Video of gantry-loaded lathe
There are many reasons why job shops are now considering automation. For some, increased pressure from low-cost regions is forcing them to reduce their direct-labor costs. For others, a lack of skilled labor encourages the use of robots to load and unload machines. It may be that the reasons to automate are not related to labor at all. A quality problem, for example, may make the inherent repeatability of robotics attractive. Whether starting from scratch or transitioning from traditional manufacturing, many shops can benefit from automation. However, misconceptions about exactly how to do so remain widespread.
Many shop owners prefer to take a safe, incremental approach to implementing automation. They believe it’s better to purchase a system that is right for a family of parts, and perfect these parts in the cell one at a time. This approach allows shops to test the automation concept and perfect issues such as part placement, presentation and programming before going to production. Automation technique can be developed and refined, and the cell’s capabilities can be determined before the shop depends on it to contribute to the revenue stream.
C.N.C. Machine Products chose the road less traveled and took an across-the-board approach to automation. The shop depended upon automated processing of parts from the start, even though it realized it faced a steep learning curve and problems would need to be resolved quickly.
The shop, led by Greg Scheurich, president, makes inner and outer bearing races for customers in virtually every industry worldwide. The recent installation of a pair of twin-spindle, robot-loaded lathes from Fuji Machine America (Vernon Hills, Illinois) is helping the company reach its lean manufacturing goals by being competitive with foreign manufacturers. It also completes another round of the shop’s automation commitment.
IN BUSINESS, AUTOMATICALLYMr. Scheurich’s primary business was a tool distributorship that bought and sold tools throughout the region. As he made his rounds though the local shops, he found that people would ask him to recommend shops he felt were qualified to machine various types of parts. As the middleman, Mr. Scheurich would put customers in contact with vendors. One day, a major bearing supplier in the region suggested that Mr. Scheurich purchase some machines and start running bearing races himself. So it is through the tool distributor relationships that C.N.C. Machine Products was born in 1988
The Joplin, Missouri shop started out just with a pair of single-spindle automatic lathes. An original machine list hangs on the shop’s conference room wall as a reminder of the original justification to buy the first two CNC chucker machines.
From the beginning, Mr. Scheurich felt it was evident that he had to find an automated stragegy to work. “As this was a second business, we really didn’t want it to distract from our primary business,” he explains. “The process had to be good enough to run automatically.” Since 1988, the company has experienced several expansions. Mr. Scheurich’s first shop was only 5,000 square feet. The second building was approximately 10,000 square feet. The third one is now more than 50,000 square feet.
From 1988 to 2000, the business grew very quickly and experienced many growing pains. In 2000, the company adopted policies that helped to control growth and make it more predictable. Mr. Scheurich admits that early on he wasn’t prepared for some of the challenges of automation and had to deal with some misconceptions. Here are three:
Misconception 1—Automation is too expensive. C.N.C. Machine Products was in business for just a couple of years when it purchased its first robotic cell. Mr. Scheurich recalls a salesman that had been calling on him for some time offering a horizontally opposed, double-spindle lathe with a gantry-style robot to load and unload parts. At a time when a single-spindle CNC lathe could be purchased for approximately $80,000, paying $320,000 for the automated lathe seemed out of reach. (It would be four times the price for only twice the spindles.) That salesman happened to be at the shop when a potential customer called, and Mr. Scheurich allowed the salesman to quote the part based on the quantity involved. It was determined that the price was competitive and the machine could be paid for in five years.
Mr. Scheurich admits that he really didn’t think the shop would run the machine long enough to pay for it because there were many things that could have gone wrong. “Aside from what the spreadsheet said, my gut told me otherwise,” he notes. In fact, the reality for Mr. Scheurich was that the machine was paid for much more quickly than five years. In addition, after the first machine was installed and running, a second machine was installed within months of the first. While the automated machines were more expensive than non-automated ones in initial cost, the benefits in gained capacity and increased productivity brought greater profits and greater throughput in the long run.
Misconception 2—Automation causes workers to lose jobs. Some shops turn to automation to reduce the direct labor portion of part cost. While robot use does help reduce direct labor, C.N.C. Machine Products turned to automation primarily to increase capacity. “Robotic automation on our lathes has not caused layoffs,” Mr. Scheurich says. “At one time we had more people than we could fully use, but demand quickly caught up.” Automation at the shop means its operators have more time to gage parts, keep inserts sharp and ensure that the machines are maintained.
