Although production volumes are going up,
the need for flexibility
in powertrain machin-ing has grown more important. Here’s a look at how things
If you go through the history of transfer lines, names like Cross and Lamb come to the fore, especially as regards the massive machining systems made for blocks and heads. Robert Pelachyk, in his career, worked for those companies and others. He’s seen a lot of changes when it comes to production systems for powertrain applications, be they in automotive facilities or plants where engines are produced for agricultural and off-road equipment use.
And as he reviews what’s happened then and now, as he looks at what was offered (e.g., “There were class-one bearings used on the old drill heads. There are better bearings in Rollerblades.”) and now (“Transfer machines took a lot of floor space because you’d have a probing station next to a drilling station to make sure that you didn’t break a drill; our machining centers have laser probes to check if that happens, and if there is a break, the machine automatically goes to another pocket for another tool.”), he quips, “There’s a lot of advantage of having been a transfer machine guy for so long”—he knows what the advantages of today’s technologies are.
Here’s the thing: Transfer lines became the post-World War II solution for high-volume machining operations. Consider that for nearly the last half of the 20th century powertrain production was pre-dicated on producing hundreds of thou-sands of the same things—blocks and heads—that had longevity and little, if any changes, over a significant period of time.
And when there were changes to things like cylinder size or spacing or bank angle or whatever, then it typically was the case that there was a shutdown measured in months while the transfer line was retooled . . . or if it was a really radical change, then there would be a whole new multi-station line that needed to be built and put in place.
Pelachyk is now the president and CEO of Heller Machine Tools (heller-us.com
). Heller builds manufacturing systems that are used to produce things like blocks and heads; systems that transfer parts from one station to another; systems that are anything but transfer lines. In fact, when you listen to Pelachyk, and his colleague Vincent Trampus, vp-Sales, Heller, you quickly realize that transfer lines are pretty much to powertrain manufacturing what dial-up is to Internet connections. Moreover, even the “hybrid” lines that deployed transfer-line-like fixed stations at the beginning for the roughing and transfer-line-like fixed stations at the end for finishing with machining centers sandwiched in between that were fairly popular as recently as 10 years ago have pretty much had their day.
Trampus admits that while the systems they build for companies ranging from automotive OEMs to Caterpillar are primarily based on robust but flexible machining centers, there are some somewhat more dedicated machines for special operations like crank or cylinder boring, especially for applications where there would be significantly long spindle overhang—think of a 15-liter block. But even in those instances, he says, there is greater flexibility now than there was as little as 10 years ago, and the parts handling—overhead transfer—is consistent across the system.
There are other ramifications of what’s happening as a result of the architecture that they’re describing. Historically, the case was that it was necessary to buy equipment that would be able to handle the capacity of the maximum projected volume. If you thought that when the vehicle was hitting on all cylinders in the market you’d need x engines, then you’d buy a system capable of producing x—or maybe even more. Trampus points out: “For a typical transfer line, output at 65% was a good day.” The OEE—overall equipment efficiency—was not something people spent a whole lot of time talking about.
So you have this high-capacity system that is capable of making V8s, then gas hits some new high and V8 sales collapse. What do you do? (1) Hope you’ve been transferred somewhere far away; (2) Retire.
Transfer lines didn’t lend themselves to changeover in any market-responsive period of time. What’s more, even before you got to that point of facing the need for a changeover, consider this: a transfer line consisting of 100 or more stations took up thousands of square feet. As we are talking about machining engines, we are in the realm of considerable precision. The transfer line manufacturer had to create that huge system in its factory, make sure that it was able to meet production requirements . . . and then it was disassembled, boxed, and shipped to the engine plant, where it was unboxed, reassembled, and, in time, capable of running production as it did when it was on the builder’s floor.
Now the objective is to have a system that allows volume to be purchased in increments. Maybe the plan is that someday, 1,000 units per day will be required. So the solution is to have machining systems that are fully capable of producing 250 per day. This allows a few things to happen. For one, investment is graduated. For another, the individual systems are much smaller and less complex. This means that there isn’t that massive reconstruction project at the engine plant. What’s more, as these are duplicate systems based on standard machines, there is greater reliability than was the case when the norm was “special” machines. In addition, there may be a slight change in demand such that three of the systems can be used to produce one part (say a 2.0-liter block) for an output of 750 units per day while the fourth is used to produce another part (1.4-liter block).
Trampus says that to make a block or a head there are seven or eight machining operations required, three or four in roughing, three or four in finishing. So a machine per operation. Then there is a washer (a robot and a dunk tank). And if it is a block, a bearing cap assembly, finishing machine, cup plug, or leak test. Simple. Compact. Low volume—say 300 per day or less—but easily replicable.
And consider that by having a very few machines versus 100 or more stations, there is less transfer and far less clamping and locating. Not only is moving parts a huge form of waste, but when you have a vast array of fixtures, maintaining the locators and clamps so there is repeatability is a massive undertaking in and of itself.
Now that auto companies have a more “global” focus in that they’re using resources all over the world to serve various markets, not necessarily just the one where those resources are based, this more compact machining system provides another advantage: it is a whole lot easier to move from one place to another. Or because the systems are based on standard machines, it is a whole lot easier to replicate a system that’s in country A for a site in country B.
For a long time, the argument being made against flexibility was the cost. High-volume transfer machines were said to be much more cost effective. Which brings us back to the long-term perspective of Bob Pelachyk. He points out that there have been changes in the way the calculations are made. For one thing, the requirement for flexibility has a much greater importance now than had been the case when vehicle demand was consistently growing and what was being offered under the hoods of those vehicles tended to stay the same. Companies can no longer afford not to have the ability to rapidly change their powertrain mix. The number of machining centers being made by Heller and its competitors in this arena—like Gröb (grobgroup.com) and MAG (mag-ias.com)—has increased such as the comparative prices have gone down. The cost of space is now factored in more so than it had been. And the ability to match capacity with real demand is exceedingly valuable.
Pelachyk says that they’ve been asked by some OEMs to retool existing transfer lines. Which turns out to be on the order of 85 to 90% the cost of buying an entirely new system based on machining centers. “Some of our customers are asking us to look at them and to try to use one or two pieces of equipment. And we do that. It may cost more than building new, but if it’s still on the books, it satisfies the financial department.”