Updated FPInnovations saw design software tool
Friday 27 Feb 2026
Sawmills are pushing the limits of sawing systems to maximize
production and recovery while trying to maintain acceptable sawing
accuracy and uptime. There are a set of calculations based on
bite per tooth, the sawdust carrying capacity of the gullets and cutting
power that have been used for decades to ensure the tooth design is
within a range that results in good sawing performance.
However, these calculations are too simple to account for
several known factors, such as:
- Double-arbor circular saws, particularly canter saws, are a
challenge because the depth of cut needs to be determined for both saws.
Also, fully buried saws require more power.
- Cutting power increases as the bite per tooth decreases because more
energy is required to reduce solid wood to sawdust. In the traditional
formula, the power factor assumes a bite per tooth of about 0.035inches.
- Wood strength, which determines cutting power, is significantly
affected by wood temperature and moisture content.
- The traditional design calculations only apply for a single saw, but
with gang saws the feed speed may be limited by motor power or the
holding capacity of the feed system, not the saw design. The feed tables
on most machines allow for reducing the feed speed as the number of saws
increases, but the feed values are usually determined by trial-and-error, which may be too conservative, leaving opportunities, or too
aggressive, creating production problems.
To address the above shortcomings, the FPI Saw Design program
has been updated to:
- Include bite per tooth, wood moisture content and temperature in
power calculations
- Estimate the holding forces that the feed system can provide and the
cutting forces on the wood. If the cutting forces exceed the holding
capacity the feed speed is reduced. From this, a feed table based on the
number of saws is produced.
A common finding in many saw design reviews is that feed speeds are too
fast for large depths of cut but could be faster for small depths of
cut. Since there are typically few deep cuts, adjusting the feed table
can result in more production while avoiding saw reliability problems.
The new program provides more realistic calculations to allow mills to
maximize saw performance.
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Source & image credit: FPInnovations
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