Removing woodworking machine noise by adjustment

The problem

This case study describes a way of setting up the machine which can be dangerous is some situations. The method is not to be used when the machine is used for planing when the timber is fed across the top of the cutter.

Timber planer-thicknessing machines usually produce high noise levels, characterised by strong tonal content. The tone was being produced by air turbulence between the cutting head and the table. In one such machine in a joinery shop, it was found that when the machine table was slightly opened away from the cutting head, the noise level appeared to be quieter. It was also discovered that noise from the extraction of dust was capable of making a significant contribution to overall noise levels.

Tests were carried out to determine whether the machine could be set to run continuously at a lower noise level. The findings of these tests are shown in the table below.

The solution

The table was set at a 25 mm clearance from the cutter, and airflow was restricted to a volume just sufficient to clear the dust. The productivity and quality of operation were not compromised by increasing the gap between the cutter and the table.

This way of setting up the machine can be unsafe in some situations - it is not to be used when the machine is used for planing when the timber is fed across the top of the cutter.

The cost

None. (1995)

The result

A noise reduction of between 7 dB with the machine cutting and 13 dB with the machine idling.

Source

Information supplied by Sound Research Laboratories Limited, Wilmslow