How to know the long grain and short grain of duplex board

duplex board grey back and duplex board white back by screen printing forming there a certain direction, generally parallel to the direction of operation of 

duplex board longitudinal and transverse direction perpendicular to the operation.

Vertical and horizontal can usually use the following methods to identify. 

1, visual method. 

Some flat duplex board can tell a little attention to a total vertical and horizontal direction, facing the look more obvious, along the fiber 

orientation to portrait. Post in the longitudinal direction of the longitudinal web. 

2, tear method. 

If visual method is difficult to determine the vertical and horizontal, you can hand the duplex board tear, if the gap straight, smooth, 

compared with longitudinal; if split oblique or jagged, and even tear the gap at the exit of the hierarchy, compared to the 

transverse direction. Or press note paper to distinguish, the tensile strength is greater longitudinal. 

3, tension measurement instrument.

a dedicated tensile testing machine to test the value of a large portrait to landscape a small value.