Plint and Partners Ltd

Citation

(2000), "Plint and Partners Ltd", Industrial Lubrication and Tribology, Vol. 52 No. 1. https://doi.org/10.1108/ilt.2000.01852aad.003

Plint and Partners Ltd

Plint and Partners Ltd

Keyword: Plint

Plint issue a regular tribology update presented as a series of 12 individual sheets giving an introduction to each machine and related technical publications where appropriate.

Abstracts are presented here to help the reader select relevant sheets.

Those in search of further information can view the Plint Web Site (http://www.plint.co.uk) where full product specifications, colour pictures and detailed technical publication listings are available.

Tribology update Issue 7: sheet abstracts

Sheet 1: DN. Acquisition of Deltalab-Nene (DN) servo-dynamic test systems. On 26 July 1999, Plint completed the acquisition of Deltalab-Nene Ltd, a company specializing in custom solutions for servo-dynamic testing of materials and components. The company has an extensive range of solutions to linear, rotary and multi axial actuation, involving hydraulic, electro magnetic, electro mechanical, electropneumatic and hybrid systems. Real time and adaptive control, based on derived parameters, are key features of the company's control and data acquisition systems and software.

Sheet 2: TE76. Micro-hardness mapping. Measurement of the macro-hardness of materials is a quick and simple method of obtaining mechanical property data for the bulk material from a small sample. It is also widely used for the quality control of surface treatments processes. However, when concerned with coatings and the surface properties of materials that have a fine microstructure, are multi-phase, non-homogeneous or prone to cracking, macro-hardness measurements will be highly variable and will not identify individual surface features. A micro-hardness indentation, by contrast, will be at a scale appropriate to typical material microstructures. Single point measurements clearly are not sufficient to define the properties of a surface. By fully automating the indentation process and sample movement, significant areas can be scanned in order to determine a range of material properties and present them as a colour map of the surface. These can be used alongside maps of surface roughness and chemical composition.

Sheet 3: TE77. Windows software and high speed data acquisition for TE 77. In 1998 Plint launched COMPEND 2000, its Windows 95/98/NT compatible sequence programmable control and data acquisition system. This was designed for use with the Plint SLIM 2000/SUPERSLIM serial link interface modules. COMPEND 2000 has become the standard control and data acquisition system for all tribology test machines, including the TE 77 high frequency friction machine. The SUPERSLIM platform also permits the addition of a high speed data acquisition expansion board that can be triggered from within a standard test sequence. Both systems are available as upgrade packages to existing TE 77 machines.

Sheet 4: TE66. Development of the micro-scale abrasion (ball cratering wear) test. The surface engineering of components for wear resistance is now an established technology and the number of successful applications has increased rapidly. However, one of the problems in making an assessment of wear resistance is the fact that wear rates of hard coatings are very low. The ball cratering or micro-scale abrasion test technique has been found suitable for measuring these low wear rates.

Sheet 5: TE89. Hip and knee joint friction simulation. Artificial joints operate in the mixed lubrication regime, not with the full fluid films observed for natural human joints under physiological loading. As a result, artificial joints will experience higher friction and wear due to metal-plastic contact. Full fluid film lubrication is achieved in the natural joint as a result of the high degree of compliance of the joint surfaces. One way of improving the performance of the artificial joint is to introduce a more compliant surface. Measuring the joint friction and plotting the resulting Stribeck curve (the relationship between friction coefficient and (velocity x viscosity x radius/load)) is of fundamental interest in the design and development of better artificial joints. Plint now offers a machine for hip and knee friction measurement.

Sheet 6: TE99. Universal wear machine. The Class I pin on disc contact (pin loaded vertically downwards onto a horizontal rotating disc) is the most widely used of friction and wear test configurations. A number of commercial machines exist, including three offered by Plint (TE 67, TE 79 and TE 88). Another well established test rig, known as the Eyre/BICERI Universal Wear Machine, was until recently manufactured and marketed by the UK company BICERI Limited. BICERI ceased trading in June 1999 and Plint purchased the rights to this machine. The Universal Wear Machine has proved a popular choice for materials specialists worldwide and it fits very comfortably within the existing Plint range. Current users, therefore, can expect to receive product support for their equipment and also benefit from mechanical, electronic and software upgrades.

Sheet 7: TE68. Improved erosion testing. A recent (1998) UK Department of Trade and Industry funded project identified that 60-70 per cent of wear problems in industry are in the abrasive and erosive wear regimes. The commonly available test methods, however, do not necessarily give good predictive data on materials performance for the application. It is only in comparatively recent years that a more detailed fundamental understanding of the important factors controlling abrasive and erosive wear processes has been achieved. Plint now offers abrasion and erosion test rigs with a high degree of control over the critical test conditions.

Sheet 8: TE65. Development of the sand/wheel abrasion tests. The wear resistance of a material cannot be predicted reliably from simple properties such as bulk hardness, elastic modulus or tensile strength. There is therefore a need for a reliable and convenient approach to the study of abrasive wear properties. The standard sand/wheel abrasion test is widely used, but has a number of well-documented limitations when it comes to predicting wear resistance for applications. Plint's TE 65 Multiplex sand/wheel abrasion tester offers an alternative measurement system suitable for use with a range of abradants and provides a higher degree of control over parameters critical to controlling the abrasion process.

Sheet 9: CD 115. Development of traction drive CVTs: the role of two roller test machines. Transmission technology has developed rapidly in recent years in response to regulatory pressures for better fuel economy and lower emissions and driver demands for improved performance and ride quality. Developments have been in the use of modulated torque converter clutches on traditional automatic transmissions, the wider use of belt drive continuously variable transmissions (CVTs) and the commercialisation of the traction drive CVT. Tribology has played and will continue to play a key role in the success of these systems where the fluid, the materials and the surfaces are all vital to the transmission's performance. In the case of toroidal CVTs, Plint two roller machines have played an important part in the development process.

Sheet 10: TE 72. Flexible two roller machine for rolling contact fatigue and lubricant studies. Two roller machines are used in the study of materials and lubricants for highly stressed engineering contacts such as gears, cam and follower and other traction transmitting devices. Using either pure rolling or combined rolling/sliding conditions, lubricant performance in terms of load carrying capacity, scuffing resistance, EHD film quality and traction coefficient may be studied. The rolling contact fatigue properties of the roller materials may also be studied. Plint's TE 72 Multiplex Two Roller Machine offers the possibility of running a wide range of two roller tests with a high degree of control functionality.

Sheet II: TE92HS. High speed rotary tribometer. Following the success of the TE 92 microprocessor controlled rotary tribometer, Plint used the same machine platform to produce a high speed rotary tribometer. The TE 92HS can operate up to 10,000rpm, but with special modifications it can run at 20,000rpm. The machine is suitable for running rolling four-ball tests, and for testing high speed journal bearings and other low friction bearings.

Sheet 12: TE92S. Taper roller bearing (KRL) shear stability test. The KRL taper roller bearing test method is concerned with the determination of the mechanical shear stability of lubricating oils with polymer additives, such as gear oils, engine oils, damper oils and automatic transmission fluids. For this a taper roller bearing is used to shear the fluid. The purpose of the test is to determine the permanent drop in viscosity caused by mechanical stresses under practical conditions. In many cases companies require to have a machine dedicated to such tests and this does not warrant the cost of a multi-functional machine.