Erichsen358 Spiral Coating Rod Testing Principle from Germany:

Suitable for various soft substrates such as cardboard, plastic sheets, leather, textiles, etc. The surface is usually uneven or partially raised, and using a general scraper type coating machine will result in uneven coating thickness. The use of a spiral coating machine can solve this problem. When the coating machine is dragged on the substrate, it will roll and flatten the substrate. The grooves formed by the threads on the coating machine are used to produce a specified thickness of film (Figure 5). The theoretical film thickness is determined by the thread clearance. The coating machine is installed on a bracket with a handle, which is corrosion-resistant.

1. The coating thickness is mainly divided into three types:
Theoretical wet film thickness, actual wet film thickness, and dry film thickness.
The theoretical wet film thickness is the moment between the edge of the coating machine and the coating plane. However, when the coating machine applies coating on the base surface, due to the effects of material fluidity and coating speed, the film layer will produce a certain shear phenomenon, resulting in the actual wet film thickness being smaller than the theoretical value (generally 60-70% of the theoretical value, and after drying, the volume of the film layer will decrease, and the dry film thickness will be about 40-50% of the actual wet film thickness).
When using a rod type coating machine, if the storage width is wider than the gap used for coating (i.e. the part where the coating machine has a gap with the base surface), the edge of the coating layer will increase by an uncontrollable increment compared to the original expected value, which will cause errors in the theoretical wet film thickness. And ERICHSEN coating machine eliminates the root cause of this inaccuracy.

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