Automotive hydraulic tappet is the core component of modern automobiles to reduce engine noise and adjust valve clearance. Connect one end to the rocker arm and the other end to the cam. It is mainly composed of precision components such as plungers, one-way valves, one-way valve springs, and tappet bodies. The fully automatic assembly line for automotive hydraulic tappet developed by ACA company: realizes the fully automatic assembly and online monitoring of plungers, one-way valves, one-way valve springs, tappet bodies, and return springs. The tempo can reach 3 seconds per piece. Multiple rotary workstations are used to achieve fully automatic feeding and assembly of plungers, one-way valves, and one-way valve springs. The outer diameter of the plunger body is measured and automatically grouped online, and the inner diameter of the plunger body is measured and automatically grouped online. Then, the fully automatic assembly, online performance testing, and non-conforming product management of the plunger body, plunger body, and return spring are completed.