Moisture Analyzer for Paper and Board Samples
By Lim Xu, Export Manager
How paper and board QC teams sample sheets, compare halogen results with oven drying, and choose a moisture test for converting control.
A moisture analyzer for paper helps a QC team check how much mass a sheet or board sample loses during drying. For a lot acceptance decision, the result must relate to the sampling plan and reference method in the specification. A fast result is useful only when the lab knows what it represents and can repeat it.
Why paper moisture matters for converting
Moisture can affect printing, copying, curl and dimensional stability, as ISO 287 explains. That is why the sampling point matters. A mill checking a roll before shipment and a converter checking incoming board may be answering different questions, even when both report a moisture percentage.
Write down whether the result is for a sample, a sheet position or an entire lot. Avoid treating a single convenient cut piece as a lot average. If variation across the reel or pallet is important, define where and how many pieces to take before testing.
What do ISO 287 and TAPPI T 412 measure?
ISO 287 describes an oven-drying method for the moisture content of a lot of paper and board. Its published scope includes corrugated and solid board when no material other than water is volatile under the specified conditions. TAPPI T 412 is a separate method for moisture in pulp, paper and paperboard. Check the current edition and your customer's specification before selecting either procedure.
A halogen analyzer is a different heating arrangement from a reference oven. It should therefore be compared on the actual paper or board grade before its readings are used against a limit established by an oven method. Coatings, adhesives and other components may change the interpretation of mass loss.
Our halogen temperature-settings guide lists oven temperatures that published methods use as reference points, including ISO 287 for paper and board, and explains confirming a setting on your own material.
Questions about a model or a test? Email Amy Zhao, Export Manager, at [email protected].
Prepare paper and board samples consistently
Keep samples closed between collection and weighing so they do not exchange moisture with room air. Cut pieces that represent the planned position in the sheet or board, and document any removal of liners, coatings or attachments. Spread the pieces on the pan without stacking them into a dense pile.
For corrugated board, decide whether the question concerns the combined board or an individual layer. Those are different samples. Record the chosen preparation so that operators do not switch between whole-board and separated-layer results without noticing.
The KHT halogen moisture analyzer uses halogen heating and an integrated balance. Its L1 product record lists laboratory paper moisture and verification of shop-floor rapid readings as applications. Ask KHT to confirm the sample preparation and program for your specific grade before treating a result as equivalent to an oven method.
Pin meters and analyzers answer different questions
A pin or handheld meter can help operators screen material at a point on the production floor. A drying analyzer weighs a removed sample before and after heating. The results are generated by different physical methods, so a numerical match should not be assumed.
Use the shop-floor method to spot changes, then establish how its readings relate to the laboratory method for the grades and moisture range you handle. When the two disagree, check sampling location and sample conditioning before adjusting either instrument.
Match analyzer results to the oven method
Prepare matched pieces from the same collected material. Run the specified oven method and a proposed halogen program, then compare the results over the range relevant to your acceptance decision. Record differences and repeatability, particularly near a limit. Keep the program settings and sample handling with the result.
Do not copy a temperature from another grade without checking the method scope. ISO 287 and TAPPI T 412 define their own procedures; the halogen program needs its own documented comparison for the material being tested.
Further reading and methods
Frequently asked questions
Can one paper sample represent a whole lot?
Only if the sampling plan supports that conclusion. ISO 287 is concerned with the moisture content of a lot, including variation; a single cut piece may miss that variation.
Is a pin-meter reading interchangeable with oven moisture?
No automatic equivalence follows from the two readings. Compare them on the actual grade and sampling locations before using one to make decisions based on the other.
Discuss paper moisture testing with KHT
We sell direct from our factory, so you work directly with our factory team. Questions about a model or a test? Email Amy Zhao, Export Manager, at [email protected]. Tell us the paper or board grade, sampling plan and reference method.
