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I See What I Saw
SEESAW is a system for monitoring and optimising the usage of sawblades in a saw mill.
Introduction
The European sawmill industry has a total annual turnover of around 15 billion Euros and employs some 100,000 people. The timber industry at large provides jobs in rural areas where employment opportunities are often poor. Europe is an important producer of timber, both for its internal use and for export. As the market for construction materials continues to become more competitive, timber must be as good or better than other materials in terms of its usability, that is it must be sawn to dimensional tolerances as good as those of steel or brick. With increasing global competitive pressure, European sawmills need to produce wood of superior quality.
An important part of the conversion of logs into sawn timber planks takes place in breakdown saws. In these saws, a major consideration is the optimal use of sawblades to maximise the yield from a piece of timber and to avoid expensive blade breakages. This short article describes a system for optimising the use of sawblades, thereby improving the quality of timber and increasing the profitablity of the sawmills that produce it.
The benefits
SEESAW enables a sawmill to get better information on log feed speeds and consequently to sharpen and use sawblades better. This results in significant gains in the quality and volume of timber sawn, together with a reduction in costs. SEESAW enables a rapid return on investment due to:
fewer unplanned stoppages due to sawblade breakage or wear
improved sawing accuracy and precision
improved filer room practices
increase in production volume.
For a sawmill with a capacity of 30,000 to 50,000 m3/year, every hour of lost production costs 3,000 to 5,000 Euro. A broken bandsaw blade can stop production for up to two hours. If 10 unplanned blade changes could be prevented, the SEESAW system would pay for itself. Sawblade related downtimes can amount to as much as 100 hours per year representing a potential return on investment in less than three months.
Background
The European sawmill industry has a total annual turnover of around 15 billion Euros, producing some 65 million m3 of wood and employing some 100,000 people. There are several thousand sawmills in Europe, which vary greatly in size. Most sawmills are SMEs, with even the larger producers employing only about 20 staff. Most timber is produced in the larger mills producing over 10,000 m3/year. There are about 400 sawmills in the EU with a production capacity of 30 to 50,000 m3/year.
Europe is an important producer of timber, both for its internal use and for export. With increasing global competitive pressure, European sawmills need to produce wood of superior quality. A prerequisite for good quality is sawing accuracy. When this is under control, given various production conditions, it is possible to use smaller sawing allowances, and thus increase yield and profitability.
The problem
The breakdown of logs to sawn timber is one of the core processes in sawmilling. Each log and its cutting process are unique. Although the control of sawblade behaviour determines quality, yield and consequently profitability, most European sawmills have no real-time means of getting information about the cutting process and take only infrequent manual control measurements.
The most basic sawmill process is the breakdown and resawing of logs and cants (partially squared logs). The developments of the SeeCon system have resulted in a real-time measuring and control system which directly addresses this process. However, during the marketing and installation of SeeCon systems, further new requirements have arisen. The most important of these is the measurement and reporting of the surface area (which depends on log length) sawn by an individual sawblade. This information is essential for the efficient operation of a sawmill. Currently there are no such monitoring systems commercially available on the market.
The central objective of the SEESAW development was to develop a control and monitoring system for the optimal usage of sawblades in a sawmill. The project integrates a real-time data gathering, management and reporting system into an automatic vision-based control system. The principal objectives of the work were:
improved sawn timber size control
integration of automatic sawblade measurement
integration of sawn timber length measurements
integration of a visual reporting system.
Optimal yield comes from a correct combination of saw feed speeds and sawblades for each log size, state of season and saw machine. Moreover, well maintained sawblades lead to improved accuracy in sawing resulting in raw material savings and better timber quality. Improved knowledge of sawblade behaviour leads to better filing and maintenance with resultant improved yields.
The solution
SEESAW is a control and monitoring system for the optimal usage of sawblades in a sawmill during the log breakdown process. SEESAW integrates a real-time data gathering, management and reporting system into an automatic vision-based inspection system.
inX Systems Oy developed the original SeeCon system to control the size of rough sawn timber leaving the saw. SeeCon operates reliably in the demanding conditions of a sawmill. SeeCon measures the thickness of all pieces of timber leaving a saw machine. This data helps the sawmill to make decisions on sawblade changes and maintenance.
When sawnlength and log diameter data are integrated into sawn size data, the total 'picutre' of the sawing event comes available. In SEESAW a line speed encoder and saw set-up controller gather data which are integrated with those from SeeCon. The resulting information is used to control and optimise the saw and sawmill operations. SEESAW provides information on :
log usage
sawn timber length by size
sawblade behaviour
the yield of the sawmill. |
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| Contact: |
Jyri Paavola
inX Systems
Lintulammenkatu 6, FIN-04250 Kerava, Finland
Tel: +358-9-41 333 111
FAX: +358-9-41 333 151
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| Email: | jyri.paavola@inx.fi |
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