What Is Material Testing?
Materials testing is a well-established technique used to determine the physical and mechanical properties of raw materials and components from a human hair to steel, composite materials and ceramics. To meet the challenges posed in testing a wide diversity of materials AMETEK Test & Calibration Instruments offers a comprehensive range of high performance materials testing machines, designed to make accurate and repeatable force measurements in the range from 0.1 N to 300 kN (0.0225 lbf - 67443 lbf). Depending on the machine, elongations of between 1 micron and 2.5 m (98.4 in) can be measured. Typical testing capabilities include: • Tensile Strength • Compression • Flexure / Bend Strength • Coefficient of Friction • Puncture Strength • Tear Resistance • Peel Strength • Shear Strength • Delamination Strength • Bond Strength • Adhesion Strength • Break Load • Creep and Stress Relaxation • Crush Resistance • Deformation Strength • Ductility • Elastic Limit • Elongation • Rupture Strength • Young’s Modulus • Toughness Applications of Material Testing Machines Materials testing machines are suitable for use in quality control, production, laboratory, R&D or education. The extensive testing capabilities listed above mean that there is a diverse range of applications in markets such as: • Plastics • Rubber • Packaging • Automotive • Medical • Pharmaceutical • Metals • Paper and Board • Wood • Textiles • Electronics • Building Materials Different Types of Material Testing Machines Universal materials testing machines can be configured for a host of applications by simply choosing the appropriate load cell, grip for holding the sample, optional materials testing software and accessories such as extensometers, thermal cabinets and high temperature furnaces. Lloyd Instruments product range is structured into machines with different maximum load frames. Thirteen ‘Plus’ machines cover the range from 1kN-300kN (225lbf-67443lbf). Robust, high stiffness load frames are at the core of each materials testing system, whilst advanced electronics ensures accurate data collection exceeding the requirements of BS EN 7500-1 and ASTM E4. Single column configurations are used for lower force instruments, while twin columns are used for higher force requirements. Single Column Test Machines Single column instruments are designed for applications requiring force from 1-5 kN (225-1124 lbf). These bench mounted test machines provide a generous working area. Dual Column Test Machines Dual column instruments are available in bench mounted versions (5-50 kN (1124-22481 lbf)) and floor mounted versions (100-300kN (22481-67443 lbf)). The bench-mounted instruments are ideally suited routine quality control testing or complex multi-stage tests in the mid force range. Floor mounted materials testers are robust, heavy duty test machines, which feature a large working area. Load System Compliance Compensation Advanced frame design and load chain compliance (or stiffness) compensation means extension errors of less than 5 microns at full load are achievable for many compression and flexural testswithout the use of an extensometer. In most cases, the instrument deformation is tiny compared to that of the sample, so the error is insignificant. Stiffness compensation, however, improves measurement accuracy in applications where the system deformation is a larger proportion of the total measurement. High Elongation Sample Testing Extended height frames are available for all single and dual column systems for testing high elasticity materials or for testing samples up to 2.5 m (98.4 in) high depending on the model used. Customised Material Testing Machines Many materials testing applications require specially adapted instrumentation for a variety of reasons, which may be related to the specific application itself, or simply due to constraints on space in which the the equipment may be sited. To deal with this eventuality, Lloyd Instruments can produce customised versions of its universal testing machines. Examples have included testing machines with an extra wide distance between the columns and shortened versions to fit into a particularly small laboratory space. Fixtures and Accessories for Material Testing Machines Lloyd Instruments offer a wide variety of fixtures and accessories for its material testing machines. They are summarised in the following. Grips and Fixtures for Material Testing Machines The extensive range of standard grips, probes, fixtures and flexural jigs transform universal materials testing machines into specialist testers for the broadest possible range of applications. Lloyd Instruments grips and fixture offerings come in a variety of sizes, gripping surfaces, styles and capacities: • Wedge action grips for rigid samples • Pneumatic action grips for faster sample clamping • Vice action grips for films and semi rigid materials • Compression platens available in many sizes • 3 and 4 point bending jigs • Self tightening grips to reduce operator fatigue • Bollard grips for wire, rope, thread and fibre testing In many cases, non-standard applications can be accommodated through the design of a special jig or fixture to hold the particular sample without needing to modify the testing machine itself. Sample holding design solutions have ranged from full robotic needle/syringe test beds to measure needle sharpness and syringe performance to jigs for testing fibre optic cable strength and a special spaghetti and noodle compression attachment designed to make thickness measurements of the cooked product in order to calculate a range of parameters including sample compressibility. Load Cells for Material Testing Machines Load cells are available in a range of capacities from 5 N to 300 kN depending on the machine used and test to be performed. They are high accuracy, self-identifying full bridge strain gauged load cells, designed to meet international standards for load cell accuracy. Extensometers for Material Testing Machines Plug and play extensometers are designed for accurate measurement of elongation and determination of results such as modulus, yield and proof stress amongst others. • Contacting strain gauge type for rigid materials such as metals • Automatic contacting long travel type for rubbers and elastomers • Non-contacting laser type for high elongation materials such as plastic film Elevated and Low Temperature Materials Testing Thermal chambers and furnaces are available for testing from -70°C to +1200°C. Chambers and furnaces can be optionally software controlled. Elevated and low temperature materials testing is used in a wide range of industries. Compression Cages for Material Testing Machines Compression cages are manufactured for testing very large samples or awkwardly shaped full assemblies such a complete car seat. The test machine is mounted above the cage, allowing a full range of compression tests to be carried out on samples having greater than 400 mm width. These rugged assemblies are constructed from aluminium and built to individual customer specifications. The sides of the cages can be open or shielded with wire mesh or polycarbonate panels. Compression platens can be integrated into the frame and mounted on guide bearings to ensure alignment. Testing and Control Software for Material Testing Machines Whilst all instruments operate as stand-alone units, there is an increased requirement for automation of operation through software control via a PC. All of the Lloyd Instruments ‘Plus’ materials testing machines can be PC-controlled using the company’s NexygenPlus test and control software. NexygenPlus provides an extensive library of pre-defined test set-ups based on international standards, and can also be used to set up routine tests or create an advanced multi-stage test. It allows the operator to control and monitor all aspects of the system from a single intuitive user interface. This ensures fast, reliable and powerful testing in addition to fingertip control of data analysis features. NexygenPlus is supplied as a complete all-inclusive package with no additional modules required. The package includes: • Complete standards library • Complete suite of test set-ups • Video and still picture capture system • Security and audit trail utility • SPC trend and histogram charts • User interface customisation facility • Data export utility for connection to LIMS and SPC packages For specialist testing, test creation wizards are included for tension/compression test, tear and peel test, cycling test, flexural test, friction test and the user configurable test for multi-stage testing. The software also supports National Instruments data acquisition cards to allow communication with external equipment. Summary on Material Testing Machines Lloyd Instruments allow an enormous range of materials testing applications to be carried out in a diverse range of industries. In doing so, they can be used to help: • Develop world-class products through extensive product development testing • Contribute to cost effective manufacture of products to the highest quality • Demonstrate the superior performance of products • Ensure that product is manufactured in conformance with international or industry standards • Verify supplier specifications • Provide traceable test results