East takes a line on optimum yield - December 2008Long-established sawmill and importer East Brothers (Timber) Ltd has significantly increased productivity and further improved yield of higher value products from the log with investment in a Stenner log carriage and Paul multi-blade edger.
East Bros' site in West Dean, Salisbury has three mills, producing fencing, softwood carcassing and construction hardwood (mainly English oak) for trade customers. The family-run company has a regular programme of investment to keep its production machinery up to date, and last year the focus was on the softwood carcassing mill.
"Our broad objective is to fine-tune the balance between throughput and yield - incrementally increasing the former while maintaining or improving the latter", said director Jim East.
 "Many sawmills are now using high speed reducer lines, but we are sticking with log carriages. We specialise in cutting sizes not available from mills that focus on long runs of standard dimensions. Every order is different, and all the pieces within each order are also often different, so the machinery we install must offer a high degree of flexibility". Six years ago the company purchased a replacement Stenner log carriage for the hardwood mill. When the softwood carriage needing changing last year East Bros returned to Stenner, taking the opportunity to upgrade to the latest technology including an integrated circular 'pop up' crosscut saw.
 "The new carriage has given us a significant improvement and met our objective of increasing productivity while maximising the yield of higher value timber from each log", said Mr East.
"Of course, any bandmill is only as good as the sawyer and we have good sawyers who know how to use them and achieve excellent results".
 At East Bros technology is seen as a tool to assist - rather than replace - the skills of the sawyers. Fully automatic scanning and positioning systems are not needed, but even so Stenner's latest electronic setworks offer features that both save time and assist the sawyer's decision-making. A typical requirement for a log might be to obtain a 12inx12in (300mmx300mm) centre with 6inx2in (150mmx50mm) sections off the sides and 38mm boards outside of those. The setworks scan the log with a 'light curtain' and measure its position in relation to the axis of the sawline. It is automatically skewed on the carriage using the independently driven headblocks to achieve the desired square section from the centre and at the same time optimally positioned for the first cut based on parameters set by the sawyer.
"It is a highly sophisticated and accurate measuring system, which saves up to 10 minutes per log compared with the previous laborious manual method", said Mr East. "While Stenner could have provided it, we did not want a fully automated decision-making scanning computer - the sawyer still uses skilled judgement to determine the best cut - but the system is highly effective in ensuring that we produce as much high value timber against the cutting lists as possible compared with the lower value palletwood".
Flexibility is a key theme throughout the site. Although there are three mills, usually cutting hardwood, softwood and fencing respectively, for East Bros they are simply three production units to be used as needed depending on customer needs. For example the hardwood line can handle very long lengths so 45ft Douglas fir logs are cut there. Conversely, a 12 tonne opepe (African hardwood) log of 30ft length was recently cut in half and processed on the softwood line, using the new Stenner carriage.
"It's a very robust construction that can handle the largest logs", said Mr East. "The opepe log was first cut into big slabs, which are still very heavy and need careful handling.
"The ability to cut hardwood and softwood on either line - simply by changing the bandsaw blades - allows us to offer a timely and effective service to customers. In this case the hardwood line was busy and we needed to produce the opepe quickly to win the order, so we put it through the softwood mill".
Another feature of the new carriage is the integrated circular saw board crosscut unit, which further improves productivity. This unit is mounted in the infeed log deck, its controls integrated with those of the carriage. When cutting long sections it 'pops up' to trim boards to the length required.
The increase in throughput from the new carriage resulted in a bottleneck down the line, with the existing single resaw unable to keep pace with the slabs coming from the bandmill. This was addressed by investing in an edger from German manufacturer Paul, which is represented in the UK and Ireland by Stenner.
Although perhaps best known in the UK for its circular crosscuts, Paul manufactures a range of multirips and edgers. The machine at East Bros has multiple moveable circular sawblades that can be adjusted by the operator to achieve the desired widths of cut. Lasers - one linked to each blade - are mounted on an overhead gantry and shine along the slab to show where the blades will cut.
"To cut several boards from a slab using the resaw required several passes and multiple handling", said Mr East. "With the edger the slab is handled just once and cut in a single pass - so even at the same cutting speed throughput is much higher.
"We have not purchased an automatic optimising scanning system on the edger, but it has excellent software and an easy to use control panel for setting the blades. As with the log carriage, the operator still makes the decision on the best way to cut the slab to obtain maximum quality yield against the cutting list, but now has more time to think about it. The blades are adjusted quickly and the laser lines make it easy to assess yield from the whole slab rather than one piece at a time".
East Bros has a history stretching some 112 years, during which the site in West Dean has been developed from a traditional village sawmill into an efficient, flexible, and sophisticated operation cutting around 10,000 cu ft per week with capacity to spare and with extensive kiln-drying facilities.
Although the size of the UK hardwood sawmilling sector has declined over the years in favour of imported sawn material, there is continued strong demand for - particularly - good quality English oak for a wide range of structural applications.
With its focus on flexibility, productivity and maximising yield of quality timber, East Bros is able to provide a quality service to trade customers seeking non-standard sizes of construction hardwood - as well as softwood carcassing and fencing.
For information about sales and servicing of the full range of Stenner equipment and Paul saws, contact Stenner (tel: 01884 255700; email: stenner@stenner.co.uk).
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