Shop Solutions: Shaft Producer Cuts Cycle Times 25%
Shop Solutions is edited by Senior Editor Jim Lorincz
Laitram Machine Shop Inc. (New Orleans, LA) is a producer of machined components for Intralox, a major developer and manufacturer of industrial conveyor systems and for Laitram Machinery, a manufacturer of automated shrimp-processing equipment, both are subsidiaries of the Laitram Corp. Like many contract shops, Laitram Machine Shop produces a large variety of production and prototype parts for internal and selected external customers.
The challenge is always to produce parts in the shortest possible time to the highest standards while reducing the cost to machine the parts. The shop’s lot sizes range from 1 to 10,000 pieces, all highly engineered, many of them having complex features, machined to tight tolerances, some as small as 0.0002" (0.005 mm).
One of Laitram Machine Shop’s recent challenges was how to improve the manufacturing of drive and idle shafts for conveyor systems. The shop determined it needed to eliminate secondary operations and machine shafts complete in a single setup. After evaluating a number of machine builders, Laitram Machine Shop selected the production turning machines and turnkey support provided by EMCO Maier (Columbus, OH). So far, their choice has been right on the money.
To machine conveyor shafts, Laitram acquired an EMCO HyperTurn 690, a turnkey solution that allows Laitram to precisely machine shafts complete in a single setup. The HT 690 is equipped with dual spindles, a 12-position lower turret with live tooling capable of holding 24 tools, and a 28.8-hp (21.5-kW) B-axis PowerMill attachment that has Y axis and a 48-tool carousel.
“We use the HT 690 to turn a family of square shafts for conveyor systems. These shafts have journals turned on each end, some get intermediate journals, multiple retainer ring grooves, keyways, drilled and tapped holes, and a sales order number gets engraved in every shaft,” explains Erick Jackson, machinist.
“Previously, we turned one end journal and machined whatever retainer ring and intermediate journals we could reach. Then we would flip the shaft around and machine the other end journal and machine the remaining retaining ring grooves and intermediate journals. If the shaft required a keyway, offset drilled and tapped holes, or we couldn’t reach the intermediate journals, we had to move it to another machine to perform those operations. We now turn the shafts complete in one setup,” Jackson says.
“Depending on the size and length of the shaft, the cycle time now is about 20 min complete for a 30" [762-mm] long, 1.5" [38-mm] diameter shaft. Previously, just the time to turn the shaft was roughly 20 min, with total time for secondary operations at other machines adding up to as much as 40 more min. Typically, we’ve seen a 25% time savings per shaft compared to the previous process,” says Jackson.
The ability to quickly alter the program and the flexibility and capability of the machine have been a big advantage to the shop, which now produces between 3000 to 4000 shafts annually. Every shaft has the potential to be different with different material, diameters, lengths, and features to be machined. “Because all the tooling resides in the machine and the shafts come out complete, very little time is lost going from one shaft to another. “We’d like to always run shafts on the HT 690 but due to the flexibility and capability of the machine we find ourselves scheduling more parts to the machine due to the efficiencies we get every time we run something there. It’s a very versatile machine,” explains Tim Thielman, a machine shop supervisor.
“One of the main reasons for us buying EMCO was their application support. Not every machine vendor offers the turnkey support that EMCO does. And we looked at many different pieces of equipment,” Thielman says. In addition to the machine purchase, Laitram asked EMCO Maier to help them optimize their production process with the new machine. The process developed for the HT 690 involves pinch turning, which is the simultaneous turning of the part using the turret below the part and the PowerMill above to turn the part. The PowerMill is also used to drill, tap mill the features in shafts too.
“One key advantage of the HT 690 is it improves our ability to respond quickly to customers’ requests. All the shafts are made to customer order. We don’t inventory any shafts and with as little as a 4-hr delivery time, the ability to run these shafts complete in a single setup allows us to meet our customers’ needs,” says Thielman.
“The challenge is always to produce parts in the shortest possible time to the highest standards
while reducing the cost per part.”
