Feed force measurement
 Simply know what nobody sees
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In addition to the drilling resistance, it is the second measured variable of the IML-RESI PowerDrill® and provides additional information about the condition of the interior of the wood. This is because while friction on the drilling needle shaft (shaft friction) can have a strong influence on the drilling resistance, it has only a minimal influence on the feed force. As a result, the feed force together with the drilling resistance allows very realistic conclusions to be drawn for assessing the wood.

Display of the feed force as an additional measurement curve

The IML analysis software displays the feed curve together with the drilling resistance curve in a graph. Both curves are color-coded. For a precise evaluation of the measurement results, it is important to interpret both curves in relation to each other and not just one measurement curve in itself.

Without feed curve, shaft friction can hide wood defects

The friction of the shaft becomes greater the further the drilling needle presses into the wood. This influences the drilling resistance curve and causes the curve to rise steadily. The impact of the shaft friction cannot be separated from the actual drilling resistance. Consequently, the measurement curve of the drilling resistance curve remains rising even if the drilling needle penetrates a wood defect, although the drilling resistance decreases.

Measurement of the feed force provides high information value

In certain cases, only a comparison with the feed curve can show how strongly the measured drilling resistance curve is affected by the shaft friction and how large the damage in the wood actually is. This is because the feed curve drops significantly in the case of a wood defect and remains largely unaffected by shaft friction. In this way, especially the wood decay in the early stages becomes visible by the feed curve. Finally, the changes in the drilling resistance at that point in time are still so small that they can easily be covered by the shaft friction in the drilling resistance curve. The measurement of the feed force is also especially advantageous for hard wood species. This is because the shaft friction is higher with hard woods than with soft woods and therefore has a stronger influence. The additional measurement of the feed force makes it possible, especially with hard woods, to detect wood decay much earlier and more precisely than the drilling resistance measurement alone.

Frequently asked questions about Feed Force Measurement

The wood inspection drill measures the force of the needle turning through the wood product. For example, when the bit hits any soft decay the force on the graph will drop and if the needle hits a hard, brittle decay the graph will spike. If the bit runs through a cavity area the graph will drop measuring no resistance for the bit. The measurements are then collected on either a wax paper strip (F-Series) or electronically recorded for an instant upload (PD-Series).

Applications for feed force measurement

IML Wood testing systems for
feed force measurement


Articles about feed force measurement