The conversion refers to a percentage comparison yield netto volume of wood against the volume of logs
Case:
Log diameter of 40cm, 2 meters long, we will convert it into clean planks 25mm thickness.
There should be additional +/- 5mm as spelling planner / thicknesser. So that the output of sawmills ripping must be set to 30mm.
It should be noted the thickness of the saw blade also create a space that reduces yield, typically about 5 to 10mm.
another factor is the log bark. usually at the beginning of the cutting should be disposed of +/- 2cm
Case:
Log diameter of 40cm, 2 meters long, we will convert it into clean planks 25mm thickness.
There should be additional +/- 5mm as spelling planner / thicknesser. So that the output of sawmills ripping must be set to 30mm.
It should be noted the thickness of the saw blade also create a space that reduces yield, typically about 5 to 10mm.
another factor is the log bark. usually at the beginning of the cutting should be disposed of +/- 2cm
The calculations are as follows:
Left image shows rough volume of log = 40cm diameter x length 2m = 0.2512m3
middle image shows how to rip at sawmill
right image shows results rough cut (of sawmills) = 0.1761m3
Then output percentage from sawmill will be = 0.1761: 0.2512 x 100% = 70%
Furthermore, after do planner and thicknesser, 30mm of board thickness should be 25mm, so the planks volume will be 0.1467 m3, the yield is 58%.
please note this 58% figure is the most that can be achieved because it uses the illustration of a full round log, while in reality the log must be irregular shape.
They can be reduced again by defects of wood, knots, sapwood, etc.
Furthermore, again cutting into smaller components, we will not discuss here because so many variations. Just to keep in mind that the smaller the size of the components, the smaller output percentage anyway.
Our experience shows the yield of teak are at 20-25%
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