Do you know what are the common quality problems in the pressing process of pre-painted sheets?
1 rust, oxidation
Corrosion and oxidation are mainly caused by two aspects: one is that the galvanized sheet, which is the base material of the color-coated sheet, is rusted and oxidized due to improper storage before painting. After the paint is painted, the internal substrate is further rusted and oxidized; the other is that this is caused by the color. Coated coils have been stored for too long and improper storage, or caused by water or rain during transportation. These two reasons are determined according to specific circumstances.
2Greasy dirt on board surface
Most of them are caused by improper use of lubricating oil or improper operation during the shearing process.
4 color difference
Generally, it is caused by the paint of the color coating factory or uneven furnace temperature.
5 side waves, medium waves, flanging
Such problems are mostly caused by the substrate itself, but improper operations during the cutting process, such as improper leveling, rubbing the spacer, etc., can also cause such problems.
6 drums
Generally, it is caused by hard substrate material and stress release.
7 Scratches, scratches, scratches
Generally speaking, such problems caused by the profiling process are traceable, and the problems generated during the processing are generally continuous linear or regular; while other intermittent and irregular problems , Disorganized, most of the problems are the color board itself. Specifically, it needs to be judged according to the situation on the spot.
8 pits
This kind of problem is generally caused by the production of the color coating factory or the substrate.
9 pits
Improper handling during storage and transportation, hard objects at the bottom of the material, or collisions with hard objects on the surface can cause pits. Such causes can be investigated regularly. If it is irregular, it is a problem with the color board itself.
10 Hanging injuries, bruising
In the process of storage and transportation, improper use of spreaders or improper operation caused.
11Thickness and width tolerance exceeded
The problem of the substrate itself is caused by the selection of the substrate of the color coating factory.
12 collapse
There are three main reasons for roll collapse: First, the tension of the production line of the color coating factory is unstable and the winding is not tight or the damp paper roll is used to cause the roll collapse; the second is the serious bump in the transportation process, which causes the roll to collapse; the third is the multi-layer stacking. Cause collapse. It needs to be analyzed in detail according to the time of collapse and the specific problems of the stacking situation.
13 missing weight
The normal weight difference is three thousandths. If it exceeds three thousandths, you can find a third-party scale approved by both parties for weighing as the final settlement weight.
14This coating is spotted, flow marks, missed, painted
Generally, it is the problem of the color plate itself, which is caused by the production of the color coating factory.
15 coating peeling off
There are two reasons for the peeling of the coating. If the paint layer falls off in pieces, it is generally caused by poor adhesion of the color-coated plate or galvanized peeling off. The peeling off of this kind of coating is generally more regular.
