1. Circular Saw Not used as headrig in softwood sawmills
Less throughput than band saw
Blades rigid, saw kerf is 1/4” to 3/8”
Relatively wide saw kerf – high waste factor

2. Circular saw

3. Waste Factor Comparison
Band Saw
Circular saw

4. Sawmill – generic overview
Log yard
Bucking
Headrig
Debarker
Cants
Side boards
Gang Saw
Trimmer
Edger
Sorter, Stacker

5. Gang Sawing
cant
gang saw blades

6. Gang saws Fixed, oscillating blades Little flexibility
Intermediate kerf
Single pass
High throughput

7. Gang saws

8. Log breakdown patterns
1. live sawing cant sawing sawing for grade & 5. sawing for edge grain dimension lumber

10. Optimization software

11. Scanning of the log to optimize the yield
Bottom profile
Mid-length profile
Top profile
Product mix selected

12. Sawmill optimization
(Halco Software Systems)

13. Sawmill – generic overview
Log yard
Bucking
Headrig
Debarker
Cants
Side boards
Gang Saw
Trimmer
Edger
Sorter, Stacker

14. Wane http://www.wdscapps.caf.wvu.edu/lumberrtk/

15. 6. Edger
The edger will rip the rough sawn board to width and remove the wane and other defects. Uses circular saws.
wane
wane
saw cuts

16. Edger optimizer

17. Sawmill – generic overview
Log yard
Bucking
Headrig
Debarker
Cants
Side boards
Gang Saw
Trimmer
Edger
Sorter, Stacker

18. 7. Lumber Grading - Trimming

19. Lumber Grading Different grades systems for hardwoods and softwoods
Different grades depend mainly on
natural defects
size, number and location of knots
size, location and type of stain or rot
amount of wane
machine defects
skip
snipe

20. Trimming The trim saw is used to cut the boards to length
Lumber is trimmed to lengths of 2 foot multiples.
Uses circular saws.

21. Trimming

22. Multi-saw trimmer

23. Sawmill – generic overview
Log yard
Bucking
Headrig
Debarker
Cants
Side boards
Gang Saw
Trimmer
Edger
Sorter, Stacker

24. The “Green Chain”

25. Descrambler

26. J-bar sorting The lumber is scanned and sorted into bins depending on
species, grade, dimensions

27. Multiple sort bins

28. Stacking

29. Drying kilns

30. Reasons for drying lumber
Increase strength of lumber
Reduces later dimensional changes
Increases decay/insect resistance
Decreases weight of lumber

31. Drying Drying factors Temperature Relative humidity Air circulation
Sticker
Lumber
Drying factors
Temperature
Relative humidity
Air circulation

32. Planermill
Planermill
Kilns
Sawmill
Logyard

33. Planer

34. Planer

35. Planer
4 knifes per planer head
24 knifes per planer head

36. Waste Management
Trim ends
Chips
Sawdust
Planer shavings
Bark
Hog fuel