Enhanced, sustainable small log processing by Wood-Mizer
Evolution of the prototype small log processing system (SLP) unveiled at the Ligna timber & forestry fair in Hannover one year ago has evolved to the state-of-the-art set-up demonstrated at Xylexpo. Several components are upgraded to enhance this Wood-Mizer arrangement and 150 of them have been acquired by European timber processors this year. The improvements are ‘general’ (eg better wheels to stabilise timber being sawn and frame changes) plus the introduction of an horizontal saw, upgrading of the single vertical saw, tables for the horizontal resaw and ramps and conveyors for better utilisation of line capacity and materials handling.
In addition to the SLP, a semi-industrial band sawmill in towing mode and a small, stationary mill showed their paces.
Small log processing, the principal demonstration, showed how small logs of often previously unviable species are converted to profitable lumber for minimal investment. It is achieved by a set-up comprising a twin vertical saw (TVS), a TVS log infeed system, a TVS slab cross-transfer conveyor, single vertical saw (SVS) to remove third sides, horizontal resaw (HR) or multihead (MH) to resaw log into boards and an edger for edging remaining slabs after resawing.
The main cant is passed after TVS, to a SVS splitting saw to remove the third side or split the cant. The three sided cants and edged slabs then pass through a 1-6 head MultiHead (or horizontal resaw) for conversion into boards.
The four-machine system, which incorporates the same narrow kerf technology as all Wood-Mizer sawmills, was demonstrated by five people. Such a configuration might normally be manned by three. The arrangement costs roughly 80 000 euros, compared with usually-utilised wide band arrangements at around 200 000. Combined (connecting) power requirement of the line of four machines is 100 kW, whereas four ‘traditional’ machines would consume 55 kW each, burning two or three times more energy. The system Wood-Mizer demonstrated is designed to process small logs from 10cm to 40cm in diameter and 1m to 3.6m length.
In Europe it is particularly aimed at softwoods like pine, spruce, poplar and other minority species like western red cedar.
Worldwide interest is growing. From Africa, for example, where it could process plantation wood from either clearfell or thinnings of managed forests which would otherwise be consigned to landfill, burning or pulp. Typical African species would be rubberwood, acacia and eucalyptus. The potential for sustainable harvesting of such common species is large.
Currently, the pallet wood market, which relies on such species, is so competitive that dedicated pallet wood sawyers using traditional wood processing equipment find it difficult to cope. Now, with lower capital investment and advantages like easy transport, faster set-up, less space (150 - 220m2 – compared to normally twice that area) and between 20% and 25% increased recovery of pallet wood, pallet makers and their components suppliers can look to a rosy future.
Wood-Mizer has designed this small log processing equipment to utilize common parts and blades where possible, and has made all components modular so that a customer can ‘mix and match’ to suit individual needs.
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