Once saw and table setups are automated, what about improving the rest of material handling? Can we lessen the 5 “touches” involved: fetching lumber, feeding saws, catching, transporting to tables, and feeding jigs? And can we better account for the cost of these indirect labor components?
Decreasing “fetch” time means shortening travel time. Originally truss plants that sprung from lumberyards used their “tried and true” material mover, the forklift. Later, many realized that forklift-wide-aisles actually lengthened the distance to the table, and they began limiting their use to feeding saws. Inside the plant, carts became their logical replacement. But there never seemed to be enough carts, and finding and delivering all required carts consumed an inordinate amount of labor.
Lessening saw feed time was helped by infeed decks. Improving catcher efficiency was addressed by off-feed conveyors. These provided a buffer for the catcher, but his position remained a full-time job. Later, just-in-time cutting demanded a powered conveyance away from the saws.
Improving transport to tables has defied even the experts. Conveyor systems parallel to tables were employed with limited success, but they restricted access, lacked the flexibility, and didn’t lessen the travel distance. In most conventional in-line truss plants, with saws feeding material at the end of long gantry lines, there are few alternatives (though Shelter Systems has achieved success with innovative use of combi-lifts).
However, linear saws challenge many of the above conventions. They can be placed much closer to the tables, and can be configured in multiple ways (see “U” and “Z” configurations below). Most linear saws will cut literally any truss part, so no other lumber needs to reach the table. Many component manufacturers have begun placing them alongside gantry tables, so that cut parts exit directly to truss builders (see “Z” configuration). Cutting, automatic marking, and grouping one truss-at-a-time enables builders to often pick up a complete bundle and place it directly on the table.
Just as important as the reduction of labor time is the reduction in staffing realized by removing the barriers to efficient material movement. As transport distances are reduced, the plant space “recovered” can be repurposed to raw material storage, further reducing “fetch” time. All of these methods work to lessen hard-to-account-for indirect labor. And as the scarcity of skilled labor continues to strangle production, expect many more material handling innovations to arise.