|Venturing into production work, NaviTek Machining discovered it was well worth it to spend the extra money on tooling if it increases productivity, such as this $400 drill (above) that drastically reduced cycle times for hydraulic components (below) done on the shop’s Makino a51.|
Many of today’s high-volume production shops have geared up to take on more low-volume, close-tolerance, precision-machining jobs that are less likely to be lost to overseas suppliers.
However, one successful precision tool & die shop that doesn’t have a shortage of skilled labor did just the opposite.
NaviTek Machining went outside its comfort zone and into the uncertain world of production machining, and it found that taking the risk was worth it.
Production work now generates 60 percent of the shop’s revenue, and its sales are up 45 percent over last year. And, the shop is better meeting the needs of its customers, who now come from the medical, aerospace, energy and fluid power industries.
NaviTek Machining has always done tool & die work and will continue to do so.
However, that type of work is never really steady. So, to fill in the gaps, NaviTek Machining pursues production-machining jobs, some of which involve 10 pieces, and some of which are for orders of more than 5,000 pieces, with part sizes that range from extremely small to larger ones that weigh as much as 20 lb.
Within NaviTek Machining, there is now a production group and a tool & die group, but just splitting the shop was not enough. Taking on production work required a change in mindset on how the shop approached jobs, how it dealt with part tolerances and in the machine tools it used. “
For one, the cost of tooling for production is no where near as important as it is for tool & die work. What is important are productivity rates,” Pete Gorny, president of NaviTek Machining, said.
To illustrate his point, Gorny cited an actual production job for which the shop spent $400 for a drill. That drill saved $12.00 per part. However, that purchase wouldn’t make sense for a 3-piece or 4-piece tool & die job because it would take forever to recoup the cost of the drill, Gorny said.
The part was a hydraulic manifold, and Tom Kelley, production team leader and journeyman toolmaker at NaviTek Machining, said the job is a perfect example of the shop’s new “production work” way of thinking.
|Production job lot sizes at NaviTek Machining, can run well over 5,000 pieces.|
|Manual equipment in NaviTek Machining’s precision tool & die area wasn’t the best match for production work, so the shop added some CNC equipment, such as this Daewoo Puma 240 MS turning center. |
“When we first started running the manifolds, one part took an hour to complete. Then, as we progressed more and more into production work, we looked at different tooling options and found the drill that helped reduce part run time down to 15 min,” Kelley said.
Prior to implementing the drill, the shop had to send the parts out to have the 0.375-in.-diameter, 9-in.-deep holes gundrilled. That work accounted for the $12.00 cost per part. Also, shipping the parts back and forth wasted valuable production time, and on top of that, the parts had to be finished when they returned to the NaviTek Machining facility.
But a tooling change is not the only hero in this story. The shop would not have been able to use the drill to full potential if it had not added a machine with the accuracy, speed and feed capability required to do the job.
The machine was a Makino a51 horizontal machining center. And, with the new tooling, it further reduced manifold run time to 7 min.
“We had some CNC equipment – three Hurco vertical machining centers, an older Mori Seiki lathe and a Ram EDM. These are all great machines, but they just weren’t enough to meet our production-work needs. What we needed were machines that reduced part handling and allowed for more parts to be machined in less setups,” Gorny said.
The a51, with full fourth axis and pallet changer, was one such machine. It lets the shop complete parts in the least number of clampings and eliminates part change time. Another machine added for production work was a Daewoo 240 MS turning center with live tooling, a subspindle and 3-in. working bar diameter.
“We wanted to keep our tool & die machines, but needed production machines to complement our existing capabilities,” Gorny said. “With production work, it’s all about getting as many parts on a machine as possible and short pallet-change times. In tool & die work, these aren’t a concern because you’re making only one or two parts – in that work, part quality and accuracy are the biggest concerns.”
About half of NaviTek Machining’s employees are journeymen machinists, and they take pride in the exacting tolerances they maintain for their tool & die work. But, as the shop took on more production jobs, that way of thinking had to change.
In tool & die work, NaviTek Machining machinists strive to hold part tolerances at the midpoint of the +/- range, or “dead nuts” on size. With some of the shop’s production work, striving for this level of perfection can cost the shop money and hurt its competitiveness.
“While a lot of our production job tolerances fall in the half-thousandth range, there are jobs with a little wiggle room as far as tolerance is concerned. And these were the ones where our machinists would unnecessarily change cutters before they were completely worn because part size began to stray from the tolerance midpoint. Believe me, the last thing we want to do is discourage our machinists from striving for perfection, but in production work, it is all meeting quality requirements while keeping part cost down,” Gorny said.
|In its tool & die area, NaviTek Machining still does a lot of low-volume precision machining jobs (Above). Note the graphite sinker-EDM electrode (below), which was ground from a solid block on a manual grinder.|
Not all the shop’s machinists were on board for the production work endeavor, which was perfectly all right, Gorny said.
“We approached all of them and asked if they’d be interested in helping get the production work off the ground. Some guys were and some weren’t, and we respected that. Two guys who were on board were Tom Kelley and Mike Borland, the machinist who sets up and runs the Makino a51. But I have to say that we still depend heavily on the guys who wanted to stay with the tool & die work, such as Shawn Vorse, tooling team leader and journeyman toolmaker,” Gorny said.
“You get the best out of people if you play to their strengths and passions. If you push them into something they aren’t interested in, the work won’t get done. I would rather pay fewer talented and motivated guys more money than more unskilled people less money,” added Gorny.