Hardness of electrophoretic lattice frame of engraved round metal logo-A

The hardness of the ‘Engraved Round Metal Logo’ is a complex issue that involves a number of factors (e.g., the electrophoretic coating process, the way the frame is handled, the metal substrate, etc.), and it is not possible to give a fixed value directly. The following are the key influencing factors and analyses:

First.influence of electrophoretic coating on hardness
Coating type and thickness
The hardness of an electrophoretic coating is directly influenced by the formulation and thickness. For example, epoxy resin-based electrophoretic coatings are usually hard (e.g. pencil hardness up to 3H-5H), while acrylic resin-based coatings may be soft (2H-3H). The thicker the coating, the surface hardness may vary depending on the degree of curing, but too thick a coating is prone to internal stresses, which in turn reduces the actual scratch resistance.
Curing process
Curing temperature and time play a decisive role in hardness. For example, an epoxy coating cured at 180°C for 30 minutes is significantly harder than one cured at 160°C for 20 minutes. If curing is inadequate, the coating may be sticky or easily scratched.

Second.enhancement of hardness by lattice treatment
Role of the lacquer layer
A lacquer (e.g. acrylic varnish) acts as a transparent protective layer and enhances the surface hardness by 1-2 pencil hardness levels. For example, when the electrophoretic coating itself is 3H, it may reach 4H-5H after lattice treatment.
Synergy between lattice frame and electrophoresis layer
If the chemical compatibility between lattice frame and electrophoretic coating is poor, it may lead to insufficient adhesion between layers, limited hardness enhancement or even cracking. Compatibility needs to be verified by adhesion test (e.g. scratching method).
Third.influence of metal substrate
Substrate material
Stainless steel substrates (e.g. 304, 316) have a significantly higher hardness (HV150-200) than aluminium alloys (HV60-120). After electrophoretic lattice treatment, the surface hardness of stainless steel may be increased to HV200-250, whereas aluminium alloys only reach HV100-150.
Surface Pretreatment
Sandblasting can increase the surface roughness of the substrate, improve the adhesion of the electrophoretic coating, and indirectly enhance the hardness performance. For example, the hardness of electrophoretic coating on aluminium alloy treated with 120 mesh sand is 10%-15% higher than that on smooth surface.