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1 OVERVIEW
The NDT James Instrument’s Digital Hammer is a digital meter used for measuring
the hardness of paper rolls. Menus are used to navigate through the functions of
the instrument. This manual covers the use of the W-D-2005 system, the W-D-
1705 and W-D-1505 systems. The differences among these units are the
capabilities to print the results in the field and the ability to upload data from the
instrument to a PC. The other functions of the systems are the same and this
manual covers the use of the all three systems.
The W-D-1705 system includes the field printer to obtain a hardcopy of the results
in the field, but it does not have the ability to upload data from the instrument to a
PC. The rest of the capabilities of the W-D-1705 are the same as the capabilities of
the W-D-2005 described in this instruction manual.
The W-D-1505 system does not include the field printer and neither has the
capability to upload data from the unit to a PC. Taken into account the mentioned
differences in capabilities between both systems, this instruction manual covers the
required material for the proper use of the W-D-1505 system.
The hardness tester is an instrument which is easy to use, to identify areas within a
paper roll structure with different properties (different stiffness or strength). It is also
a useful tool for quick and approximate measurement of the compression strength
of manufactured concrete products.
The principles on which it works are based on the rebound impact of a hammer on a
piston which rests against the surface of the material: the greater strength and
stiffness of the roll, the greater the rebound impact.
The test makes possible to estimate the strength of paper rolls by the energy
absorption of the material of the impact energy delivered by the hammer. The
energy absorption depends on the strength and stiffness of the paper roll, in the
absence of large inert lumps or clusters of lower density. From the impact and
using the rebound number, these areas can be identify.
With the aid of the test hammer the quality of paper rolls in different industries can
quickly be examined.
