Lunawood planing guide

1. 18.11.2010
Planing Guide and Recommendations
Planing In General
As a result of the ThermoWood heat-treatment process, cupping can occur in sawn raw material. It is
necessary when planing thermowood which has not been re-cut before planing to install infeed rollers as
illustrated below:
With both methods this enables a solid contact surface to be formed as the piece proceeds through
the planer, thus reducing the risk of surface cracking and enabling higher infeed roller pressure. It is
important to adjust the roller pressure to suit the section and profile being planed to avoid splitting.
Figure 1. Recommended infeed rollers to avoid cracking of the boards.
Furthermore the colour, structure and moisture content of the material is changed significantly. The
material becomes more susceptible to mechanical damage and this must be taken into account when
handling the material. In order to avoid cracking of the boards, it is advisable to make a flat base surface
with a planer or band saw first before profiling.
Lunawood causes less friction during infeed and enable a smoother planing process. This is due to the lack
of resin in the wood.
Speed
In some planing lines, the speed must also be decreased. If the infeed speed is decreased, the rotation
speed of the cutters must be decreased accordingly. Too high a ratio of rotation speed to infeed speed can
cause the wood surface to burn.
The rotation speed of the cutter heads must be in right level compared to infeed speed because too
high rotation of cutter might cause that wood cells on the surface to closes and this can lead to
difficulties when applying surface coatings.
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The roller pressure, infeed speed, cutter rotation and mechanical handling, is highly dependent on the
planing line and machinery. Therefore, no general values can be cited. When planing Lunawood®, the
parameters are set separately for each planing machine.
Cutters
It is important that cutters are set accurately in the cutter block; they have to be on same radius. Using
similar cutter settings as normally used when planing hardwoods or more brittle wood species such
Western Red Cedar have brought good results.
Machines (cutters and other surfaces) remain very clean after working with Lunawood due to the lack of
resin in the wood.
More recent tests have found that by using spiral cutters there is less damage to the knots and the
material around the knots. Results have shown that star shakes which are typically found in Spruce and
to a lesser extent in pine have fewer tendencies to break out when using the spiral cutters and similar
results can be obtained as with normal kiln dried Spruce and Pine.
It is essential to keep good sharpness of the cutters, once dulling starts to occur the damage to the
knots and material around the knots increases and also splintering of the arises increases. Effects of
dulling can be seen from the surface of the material. Dulling occurs more quickly than when planing
normal kiln dried pine or spruce but at about the same rate as hardwoods and Western Red Cedar.
Dust
Dust is more micronic compared to normal Pine and Spruce so care should be taken to ensure adequate
extraction. The dust particles are a similar size to that of Western red cedar and hardwoods. The dust
cannot be used for making bio fuel pellets or included for animal bedding.
Storing
It is important to store the raw material prior to planing in a dry and well ventilated environment such
as a warehouse. Care should also be taken during colder periods that the material is not frozen when
starting to plane or further process; this can lead to poor surfacing. When stacking there should be
sufficient bearers underneath the packs to prevent distortion. ThermoWood which is stored outside
without covering is susceptible to colour change due to UV degradation and general constamination
from the environment- therefore under cover storage is recommended.
Planing Lunawood Thermo - Pine – Pinus Sylvestris
When planing Lunawood Thermo-Pine it is recommended to plane the heart side to the face side /
weathered side. This is to avoid the risk of year ring loosening in end use.
Lunawood’s production process of Thermo-Pine is optimised so that the heart side of the thermally
modified board is the use side /weather exposed side.
Planing Lunawood Thermo - Spruce – Picea abies
The structure of spruce differs from pine. When considering thermally modified Spruce, the risk of year ring
loosening acts just the opposite way, compared to Thermo-Pine.

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Therefore when planing Lunawood Thermo-Spruce it is recommended to plane the weather exposed
surface to the outer side of the board and the heart side/pith to the backside or under side.
The production of Thermo-Spruce is optimised so that the ‘outer side’ from the thermally modified
board is the use/weathered side.
Planing Lunawood Thermo - Radiata Pine – Pinus Radiata
When planing radiata pine, there is no difference in which side to be planed to face side. The planer may
choose according to appearance the best side to be planed as weather exposed side.