In the production process of aluminum foil, after rolling, finishing, annealing, packaging and other procedures, interlocking production process, any one link problem may lead to aluminum foil quality problems. Buy back the aluminum foil products have quality defects will not only affect the aesthetic, but also directly affect the quality of the products produced, or worse, directly lead to aluminum foil pull off the downtime, thus greatly affecting production efficiency. How to distinguish between good and bad aluminum foil?
According to the aluminum industry people's experience, to distinguish between good and bad quality aluminum foil can be directly detected with your "eyes". However, to distinguish between good and bad aluminum foil, we should first understand the common quality defects of aluminum foil, only have a number in mind, and then against the common quality problems of aluminum foil to check one by one, in order to put an end to the quality of defective aluminum foil into the warehouse.
| Alloy | 8021 grade |
| Temper | O - H112 etc |
| Width | 100mm - 1200mm |
| Thickness | 0.0053mm - 0.2mm |
1. Aluminum Foil Bruise
Aluminum foil bruising refers to the damage produced on the surface or end face of the foil after collision with other objects during handling or storage. Most of the bruises are caused by the lack of attention to aluminum foil packaging.
2.Corrosion
Aluminum foil surface and the surrounding medium contact, chemical reaction or electrochemical reaction, the defects produced on the surface of the foil, the surface of the corroded aluminum foil will lose its luster, and in serious cases, it will also produce gray corrosion products. The corroded aluminum foil will have a great influence on the beauty of the products produced at the end.
3. Surface bubbles
Aluminum foil with surface bubble defects will have irregular round or strip-like cavity bumps on the surface of the foil; the edges of the bumps are rounded and smooth, the two sides are asymmetric, and the distribution is irregular, and the surface bubbles will make the force at each point of the foil belt unbalanced, which will probably lead to the pull-off downtime.
4. Dark surface stripes
Dark surface stripes mostly appear on the double products, the dark surface has obvious light and dark stripes along the rolling direction, affecting the aesthetic appearance.
5. Marks
There are many situations that can cause marks on the surface of aluminum foil, such as defects on the surface of rolls or guide rolls or dirt such as metal shavings, uncleaned surface of sleeves or cores or local smooth bumps, or foreign matter sticking to the surface of the foil when it is rolled, and so on. The surface of the foil with marks is usually characterized by single or periodic depressions or bumps, which are easy to identify.
6. Oil spots
Common aluminum foil oil stains are formed after annealing, generally yellowish, brown, yellow-brown spots.
7. Degreasing is not clean
Detect whether the oil removal is clean, generally after annealing, using the brush water method to detect the degreasing level, not up to the level of the brush water test provisions, the aluminum foil may be with oil.
8. Split edge
The phenomenon of longitudinal edge rupture on the surface of aluminum foil is called cracked edge. In serious cases, the edge can be seen obvious gap.
9. Poor sheet shape
The phenomenon of unevenness on the surface of aluminum foil due to uneven deformation is known as defective plate shape. According to the defective parts, divided into the middle wave, edge wave, two-ribbed wave and composite wave. In the side of the side of the wave (as shown), in the middle of the middle wave, both of which is called composite wave, neither in the middle nor in the side of the two-ribbed wave.
10. Adhesion
Aluminum foil roll single sheet is not easy to open, more than one sheet is opened in the form of a knot, the product free hanging length can not meet the standard requirements, in serious cases, a single sheet can not be opened, aluminum foil adhesion will seriously affect the production of the product.
11. Holes
Foil surface is prone to holes.
12. Loose roll
Due to the slitting of the coil is not tight, along the core direction of the foil, the foil take place between the layers of the wrong movement; finger pressure on the foil, the phenomenon of localized depression can be produced.
13. Burr
After cutting, there are different sizes of burrs on the edge of the foil.
14.Mislayer
The end surface of aluminum foil roll is irregularly misaligned between layers, resulting in an uneven end surface.
15.Tower shape
Misalignment between the layers of the aluminum foil end face and the layers causes a tower-like offset, called tower shape. Tower shape is a special case of misalignment, where the side looks like a tower tip.
16. Warp
The phenomenon that the ends or one end of the aluminum foil rolls are upward is called warping, which is characterized by the edge of the aluminum foil rolls warping upward, and it can be touched by hand, and there will be obvious concavity and convexity.
17. Pinhole
Irregular small holes on the surface of aluminum foil visible to the light, for the production of aluminum foil packaging materials, pinhole problem will affect the sealing.
18. End surface pattern
When the end of aluminum foil is viewed locally or on the whole roll, there is a radial pattern along the wall thickness at the core; after unrolling, there is a slight wave at the edge of the foil.
19.White stripes
White stripes on the surface of aluminum foil with varying widths or intervals along the rolling direction. Generally corresponds to the casting of the lower surface of the rolled strip, stripes are concentrated in the middle of the aluminum foil, two ribs position, with the thinning of the aluminum foil calendering, the stripes are obviously aggravated trend.
20. Wrinkle
The surface of aluminum foil presents small, longitudinal or oblique local raised, one or several smooth grooves.
21. Wrinkle
Longitudinal or transverse wrinkles on the surface of aluminum foil rolls that cannot be flattened.
22.Highlights
Unevenly bright spots on the dark surface of aluminum foil that appear when aluminum foil is rolled in double combination are called bright spots.
23.Arrowhead (Bird's Nest)
A certain number of layers on the end surface of an aluminum foil roll are raised in the same place from the inside to the outside, and the degree of raising gradually decreases from the inside to the outside or from the outside to the inside.
24.Black Line
A longitudinally continuous dark line on the surface of aluminum foil, which produces a clear color difference between the part and other parts of the foil.
25. Bright Line
Similar to the dark line, the bright line is a longitudinal continuous bright strip on the surface of aluminum foil, which has obvious color difference with other parts.
26. Drumming
Aluminum foil surface longitudinal strip-shaped bulging, hand touch has obvious convex and concave feeling, sometimes remove the outer layer of aluminum foil disappeared, sometimes through the whole roll of aluminum foil.
27.Dark surface color difference
The surface of aluminum foil is longitudinally striped with obvious concavity and convexity when touched by hand, sometimes disappearing after removing the outer layer of aluminum foil, sometimes running through the whole roll of aluminum foil.
28. Transverse lines
Aluminum foil surface transverse regular fine stripes, generally white, no concavity, sometimes in the coil local, sometimes full of the entire surface, also affect the aesthetic.
29. Herringbone pattern
Regular herringbone pattern on the surface of foil, generally white, with obvious color difference on the surface, but very smooth.
30.Air channel
Due to the high hydrogen content of the melt, caused by the aluminum foil in the rolling process along the rolling direction of the strip crushing, with a certain width.
31.Scratch
Due to the material between the prongs and surfaces, or surface to surface contact occurs after the relative sliding in the foil surface caused by bundles (or groups) distribution of scars.
32.Scratch
Foil surface showing intermittent or continuous groove-shaped scars. Generally in the sharp objects and foil surface contact relative sliding.
33. Non-metallic inclusions
Non-metallic inclusions pressed into the surface of the foil, the surface of the obvious points or long yellowish-black defects, this can be more obvious to see.
34.Open seam
Aluminum foil after rolling along the longitudinal natural cracking phenomenon.
35.Roll eye
Aluminum foil surface appears periodically with calendering traces of small holes, some of which are in the form of a network, the size is generally larger than a pinhole.
