- July 20, 2017
- Posted by: Programmed Timber Supplies
- Category: Uncategorized
Last year saw the installation of a Microtec Goldeneye scanner on our main component docking line in the St Marys processing facility where product quality is initially determined.
Prior to installation most of the timber grading function for components was performed visually by highly trained and qualified graders. Using their training and experience, boards were marked with a luminescent crayon then read by a camera and a cutting pattern was determined by the saw software then cut accordingly. Production this way was very popular with our customers as these operators were top performers.
Any new equipment had to ensure our quality average did not fall below the high standards our customers had come to expect. Motivation to replace the operators with technology was primarily driven by customer demand. Demand for our products were increasing and the need to start a second production shift was there. It would have been unreasonable to expect the continual high quality of performance from staff when working the irregular hours of a second shift or on weekends.
The main docking line already consisted of a high speed, high accuracy saw from the internationally recognised company System TM. This Danish equipment manufacturer continues to enjoy a reputation of making some of the best equipment available for this application. The decision to incorporate scanning technology into that line was a major commitment in capital but the benefits would be significant.
Timber samples were shipped from the St Marys plant to the Italian factory of Microtec so initial analysis of the fibre could be performed to ensure our quality demands were met. This was followed up by Programmed Timber Supplies staff travelling to northern Italy to oversee final preparations before shipment.
As the volume capacity of the line would increase significantly additional handling equipment was also required. System TM were able to design, manufacture and install pack transfers, vacuum lifting equipment (where a whole row of boards are vacuumed lifted from an infeed pack onto the infeed conveyors) and feed drives to and from the Microtec Goldeneye scanner.
Technicians from both System TM and Microtec travelled to Australia to supervise the installation and final calibrations. Immediately the realisation of the capacity of the new equipment and technology was apparent. Not only were we able to meet our quality expectations but consistency snapped straight into place. Only after the installation were other significant benefits to become obvious.
The scanner incorporates X-ray function that allows a continual reading along each infeed board of density and internal knot structure. Density in radiata pine can be an indicator of stiffness, the timber property that often determines the grade suitability for application. Density is measured excluding knots. Knots are more dense than the surrounding wood fibre but generally don’t improve performance. Nail and screw holding capacity is also related to density. Our structural grade has certainty improved in consistency, even though there were no performance issues previously.
The scanner also utilises 2 different laser functions. One is able to measure grain angle or slope of grain. This is a determining factor in structural grade analysis. The other allows each board to be accurately measured for not only width and thickness but also for damaged or missing edges (want & wane). There are limitations within the structural grade rules around these measures. Splits, cracks, voids, gum pockets etc. are also detected.
A significant advantage of being able to measure this ‘missing’ wood is in our truss web production. Timber grade allowance is usually more liberal than what is required in nail plate specification. All our F7 grade truss webs now meet the nail plate tolerances on the ends where they will be plated but can have the timber grade allowance in the centre portion. This difference is not highly visible but an important one when we commit to offering a ‘fit for purpose’ product.
Components that are used in furniture manufacture benefit from being scanned this way to avoid problems when they are eventually upholstered or exposed to mattresses so tearing of fabric is eliminated.
Two different cameras take constant images along each board. One takes a colour image and the other black & white. Interestingly it is the black & white image that can offer significant information. Knots and other defects can be identified, measured and assessed more accurately. The colour image lets us know generally what the board looks like for when an appearance criteria is required by the customer.
By knowing now all the above information the optimisation software will then determine how the saw will cut each infeed board. Any component that will be used in the final application where it will be nailed or plated on the ends can be cut defect free in the ‘end zone’. Great for truss webs as mentioned but even better for wall nogs or truss trimmers where a nail will be shot into the end grain. Our nogs/trimmers can be ordered with this quality. Although usually a very utilitarian looking component it is now truly ‘fit for purpose’. Think about the reduced risk of injury in the fabricator’s plant or the carpenter using nogs as a ladder on-site.
Furniture components where holes or T-nuts are going to be inserted at some specific point on the board can be nominated so defects will not be located in the critical sections. Likewise in structural components a consideration for a point load can be accommodated.
This type of scanning technology is used in some of the major sawmilling operations in Australia. None other though is used for the preparation and production of the wide range of components where actual customer specification is required.
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Microtec has also published an article in regards to this installation. Click here to read more on the Microtec Website.