Teach you how to distinguish 35 common aluminum foil quality problems!

In this article you will see thirty-five common quality defects of aluminum foil, a collection of pictures.

In the production process of aluminum foil, it has to go through multiple processes such as rolling, finishing, annealing, slitting, packaging, and interlocking production processes. Any problem in any link may lead to aluminum foil quality problems. The quality defects of the purchased aluminum foil products will not only affect the appearance, but also directly affect the quality of the products produced, and even lead to the shutdown of the aluminum foil, which greatly affects the production efficiency. How to distinguish the quality of aluminum foil?

According to the summary of the aluminum foil production experience of the leading aluminum industry for ten years, distinguishing the quality of aluminum foil can be directly detected by your “eyes”. However, to distinguish the quality of aluminum foil, we should first understand what are the common quality defects of aluminum foil. Only when we have a count, and then check the common aluminum foil quality problems one by one, can we prevent the storage of aluminum foil with quality defects.

Today, Jack sorted out the most complete aluminum foil quality defects in history for all of you, and attached a high-resolution large picture of the aluminum foil. When we bought the aluminum foil back, as long as we diagnose the problem of this batch of aluminum foil, the quality is good or bad. It can be drawn naturally!

1.Foil bump

aluminium foil's foil bump

▲ Foil bumping refers to the damage that occurs on the surface or end surface of aluminum coils during collision with other objects during transportation or storage. Most of the bruises are caused by carelessness during aluminum foil packaging.

2.Corrosion

aluminium foil's Corrosion

▲ The surface of the aluminum foil is in contact with the surrounding medium. After a chemical reaction or an electrochemical reaction, the defects generated on the surface of the aluminum foil will lose their luster and the gray corrosion products will be produced in severe cases. The corroded aluminum foil will have a great influence on the appearance of the products produced by the terminal.

3.Surface bubbles

aluminium foil's Surface bubbles

▲ For aluminum foil with surface bubble defects, the surface of the foil will have irregular round or strip-shaped cavity protrusions; the edges of the protrusions are smooth, the two sides are asymmetrical, and the distribution is irregular. The surface bubbles make the aluminum foil suffer from various points. Unbalanced force is likely to result in pull-off and shutdown.

4.Dark stripes

aluminium foil's Dark stripes

▲ The dark surface stripes mostly appear on the double product. The dark surface has obvious light and dark stripe patterns along the rolling direction, which affects the appearance.

5.Imprint

aluminium foil's Imprint

▲ There are many situations that can cause marks on the surface of the aluminum foil, such as the surface of the roller or guide roller is defective or the metal dust is stuck, the surface of the sleeve or the core is not clean or there are local smooth protrusions, or the foil is taken up There are foreign objects stuck on the surface. There are usually single or periodic depressions or protrusions on the surface of the foil with imprints, which is easy to distinguish.

6.Oil spots

aluminium foil's Oil spots

▲ The common aluminum foil oil stain is formed after annealing, and it is generally light yellow, brown, and yellowish brown.

7.Degreasing is not clean

aluminium foil's Degreasing is not clean

▲ Check whether the degreasing is clean. Generally, after annealing, the degreasing level is detected by the brushing method. If it does not reach the level specified in the brushing test, there may be oil on the aluminum foil.

8.Cracked Edge

aluminium foil's Cracked Edge

▲ The surface of the aluminum foil is in contact with the surrounding medium. After a chemical reaction or an electrochemical reaction, the defects generated on the surface of the aluminum foil will lose their luster and the gray corrosion products will be produced in severe cases. The corroded aluminum foil will have a great influence on the appearance of the products produced by the terminal.

9.Bad shape

aluminium foil's Bad shape

▲ Due to uneven deformation, the surface of the foil is locally uneven, which is called a bad shape. According to the location of the defect, it is divided into middle wave, edge wave, two-rib wave and composite wave. It is called the edge wave at the edge, the middle wave at the middle, and both are called composite waves, and the two-rib wave is neither at the middle nor at the edge.

10.Adhesion

aluminium foil's Adhesion

▲ The single sheet of aluminum foil roll is not easy to open. When multiple sheets are opened, it is in the form of a knot. The free drop length of the product cannot meet the standard requirements. In severe cases, the single sheet cannot be opened, and the adhesion of aluminum foil will seriously affect the production of the product.

11.Hole

aluminium foil's Hole

▲ The surface of the foil is prone to holes.

12.Unwind

aluminium foil's Unwind

▲Since the winding is not tight during slitting, when the foil is held upright in the direction of the tube core, the foil will move between layers; when the foil is pressed with your fingers, it may cause local depressions.

13.Burr

aluminium foil's Burr

▲ After cutting, there are thorns of different sizes on the edges of the foil.

14.Split Level

aluminium foil's Split Level

▲ Irregular displacement between the end layers of the aluminum foil roll, resulting in uneven end surfaces.

15.Tower shape

aluminium foil's Tower shape

▲ The misalignment between the aluminum foil end layer and the layer causes the tower to shift, which is called the tower shape. The shape of the tower is a special case of split levels, and the sides look like a spire.

