Babulnath Engineering Manufacturer and exporter best
quality all kind of Plastic & Scientific testing machine such are Universal
Testing Machine, Tensile Testing Machine, Hydrostatic Pressure Testing Machine,
Compression-O-Meter, Hot Air Oven, Muffle Furnace,0°C Cooling Chamber ,Sheet
Molding Press, Tearing Strength Tester, Impact Tester ,Carbon Black Dispersion
Test Apparatus, Tearing Strength Tester, Opacity Test Apparatus, Pipe Impact
Tester, Carbon Temperature Waterbath, Constant Temperature Waterbath , Muffle
Furnace, VSP/HDT Test Apparatus, Melt Flow Index Test Apparatus, Oil Bath Machine,
MFI Testing Machine, Humidity
Chamber Machine, Conditioning Chamber Machine
Tensile testing is less commonly used than compression
testing, because it is more difficult to grip the sample in such a manner that
a tensile load can be applied. If the ends of a bar of uniform cross-section
are clamped, compression of the ends causes stress concentrations to develop,
which promote failure in the vicinity of the clamp. This problem is usually
overcome by making the sample wider in the vicinity of the clamp and ideally
the sample will fail at its narrowest point. Therefore stress is calculated
from the minimum cross-sectional area (see diagram A).
More unusual sample mounting techniques for Melt Flow Index Tester:
Cummings and Okos
(1983) tested noodles using rapid-setting glue to secure them in a metal tube
slightly larger in diameter than the noodles. The tubes were attached to a
tensile testing machine via wires and loops which allowed the sample to align
itself with the line of application of the force (see diagram B). Murase and
Merva (1977) wrapped tomato skin samples in aluminium foil, clamped the ends,
severed the aluminium foil to expose the sample, and then soaked the sample in
solutions of known water potential while applying a tensile force (see diagram
C). Here at Stable Micro Systems we have used a similar sample supporting
device – a business card – to enable the mounting of fragile samples such as a
hair fibre.
An aperture is cut into the mounting card and the strand
affixed either side of this aperture via a hot glue bead. The mounting card can
then be secured in tensile grips and just prior to testing the card cut either
side of the sample so that it is then ‘free-standing’. We have also encountered
researchers – needing to grip food samples that are either moist or prone to
slippage – who have used liquid nitrogen to dip the sample ends into before
mounting as a means of providing a more solid grip face. We also occasionally
recommend the wrapping of the ends of the sample with cardboard before
gripping, so that the tensile rig grip faces tighten against the cardboard
rather than potentially damaging the surface of a softer sample.
Over the years, Stable Micro Systems have developed a wide
range of MFI Testing Machine, each addition
being as a result of the requirement for a more ideal and successful way of
mounting a specific sample. There are of course a couple of basic and popular
tensile rigs that suit many requirements.
These universal testing machines are specifically designed
for demanding testing situations and are suitable for applications from all
fields, whether for quality control or for research projects. Zwick universal
testing machines are developed, produced and assembled exclusively in Germany.
All universal testing machines can be modified as required to suit individual
requirements. You can visit their site at http://www.babulnathengineering.com/
No comments:
Post a Comment