Mention automation and most people think high-volume production environments in which millions of parts are pumped out on a regular basis. While that may be true in many instances, it is definitely not the case at Choice Precision Inc. (Whitehall, PA). In fact, the situation is quite the opposite. Choice’s lot sizes usually run only 20–50 pieces. At any one time, there can be upwards of 1000 different open jobs in various stages from engineering to packaging—a typical job-shop environment.
At Choice, production volumes do not dictate the use of automation. Instead, the shop automates for production flexibility and to boost the output of its advanced machine tool technology and its highly skilled machinists, as well as to reduce cost per part. Automation also plays a critical role in achieving shorter job turnaround times and streamlining workflow through the shop.
In business since 1992, Choice grew from a small garage-type shop to one that now employs 46 people and specializes in serving the automation market. The shop manufactures complex components for industrial and factory automation systems used in such industries as paper processing, automotive, product packaging and biotech. Choice’s components can be found on overhead robots, gantry loaders, pick-and-place robots, end-of-arm tooling for robots or within production assembly lines.
For a supplier of automation components, Choice’s incorporation of automation into its own manufacturing operations seemed a natural progression. And the shop did so, as early as 1998 with the installation of two Palletech Manufacturing Systems from Mazak Corp. (Florence, KY). From the time it opened its doors for business, Choice has partnered with Mazak for machines and automation. Currently, all of the shop’s 29 turning and milling machines are Mazaks. The shop’s automation includes three Mazak Palletech Manufacturing Systems, bar feeders, gantry loaders and robots.
“Our customers want us to be constantly pushing the envelope,” said Beth Rothwell, president. “Tomorrow’s successful shops will be those that constantly raise the bar in terms of ingenuity and productivity. This is why we partnered with Mazak—to stay locked in step with the company as it continues to raise its game technologically, and we raise ours. Plus, our customers continue to move forward and innovate, which, in turn, drives the type of advanced technology we need—technology that Mazak continues to develop.”
Choice incorporates all four of Mazak’s four levels of automation—bar feeders, gantry loaders, Palletech systems and articulated robots. The four levels of automation are part of Mazak’s 3-4-5 Next Level of Productivity manufacturing solution. Mazak’s 3 Levels of Control, 4 Levels of Automation and 5 Levels of Multi-Tasking allow manufacturers to identify the right level of technology, including automation, needed for improving their specific operations and advancing productivity.
Choice’s Palletech systems—two of which are paired with 320-tool capacity Mazak Tool Hives—are modular in design and can expand along with the shop’s growing demands. The two single-level Palletech systems service the shop’s lines of Horizontal Center Nexus (HCN) horizontal machining centers—two HCN 6800s in one cell and two HCN 580s in the other. The third system is a double-level 12-pallet stocker station configuration that serves a recently acquired Mazak Variaxis 730-5X II five-axis vertical machining center, and the shop plans to add another machine to that cell.
Choice Precision loads its three Palletech systems with as many different jobs as possible. This not only increases efficiency for each individual job, but also allows for continuous machine operation, which is also why the shop opted for Mazak’s large capacity Tool Hive tool storage systems to accommodate all the necessary tooling for these different jobs.
“Typically, we’ll set up each pallet of our Palletech systems with several completely different jobs,” said Greg Willet, Choice’s general manager. “So we are running about 100–150 different jobs at the same time. Plus, we’ll keep certain job fixtures on pallets because we know the customers will want more parts in a month or so.” Even for parts with multiple operations, the shop always tries to run whole jobs on one pallet using four-sided tombstone fixtures. This has significantly improved consistency in accuracy because parts are not traveling to various setups on different machines.
The bulk of the shop’s parts are made from stainless steel, Inconel, ductile iron, steel and aluminum. With small lot sizes, optimum speeds and feeds must be quickly established with the first part. Determining reasonable starting points is typically reliant on the experience of Choice’s machinists.
“Just because the shop has such advanced levels of automation as its Palletech systems doesn’t mean there is any less of a need for skilled labor,” said Beth Rothwell. “Quite the contrary, and in fact, the automated systems require machinists with even higher skill levels. As opposed to just mastering an advanced machine tool, machinists must have a thorough understanding of the automation, processes and workflow through the system to get the most out of the machine tool and the automation.”
The shop’s advanced manufacturing operations require that machinists know how to program, build fixturing to a certain extent, set up jobs, choose optimum tooling and determine part flow through automated cells, besides knowing how to machine a part.
“We do all our programming at the machines because it is much faster, especially with the Mazak Mazatrol CNC control’s interactive-style input,” said Paul Sickels, design engineer. “Our machinists do get support from the shop’s two design engineers when needed, but for the most part the machinist at the machine is the key to the success of a job.”
