Drilling Resistance Measurement
Approved procedure, quick results
Just know what nobody sees!

The IML-RESI systems are based on the principle of drilling resistance measurement. In this process, a drilling needle is pressed into the wood at a uniform feed rate.

In this way, structures, internal defects or residual wall thicknesses of trees and wood can be determined anywhere and without great effort. Depending on the instrument series, the obtained data can be recorded electronically and then transmitted, evaluated and processed on your PC with a specific software. This is a precision job that delivers significant results.

Drilling Resistance Measurement Results

The measurement profile delivers information about the internal condition of the wood. It show annual rings and density behavior as well as decayed zones in the wood.

The y-axis describes the drilling resistance in % (Amplitude height).
The x-axis describes the drilled way in cm.

Frequently asked questions about Drilling Resistance Measurement

This highly depends on the carefulness of the operator when inspecting where to conduct drillings. You want to avoid any nails or metal plates in any wood products as much as possible to preserve the bit. You will also need to be careful and aware of what type of substance the needle will exit through whether it’s sand, soil, granite or etc.

One of the best features of our drills, especially for arborists working in the field of inspecting live trees, is the fill-in methods of the bits. Our bits are 3mm and while they are already small in size, when the needle retracts it pulls the wood back in to fill the hole. Immediately after you would not be able to stick the bit fully back in the hole that was drilled. As time goes on the tree seals the hole.

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).

Application areas Drilling resistance measurement

IML drilling resistance systems

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