straight guide bushes are usually applied to simple molds or molds with thin plate; I-type headed guide bush is mainly applied to complicated molds or the guide of fixed and moving molds of large- and medium-sized molds; II-type headed guide bush is principally used in the guide of injection mechanism. To reduce friction, an oil storage tank can also be cut in the guide bush or use a self-lubricating guide bush( Use MoS2 in the annular groove of steel guide bush and use solid graphite in the side wall hole of high-intensity brass guide bush)