This paper introduces the working principles and application of the module of the adjustable three-roller rolling mill.

Taking the working principle of the imported material receiving machine as reference, an automatic material receiving machine was designed with the mechanical part adopting the combination of winding reel spiral motion and floating core structure, and with the electrical part adopting silicon_controlled DC servo motor.

Based on the focus pre-search a method is presented to measure the characteristics of the traverse focus error detection system:focus offset,focus error sensitivity and linear range.

The radial and tangential tilt angles between the emission laser axis of objective lens and test disc are the key parameters to develop,produce and detect the DVD traverses.

Checking technology of mobile phone chip is an important part of producing.