Trouble name

Blocking

Film is easy to drop when it is folded. Blocking occurs between the internal or external sides on the tube type film, whereas the folded sides cause blockage while the film is taken up in the cylinder.

Non-standard transparency

Transparency of the film deteriorates.

Fish-eye

Fisheye is a lump with the shape of a small ball that is formed inside the film. It is called a "fisheye" since it contains lots of transparent material like the eye of a fish. The thermally degraded material created inside the bubble has a yellow, brown, or black color. A small lump in the shape of a bubble is generally called a "booth"(meterials) , base on its appearence. Materials with the low molecular weight attached on the die lip is also called a fisheye.

Wrinkle

Appearance deteriorates due to wrinkles that are formed on the film surface. Shape of the wrinkle Include vertical, sliding, horizontal , ear, and drop wrinkle(curved shape).

Stretching

Stretching of the inflated film occurs slightly or severely. Stretching includes sectional stretching, stretching of both sides, stretching that is bent when spreading the film to several meters wide, ear stretching such that the ear is elevated when taking up the film, and stretching of the film center.

Poorly mixed

When observing through the film or bubble, it is not transparent completely. This state is called poor mixing.

MD Spliting

When removing the general purpose HDPE tube, it splits easily. Such phenomena of easy splitting in the horizental direction is called the MD splitting. This defects is severe for HDPE than the low density grades of LDPE. In some cases, it occurs depending on the molding condition.

Tear Strength in Folded Side

When pulling out the folded side of the HDPE film, it split easily and its shape has a linear formation. Folded side of the film is easily split in the vertical direction.

Improper material change

When the woker changes grades during film extrusion, defects may occur due to difference in the M.I(Melt Index) and resin density.

Masterbatch Unmixable

Speckles appear on the film surface due to the uneven coloring when mixing color masterbatch.

Corona

Surface processing is performed to increase the printing capability. Corona appears because of tube wrinkles, inconsistency of the film tensile force, and improper electric discharge when processing the surface.