Nearly every part that has moved from an older process to one utilizing Emco’s machine features has shown an average 25% time savings. Parts come off complete and no longer need to be run in batches before deliveries can be made. Additional setups and temporary storage of parts awaiting a second operation on parts that run across the Emco’s are no longer necessary at Laitram and workpiece precision is greatly improved. Total production time, fixture and personnel costs have been cut in half.
“One of the main reasons we were able to reach our goal of process improvement is Ed Marr, our EMCO applications engineer. His knowledge of the Siemens’ control and capabilities of the HT690 allowed him to develop a process specifically designed to make us more efficient machining conveyor shafts,” Thielman explains. The Siemens’ program storage is larger than other controls, the editing features are 10 times faster, the response on the machine is faster than other controls, and there is greater versatility in programming on the control.
All linear movements take place on preloaded precision roller slides. This results in significant advantages concerning feed rates, zero backlash, service life, lubricant consumption, and positioning accuracy. The tailstock version of the HyperTurn is well-suited for mass machining shaft parts. The tailstock is completely NC-controlled and can be positioned using a recalculating ball spindle. This enables the movement interpolating with other axes, saving machining time. ME
For more information on Emco Maier Corp., go to www.emcomaier-usa.com, or telephone 614-771-5991.
Multispindle CNC Business Strategy
C&A Tool (Churubusco, IN) has elevated precision-part production to a fine art. Its 750,000 ft² (69,677-m²) manufacturing floor is filled with some of the most technically advanced machine tools available. The main plant of 200,000 ft² (18,580 m²) is organized into eight individual pods, dedicated to different operations, including grinding, turning, milling, direct-metal laser sintering and more. C&A has evolved from a small mold shop to prototype, contract manufacturing, and high-volume production work. Today, it specializes in producing very difficult, high-production, complex parts with ID and OD grinding and turning as its specialties. In addition, it produces its own tools, fixtures, and many of its gages.
C&A, which started out with one person, President Dick Conrow, in a small garage, today has more than 525 employees and ten buildings. One of the newest machines at C&A is an MS22C multispindle CNC from Index Corp. (Noblesville, IN). Purchase of the machine was a strategic decision based on the company’s experience with other Index multispindles at C&A. The company saw the need for the flexible machine because of work in high-volume precision fuel system components for diesel engines.
“We set our people up to succeed with the equipment we buy, our plant layout, our tool management, our metrology capability [scanning CMMs, surface and roundness measuring devices] and more,” explains Rob Marr, an owner of the company. “Our philosophy has been to align ourselves with the leading machine-tool builders, including Index, Star, Voumard, Kellenberger, and Mori Seiki. Index has done a good job supporting us over the years. We’ve gotten to know the machines and controls and how to employ the Index machines to position ourselves for the next opportunity.”
When asked how the company justifies the equipment it buys, Marr explains: “We have never formally justified a piece of equipment. We buy the equipment and put it in place before we have a need for it. We’re putting ourselves in position to do the business we are confident we can get—moving to the next level. It’s not excess capacity to us; it’s putting ourselves in position to handle increases in customer needs,” Marr says. C&A’s level of investment per employee is about double the norm in the contract manufacturing industry.
“The metrology capability drives our business, because we can develop the process, prove it out, and provide documentation. Customers like the idea that we can use metrology to develop manufacturability of the parts to drive the part cost down. We operate in five major disciplines: tool making and prototyping, higher volume automotive parts, medical group, aerospace group, and a fuel systems group, which is where the MS machines are valuable,” Marr explains. The multispindle machines are assigned to produce many different high-precision parts in mid to high volumes.
“We do a lot of low-volume activity at C&A also, and we are able to match our production to the equipment we have. Part complexity and volumes drive parts to the multispindles, which complement C&A’s overall machining capacity. They have helped C&A move into new market areas and expand existing customers,” Marr says.
“The multispindle turning machines we added over the years are a natural extension of our production capacity. Today, it is critical to automotive and fuel systems production, which is high-volume work, anywhere from 6000-part lots up to 2 million,” explains Gary Sroufe, who heads up the multispindle area.
C&A owns nine Index multispindles, all neatly arranged in an area of about 20,000 ft² (1858 m²). Throughout the 1990s, C&A purchased seven Index MS36E multispindles and then more recently purchased an Index MS32B, and now the MS22C, both of which are full CNC.
