The chatter always occurs in precision hole boring process

which is one of the main abnormal cutting conditions that influences the quality of workpicece. To solve this problem

firstly

the dynamic model of regenerative chatter is established

which is the main type chatter in boring process. Then

the chatter suppression mechanisms of variable speed cutting method and variable structural stiffness method were analyzed. Through comparing

it can be seen that the chatter suppression mechanism of variable speed cutting method is similar to variable structural stiffness method

but the variable structural method is much more suitable for deep hole precision machining. Secondly

the magnetorheological (MR) intelligent boring bar was developed for application of variable structural stiffness method. The dynamic characteristics of MR intelligent boring bar can be adjusted by MR fluid

whose stiffness and damping parameter can be controlled by applied magnetic field. Finally

the experimental setup of MR intelligent boring bar was built on the CA6140 type lathe. A series of experiments were carried out

and the results show that the method can suppress chatter efficiently and surface quality of workpiece can be improved significantly

whose roughness decreased from10μm to 1.5μm.