Benefits of Automatic Grader at the sawmill

Most sawmills today have a dimensional optimizer at the sawmill before the trimmer. Those optimizers make trimming decision based only on dimensional defects. One of many advantages of automatic graders is the ability to not only rely on dimensional analysis but also on visual analysis early in the process. 

• Why dry wood that doesn’t need to be dried?
• Why not trim and optimize the boards’ grade with all the info that is used for grading?
• Why trim too much and slash into your profits when current tools allow you to optimize yield?

The Benefits

• Removes defects as early as possible in the production process
• Grade sorting in green mill means that only drying defects (i.e. shakes, deformation) need to be considered in dry or planer mill -> final sorting can be run with higher capacity and less people (only down grading)
• Optimized drying (lower grades can be dried faster, better grades slower)
• Removes poor quality boards before drying
• Green trimming removes waste parts before drying (drying savings)
• Higher green chip volumes, lower dry chip volumes

Let’s look at this yield and profit issue!

​For example, take a 2” X 6” X 16’ with a simple defects layout (ends only).

Traditional Process
The board is initially 198” long and have wane or dimensional defects at the far end 3” long and rot, crack, splits or any visual defects that will degrade the board at the near end for 2” long. Your standard length of 16’ board is 193” long.

The dimensional optimizer will see only the wane and will not see the splits or cracks or other visual defects and will make the decision to cut 5” at the far end to do a 193” long board.

When this board gets to the planer and gets graded, you will only then manage the visuals defects at the near end. You will have to shorten this board to 168” long (14 FBM), or degrade the board.

Automatic Grader process
With an automatic grader at the sawmill, you will look at this board and will immediately (and automatically) take the decision to trim 3” at the far end and 2” at the near end to do a board 193” long. When this board gets the planer you will trim it to do a 192” long board with the expected grade (16 FBM) so you will save 24” of lumber (2 FBM).

You can see in the following chart that an automatic grader analyzing visual defects at the same time as dimensional characteristics optimizes your production yield and minimizes unnecessary processing. In the third scenario, even if the yield is the same, the simple fact that you are able to make the proper decisions early on in the process allows you to save both time and money by only applying a process (drying in this case) to products that require it.

Traditional solution

Solution with the use of an Automatic Grader

Automatic Grader Benefits

Conclusions

Let say you process 100 boards per minute at the sawmill and boards with visual defects at the opposing end of the dimensional defects (like the first and second scenarios) represent 10% of your production, this means you will save 20 FBM per minute at an average price of $300.00 U.S per 1000 FBM. In an eight hour shift at 85% runtime, you will save $6.00 per minute or $2,448.00 per shift.

With 240 production days per year, this simple scenario implies a saving of $587,520.00 per year per shift without the drying saving time economy.

​And we didn’t even start addressing any grading benefits, edging optimization or labor or process cost economy!