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In-line moisture measurement in wood-based panel production: Where should measurements be taken?

GreCon MOISTURECONTROL

  • Published 17 September 2026
After the dryer, before the press or at the finished sheet: moisture can be measured at various points in the production process. However, not every measurement point provides the same information. The key factor is what information is required for the process.

The measurement point determines the conclusion

In the production of MDF and chipboard, moisture content can be measured continuously at several points. However, depending on the measurement point, the value reflects a different material condition.

Measuring point What question is being answered?
After the dryer What moisture content has the material reached after drying? 
Before the press What moisture content does the material have as it enters the pressing process?
On the finished board What moisture content does the produced material have?

This means that the selection of an in-line moisture measurement system does not begin with the sensor, but with the process requirements.

The measurement principle plays a second key role. MOISTURECONTROL IR measures moisture non-contact at the material surface. MOISTURECONTROL MW uses microwave technology and penetrates the material to take a reading. Which technology is used therefore also depends on what information is required at the respective measurement point.

After the dryer: Has the desired material condition been achieved?

Immediately after drying, in-line moisture measurement shows the condition in which chips or fibres leave the drying process.

The trend over time is particularly important here. If the moisture content rises or falls, or if fluctuations increase, the change becomes apparent whilst production is in progress. The measurement initially indicates that the drying result has changed. The cause must then be investigated on the basis of further process parameters.

A consistently lower moisture content than required is also relevant. It may indicate that the material is being dried more thoroughly than is necessary for the subsequent process – and that energy is therefore being wasted.

The choice of suitable measurement technology depends on the specific installation situation. MOISTURECONTROL MW, for example, can be used in chutes, screw conveyors or hoppers. MOISTURECONTROL IR is suitable, amongst other things, for material on conveyor belts and for measurements at the inlet or outlet of a dryer.

In addition to the measurement position, the way in which the material is present and transported at the measurement point is therefore also a decisive factor.

Grey industrial inline dryer
In-line moisture measurement using MOISTURECONTROL after the dryer reveals the condition of the material as it leaves the drying process and how stable the moisture content remains throughout the process.
GreCon MOISTURE CONTROL MW installed on a production line
GreCon MOISTURECONTROL MW is a penetrating in-line moisture measurement system based on microwave technology and can also be used in the mat forming process.

Before pressing: What is the initial state of the material at the start of the pressing process?

Before the press, the focus is on a different issue. Here, moisture measurement describes a material condition that feeds directly into the pressing process.

During hot pressing, the mat moisture content influences, amongst other things, heat transfer and steam formation, as well as the conditions for the curing of the binder. It is therefore a relevant input parameter for the manufacture of MDF and chipboard. However, no universally applicable target value can be derived from this. The appropriate moisture range depends, amongst other things, on the material, mat structure, binder and pressing conditions.

Under certain conditions, excessive moisture content can contribute to increased vapour pressure, thereby raising the risk of defects such as bubbles or delamination. Conversely, a very low moisture content may indicate that the material has been dried more thoroughly than is required for the process.

The measurement principle also plays a role here. MOISTURECONTROL IR measures the moisture content on the surface of the moulded mat non-contact from above. MOISTURECONTROL MW, on the other hand, operates by penetrating the material and can also be used during the mat moulding process. It is therefore not only the moisture value that is crucial, but also what moisture information is required prior to pressing.

On the finished board: how does the product’s moisture content develop?

After pressing, the focus is no longer on an input parameter, but on the final state of the product. Continuous moisture measurement can show whether the product’s moisture content changes during ongoing production and whether the specified range is being achieved at this stage of the process.

This value does not replace a full quality assessment of the board. However, it provides transparency regarding how the moisture content of the produced material develops. Changes can thus be detected at an early stage and subsequently investigated further within the process.

For sheet-like materials, MOISTURECONTROL MW can be used non-contact with a gap sensor. Possible measurement positions include, for example, the cooler outlet or the sanding line.

Folding rule featuring a stylised water droplet design

In-line measurement and sampling serve different purposes

Random sampling and laboratory measurements remain key components of moisture determination. They provide information about a specific sample at a particular point in time.

An inline measurement supplements this snapshot information with a continuous trend. It reveals how moisture content changes during production – for example, due to short-term fluctuations or a slowly drifting process.

In-line measurements highlight changes at an early stage and attribute them to a specific stage of the process. The moisture measurement initially shows what is changing; why it is changing must be clarified by examining the overall process.

Selecting the measurement point and measurement method for in-line moisture measurement

When selecting an in-line moisture measurement system, three questions should be answered first:

  1. What process question is the measurement intended to answer?
  2. At what point is the relevant material condition present?
  3. Should the moisture be measured at the surface or deep within the material?

This is followed by factors such as the installation situation, material flow, temperature, measurement range and the selection of the appropriate measurement system. GreCon MOISTURECONTROL utilises infrared and microwave technology for various measurement tasks in wood-based panel production.

The right moisture measurement for your process

Do you want greater transparency regarding moisture in your process? Our measurement technology experts will show you where measurement delivers the greatest added value and which MOISTURECONTROL solution is best suited to your plant.

We look forward to hearing from you.

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