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Optimising cross cutting saw doubles value-added production at Allies Creek

AustralianTimberman, September 2001

Innovative hardwood Processor Queensland Sawmills Pty Ltd has doubled production of its value-added range of furniture and decking timbers with the installation of a revolutionary optimising cross cutting system.

The Opti-Kap 2002 system with defect and quality marking and full optimisation has been put to work at the Allies Creek sawmill, cutting spotted gum sections into furniture grade material straight off the planning machine - "and the accuracy speed and finished result has been remarkable,” says company principal John Crooke.

Commissioned by Southern Cross Engineering (Aust) Pty Ltd, the computerised Opti-Kap 2002 reduces manpower, boosts production capacity per employee, maximises utilisation and dramatically cuts machine setting times.

"Travelling at 168 metres a minute with wood pieces 400-500 mm long, the optimiser is incredibly accurate; every piece is the same." Mr Crooke said.

"Everything goes through the machine. Before this we had to make timber up into lengths that suited the docking without the waste. Now thanks to the Opti-Kap's computer we can take out nine different lengths at one pass. If we wanted we could take out 12 different lengths."

The versatility and pin point accuracy of the optimiser with a possible accuracy of +/- ½ mm per minute is reflected in its ability to satisfy a diversity of production-line requirements at the one time - completing orders for decking, balustrades and furniture grade material.

Producing a truckload of furniture timber a day, Queensland Sawmills has doubled production and is restricted only by the ability to feed the docker. "The faster we run in the timber, the faster the machine processes it," Mr Crooke said.

"We're machining at around 20 metres a minute and the optimiser is handling at around 168 metres a minute."

The Opti-Kap 2002 infeed conveyor consists of a 4000 mm driven roller conveyor and a 6500 mm driven belt conveyor on which the measuring unit is mounted. Drive and turning rollers are made with a camber which ensures that the belt always stays in the middle of the rollers.

The belt conveyor is driven by a servo motor through a notched belt driver which ensures a minimum of maintenance and slackless driving. The fences are polyurethane covered rollers which reduce noise when the workpieces hit the fence.

A measuring unit with a pair of height adjustable top pressure and measuring wheels are mounted on the belt conveyor. At this point, a reference photoelectric sensor has been fitted.

The measuring wheels, which run directly on the workpiece, ensure exact measuring even though the workpiece may slide on the belt conveyor during the start/stopping of the saw.

The reading head is mounted so it scans the luminescent lines made by the operator on the surface of the workpiece both defect and quality markings.

The raw workpiece is measured while on the move; when the reference photoelectric sensor is activated, the measuring begins.

"If a board has a knot in it, we scribe or mark the defect and the machine cuts it out - gone, finished - then the finished product goes straight into bundles,” Mr Crooke said.

"Before this we had to take it down and re-dock it, then re-pack it and then check the docker and the lengths. Now we accept the lengths as being perfect.

"We completed a special furniture project requiring 18,000 pieces of one particular length in a day and a half - all pre-counted by the machine - and there were thousands of other pieces in the order."

Up to 25 different orders can be saved in the Opti-Kap programme. Each order contains up to 50 different cutting lists and each cutting list contains order names, numbers, quality, lengths, number of pieces, sorting, values, priorities, widths and ID codes.

The Opti-Kap 2002 offers four optimising options:

1. Minimisation of waste - work pieces are cut in the most efficient way to keep the waste factor at an absolute minimum.
2. Value optimisation - for each length a value is specified. Taking into consideration the quality of the wood and the specified value, the optimum cutting combination is calculated and the workpiece is cut accordingly.
3. Parallel production - when several various lengths in the cutting list have to be finished simultaneously, each length is automatically optimised according to an internal calculated value.
4. Optimisation for finger jointing - optimising on entire lengths for finger jointing or as a combination of workpieces from the cutting list and finger jointing pieces for 100% utilisation of the wood.

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