16.Warping

aluminium foil's Warping

▲ The phenomenon that the two ends or one end of the aluminum foil roll is raised upwards is called curling, which is characterized by the aluminum foil curling upwards, which can be touched by hand and will have a noticeable unevenness.

17.Pinhole

aluminium foil's Pinhole

▲ Irregular small holes visible on the surface of the aluminum foil. For the production of aluminum foil packaging materials, the problem of pinholes will affect the sealing.

18.End pattern

aluminium foil's End pattern

▲ When looking at the end of the aluminum foil partially or in a full roll, the tube core has a radial pattern along the wall thickness; after unwinding, there is a slight wave at the edge of the aluminum foil.

19.White bar

aluminium foil's White bar

▲ White stripe on the surface of aluminum foil with different rolling direction, width or interval. Generally corresponding to the lower surface of the cast-rolled strip, the stripes are mostly concentrated in the middle of the aluminum foil and the position of the two ribs. As the aluminum foil is rolled and thinned, the stripes tend to increase.

20.Wrinkles

▲ The surface of the aluminum foil is thin, longitudinally or diagonally partially convex, one or several smooth grooves.

21.Wrinkle

aluminium foil's Wrinkle

▲ Longitudinal or horizontal wrinkles on the surface of the aluminum foil roll that cannot be flattened.

22.Highlights

aluminium foil's Highlights

▲ When the aluminum foil is double-rolled, the uneven bright spots on the dark surface of the aluminum foil appear as bright spots.

23. Arrow (Bird’s Nest)

aluminium foil's Arrow (Bird's Nest)

▲ A certain number of layers on the end of the aluminum foil roll are raised from the same place from the inside to the outside, and the degree of protrusion gradually weakens from the inside to the outside or from the outside to the inside.

24.Black line

aluminium foil's Black line

▲ The continuous dark lines on the surface of the aluminum foil have obvious color differences between the generated parts and other parts.

25.Bright line

aluminium foil's Bright line

▲ Similar to the dark line, the bright line is a longitudinally continuous bright strip on the surface of the aluminum foil, and the generated part has obvious color difference from other parts.

26.Drumming

aluminium foil's Drumming

▲ The surface of the aluminum foil is longitudinally protruded in strips, and the hand has a pronounced convex and concave feeling. Sometimes it disappears after removing the outer layer of aluminum foil, and sometimes it runs through the entire roll of aluminum foil.

27.Dark color

aluminium foil's Dark color

▲ The surface of the aluminum foil is longitudinally protruded in strips, and the hand has a pronounced convex and concave feeling. Sometimes it disappears after removing the outer layer of aluminum foil, and sometimes it runs through the entire roll of aluminum foil.

28.Horizontal stripes

aluminium foil's Horizontal stripes

▲ There are regular thin stripes on the surface of the aluminum foil, which are generally white and have no unevenness. Sometimes it is localized in the coil and sometimes covers the entire surface, which also affects the appearance.

29.Herringbone (the shape of herringbone in Chinese)

aluminium foil's Herringbone (the shape of herringbone in Chinese)

▲ The regular herringbone pattern on the surface of the foil is generally white, with obvious color difference on the surface, but it is very smooth.

30.Airway

aluminium foil's Airway

▲ Due to the high content of hydrogen in the melt, the aluminum foil in the rolling process is crushed in a strip shape along the rolling direction and has a certain width.

31.Scratching

aluminium foil's Scratching

▲ Bundles (or groups) of distributed scars caused by the relative sliding between the edges and faces of the materials, or the relative sliding that occurs after the face-to-face contact.

32.Scratch

aluminium foil's Scratch

▲ Intermittent or continuous groove-shaped scars on the surface of the foil. Generally occurs when a sharp object slides relatively after contacting the foil surface.

33.Non-metallic pressing

aluminium foil's Non-metallic pressing

▲ Non-metallic inclusions are pressed into the surface of the foil, and the surface is obviously dot-shaped or strip-shaped yellow-black defects, which can be seen more clearly.

34. Open seam

aluminium foil's Open seam

▲ The phenomenon of aluminum foil naturally cracking in the longitudinal direction after rolling.

35.Roller eye

aluminium foil's Roller eye

▲ Periodic small holes appearing on the surface of the aluminum foil, some of which are mesh-like, and the size is generally larger than the pinhole.

The common quality defects of aluminum foil are roughly the above 35 kinds. If you have any of the above defects when you check the quality of the purchased aluminum foil, you should consider returning the product. Of course, aluminum foil production companies generally carry out strict inspections during production and shipment. The sight-seeing defects such as “tower shape”, “holes”, and “split layers” generally do not occur when you receive the goods. . At the same time, it also reminds aluminum foil manufacturers to take a responsible attitude to customers, conduct quality inspections during aluminum foil production, analyze the causes of aluminum foil defects, improve their product quality, and ensure the successful conclusion of transactions. Xianxing Aluminum Co., Ltd. has passed seven rigorous inspections before leaving the factory. The quality of the products is worth guaranteeing!

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