Pressure in the contact is very high due to the large instantaneous force caused by the impact with the ball.īouncing ball tribometers have been used to determine the shear characteristics of lubricants under high pressures such as is found in ball bearings or gears.Ī pin on disc tribometer consists of a stationary pin that is normally loaded against a rotating disc. Frictional force is determined by finding the rotational speed of the ball using high speed photography or by measuring the force on the horizontal surface. The friction produced in the contact between the ball and the surface results in a horizontal force on the surface and a rotational force on the ball. During a typical test, a ball is slid on an angle along a track until it impacts a surface and then bounces off of the surface.

Reciprocating pin (usually referred to as SRV or HFRR) Ī bouncing ball tribometer consists of a ball which is impacted at an angle against a surface.Tribometers are often referred to by the specific contact arrangement they simulate or by the original equipment developer. Equipment and methods used to examine the worn surfaces include optical microscopes, scanning electron microscopes, optical interferometry and mechanical roughness testers. In most test applications using tribometers, wear is measured by comparing the mass or surfaces of test specimens before and after testing. Then using the general equation for friction force:į = μ N The coefficient of friction, µ, when the system is stationary, is determined by increasing the hanging mass until the moment that the resting mass begins to slide. An example is that of orthopedic implant manufacturers who have spent considerable sums of money to develop tribotesters that accurately reproduce the motions and forces that occur in human hip joints so that they can perform accelerated wear tests of their products.Ī simple tribometer is described by a hanging mass and a mass resting on a horizontal surface, connected to each other via a string and pulley.

Often tribotesters are extremely specific in their function and are fabricated by manufacturers who desire to test and analyze the long-term performance of their products. It was invented by the 18th century Dutch scientist Musschenbroek Ī tribotester is the general name given to a machine or device used to perform tests and simulations of wear, friction and lubrication which are the subject of the study of tribology. Pneumatic tribometer Static Friction Tribometer Hydrogen TribometerĪ tribometer is an instrument that measures tribological quantities, such as coefficient of friction, friction force, and wear volume, between two surfaces in contact.

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Equation maker for bouncing ball