Drymill Control Systems
Board scanning & tally systems
|
|
Lug deck with photo eyes mounted above to determine board length. |
|
|
The timber being processed through the drymill is often scanned to determine its dimensions and subsequent board foot measurement. This information can be monitored to provide production information, or taken further to determine the makeup of each individual packet of timber produced by the mill.
A common method for determining the length of the board when conveyed in a transverse arrangement, is to pass it beneath a row of photo-eyes that have been spaced at 300mm (1 ft) increments above the timber deck. While this method provides only limited resolution for the length of the board, it is usually sufficient for this purpose and is much less expensive than other non-contact length metering methods.
It is possible to determine length with much greater accuracy by using either a long-range laser arrangement, or by taking a 3D true-shape scan of the board as it passed along the lug deck. The advantage of the true-shape scan is that it is also possible to determine any wane that may be present on the board and give more accurate board footage as a result.
It is also possible to process random thickness and width boards with the use of additional sensors to accurately determine these dimensions. The boards must be singulated and conveyed along a lug chain in order for the dimensions of the board to be determined accurately.
Grade input can either be via a manual button press, or by an automatic grade mark reader. If grade information is added to the above dimensional data, full production reporting and board sorting is possible. The level of reporting can be tailored to the needs of the mill and can also be integrated into the inventory control database for the site. This level of integration makes the most up to date production information available at the fingertips of the user and job progress or order filling can be easily monitored.
It is also possible to integrate in-line moisture metering to a tally system for even greater grading information on each board. For more information on these systems please see inline moisture meter systems.
Board marking systems
Boards processed through the Jaymor scanning and tally system can be marked to indicate grade or packet allocation. This can be as simple as a set of spray nozzles with a fine spread over the top of the board, marking each board with a code of colours. More complicated applications justify the use of an ink-jet printer, which offers a great deal more detail and flexibility to the marking of each board.
A typical printer would be set up to produce 20mm high print, with the height automatically reducing where space is limited. The text produced is in a dot matrix format, and is clearly readable by those personnel required to pull the boards into packs or similar. If the board is printed on a clean end it is also possible to read the grade and volume information for each board even after the packet has been stacked.
 |
 |
Print controller & head alongside an example of printed text |
