The polishing and grinding process effect of gold jewelry
Polishing and grinding are key technological processes in the production of gold jewelry, directly affecting the texture, luster and wearing comfort of the jewelry. Its core effects can be deeply analyzed from the following five dimensions:
1. Gloss enhancement: An artistic balance between mirror surface and soft light
Mirror polishing: Through the combination of a high-speed rotating polishing wheel and grinding agents (such as chromium oxide, diamond gypsum), the surface of gold achieves a mirror-like reflective effect. This technique can eliminate processing marks and make the jewelry present a strong high-gloss reflection under light, especially suitable for simple geometric shapes or large-sized jewelry.
Matte/soft finish: Use sandpaper, wire wheels or chemical etching methods (such as acid etching) to create tiny concave and convex patterns on the surface of gold, reducing the reflection intensity and presenting a low-key frosted texture. Matte treatment is often used in retro styles or partial decorations to avoid the flamboyance caused by excessive reflection.
2. Tactile optimization: A transformation from sharp to warm
Eliminating burrs and sharp edges: During the casting, welding or engraving processes of gold jewelry, tiny burrs or sharp edges may occur. Polishing and grinding are carried out through step-by-step sandpaper grinding (such as from 400 mesh to 2000 mesh) and cloth wheel polishing to make the surface as smooth as silk, avoiding skin scratches or snagging on clothes when worn.
Edge rounding: Chamfering is applied to detailed parts such as ear stud pins and necklace clasps to enhance wearing comfort. For instance, after polishing, the diameter error of the ear stud needle can be controlled within 0.01 millimeters, ensuring a painless ear-piercing experience.
3. Enhanced durability: A barrier against the erosion of time
Reduce oxidation risk: After polishing, a dense oxide layer forms on the surface of gold, reducing the contact area with sulfides in the air and sweat, and delaying discoloration. Actual measurements show that finely polished gold jewelry can reduce its oxidation rate by 30% to 50% under the same wearing conditions.
Enhance wear resistance: During the polishing process, through mechanical compaction, the grains on the surface of gold are refined, and its hardness slightly increases (by approximately 5-10HV), thereby enhancing its scratch resistance.
4. Visual hierarchy Shaping: The aesthetic elevation from the two-dimensional to the three-dimensional
Enhance the expressiveness of details: For jewelry with complex techniques such as relief and hollowed-out designs, polishing can highlight the contrast between highlights and shadows. For instance, after partial polishing of dragon-patterned jewelry, the three-dimensional effect of the dragon scales can be enhanced by more than 40%, making the pattern more vibrant.
Achieve color gradient: By controlling the polishing intensity and area, a gradient effect from high gloss to matte can be created on the surface of gold. For instance, the lustrous transition from the center to the edge of petal-shaped jewelry can simulate the soft and delicate texture of natural flowers.
5. Process adaptability: The integration of tradition and innovation
Traditional ancient gold polishing method: Natural tools such as agate knives and charcoal are used for manual polishing to retain the warm and mellow texture of gold and avoid the cold feeling of mechanical polishing. This kind of craftsmanship is commonly seen in ancient-style gold bracelets and pendants, emphasizing the aesthetic of "returning to simplicity and nature".
Modern 3D hard gold polishing: For 3D hard gold jewelry with hollow structures, a combination of ultrasonic cleaning and flexible polishing wheels should be adopted to achieve a high-gloss effect while maintaining the integrity of the shape. This type of craftsmanship can reduce the weight of jewelry by 30% to 50%, while enhancing its luster by more than 20%.
The influencing factors of process effect
Gold purity: 24K gold (99.9%) is relatively soft in texture. After polishing, its luster becomes more gentle but it is prone to deformation. 18K gold (75%) has a relatively high hardness and is suitable for fine engraving and high-gloss polishing.
Polishing medium: Chromium oxide paste is suitable for mirror polishing, but it may leave minor scratches. Diamond gypsum (with a particle size of 0.5 to 1 micron) can achieve ultra-fine polishing, but it is relatively expensive.
Operating temperature: High-temperature environments (>40℃) may cause oxidation on the surface of gold. Operations should be carried out in a constant-temperature workshop to ensure consistent results.