What is unvarnished area and no printing area?
1) No printing area is a blank space on PE tube shoulder, about 3mm. PE tubes are extruded one time directly, and printing machines are unable to print that angle due to the bending. It is avoidable by making second heading.
2)Unvarnished area is at the tube tail to ensure the firmness of tail sealing.
The length may be different based on different sealing machine. Most common length is 6mm and 12mm.