Cutting the losses at Tangiwai Sawmill

Ruapehu Bulletin, Volume 12, Issue 573, 14 February 1995, Page 11

Cutting the losses at Tangiwai Sawmill

Tangiwai's new sawmill equipment looks pretty ordinary at first glance — there's saws buzzing, chips and sawdust flying and slabs of timber rushing along conveyors as yoli would expect. It's when you see the laser lights, computer and video screens and joysticks that the layman begins to notice signs of the $1.4 million worth of changes at Winstone Pulp International's Tangiwai mill. Having seen a slight drop in production during January due to settling-in teething problems after the equipment was installed, staff are now reaching and bettering daily budget targets. Mill assistant manager Paul Trow said by March operators should be fully trained on the new systems and the target increases should be reached. The aim of the upgrade is to increase production by 20 per cent. "We're getting better figures every day," he said last week. Part of the improvement is the increased production rates, but also there is an increase in the conversion of logs to timber of around three per cent. The new equipment sees less wood going to dockings, and sawdust and more to timber. Under the old system the first cut made, to get a flat side to work on, meant a round-sided slab was cut which went to waste. Now, a flat face is shaved off and a flitch (slab) is cut in one pass. The next improvement sees sawing the log taking the most of the good wood possible. This computer controlled system of 'taper cutting' allows the operator to take the most of the good clear wood from the outside of the log. The operator mechanically manoeuvres the log and the three 'knees' which hold the log while sawing takes place to line it up to cut off the least amount of waste wood. Laser lines are shone along the log to help the operator see which is the best position in which to line up the log for cutting. The log is then flipped and the knees repositioned to the best line to cut the next face. Now, instead of chipping good clear outer wood, a section of tapered centre

wood is left for chipping. Next in the line is the new edger, less spectacular but very important for increased performance. The edger operator uses one fixed and five moveable saws to allow the best grades and sizes of timber possible out of each flitch (slab) of timber. He can alter the saw's positions almost instantly, for every flitch, whereas the old edger had fixed blades which meant they were committed to cutting a certain size of timber. Once again laser beams shine along the flitch to show where the saw lines will be, aiding the operator in making decisions on the best possible combination of timber sizes to cut. The choices of sizes of timber cut for both machine operators is also dictated by the current orders, which is monitored on computer. The operators are constantly updated on how the orders are filling so they can make their cutting decisions — for 30 different sizes and grades — accordingly. The next new piece of equipment is an anti-sap stain spray unit. (Sap stain is the black mould that is sometimes found in the grain of pine). The unit improves on the Mill's old system both in speed and environmental effects. The old system saw packets of timber dipped into a treatment tank, then set aside on a drip pad to dry. Turn to Page 12

Tangiwai upgrade

From Page 11 Now each length of timber is passed through an enclosed fine spray tunnel which captures all the excess treatment material . The lumber passes out of the unit touch-dry, so it can be handled straight away. Mr Trow said while the investment has meant some staff being taken off the production line, they have been redeployed elsewhere at the mill. He said generally the staff morale has been high, seeing the company investing in the plant, and is rising every day as productivity increases. Tangiwai 's main products are framing timber for the domestic market — Auckland and Bay of Plenty — and cutting grade timber (which is further processed) for the overseas market.