Force testing, where a known force is applied to a sample in
a controlled manner, has become an integral part of the
manufacturing process, as Carl Bramley, export sales
manager, AMETEK Test & Calibration Instruments, explains

The forces required to insert or extract
a component; make or break an
electrical contact and prove that a
component can withstand an applied load
after a number of cycles all are common
measurements that can be made on the
production floor. These can validate a
product’s ultimate performance, helping to
determine its lifecycle, safety factor and
warranty period. The measurements also are
used to identify non-conforming products
more immediately within the manufacturing
process, frequently with a real-time ‘pass/fail’
analysis based on tolerances, so that
efficiencies in production and eliminations
in waste and scrap can be achieved.

Modern force testing
Force measurement systems can be
used to measure peak loads, average
loads, break loads based on varying
sample break characteristics and
statistical analysis such as mean,
percent variation and standard
deviation. Test data can be displayed
graphically, or as an overview
showing batch results or as statistical
results. Use of the appropriate
sample holder or test jig means that
these forces can be applied in such a
way to allow tensile testing,
compression
testing, sheer
testing,
flexural
testing or
advanced
multi-stage testing to be carried out.

Tests can also be carried out to
conform to ISO or ASTM
testing procedures.

Touch screen menus
help the operator
quickly and easily
select the appropriate
method of measurement
for the application. With USB and Ethernet
connectivity, data can be saved to a flash
drive or exported directly to Excel or OLE2
formats.

Testing examples
Force testers can be used to test raw
materials, finished product and packaging
materials as part of a factory floor quality
control process. The rich array of sample
holders and test jigs available include
bending and flexural jigs; compression
plates; peel and friction grips and wire, yarn,
thread and cable grips. There are chuck
fixtures for holding small cylindrical samples
during tension or compression testing and
self-tightening eccentric roller grips for all
types of flat samples such as rubber, plastic
film, plastic dumbbells, paper and cardboard,
sheet metal and foils. There is also a
specialised range of fixtures for food testing.

Testing of raw material before the
manufacturing process even begins helps
minimise waste by ensuring defective
material does not enter the process. Force
testing of raw materials such as metals,
plastic, wood, wire, fibres etc, provides a
good measure of their mechanical properties.

Once manufacture begins, force testing could
be used at a variety of stages of the
manufacturing process right up to testing of
the final product. By testing during the
manufacturing process, early identification
of problems can reduce the amount of waste
and rework that may be required. With
literally thousands of different tests possible,
I shall just highlight a few from different
industries:
Automotive and aerospace: quality testing
of gaskets through a pull to break test;
force required for push button activation;
spring clip insertion and extraction
Electronic components: solder strength on
components; insulation crush strength on
cables/looms; keypad actuation strength
Plastics: compression strength of plastic
containers; peel strength; snap on/snap off
Cosmetics: lipstick break strength; liquid
soap dispenser action; soap/wax hardness
Medical devices: in-line testing of catheter
and cannula components to test the
bonding strength of the parts; metered
dose inhaler actuation strength.

Finally force testing also has a key role to
play in packaging testing for the finished
product, from testing bottle tops and
enclosures to inline compression testing of
‘egg tray’ packaging used to protect mobile
phones in their boxes.

Latest generation
The latest generation of digital force testers
brings some of the functionality, accuracy
and precision previously reserved for more
complex, dedicated materials testing
machines to the factory floor. For example,
the new Chatillon CS Series of single column
force testers from AMETEK Test &
Calibration Instruments (Figure 1) feature
the latest linear guide technology, pre-loaded
ball screws and advanced software
compensation systems, ensuring a high level
of precision displacement measurement.

Control is provided via an industrial-grade
touch screen (IP65), with no external PC.

Key to the versatility of these systems is the
availability of an extensive range of grips
(Figure 2), fixtures, extensometers and
software options and a wide range of work
tables which means that they can readily be
adapted to applications in plastics,
packaging, medical devices, automotive,
electronics, textiles, rubber and
pharmaceuticals.