When selecting the supplier for the sawmill grading line there are a few things you should take into consideration.
Where and how?
The first thing is to determine where and how the quality grading is done: at the green mill or the dry mill or at both locations? How about the layout? At the sawmills the scanners are normally installed transversally, because that gives the highest efficiency and is generally most suitable for the layout. What is the maximum speed the automatic system can manage? Old lines can typically manage about 80 - 120 lugs / minute, but many new lines are designed for a speed about 200 lugs / minute. Is the proposed grading system capable for higher speeds?
Experience of the supplier candidate?
One key point in suppliers is their experience:
Sawmill business is quite global, and mills typically deliver their products to many different markets. Does the supplier have the ability to assist with implementing various grading rules (Scandinavian, British, American, Russian, Japanese)? Is the user interface and documentation available in your local language?
The grading scanner is connected to the line controls. Does the supplier have experience in working together with your local automation and machinery supplier?
The rapidly growing machine vision technology includes a lot of technical details, which might be confusing. Looking at perfect defect detection can cause inability to select the supplier. Does the scanner analyze the whole board? How well is the geometry of the board analyzed? Is the pith location detected? Is inner and outer surface determined? Are all “your” defects analyzed with high accuracy?
The key issue is to look at the grading results. The biggest economical benefit from an automatic grading system comes from the value yield which should be at least 96%. Does the supplier have recorded results?