In the metal polishing industry, there is a technical term called 8K.
What exactly is 8K?
When you ask people this, most people in the industry will give you the simplest explanation, that is, what is as bright as a mirror is 8K.
In fact, this is a very simple cognition.
After all, a thousand readers have a thousand Hamlets.
You think the mirror is bright enough, but I think the mirror is still a little vague. Whether the mirror is bright or not, each person's senses are different, and we cannot say clearly.
For manufacturers who can produce 8K products, the so-called 8K is not a general statement that can be measured and summarized.
First of all, before understanding 8K, let's first understand the classification of mechanically polished shiny metal surfaces.
This is actually based on the number. From 1 to 12, the higher the number, the brighter it will be.
Among them, No. 4 and No. 8 are the best known.
NO.4 refers to unidirectional surface processing, which is not reflective, but is more widely used in daily applications.
NO.4 is the initial step of mechanical polishing, also known as wire drawing.
The surface gloss of NO.4 is the product processed by an ordinary sander.
Because NO 4. is processed by coarse grinding, the surface will generally leave a certain amount of silk grains.
The long silk grain is called filament, and the short silk grain is called broken silk or snowflake silk.
After number 4 there is another number 6.
In fact, the No. 6 card also occupies a considerable market 6, which is often referred to as 6K.
Here, K refers to the degree of reflection after polishing (K is the degree of specular reflection).
6K looks like a mirror, which is close to the mirror reflection, so the unit is called K.
The 8K standard is only related to roughness and brightness.
For roughness, the international 8k standard is <0.04μm.
In fact, this is a bad mirrored panel. The best can reach <0.01μm.
Gloss can be measured directly with the most common gloss meter on the market.
In international standards, when the brightness reaches 550-650, it can be called 8K.
Gloss is not a direct value, because the gloss of the sheet is different when measured at different angles.
We generally specify brightness of 20°, 60° and 85° in the contract.
Brightness decreases from 20° to 80°.
The brightness of 550-650 in the international standard is generally standardized as 60°.
For example, brightness 20 is 1300, 60 is 600, and 85 is 120.
Some people also asked about reflectivity.
In fact, gloss is a physical quantity used to evaluate the ability of a material surface to reflect light under a set of geometric conditions.
Reflectivity is the percentage of radiant energy reflected by the object in total radiant energy.
Reflectivity depends only on the surface material, but gloss depends not only on the surface material but also on the roughness.
The two concepts are completely different.
8K is only measured by roughness and brightness.
But there is a precondition.
That is, firstly, 8K is the scope of the mirrored panel. Because it is called a mirrored panel, it must be free from scratches and silk lines.
If there are any marks on the board, even if it is glossy, it cannot be called a mirrored panel.
What is a ground head flower? On the left side of the figure below, there are light friction marks left during sanding, and on the right side of the figure below, there are traces of the abrasive.
This type of flower is all ground flower.
Simply put, the 8K machine for mechanical grinding uses a special grinding head to grind.
All the fine traces left by the grinding head, like hairs, are called flowers brought by the grinding head.
This type of flower may not look like it, but it greatly affects the beauty and use value of the leaf.
Additionally, there are dark lines that can be seen in dark light.
This doesn't seem like a big problem, but in fact, it's all caused by quality issues with the processing equipment itself.
Processed boards cannot be used directly in high-level situations.
Especially when your plate goes through the next process such as color coating, it will have a great impact on the quality of subsequent processing.
In short, there are no grinding head patterns or dark lines on the board. The roughness of the board is less than 0.04μm, and the 60° brightness of the board surface is between 550-650, so this board is a real 8K board.