Each machinist is completely responsible for all workflow through a machining system. The goal of that workflow management/scheduling is keeping machine spindles running as much as possible. Jobs with long cycle time parts will run at night, while shorter cycle time jobs run during the day. Workflow is very dependent on job-lot sizes, part complexity, tooling required and other characteristics of the job. To assist in optimizing workflow, Mazak provided training on cell management of the Palletech and Mazak’s cell management software, which works in unison with existing job scheduling MRP/ERP software at the shop.
“We are a Mazak shop,” said Rothwell. “Staying with one supplier gives us consistency throughout the shop floor—consistency with our employee base in terms of training, with machine maintenance, tooling and controls/programming. By standardizing, our machinists easily run one machine one day and a different one the next day. Most important, our partnership with Mazak has resulted in us incorporating some of the industry’s most advanced technology, including five-axis multitasking and full five-axis milling, in addition to automation. We rely on Mazak to keep us at the cutting edge of manufacturing.”
For example, the shop’s recently installed a Variaxis 730-5X II five-axis machining center and an Integrex i-200S multitasking machine featuring twin spindles and gantry loader. They have significantly boosted the shop’s five-axis and done-in-one machining capabilities. The machines allow the shop to easily and efficiently process those parts with complex geometries and requiring multiple machining operations, as well as full simultaneous five-axis machining.
The Variaxis 730-5X II is equipped with Mazak’s new Mazatrol Matrix 2 CNC control with enhanced hardware and software functionalities for high accuracy, superior surface finishes and faster cycle times. A five-axis spline interpolation function included in the control’s five-axis software package provides smooth toolpaths from long block-by-block programs, easy tool-vector control and shorter cycle times.
Choice’s Integrex i-200S multitasking machine with its twin turning spindles allows the shop to productively turn, drill, tap and mill, in addition to off-centerline and full simultaneous five-axis contouring. The machine incorporates all processes from raw material input through final machining in a single setup for done-in-one machining, reducing production lead times, improving machining accuracy and lowering the shop’s operating expenses.
Choice is currently working to incorporate MTConnect for the remote monitoring and tracking of machine tool utilization. Its new Mazak machines are MTConnect capable, and the shop wants to acquire adaptors for its older models so they too can use the protocol.
“Right now we’re experimenting with MTConnect on the Integrex i-200S,” said Derek Rothwell, engineering manager at Choice Precision. “We’re just looking at general machine status simply to verify the machine is up and running. Our intent, however, is to run our machines lights-out and monitor them remotely using smart phones. This is our first level of MTConnect integration, but we see doing much more with it in the future.” ME
For more information from Mazak, go to www.mazakusa.com, or phone 859-342-1700.
Karl Brenneman is a strong-minded New Englander, owner of Cheshire-NC (Keene, NH) and a life-long machinist. Brenneman founded his job shop in 2006 and has been successful focusing on only volume production/repeat jobs versus prototyping or one-off parts. His jobs generally cover a broad range of industries including defense, aerospace, geo-monitoring, electro-optical and commercial commodity parts. Until 2011, he was the sole operator at Cheshire-NC.
A couple of years into the business, Brenneman found he couldn’t always meet delivery schedules for large orders by machining on his used pallet machine. The pallet machine required manual loading and unloading to run jobs, requiring him to tend the machine most of the day. Also, due to limits on how many parts could be mounted to each pallet, untended run times were very short—typically in the range of 20 minutes to one hour for each pallet. In a best-case scenario, with both pallets allowing one hour each, two hours of untended run time was all that could be achieved.
This challenge became critical when a customer approached Brenneman with a large, multiyear contract for an electrical component for an electrical panel used in the defense industry. The delivery requirement was 1000 pieces a month. “When machining the electrical component on the pallet machine, I was tending the machine full-time and only realizing 32–35 finished pieces per day with a monthly production of 700 pieces,” he said.
Brenneman wondered how a one-man shop could compete. With extensive expertise in manufacturing, he knew the only way to complete was to run lights-out and gain more production hours. This would increase throughput and allow him to lower his prices to become more competitive. At this same time, Cheshire-NC needed to maintain the quality of their part manufacturing. Customers require the job shop to be ISO 9001:2008-compliant, and typically meet tolerances ranging from ±0.002 to 0.0005″ (0.05–0.013 mm).
Brenneman chose Methods Machine Tools Inc. (Sudbury, MA), which provided a viable solution. The Methods’ field representative had already been calling on Cheshire NC, and proposed a pre-engineered, integrated cell solution. Called a JobShop Cell, it combines the drilling, tapping and milling capability of a fast Fanuc RoboDrill VMC with a fully interfaced Fanuc six-axis robot for automated loading/unloading. The cell is designed to meet a job shop’s need for simple installation, fast setups, quick changeovers, operator safety and production flexibility. The JobShop Cell is easily configured to handle virtually any part that will fit in its 6″ (152.5-mm) vise or chuck.
