1. Lumber Manufacturing---Debarking Purpose—Increase value of byproductsPurpose—Increase value of byproducts -- Scrapes and edgings → chips without bark → pulp -- Scrapes and edgings → chips without bark → pulp --Bark particles → burn (energy) --Bark particles → burn (energy) Types of debarkersTypes of debarkers --Drum debarker: removing bark from pulp logs --Drum debarker: removing bark from pulp logs --Ring debarker: removing bark from saw- and veneer logs --Ring debarker: removing bark from saw- and veneer logs --Pole shaver: shave bark off utility poles --Pole shaver: shave bark off utility poles

2. Drum Debarker To remove bark from pulp logsTo remove bark from pulp logs Corrugated interior tumbles the logs and scrapes off bark; Corrugated interior tumbles the logs and scrapes off bark; logs rub against each other to knock off bark; water shower logs rub against each other to knock off bark; water shower softens bark and washes bark out of the drum. Because of softens bark and washes bark out of the drum. Because of gentle rubbing action very little removal of quality fibers from surfaces.

3. Ring Debarker To remove bark from saw- and veneer-logsTo remove bark from saw- and veneer-logs Logs are centered in a ring of rosser heads with projecting teeth; bark is removed with a pressure about 30 to 50 psi. Bark is removed at high speed with substantial surface removal of wood but does not affect lumber or veneer yield.

4. Pole Shaver To move bark from utility poles to obtain smooth surfacesTo move bark from utility poles to obtain smooth surfaces Pole rotates as it passes under a floating peripheral-milling cutterhead, removing the bark with a minimum of wood loss and retaining the natural taper.

5. Primary Breakdown—Head saws Band saw: Able to handle large logs,Band saw: Able to handle large logs, provide straight cuts and thin saw kerf provide straight cuts and thin saw kerf increase lumber yield. increase lumber yield. Circular saw: Saw diameter limits log sizes,Circular saw: Saw diameter limits log sizes, thick saw blades for stability (1/4”) thick saw blades for stability (1/4”) large saw kerfs large saw kerfs reduces lumber yield. reduces lumber yield.

6. Saw Mills Scragg MillsScragg Mills Consists two or four circular saws on a common arbor. Distance Consists two or four circular saws on a common arbor. Distance between blades can be adjusted to produce 4-, 6-, or 8-inch cants. between blades can be adjusted to produce 4-, 6-, or 8-inch cants. The logs are commonly moved through saws by a conveyor. The logs are commonly moved through saws by a conveyor. Multiple Band MillsMultiple Band Mills Similar to scragg mills except that breakdown is done by 2 or more Similar to scragg mills except that breakdown is done by 2 or more opposing bandsaws, producing two slabs and one cant if two bands opposing bandsaws, producing two slabs and one cant if two bands are used. are used. Chipping HeadrigsChipping Headrigs Logs pass through a set of side cutterheads to remove excess Logs pass through a set of side cutterheads to remove excess wood into chips, followed by another set of top/bottom cutter- wood into chips, followed by another set of top/bottom cutter- heads to produce a cant. Chips are to be used for pulp & paper. heads to produce a cant. Chips are to be used for pulp & paper.

7. Chip-N-Saw Designed to process small straight Logs 6 to 16 inches in diameters. Logs first pass through two pairs side and top/bottom) chipping cutterheads to square or shape logs, followed by passing the cant through a series of circular saws mounted on a common arbor to produce multiple pieces lumber.

8. High-Tech Mills BOF (Best Opening Face)BOF (Best Opening Face) For high efficiency: Electronic hardware (scanner & computer) and good computer software; machine that is able to position logs quickly & saw accurately with thin kerf.

9. Resawing Ripping— Ripping is to saw lumber along the grain. Slabs produced by headrigs are cut with a pair of circular saws (called an edger) to square the edges to a specific width simultaneously.Ripping— Ripping is to saw lumber along the grain. Slabs produced by headrigs are cut with a pair of circular saws (called an edger) to square the edges to a specific width simultaneously. Large slabs are rip into multiple pieces with a series of circular saws mounted on a common arbor (gang saws). Rough trimming— Trimming is to saw lumber across theRough trimming— Trimming is to saw lumber across the grain to a specific length. Rough trimming follows the ripping to cut green lumber into pre-determined lengths, usually done with a pair of hollow ground circular saws.

10. Sorting & Drying Sorting— This operation is to sort cut lumber into differentSorting— This operation is to sort cut lumber into different grades, species or species groups, thickness, length and sometimes according to moisture content. Drying (seasoning)Drying (seasoning) --Reasons to dry : Seasoned wood is dimensionally stable Dry wood is durable against inscets & decay Dry wood is durable against inscets & decay Dry is stronger Dry is stronger --Air-dried lumber: moisture content >15% ≤19% --Kiln-dried lumber: moisture content ≤15%