Friction characteristics of moving joint surface from the micro and macro scale

Purpose - The nonlinear friction disturbance of the moving joint surface of the feed system can lead to the residual vibration of the system, prolong the stability time of the system and reduce the motion precision and machining precision of the machine tool. This paper aims to concern the vibration between joint surfaces caused by nonlinear friction. Design/methodology/approach - The model is established from the micro and macro scale based on the LuGre model. The friction characteristics of the moving joint surface are explored. The friction experiment of GCr15 pin and 45 steel disk is designed and the influence of lubrication condition, speed, acceleration and normal load on friction characteristics are studied. Findings - Among the drive speed, damping and stiffness, the negative gradient effect of friction, which is characterized by the difference of static and dynamic friction coefficient Delta mu, is the main cause of friction vibration between moving joint surfaces. Sufficient lubrication, a proper increase of speed and acceleration, a reasonable reduction of normal load can reduce the negative gradient effect, which can weaken the vibration caused by the nonlinear friction and improve the friction characteristics of the moving joint surface. Originality/value - In the past studies, more attention has been paid to revealing the relationship between the relative speed and friction, while the acceleration is often ignored. The negative gradient effect of friction is improved in this paper by changing the contact conditions. Research findings of this paper effectively improve the friction characteristics of the moving interface and provide the basis for restraining the nonlinear vibration between the moving interfaces. Peer review - The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-11-2019-0476/