Productivity News
Volume
10-No. 3
We
help you produce more for less!
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Dear
Frederick,
Get
the Precise Hardness Results You Need....
and
here's how to select the right
hardness tester!
Phase
II+ Bench Hardness Tester Model
No. 900-331
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Whether in a materials testing
laboratory or on the shop floor,
there is a hardness tester to suit
your specific requirements.
The two main categories are
bench-top hardness testers and
portable hardness testers. But,
within these two groups,
there are many more criteria
to consider when selecting an
instrument from the enormous
selection available.
The
operating environment, material
types, the accuracy required and
standards compliance are a few of
the many considerations.
Phase
II+ Portable Hardness Tester
Model No. MET-U1A
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Non-metallic hardness testing of
rubber compounds and plastics
typically require another type
of hardness testing instrument. Durometers
are used for these materials and
are also discussed below.
This issue of Productivity
News focuses on the
basics of selecting the right
hardness testing instrument for
your special needs.
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Bench
Hardness Testers
Phase
II+ Bench Hardness Tester Model
No. 900-370
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Bench hardness testers are usually
used in laboratories, workshops, tool
rooms and inspection labs. If
operating conditions are severe,
instrument toughness will be an
important consideration, for example
on the floor of a heat-treat shop.
Operator skill and the degree of
accuracy required will also dictate
the model and features. Analog
dial reading testers are typically
easy to operate yet can still be
highly sensitive for accurate readings
and good repeatability. Consider
testers with digital displays for
greater reading ease and greater
precision.
Motor driven instruments provide extra
test force control for further reading
precision.
More expensive bench hardness testers
may feature fully automated
load/unload procedures and more
sensitive and accurate readings.
Micro computer controlled instruments
with USB outputs may come with
built-in mini printers or PC
programmable scale conversions, dwell
time controllers, statistical
capabilities and test counters.
Other important features to consider
are features that simplify determining
averages and min/max readings, S, R,
menu selectable systems, upper/lower
limit settings, a large test result
memory capacity and curved surface
auto correction.
And,
depending on your needs, the
instrument could be capable of the
regular Rockwell scales plus automatic
conversions to HB, HV, HLD and b.
Accessory selection will be dictated
by your applications.
Accessories to consider are different
types of indentors (diamond conical,
balls, etc.), test blocks and test
tables, anvils (flat, spot, Vee,
etc.), test counters and statistical
displays.
Advanced instruments can digitally
compute standard Rockwell and
Superficial Rockwell Hardness scales
in a single versatile tester with an
interface that converts hardness
scales with a push of a button. Such
instruments feature a complete micro
computer controlled operation that can
drive the hardness tester to highly
sensitive yet very accurate readings.
Multi-year warranties and lifetime
technical support is offered by
reputable hardness tester instrument
manufacturers, so you can test away
with confidence.
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Portable
Hardness Tester Selection
Phase
II+ Model PHT-1700 Portable
Hardness Tester with D Impact
Device
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Portable
hardness testers suit testing large
metal parts. Some models are suited to
soft metals and others to hard metals.
Some
economically priced portable hardness
testers are loaded with features to
measurethe surface hardness of a broad
variety of metals on flat and round
surfaces. Most come complete with impact
device, calibrated test blocks and
rugged carry cases.
Operation
of these units typically involves
loading the impact body, placing the
impact body on a test piece and
pushing a button to begin testing.
Important
features to look for include an easy
to use keypad, a large LCD display
with back light, automatic conversions
to Brinell, Rockwell, Vicker and
Shore, automatic mean values as well
as min & max values and ample
multi-functional data storage capacity
Phase
II+ Model PHT-1740 Portable
Hardness Tester with DL Impact
Device for Gear Teeth hardness
testing
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Useful
standard accessories beside the base
unit are calibrated test blocks, carry
case, cleaning brush and of course a
readily understood operation manual. Top
of the line portable hardness testers
often incorporate multiple statistical
and printing features, high accuracy
and ease of use bundled in rugged body
for lightning fast test results with
the touch of a button. With a USB
output, these portable units will
print directly to your PC or to a
built-in printer.
Usually, the tool steel should be
close to 1" thick solid material
for reliable readings.
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Durometer
Testers
Phase
II+ Shore A Durometer
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Durometer
testers are used for testing the
hardness of soft and hard rubbers and
plastics in Shore A and Shore D
readings.
Shore A
durometers are used to measure soft
rubbers and soft plastics and Shore D
durometers are used to measure hard
rubbers and hard plastics.
Soft
Grades
Typical soft rubbers would be soft
vulcanized (ie tyre) and natural
nitrile. Other elastomeric
materials include (rubber & rubber
like): GR-S, GR-1, neopene, thiokol
and flexible polyacrylic ester
compounds. Other suitable test
materials are wax, felt and leather,
ie. materials that normally yield
under fingernail pressure, such as the
heel on your shoe.
Hard Grades
Hard rubbers and hard plastics
including grades such as rigid
thermoplastics, plexiglass, thermo-poloystrene,
vinyl, sheet, cellulode acetate and
thermo-setting plastics. Laminates
(ie formica) are also considered hard
grades. Paper filled calendar
rolls and calendar bowls and materials
that would not normally indent under
fingernail pressure, such as a pocket
comb or bowling balls.
Durometers should be engineered for
consistent accuracy and be lightweight
and easily handled for accurate
positioning and use.
Popular durometer features include
an ample measuring range and deviation
standard and resolution for the range
of materials being tested, a
digital read out, accurate and
repetitive deviation plus conformance
to ASTM, ISO and DIN standards. The
ability to lock in peak values and to
determine statistics such as mean
values, max, min, number of
measurements and standard deviations
are important for many users.
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We hope you found this informative
and useful and we welcome your
comments.
Sincerely,
Frederick J. Oille, P.Eng.
Industry Depot |
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OTHER
MATERIAL TESTING INSTRUMENTS
Industry
Depot is your source for a wide
choice of other material
non-destructive testing instruments;
Call
888-849-8034 to discuss any of your
special needs.
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