At different points in our tour of the veneer mill, our guide would point out a certain element, or an individual who played a critical role in keeping the operation moving efficiently and profitably. The veneer slicing machines are large and complicated, but each of the dozen in the facility depends on a simple knife.
The knife above is typical, about 6″ wide and about 12′ long. Maintaining the knives is a never-ending task; the knives need resharpening every day or two depending on the species of wood being sliced. The knives are removed from the slicing machines and brought to a dedicated room nearby.
In the room the knives are loaded in a special machine for grinding. A motorized carriage travels laterally across the knives. A grinding wheel is mounted to the carriage, and the grinding takes place under a steady stream of water. The sharp knives are then inspected and returned to the slicing machines.
When the freshly sliced leaves of veneer come off the slicing machine they are still wet. These leaves are stacked in the order they were sliced, and they start to curl from their own weight and from the moisture within. To be usable, they need to be dried and flattened. Directly across from the slicing machines are driers. Like everything else in the veneer mill, the driers are large and almost completely automated.
This is the outfeed side of the drier. On the infeed side, workers unstack the leaves and place them one at a time on the conveyor belt. The leaves are still kept in the order they were sliced, and will stay that way throughout the plant. Within the dryer, the leaves are heated as they travel between platens that keep the leaves flat. Fifteen or 20 minutes later they emerge from the other end, flat and dry. As they emerge from the machine they are stacked in groups of 24 leaves. These stacks are called books, and for the rest of their trip through the plant they will be graded and trimmed as books. The top leaf tells the story of those below it.
The books are placed on another conveyor belt, heading to a trimming machine along the far wall. On the way uphill each book is graded and marked for an initial trimming. The graders are critical to the profitability of the mill. They make quick decisions that can dramatically change the value of the material as it passes by.
These books are heading toward an edge-slicing machine. As each book passes under the machine a pressure bar holds the book in place as a large knife drops down to trim the book. These books will have the lighter-colored sapwood removed, leaving the valuable heartwood.
The scrap from the edge trimming falls to waiting conveyor belts, and as with almost all the waste from the mill, this scrap will fuel the boilers that provide heat for the soaking vats and driers. Upon leaving this machine, the books are turned 90Ã?Â° and the ends are trimmed.
After trimming, the books of veneer leaves are stacked on pallets by species and by grade. Rows of pallets continue in yet another long line of material. From this point, the pallets are moved to another part of the mill for more sorting and grading, then shipment to waiting customers.
To read the first part of my visit to the Atlantic Veneer Mill, click here.
Next time, we’ll follow these finished veneers to the Veneer Tech plant, where they will be spliced together in to finished faces.
– Beginning in the October issue of Popular Woodworking Magazine, we have a series of in-depth articles from Marc Adams on veneering. Subscribe now so you don’t miss out.