“Even though I had never operated an automated cell, I could foresee the productivity benefits of using the JobShop Cell,” said Brenneman. “For a one-person shop, the cell was a significant investment, so I carefully weighed the benefits. The deciding factor was that Methods would be a single-source provider for both the machine tool and the automation. The JobShop Cell solution didn’t require an additional system integrator to be involved.”
The JobShop Cell was installed in August 2009. The initial project done on the JobShop Cell was the on-going contract for 1000 electrical components per month. “Production was immediately increased to 60 pieces per day bringing our monthly yield to approximately 1300 pieces,” said Brenneman. “Then, as I gained experience with the JobShop Cell and untended operations, monthly production improved to about 1500 parts.” Having excess capacity on this job enabled Brenneman to run additional work on the JobShop Cell, further increasing productivity.
“Because I was now able to run jobs 16 hours a day versus nine, without adding new labor, I saved an average of 40% across the board. Due to the speed of the RoboDrill, we were able to reduce cycle times somewhat, but the home run came with the additional untended run time,” Brenneman said.
When some parts required more complex features and a multiaxis design, Karl confronted his next challenge. He recognized the need for an automated machining solution for indexing parts.
“The JobShop Cell solution is excellent for general-purpose parts. It does an extraordinary job of picking up square blocks and putting them in vises,” Brenneman said. When requirements demanded machine tool indexing, Methods recommended its Med Cell solution. Like the JobShop Cell, the RoboDrill Med Cell is a complete pre-engineered, fully integrated production machining cell which automates loading and unloading of parts. At the core of the cell is the Fanuc RoboDrill Machining Center providing full five-axis machining capability as well as 3+2 positioning.
Although Cheshire-NC was not making medical parts per se, the complexity of the parts being produced and the indexing requirements made Med Cell an ideal solution for his applications. The Med Cell was acquired in the summer of 2011, doubling production.
For example, when producing a geo-monitoring part job that requires 3200 pieces every three months, it was taking five working days with nine hours per day of attended operations to run the job for a total of 45 hours on the previous machine setup. When the job was moved to the JobShop Cell, labor costs were saved because operations only needed tending every 2.5 hours over four-and-a-half days. Finally, the job was moved to the Med Cell, reducing job run-time to two-and-a-half days and only needing to tend the machine every six hours.
“We have cut our cost in half on this one job. By running 24/7, we can now do a week’s billing for this job in just two-and-a-half days,” said Brenneman.
In another example, when producing aerospace parts made of 347 stainless steel, it was taking three days to run this job on the pallet system, plus one more day to deburr the parts by hand. Manual deburring was an enormous challenge due to very tight tolerance requirements to hold a 0.002–0.005″ (0.05–0.13 mm) edge break on six precision +0.001/-0.0 thru holes on both sides. Cheshire-NC was typically running 300–400 pieces at a time on the prior machine.
The stainless job was moved to the Med Cell, which now runs 600–700 parts at a time with all of the deburring happening on the RoboDrill. The RoboDrill is able to deburr the entire part because the part can be flipped over to present all sides to the machine spindle. “With the machine doing all the deburring work, the result is much more uniform and consistent than doing this by hand.” The Med Cell is also equipped with a Renishaw spindle probe, which is used to find part-thickness variations, and make machine adjustments in order to hold the edge break.
“I have been able to win back and keep work in the US that may otherwise have gone overseas—this is extremely important to me. I think it shows that small machine shops can compete and survive by embracing technology and using it to level the playing field with overseas competitors. And for nearly five years, I was completely on my own,” said Brenneman, who hired his first employee, a machine tool operator, in late 2011 to assist with machine setup and operation.
Being able to leave the shop untended with the cells running jobs has been further aided by the ability to remotely monitor operations with software called Asset Monitor by Langlais Computer Consultants (Bristol, CT) which runs on smart devices—another recommendation by Methods.
Others have taken notice of the success of Cheshire-NC. As of this writing, Cheshire-NC is completing its sale to a larger turning shop named Swiss Precision Turning in Brattleboro, Vermont, which also runs lights-out operations. Swiss Precision Turning wants to expand its capabilities and product offerings by adding in-house CNC milling to its CNC Swiss turning and CNC lathe operations. ME
For more information from Methods Machine Tools Inc., go to www.methodsmachine.com, or phone 978-443-5388.
This article was first published in the July 2013 edition of Manufacturing Engineering magazine.
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