TE 87 Multi-station Circular Translation Pin on Disc Machine is manufactured under licence from Dr Vesa Saikko, Laboratory of Machine Design, Department of Mechanical Engineering, Helsinki University of Technology. It is based on his Super-CTPOD machine design. It is a highly compact, cost effective and easy to operate wear test device for the evaluation of prosthetic joint materials. It can be supplied with a total of either 50 or 100 sample test stations. This capacity makes it possible to test many different material combinations simultaneously, under identical test conditions.
Although nominally a pin on disc machine, the motion is not that of a conventional machine in which the disc rotates about its own axis, with corresponding uni-directional sliding at the pin face. In the TE 87, the disc follows an orbital path without rotation. The pin track may be adjusted to be circular, elliptical or linear reciprocating.
This orbital motion following a circular or elliptical path is similar to that generated in multi-axis hip joint simulators and produces wear that correlates well with these types of device and with in vivo behaviour. Typically, for tests with a UHMWPE pin loaded against the Co/Cr disc, the wear is confined exclusively to the pin, with well-rounded PE debris generated, with a size range of 0.1 to 1.0 microns, with the majority of particles of 0.25 microns diameter.
The machine is floor standing and comprises a load module, a pin carrier module, a motion module and a test bath.
The pin carrier module provides the location for pin carrier rods, each carried in a polyacetal sleeve and restrained against rotation. The loading module mounts on top of the pin carrier module such that each loading cylinder aligns with a carrier rod.
The motion module comprises a platform mounted on an x-y slide assembly and actuated by a double scotch yoke mechanism driven by an a.c. gear-motor. The frequency of motion is controlled by inverter and may be adjusted in the range 0.8 to 1.2 Hz. The displacement on one axis is set at an amplitude of 5 mm (stroke of 10 mm) and the amplitude on the orthogonal axis may be set at 0 mm (reciprocating), 1, 2, 3, 4 mm (elliptical orbital motion) or 5 mm (circular orbital motion).
Flat-faced pin samples, with a recommended diameter of 9 mm (with UHMWPE) are pressed onto the end of the carrier rods, using a simple hand tool provided. Spherical ended samples may also be used if required.
Disc samples are 28 mm diameter and may be of varying thickness, but 10 mm is typical. These may be manufactured from a variety of materials as required. Each disc sample is machined with an O-ring groove and with two blind holes for location in the test bath. With a silicone O-ring in place, a short tube of shock-resistant PVC may fitted to each disc to form a local receptacle with a fluid capacity of 16 ml. Typical fluids used are diluted calf or bovine serum, but tests may also be run dry or with alternative lubricants or solutions.
The disc samples, with tube receptacles fitted, are mounted on pegs in the bottom of the test bath. No screw fixing is required. Temperature is controlled by circulating water through the test bath and around the receptacles. An integral water circulating system is provided for this purpose, drawing water from the mains supply with a thermostatically controlled discharge to waste. By maintaining a bath temperature of, say, 20 °C, evaporation and degradation of test fluid can be minimized.
Test Configuration: Pin on orbiting disc Pin on reciprocating plate Number of Test Stations: 50 or 100 Pin Diameter: 9 mm (typical) 12.5 mm (maximum) Disc Diameter: 28 mm Fluid Sample: 16 ml Frequency: 0.8 to 1.2 Hz Amplitude: 10 mm Load: 71 N @ 4.25 bar air pressure Maximum Air Pressure: 10 bar Motor Power: 180 W Controlled Parameters Test Load Circulating Fluid Temperature Circulating Fluid Flow Rate Number of Cycles Orbiting Frequency Services Electricity: 1.5 kW 240 volt 50 Hz single phase plus neutral 1.5 kW 110 volt 60 Hz single phase plus neutral Compressed Air: 4 cfm at 8 bar (typical) Cooling Water and Drain: 0.5 l/min (typical) Footprint: 1100 mm x 750 mm
Paper # 606 A hip wear simulator with 100 test stations Saikko V J Eng Med, 2005, 219, 309-318. Paper # 711 Performance analysis of an orthopaedic biomaterial100-station wear test system V Saikko Proc. IMechE Vol. 223 Part C: J. Mechanical Engineering Science 2010 DOI: 10.1243/09544062JMES1626 Paper # 712 The wear of PTFE against stainless steel in a multi-directional pin-on-plate wear device T J Joyce, P Thompson, A Unsworth Wear 255 (2003) 1030–1033 Paper # 713 Comparative Wear Tests of Ultra High Molecular Weight Polyethylene and Cross-Linked Polyethylene T J Joyce and A Harsha World Tribology Congress 2009, Kyoto, Japan Paper # 740 Large Capacity Wear Testing Vesa Saikko Chapter 4, Biotribology, Edited by J. Paulo Davim, 2010, ISBN: 9781848212756 Paper # 804 Laboratory Wear Testing V Saikko Chapter 7, Tribology and Bearing Surfaces in Total Joint Replacements, Edited by Robert M. Streicher, 2011, ISBN: 9788178955254 Paper # 952 Comparative wear tests of ultra-high molecular weight polyethylene and cross-linked polyethylene AP Harsha, TJ Joyce Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine May 2013 vol. 227 no. 5 600-608 Paper # 953 Advances in tribological testing of artificial joint biomaterials using multidirectional pin-on-disk testers D Baykal, RS Siskey, H Haider, V Saikko, T Ahlroos, SM Kurtz, Journal of the Mechanical Behavior of Biomedical Materials Available online 29 May 2013 Paper # 965 Can Pin-on-Disk Testing Be Used to Assess the Wear Performance of Retrieved UHMWPE Components for Total Joint Arthroplasty? S M Kurtz, D W MacDonald, S Kocagöz, M Tohfafarosh, D Baykal BioMed Research International Volume 2014, Article ID 581812 Paper # 1059 A tribological assessment of ultra high molecular weight polyethylene types GUR 1020 and GUR 1050 for orthopedic applications BJ Hunt, TJ Joyce Lubricants 2016; Volume 4, Issue 3 Paper # 1095 Effect of Contact Area on the Wear and Friction of UHMWPE in Circular Translation Pin-on-Disk Tests Vesa Saikko Journal of Tribology November 2017, Vol. 139
Falex Tribology NV Belgium DSM Research Netherlands Zimmer Switzerland Newcastle University UK Exponent USA
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