In our country, due to the restriction of the ability and level of machining, the Precision large circular-arc drum-shaped roller can only be machining in using the method of changing the two terminal of the roller into double chamfer, and then the problem of the deficiency of carrying capacity is solved.

Calculation about the arc glass cover of a lift for sightseeing on a bridge;

The anti-drift principle and drift-reduction rate of double-foil shield spraying technology was studied in this paper.

Machine tool guideways perpendicularity error brings hole position,line and arc contour error.