How do Thickness Testing work?
Because paper is compressible, thickness depends strongly on the pressure applied, the area of the measuring foot and the dwell time. Standards therefore define the contact pressure, usually 100 kPa for paper, the foot diameter, and the time between lowering the foot and reading the value, so results from different laboratories are comparable. A dead-weight instrument applies the load through calibrated masses on a fixed-area foot and reads displacement with a dial gauge or digital sensor, while motorised instruments lower the foot at a controlled speed and hold the specified pressure for a set interval. Board and tissue thickness use larger pressures or different foot geometries, and corrugated board requires a foot large enough to bridge the flutes and a comparator plate, so the correct geometry is defined by the product standard rather than chosen freely by the laboratory.
Which Thickness Testing variants are available?
- Dead-Weight Paper Thickness Gauge — A dead-weight thickness gauge applies a defined load through calibrated masses to a fixed-area measuring foot and reads deflection on a dial or digital indicator.
- Motorized Paper Thickness Tester — A motorized thickness tester lowers the measuring foot at a controlled speed and holds the specified pressure for a set interval before reading.
- Digital Micrometer for Paper and Board — A digital micrometer measures the thickness of a single sheet, a stack or a laboratory hand sheet with a flat spindle under a defined low pressure.
- Corrugated Board Thickness Gauge — A corrugated board thickness gauge uses a large-diameter foot and a rigid comparator plate to measure the combined thickness of fluted board under a specified low pressure.
- Online Laser Caliper for Paper Webs — An online laser caliper measures sheet thickness continuously on the paper machine using non-contact triangulation heads on both sides of the web.
How do I choose the right variant?
Select the instrument from the product standard you test against. Flat paper and board are measured with a 100 kPa dead-weight or motorised instrument with a defined foot area, tissue papers require the smaller pressure and foot of their own method, and corrugated or heavy board needs a dedicated gauge with the correct foot diameter and a rigid comparator plate. Choose a motorised instrument when many readings are needed or when operator technique must be removed, and a dead-weight instrument when simplicity and direct traceability of the applied load matter. An online caliper is specified only when continuous reel or sheet thickness data must be recorded during production, since it is measured without contact pressure and therefore correlates with, rather than reproduces, laboratory values.
Where are Thickness Testing used?
Thickness Testing are specified in thickness and apparent density of paper and board, corrugated board caliper verification, tissue and lightweight paper thickness testing, converting and printing runnability checks, reel and sheet thickness profiling on the machine and comparison of suppliers for the same grade.
Which standards and certifications apply?
Work with Thickness Testing is commonly governed by ISO 534, ISO 3034, ISO 12625-3, TAPPI T411, TAPPI T551, ASTM D645 and IEC 61010-1. Instrument certifications such as CE marking are confirmed per configuration and never assumed.
What are the key considerations before purchase?
Condition specimens to the standard atmosphere before testing, because thickness changes with moisture and the change is not fully reversible within a short time. Clean the foot and anvil, since dust or fibre on the surfaces is added to the reading, and check the foot diameter and parallelism at intervals. Lower the foot gently at the defined speed, take the reading at the specified time and lift the foot between readings, and avoid taking measurements on the same spot twice. Verify the instrument with certified shims or gauge blocks at several points in the measuring range, and keep the calibration certificate with the instrument record.