The MS22 at C&A is key to producing a certain range of precision parts less than 22-mm diameter with multiple operations. “Manufacturing people like our one-stop approach, because it allows us to develop and learn the part and process, then produce the parts in required volumes. We learn how the material cuts, how the process is optimized. If it’s a part that is difficult to produce, it’s a C&A Tool part.” Marr says.
One of these parts is now running on the MS22. A fuel systems component C&A had developed from prototype was difficult to produce in the required volumes due to complexity, tolerances, and material—precisely those challenges made it well-suited for the Index multispindle. With its MS22, Sroufe and his crew, including operator Eric Scott, were able to complete the steel part—all nine operations—in an 11-sec cycle time. “This is 15–20% faster than we had been able to do it on the older multispindles, and much faster than is possible on conventional turning centers,” Sroufe says.
“The MS22 is much quicker, and provides more options, , resulting in a better process and faster cycle times. The Siemens controls are fantastic, and the machine allows us to pull together combinations of operations that had previously been done on several machines. The quick-change, pre-settable tooling provides additional setup and changeover time savings. In fact, the machine is so successful, we need to find other work for it. It’s a good problem to have,” Sroufe says.
“The multispindle turning machines we added over the years are a natural extension of our production capacity.”
“For C&A, key capabilities of the MS22 are the ability to utilize the tool slides as either cross or end working slides, and arrange them where you want or need to, at each of the six spindles. Having 12 tool slides allows us to distribute the process evenly among multiple tools. This reduces tool wear and cycle time, while doubling uptime due to fewer tool changes. The tool mounting and pre-settable tools also give us the ability to hold tighter tolerances, in a highly capable process,” Sroufe says.
“We like that it permits complete machining of precision parts with different features in one single-step operation—precisely the type of capability, that precision parts manufacturers such as C&A must have in order to remain globally competitive,” Marr says.
“We want to have the equipment in place to do the jobs we can get and to constantly improve our capabilities. It is not about sticking to core
competencies, it is a strategy of improving and gaining new capability, and Index certainly has helped us to do that successfully,” Marr concludes. ME
For more information on Index Corp., go to www.indextraub.com, or telephone 317-770-6300.
Partnering on Tough Jobs for Subcontracting Success
The team at Centerline Machine (Waupaca, WI) doesn’t shrink from a challenge. In fact, the company has made a name for itself by taking on the tough jobs from start to finish—those that other shops have failed at. Since Centerline began in 1996, owner Charles Leiby has understood the importance of partnership and the need for solid, ongoing investment in the latest technology.
From humble beginnings in Leiby’s garage, Centerline has grown to a 45,000-ft² (4180-m²), state-of-the-art facility with six HMCs, nine VMCs, six turning centers, a five-axis machining center, a press brake, two waterjets, a laser and several other specialty machines for fabrication, inspection, and portable welding and boring. Two 5-t cranes hover overhead to assist with part and material transfer.
“Our diversity allows us to take a part from start to finish under one roof,” says Leiby. “And from rapid part-prototyping and small-run production to high-volume orders, we have it covered.” The company’s customer base is as diverse as its machining and fabrication capabilities. From food to automotive, Centerline has done it all, but the job that put them on the map was, perhaps, the most daunting of all. In late 2008, Centerline secured an exciting, yet difficult, opportunity from a government contractor. The job required an accelerated prototype turnaround for a confidential high-profile project. Should the prototype be a success, it could mean a profitable production contract for Centerline, adding financial stability during difficult economic times.
With a December kickoff, Centerline was tasked with delivering several parts for testing in just two months over the holiday season, no less.
“Our customer needed to reduce weight in the product it manufactured, and using aluminum for the part we were making was one way to do this,” says Centerline GM Kip Lussenden. “At this point, they still needed to test the feasibility of the part.”
Centerline staff sprang into action, but very quickly realized that to meet the tight timeline and keep the cycle time down, they needed some extra support from their tooling partner, Sandvik Coromant (Fair Lawn, NJ). “We had been working with Sandvik for about a year and a half before this prototyping job came in,” says Leiby. “It was an exciting challenge for them, and they stepped up to the plate to help us revamp our tooling and machining processes to get the job done in time.”
