They concluded that for evaluating temperatures and stresses generated in the cutting tool, numerical methods, such as the finite element method, offer a more promising approach compared to direct measurement techniques. Marusich and Ortiz developed a Lagrangian finite element model of orthogonal high speed machining. Both ductile and brittle fracture initiation and propagation were accounted for during processing; an essential feature for determining shear-localized chip morphologies . The method helps in proper selection of machining parameters.
It is now a well-established research and development tool for evaluation of lubricants, materials, coatings and surface treatments. With the TE 77, sliding contact conditions can be matched to a number of machine elements. Specimens may either be of a standard format, or cut from real components, preserving surface finish and other properties.
Although not included in the inter laboratory test programs, the TE 77, in conjunction with selected adapters, can also accommodate tests specimens and provide test conditions as specified in the following standards: The system provides sequence control of load, frequency and temperature plus data acquisition of measured parameters, at both low and high speed.
Moving Specimen The moving specimen is mounted in a carrier. A number of different geometries can be accommodated by using a range of simple clamping fixtures.
Two fixed cams are provided as standard allowing strokes to be set from 0 to A continuously variable double cam arrangement is included, which allows continuous variation of the stroke in the range 0 to Fixed Specimen The fixed specimen is located in a stainless steel reservoir.
The reservoir is clamped to a block that is heated by four electrical resistance elements and the temperature is monitored by a thermocouple pressed against the side of the specimen or holder. The reservoir can be moved sideways on the heater block so that multiple tests can be performed on one fixed specimen.
Friction Measurement The piezo electric transducer used to measure the friction force has a sensitivity of typically A charge amplifier converts the measured force to a proportional voltage. This is followed by a low pass filter, which fixes the upper cut off frequency of the measuring system.
This serves to suppress transducer resonance. Final scaling of the signal for voltage output takes place in a second stage amplifier. This eliminates the effects of d. The instantaneous friction signal may also be logged in bursts using the integral high speed data acquisition interface.
This gives signal decay times of up to ,s, sufficiently long when compared to typical measurement time scales for the zero not to have moved significantly during the measurement.
Electrical Contact Resistance Measurement The moving specimen carrier is electrically isolated from the drive shaft and therefore from the fixed specimen. This allows a millivolt potential to be applied across the contact using a Lunn-Furey Electrical Contact Resistance Circuit.
Variations in this voltage are indicative of the level of metallic contact, provided that both test specimens are conductors of electricity. This measurement may be used for observing the formation of chemical films from anti-wear and extreme pressure lubricants, the breakdown of non-conducting layers and coatings or the build-up of oxides.
The instantaneous value of contact potential is also available for data logging as high speed data. Temperature Measurement Many wear processes are driven by temperature, be they the formation of oxides on the surfaces, the transformation of microstructure, the formation or break-down of lubricant additive or other tribochemical films, the melting of the surface the PV limit of the material or thermal stress induced failure.
To be more specific wear occurs as the result of the dissipation of frictional energy in the contact and this is irresistibly accompanied by a rise in temperature. The frictional energy is generated by the combination of load and sliding speed and its distribution and dissipation is influenced by other contacting conditions such as size and relative velocity.
In the reciprocating contact of the TE 77, sliding velocities are deliberately maintained at low levels in order to minimise frictional heating and, in the case of lubricated tests, to promote boundary lubrication.
Minimisation of frictional heating means that contact temperature can be controlled effectively by controlling the bulk temperature of the fixed specimen. The temperature is measured with a thermocouple pressed against the fixed specimen and control is by software PID with PWM output.
Wear This is not directly monitored on the TE 77 and assessments are made from wear scar sizes on the moving specimen and wear volumes on the stationary specimen. Specimen sizes are small enough to be placed in SEM and other surface analysis equipment for detailed chemical analysis of surface films.
This measurement can be used as an indication of the combined wear of both surfaces and for identifying wear transitions. Data is stored to hard disc in standard spread sheet compatible file formats.
Sequence Control Tests are defined by a sequence of steps, each step containing set-point, data recording rates and alarm level information. Set-points may be adjusted by step change or ramp.
The test sequence is followed unless interrupted by the operator or an alarm. Set-points may also be adjusted manually using on screen toggles. Low Speed Data Analogue input channels are sampled and data logged at a maximum rate of ten samples per second.
Time smoothing and averaging functions are provided by in hardware and software.Applications: A Literature Review Suryanarayanan K. 1, R. Praveen 2, S. Raghuraman 3 Research Assistant, SASTRA University, Thanjavur, Tamil Nadu, India 1 example of such a combination includesa family of materials known .
Background. The TE 77 High Frequency Friction Machine is a versatile reciprocating tribometer with a maximum stroke of 25 mm and maximum load of 1, N. Zinc oxide can be called a multifunctional material thanks to its unique physical and chemical properties.
The first part of this paper presents the most important methods of preparation of ZnO divided into metallurgical and chemical methods. The mechanochemical process, controlled precipitation, sol-gel method, solvothermal and hydrothermal method, method using emulsion and microemulsion.
Paper # Wear evaluation of journal bearings using an adapted micro-scale abrasion tester LI Farfán-Cabrera, EA Gallardo-Hernández Wear – Volumes –, Part B, . The mach inability and mechanical properties of the metal matrix composites was studied by performing machining in lathe, hardness test and tensile test.
In this paper mach inability is evaluated.
Study of Aluminium Metal Matrix Composites – Review Balamurugan Adhithan1, Dhanusiya B2 1, This paper provides a literature review, on machining of Aluminium metal matrix composites (AMMC) especially the particle reinforced Aluminium metal matrix composites. This paper is an attempt to give brief account of recent work over .