griffin lumber ’ s pglr makes every turn count
griffin lumber ’ s pglr makes every turn count
“ It is a real testament to the whole system when you can scan a log , rotate it , impale it on the sharp chain , send it through the chip heads and saws , and the log only moves 3 degrees . That really shocked me when the results started coming in .”
The Griffin team understands the importance turn accuracy makes to recovery . They chose USNR ’ s PGLR system to ensure they get the best turn on every log .
Griffin Lumber Company at Cordele , Georgia sourced a used USNR DLI line and a used quad bandmill with reducer heads to replace two aging C-frame carriage lines . USNR was selected to supply the optimization components comprising log rotation , Precision Geometric Log Rotation ( PGLR ), log optimization and System Quality Inspection ( SQI ), with Smart TriCam™ sensors for scanning . The optimization platform chosen was MillExpert , and this was already familiar to mill personnel .
Optimizing the line
In choosing a vendor for the optimization system , Jesse Griffin said they chose USNR because , “ We know USNR can optimize a log better than anyone out there , and start-ups have always gone flawlessly . The project managers are always prepared and extremely helpful .”
The Griffin team was clear about the significance of accurate log rotation , particularly on logs that need to be turned horns down for sweep . Because of the rising sharp chain arrangement configured for their mill , they realized the importance of having two points of contact on the sharp chain on logs with lots of sweep . This could only be guaranteed with a PGLR system that would ensure the log was being rotated correctly .
Jesse related that the optimized log turning system would do a better job with recovery than the manual systems they had prior . “ When you are talking about measurements in degrees , I don ’ t think any machine without auto correction ( PGLR ) can get that log turned right .” He said that consultants he spoke with and mill owners who used auto correction for log turning all recommended that accurate log orientation is essential to realizing the greatest value recovery .
Log rotation , correction
The PGLR scanning system is located at the log turner section . It monitors and corrects the log rotation process in real time to increase recovery by reducing log rotation error . Four SmartTriCam 3D sensors scan the log as it is being rotated . The actual log rotation path is compared to the autorotation optimizer ’ s projected log rotation path to generate log rotation corrections . The log rotation corrections are transmitted to the PLC for correction of the log rotation path on-the-fly as it continues through the log turner . Log rotation error is typically reduced by 50 % or more . PGLR can be installed with a new MillExpert optimized primary breakdown system , or as an addition to an existing system .
The PGLR software is straightforward with a host of diagnostic tools to help tune the mechanical as well as the PLC control systems . Graphs and onscreen indicators permit early detection of problems and overall performance at a glance . Reports are generated to isolate issues relating to a particular class of log and to track longer term trends . PGLR can compensate for the following causes of log turning errors .
►►Mechanical wear
►►Feed speed changes during the turn
►►Irregularly shaped and crooked logs
►►Transfers from one conveyor to the next
►►Interaction with pressrolls
►►Slippage and hesitations
How did PGLR perform ?
The final performance test numbers tell the story . Jesse explained , “ We ran 20 logs , and 19 out of 20 were off 3.19 degrees and 18 out of 20 were off 2.84 degrees . We also only lost 0.375 % of the volume from the initial scan to the final solution scanner . I don ’ t think anyone can argue against those kinds of numbers .”
Jesse went on , “ As far as me personally , it has exceeded my expectations . It is a real testament to the whole system when you can scan a log , rotate it , impale it on the sharp chain , send it through the chip heads and saws , and the log only moves 3 degrees . That is virtually not moving , and it really shocked me when the results started coming in .” Jesse is very happy with the results . “ We ’ ve seen enormous uplift in productivity and yield . We are very satisfied .”
16 Millwide INSIDER | ISSUE 3 - 2013