When people and their companies unite behind a common goal amazing things can happen. This is true in any realm of human endeavor, not the least of which is manufacturing. We’re often faced with complex machining challenges, time-intensive processes and relentless economic realities that require us to drive down part and product costs. And with the right partners, we can achieve exceptional results.
Consider Machining Manager Steve Sander, for example. Steve’s company, Nilpeter, manufactures and markets flexographic printing presses to companies that produce labels for a variety of applications. Nilpeter began making printing presses in 1919 in Copenhagen, Denmark. Today they are a worldwide manufacturer of narrow web presses for specialized applications. Through an acquisition in 2001, Nilpeter established its manufacturing and marketing presence in North America.
In the company’s 65,000 square foot, Cincinnati, Ohio facility, Nilpeter makes six models of flexographic presses that include a number of high-precision machined parts. One such family of parts is a series of impression cylinders that are critical components of each press. A typical Nilpeter flexographic press has eight impression rollers. Each roller must be precisely machined to final diameter tolerances of +/- 0.00005” in order to evenly apply images to the label material. Each roller in this family of parts has slightly different diameter dimensions, ranging from 2.2621” through 2.2618” Steve’s challenge was to reduce production time for these and other press components.
The manufacturing process for each roller included a series of seven steps:
- The 1215 stainless steel bar stock was cut to length
- The stock was then blanked
- The blank was faced on a manual lathe
- The part was sent out for gun drilling
- Upon return to Nilpeter, the part was turned on a CNC lathe
- Following turning, the part was sent out for pre-grinding and chroming
- The part returned to Nilpeter for finish grinding
The internal manufacturing time for this process was 4.5 operator hours per impression roller. Additionally, production schedules had to allow for the parts to be sent out for gun drilling and returned for further operations. Obviously, some form of automation could help reduce the part production time, but Steve wanted a solution that could also help his overall machining requirements. So he went looking for expert advice.
Among those he consulted was Dayton, Ohio based Gosiger, Inc. Gosiger sales and applications specialist, Dave Marsh,
recommended a 7-axis, twin spindle CNC machining center for its speed, accuracy and versatility. According to Marsh, “Considering the various processes that the Nilpeter parts went through, this was an easy decision. The twin turrets let them precisely turn both ends of the part at the same time as well as mill and drill in the other axes.”
Clearly, the CNC machine tool would handle a number of machining functions and eliminate the need to send the impression rollers out for gun drilling. But taking full advantage of the machine’s capabilities to maximize productivity required the addition of a precision bar loading system. According to Sander, the obvious choice was the LNS Sprint S3 automatic magazine barfeeder because it has a patented hydrostatic, self-opening bearing block design for smooth, continuous bar loading and bar support. “These impression rollers are held to strict tolerances, so it’s important that the barfeeder supports the bar stock to reduce vibration and let the machine spindle operate at Maximum RPM. The Sprint S3 also eliminates the need to cut up 12’ bar stock and it continuously feeds the lathe, so there’s no lost time between operations.”
Sander also notes LNS’ reputation for reliability and support as reasons to agree with Gosiger’s barfeeder recommendation. However, there was one more important factor that made the marriage of the turning machine and the LNS barfeeder attractive. LNS has the capability to interface their e-Connect Ethernet communications system with the lathe’s PLC so that the barfeeder and machine tool can exchange critical data with one another. This would make changeovers within the impression roller parts family quick and easy. As a bonus, LNS provided the BlazeAir vacuum unloading system, an ideal complement to the proposed manufacturing cell, which also links to the lathe’s control and the LNS e-Connect system.
One of the unique features of this cell is the Part Library function of the LNS e-connect system that enables Nilpeter to run other parts, including a family of idlers, on the same cell along with the impression rollers. Nilpeter currently runs 40 parts on this cell, using e-Connect to “talk” with the lathe’s production scheduling program and controller to maximize productivity and materials usage. LNS developed the Part Library to allow storage of the individual part configuration data the barfeeder needs to make a specific part. Through the e-Connect system, the barfeeder automatically detects the part program currently in use by the lathe and loads the correct setup data for that part from the Part Library. In this way the barfeeder changeover is accomplished on the fly, thus eliminating downtime.
Cell operator Bob Silcott quickly mastered the menu-driven control interface that enables him to begin his shift by loading the day’s production schedule. After entering the schedule, Bob sees that the LNS Sprint S3 bar feeder magazine is loaded with the appropriate bar stock. The cell typically runs 60 impression rollers each week from 2 ¾”, 1215 cold finished bars and 600 idler shafts from ¾” stock.
After each part is machined, the production scheduling program checks the remaining parts to be produced and determines if there is adequate bar stock available for the next scheduled part to be made. If not, the system scans the production list for another part that could be made from the remaining material. Because Nilpeter assigns priorities to each part in the schedule, the system identifies the highest priority part that can be machined from the remaining bar stock. The production scheduling program then loads the appropriate part program to the lathe. Once the new part program is loaded, the barfeeder recognizes the change, recalls the associated part data from the Part Library, and automatically changes over to feed the new part. Further, the system checks the part program to determine if the new part requires a change in bar stock diameter or profile. If so, the system sends out an alert that some mechanical adjustment may need to be made.
If the system determines that there is no part in the schedule that can be made from the remaining stock, the remnant is ejected and the next bar loads into the barfeeder, the system confirms the next part to be made and makes any adjustments necessary. All of these communications between the LNS barfeeder, the turning machine, the LNS BlazeAir vacuum unloader, and the production scheduling program are virtually instantaneous and require no operator assistance.
Sander adds, “We really pushed the envelope on the Ethernet system, asking it to do things that had never been done before, and LNS and Gosiger worked together to create new software and tweak it until it does everything we asked for – and then some. We can set up the part production schedule and monitor the entire cell remotely, and even have the ability to receive alerts on our personal computers. It took some time to get it there, but we were patient because we knew we were asking a lot and I’m pleased that all of us stuck with it.”As a result, the time and cost savings for Nilpeter are significant. According to Steve Sander, machining of the impression roller that once consumed 4.5 man-hours now takes less than 30 minutes to complete. “None of this would have been possible without the cooperation of the three suppliers involved.” Sander reports. “Gosiger and LNS are both great to work with because they take the time to listen to what you want to accomplish and then make it happen. What really pulls it all together, of course, is the LNS e-Connect System working with the lathe’s PLC, the LNS Sprint bar loader, and the LNS BlazeAir unloader. This combination gives us the productivity we need and also saves on material costs. Plus, we’re not even close to utilizing the cell’s capacity, so we’re looking at other parts we can add to the production schedule.”
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