is going to laser-process. LASERDYNE systems are designed to support manufacturing flexibility regardless of whether a small or large system is purchased."

Prima Power Laserdyne's latest addition is its LASERDYNE 811 system, which supports the flexible manufacturing philosophy in several ways, Rickard explained.

"First, the same system supports a manufacturer who has a high part mix and low volume or a manufacturer who orders the system to build a single part for a number of years. Second, the customer can integrate automation at the time the system is installed or anytime in the future. The system is modular and adjustable. Third, the system can be a stand-alone piece of equipment or an integral part of the manufacturing cell."

The system has been a boon to one customer, a subcontractor to the automotive, food processing and home goods market, he said. That customer wanted to expand its processing capability and shorten part-to-part time for a variety of 3D metal parts and several cylindrical parts. Additionally, the customer wanted to reduce the part fixture switching time.

"We provided the customer with the LASERDYNE 811 with a two-position index table [turntable] to laser-cut 3D parts. In addition, we provided a common fixture interface so the operator can easily switch part fixtures on the turntable. To support the cylindrical part, we provided a rotary table using the same part fixture interface so the customer could easily add and remove the rotary table. Adding the rotary table is the same as adding and removing the part fixture.

"The result is the customer can laser-process in high SKU mix and reduce the part-to-part cycle times, which reduced overall costs, increased the factory throughput, reduced part lead-times to end-users and enabled the customer to remain competitive without any reduction in quality."

Rickard explained how the evolution of the FMS was critical to his company's success.

"Out of necessity, Prima Power Laserdyne was an early pioneer in 3D laser processing. To be successful we needed to offer flexible manufacturing systems. In the early days of the business, it was very difficult to sell a single-use machine. Customers insisted the systems needed to be flexible. FMS is a core part of our DNA, so to speak.

"Over the years, the system's laser sources started at CO2 lasers, migrating to Nd:YAG systems to now fiber laser systems. With each change in the laser source, a higher number of materials could be laser processed. Over time, we designed and enhanced our systems to support welding, drilling and cutting by changing the nozzle at end of the optical laser chain."

Another change was the company's introduction of SPC and MTConnect into its systems. "With SPC, the manufacturer can record all the process and machine parameters for analysis or record keeping. With MTConnect, the manufacturer can stream the parameters in real time, providing real-time process monitoring. Lastly, the system has real-time control over all aspects of the machine, including pulse-by-pulse control of the laser. The real-time control enables the controller to support seven or more axes and simplifies the integration of automation with LASERDYNE systems."

Ultimately, he concluded, "the general manufacturing sector and contract manufacturers are the leading edge when defining and needing FMS. This group of customers needs the ability to adapt their manufacturing processes.

Typically, this group supports a variety of products and customers. The livelihood and success are dependent on how quickly and efficiently they can adapt to the work available with the market. Every market sector has an up and down cycle. If one market sector is down, the speed at which the manufacturer can adapt to the growing market sector can mean the difference between growing the business and going out of business."

Connect With Us