“There was no single issue when it came to this particular job,” says, Tim Trzebiatowski, Sandvik Coromant productivity engineer. “There were several challenges that we hoped to overcome through optimizing all of the tooling and machining processes.” For this reason, the team’s first course of action was to launch a Productivity Improvement Program (PIP) to assess and optimize all of the current processes that the job would entail.
“While no two PIPs are alike, we use a step-by-step method to streamline process optimization as much as possible,” says Trzebiatowski. “Basically we identify bottlenecks, potential tooling optimizations and logistical issues and help carry out operation improvements.” Soon after the job began, it became a group effort on the part of Centerline, Sandvik Coromant, and Mazak, the shop’s main machine-tool supplier. “Our Original Tooling Systems [OTS] group worked with Mazak to develop solutions that would work with its machines, for this specific job,” says Trzebiatowski. “We worked in Mazak’s application center to test new tooling and machining processes. For Centerline, this was a really valuable collaboration.”
During the initial prototyping and PIP process, the large size and complex shape of the part created some obstacles. “The amount of material we had to begin with for each part was staggering,” says Trzebiatowski. “As a result, one of the number one goals was to find a way to accomplish faster metal removal during machining so we could keep cycle time down.”
The complex shape of the part also required some creative thinking on the part of Sandvik Coromant. The processes Centerline used may have gotten the job done, but not nearly in the time required. To resolve the issues, Sandvik Coromant replaced certain tools with Capto tooling. “Capto has the long reach we needed for the job,” says Trzebiatowski. “We also replaced the plunging operations by cutting with a 2" [51-mm] 790 router. The advantage of this is that we could achieve more in the roughing process and remove material much faster.”
“There were several challenges that we hoped to overcome through optimizing all of the tooling and machining processes.”
“The ramp-up period was challenging. We were working around the clock, with limited staff and limited equipment, but still managed to deliver the first prototypes more than two weeks in advance of our deadline,” says Lussenden. “Then, things began to fall into place, and we got word that production for the part was a go.”
While Centerline didn’t have a contract yet, a quick ramp-up was imperative to meet the impending production timeline. “We still needed to get more equipment and staff to meet the production demands,” says Leiby. “We hired about 14 people and worked with Sandvik to tool up three new Mazak Nexus 6800 HMCs, which we would use to produce the part for the better part of the year, around the clock.”
Growth this rapid and initially based on just a single job was nerve-racking, Lussenden and Leiby admit. “It was a question of what we might do with the capacity after the job,” says Lussenden. “But this was the opportunity of a lifetime, and we couldn’t pass it up.”
In June 2009, Centerline got the contract, and full-fledged production began. At peak production, the shop was processing 20,000 lb (9072 kg) of aluminum per day and spending more on aluminum in one month than the company had brought in the previous year. Sales soared 600%.
“This was a much higher volume than we had ever had before, so we really had to align ourselves with our material suppliers and hammer out all of the details. It has been an exercise in relationship-building and the whole growth process has enhanced the fundamental nature of our organization,” Lussenden remembers.
When the dust settled, Centerline had produced several thousand parts without missing a single delivery deadline. “We played a major role in that piece of the customer’s business,” says Leiby. “To get the project done in that amount of time was unheard of.”
To fill the extra capacity it acquired from the job, Centerline took preemptive efforts to sustain the growth. “We added staff to support the sales and marketing side of the business so we could help bridge the gap after that job ended,” says Lussenden. Now, he says, business is booming and the HMCs they purchased for the job are some of the busiest in the facility.
While it may seem that Centerline is on top of its game, Leiby isn’t one to rest on his laurels. “We look at it this way: The subcontractor job opened the door to all of the other work we do in terms of how Sandvik can help us optimize,” he says. “There is always room for improvement somewhere, and you have to continue to evolve to stay ahead.” ME
For more information from Sandvik Coromant, go to www.sandvik.coromant.com/us, or telephone 201-794-5000.
This article was first published in the February 2012 edition of Manufacturing Engineering magazine. Click here for PDF.