Gary Hoofnagle, the shop’s vice president and manufacturing manager, believes that while automation has enabled the shop to grow, that growth couldn’t have happened without dedicated people. Mr. Hoofnagle feels that automation helps people, and people help automation. He believes people are more adroit than machines at adapting to varying conditions, while machines are more appropriate than people for repetitive tasks. He says that when the two are married together properly, the result is successful, efficient automation.
Misconception 3—Automation is only appropriate for high volumes. C.N.C. Machine Products purchased its first automated machines for a couple of contracts from a stable supplier totaling 250,000 bearing races annually. However, years of experience with automation has made the company profitable with high-mix, low-volume orders that number only about 5,000 parts per year. From then to now, nothing has changed when justifying new machinery, except that Mr. Scheurich is willing to trade high volumes from a single part number for a family of parts with less volume. Improvements made in the use of automation allow him to accept orders with a three-year contract and volumes between 5,000 and 100,000 and still remain profitable.
Although some shops try to hold on to machines because they are paid off, C.N.C. Machine Products has a different approach. From the beginning, Mr. Scheurich planned to use the machines for only five years. Today, he can extend the period to seven or eight years because developments in mechanical and electrical design have improved machine reliability. The company replaces old models with new ones periodically to maximize the residual value of the machines and to maintain accuracy. This also provides an opportunity to routinely review the process and keep personnel involved with current technology. At this shop, developing the people side of the equation is a critical step to making automation flexible and profitable.
THE BENEFITSOne way this shop has benefitted by embracing automation from the get-go is an across-the-board improvement in productivity. Mr. Hoofnagle estimates that a pair of single-spindle lathes without automation tended by one operator had 50 to 65 percent spindle utilization, depending on the operator. On the other hand, having an arrangement of two automated machines (four spindles) offers spindle utilization ranging from 80 to 90 percent.
In this case, the machines pace the operator, not the other way around. The robot loads slugs or rings from the workstocker into the lathe’s chuck. When processing completes, the robot takes the finished part from the chuck and drops it onto a small conveyor at the other end of the machine. The line of parts that forms keeps finished parts in order. This can be useful when perfecting process changes and acts as a queue for the operator, allowing every part to be checked before being sent to the heat-treatment department. The operators take pride in having the loading tables full and the unloading ramps empty. This is something that Mr. Hoofnagle says he’s noticed where the gantry-loaded lathes are used.
One thing that Mr. Scheurich does to help keep stock shortages from disrupting work scheduling is to keep an ample supply of stock on-site. This practice may be discouraged by some who label it as extra inventory. However, Mr. Scheurich treats the stock like a business of its own. He buys when opportunities arise and sells to himself and others when there’s a need. This has helped keep lines running when shortages of material would mean shutdowns.
In addition to increasing productivity at the work center, another benefit of having well-engineered automation is that it will increase capacity. When automated processes become more natural and dependable, the amount of time that the machine can run unattended at the end of the shift increases. Adding other machines to the cell spreads direct and indirect labor over more parts, and costs begin to drop. The best automated job shops don’t see 40 or even 80 hours in a work week. They see 168 possible hours (not for the operator, just for the machines). Trusting the machines to always do the right thing is the first step in attaining this level of performance.
Automation also has an interesting side benefit: improved quality metrics. Because the machines do exactly the same thing every time, process flaws surface quickly. Machines won’t do little things that human operators do unconsciously to help mitigate these conditions unless they are designed to do that. For example, thought must be put into getting chips to break every time. Chip bird-nesting is something that human-loaded machine cells don’t try too hard to eliminate. It is viewed as unstoppable and the operator will clean the tool when loading the part anyway, so why bother? In automated cells, however, keen forethought must take into account chip formation and evacuation. The Fuji TNW-3500R machines that C.N.C. Machine Products recently installed take an innovative approach to this situation. The machines use a combination of through-the-spindle coolant and programmed air blasts to wash the parts and flush the chucks. They also use flip stations to turn the parts several times from one operation to another. This causes any remaining chips to fall from the parts during the flip. Machines that have the spindles that meet to exchange the part typically do not have this capability.