Today's saw blades have to comply with increasing standards. On the one hand, the demand for cutting quality is on the rise, on the other, higher throughput is sought after.
Band saw blades are used in a wide variety of industrial sectors. They are used for sawing wood, metal, plastics, textiles, leather, and aerated concrete, to name a few. Nevertheless, the main focus of the use of band saws lies in woodworking.
The woodworking field is characterized by ever-increasing quality requirements, including the so-called log band saws, a special band saw that produces sawn timber from tree trunks.
In order to guarantee machine safety and meet the cutting requirements, the saw band must be in optimal conditions, and cracks in the saw must be absent. If a tear occurs in the saw blade, not only the quality of the saw cut is affected, the saw band might also tear. Furthermore, if the saw band breaks at full speed in production, this can damage neighboring components or pose a grave danger to people. Often times, machine downtime for several hours happens as a result, especially in fully automated sawmills.
Sawing boards from logs
To prevent this, a non-destructive and automated test for continuous process monitoring is recommended. If cracks appear on the saw band, this can be calmly welded, ground, and changed immediately. Machine downtime can be reduced to a minimum and the quality of the cut remains at the same high level.
With the eddy current method, saw bands can now be easily monitored during operation. A modern testing device enables non-destructive testing of metallic surfaces for defects such as cracks or point defects. These are automatically recognized and evaluated by high-frequency electromagnetic fields.
Under optimal conditions, defect resolutions of up to 30 µm are possible. In addition, surfaces are neither damaged nor soiled by eddy current testing, since the testing is typically contactless.
On this note, FOERSTER offers the STATOGRAPH, an eddy current testing device for testing saw bands. The saw band is scanned in conjunction with a robust eddy current sensor, which can also withstand large wood chips. After the test, the results are automatically classified as OK and not OK in due time. This way, cracks that arise on the tooth base can be recognized in a timely manner, which gives the plant operator the opportunity to react immediately to prevent worse.
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