Comparing the Differences between Zinc and Epoxy Coatings

There are significant differences between zinc-based and epoxy coatings in industrial marking.The company compares and analyzes the strengths and weaknesses of the two materials from the perspectives of material characteristics, marking effects, cost, and applicable scenarios, helping users select the appropriate coating solution based on their actual needs.

Why does the type of coating affect the marking effect?

For metal parts or industrial machinery, the surface coating directly affects the results of laser marking or mechanical engraving.The zinc-based coating and the epoxy coating are the two most common types of protective layers, and each has its own characteristics in terms of corrosion resistance, adhesion and hardness. This also means that they have very different levels of "laser-friendly" qualities.

Comparison of materials.

Corrosion resistance.

The zinc coating mainly works by sacrificing the zinc as an anode to prevent rust, and is suitable for wet or saline environments. However, the surface is relatively soft. The epoxy coating relies on a dense resin layer to block water, and is tougher. However, it is prone to flaking off when exposed to UV light or high temperatures for long periods.

Different adhesion properties.

Epoxy coatings generally have stronger adhesion, especially those that are baked after application. The edges of the marking are even crisper.If a zinc coating is applied too thickly, it may cause a slight "bleed" when being engraved, and the power or depth of the laser must be controlled.

Actual impact of labeling.

Clarity and contrast.

When a fiber laser is used to mark epoxy coatings, the result is usually a deep black or brownish-black mark with high contrast, while zinc coatings tend to be gray to white. If higher contrast is needed, it may be necessary to adjust the marking parameters or to add post-processing (such as oxidation).

Speed and energy consumption.

The speed of marking on epoxy coatings is even faster, with a single scan completing the task. Because zinc coatings have a higher reflectance, they may require a slower speed or additional scans, resulting in an increase in power consumption of 15-20 %.

Costs and maintenance.

Initial investment: NT $ 10 million.

Zinc coatings have a low raw-material cost, making them suitable for mass production on a limited budget. Although epoxy coatings are more expensive per unit, their efficiency and low maintenance costs make them a more cost-effective option in the long term.

Aftercare.

If the epoxy coating is exposed outdoors, it is recommended that the transparent protective layer be reapplied every two years. Zinc-based coatings can be used directly after marking, but should be kept away from contact with strong acids or bases.

How can you be sure you're making the right choice?

For outdoor signage or for parts that need long-term rust protection, zinc-based coatings are the first choice. But for precision instruments, high-resolution barcodes and the like, the stability and clarity of epoxy coatings are more obvious advantages.In the case of special work conditions (such as high temperatures), it is recommended that a sample be tested first before large scale application.