Research On The Influence Of The TFC Head Thermal Deformation On Its Flying Height Under Operational Condition

As the demand for large data improving，the requirement of the storagedensity and stability of hard disk drives is more and more higher. Decreasing thespacing between the head and the disk interface makes it available to achieve higherstorage density. With the Thermal Flying-Height Control (TFC) Technology aheater is deposited near the read/write element, and the flying height is reduced bywarming up the head through the heater to induce the protrusion. At the same timeTFC Technology can compensate the thermal protrusion induced by the read/writeoperation.This paper aimed to study systematically the influence of the TFC headthermal deformation on its flying height. Firstly, the present situation of the TFCtechnology research was analyzed. And based on the micro-nano heat transfertheory a heat transfer model between a slider and the air bearing with2-orderdiscontinuous boundary conditions combining continuous fluid motion equationswas proposed. The induced heat transfer coefficient was used as the boundarycondition to solve heat transfer problem. The improved simplified finite elementmodel of the slider was built and laid the foundation for simulation study.From aspects of the material, heat generation rate and location of the heater,the coefficient of thermal conductivity, length, thickness, height and power of theheater was deemed as the research object. The influence of factors above on thetemperature distribution, thermal deformation and air bearing pressure wasanalyzed by solving the heat transfer-structure-fluid multiphysics problem whichdescribed the TFC head heating situation. The results provides theory basis for theheater design.Based on the fact that the steady flying height of the TFC head is the outcomeaffected by the air bearing pressure and thermal protrusion, and on the interactionbetween the temperature rise and flying height of heads, an iterative method solvingthe heat transfer-structure-fluid-movement nonlinear multiphysics problem wasproposed and the steady flying height of the TFC head was obtained. The influenceof the discontinuous/continuous boundary conditions, heater power and height ofthe heater on the flying height was discussed. The necessity of using discontinuousboundary conditions was proved. And a new method to study TFC slider flyingheight was provided.