Sixty Years of Machines, Part IX

Back to Library

Issue #12253 - August 2020 | Page #10
By Joe Kannapell, P.E.

Part IX: Automatic Setup

“I think this will work,” said Dick Rotto at the unveiling of auto-jigging at the 1988 BCMC in Nashville. This was a high compliment from the founder of the most prolific truss business, Trussway, Inc. And Dick had no equipment compatible with auto-jigging in his highly productive plants. But the system he perfected in Houston powered Trussway through Texas’s severe downturn. Though auto-jigging would be in Trussway’s future, Rotto and many other incumbents demurred. However, Alpine’s largest customer deployed such a system.

But the new blood in our industry had no hesitation to try to get a leg up on the Dick Rottos of the truss world. And so rather hurriedly, a Koskovich Jet Set showed up at the home base of Builders FirstSource. Its appeal was its apparent simplicity. The mechanism seemed well protected in its own enclosure. And like all auto-jigging, it relied on only 3 simple mechanical components: a motor, belt, and screw. An electrical component, called an encoder, directed the motor how many revolutions to turn. In the example shown here [See PDF or View in Full Issue], the puck is moved 10 inches by turning the screw 100 revolutions. If the mechanism delivers 1000 rpm (revolutions per minute) to the screw, the time to turn it 100 revolutions would be 1/10 minutes or 6 seconds. Likewise, to move 100 inches, or over 8 feet, would take one minute.

The labor savings of auto-jigging becomes immediately apparent. If without automation a build crew spent half their time setting up and half building trusses, they’d recover nearly half a day’s work. In other words, they could build twice as many trusses with the same staff, on the same equipment, without additional plant space. Who wouldn’t jump on that opportunity? In the long run, nearly every truss plant with enough volume can justify such a system. The questions became, in the early 1990s, how much does it cost, and how long is the pay off? A rough price of $250,000 was suggested at BCMC, but no systems had yet been installed.

To invest a quarter of a million dollars in 1988, when the economy was in free fall, would have been questionable. And by 1991, when housing tanked again, that kind of investment would have been unthinkable for most CMs. Less truss capacity was needed, not more. In addition, CMs anticipated that builders would simplify roofs to enhance affordability and reverse the 8 year downward spiral. That trusses could (and did) get more complex during this period did not seem reasonable at that time.

Yet, those who took a chance, like Builders FirstSource, should have reaped the benefits going into the rapid rebound which commenced in the early 1990s. However, despite its alleged simplicity, this was a new and unproven technology. BFS and others would need to take auto-jigging through hundreds of setups over many months just to learn how to properly maintain it and use it. They would need to determine which type of trusses it was best adapted to handle. Would it work with current cutting equipment? What can go wrong with it and how do we fix it?

Beyond the mechanism itself, a common question arose, “what supplemental jigging is necessary.” Ideally none would be required. However, many crews affixed stops at overhangs, heels, peaks, collar ties, room walls, and end verticals (see arrows in diagrams [See PDF or View in Full Issue]). It is unlikely that auto-jigging pucks would coincide with such locations. Experienced truss builders and plant managers were hesitant to discard the practices that seemed quality-based. Auto-jigging was going to require a paradigm shift.

The early 1990s became the proving ground for auto-jigging systems, mechanically and operationally. The truss business was recovering but many questioned its sustainability in the face of 10% mortgage rates. Many CMs’ finances had been drained by the long downturn. Any increased cash inflows were needed to fund increased working capital. However, there were pockets of prosperity across the country that sustained the growth of automation. And in the prolonged expansion ahead, many more would adopt auto-jigging and take it through its paces. Manufacturers would react and adapt.

Next Month:

Lasers Shine

You're reading an article from the August 2020 issue.

External links

Search By Keyword

Book icon Issuu Bookshelf