NBS Crumpling device

The NBS Crumpling device is especially used for banknote testing. It consists of a so called fork for rolling up the paper sample and a device in which the rolled paper is crumpled under a fixed pressure.

IGT Testing Systems has developed a device that prevents any variation in applied pressure. This NBS Automated Pressuring Device with driving unit ensures that the plunger is always pushed down with the same force. When the weight of the crumpling device starts to rise, it exerts a pressure of 100 N over a fixed period of time, thus eliminating the danger of the crumpled ball being pushed too far. The crumple test shows more reproducible test results if the automated driving unit is used. All versions of NBS crumple testers fit on the NBS Automated Pressuring Device which can therefore be ordered for use with all existing devices, article number 422.250.

General

The crumpling test simulates the extreme conditions of handling of banknotes and can be executed using either wet or dry printed and unprinted samples. When paper is crumpled the interlaced fibres are disturbed, the bonds are loosened, and the disarranged structure becomes less compact, weaker and more permeable to air. The effect of the crumpling treatment is measured by the change in air permeability (porosity), water absorption and/or in tensile strength. The properties of the paper before and after crumpling are measured on the same or an identical paper sample.

Method of operation

• The (banknote) paper is brought rolled up with the fork.
• The rolled up sample is inserted in a tube.
• Force is applied to crumple.
• After crumpling the diminished properties of the sample are checked.

Standards

The crumpling test method is standardised according to the American National Bureau of Standards (NBS)