Time：2026-09-17
The same display cabinet render, sent to different manufacturers for prototyping, often comes back barely resembling the original. Uneven color depth, paint chipping at edges, peeling after half a year—such problems mostly arise in surface treatment, especially the electrostatic spraying step. Electrostatic spraying may look like merely "spraying powder on steel and baking it," but it is the superposition of three process stages—pre-treatment, powder spraying, and curing—and if any stage loses control, the finished texture diverges. From four dimensions—line composition, adhesion, color-difference control, and environmental VOCs—this article breaks down the underlying causes of different results from the same design, helping purchasers seize the key vulnerability during factory audits and acceptance.
The electrostatic spraying (powder coating) line usually consists of three core stages: the pre-treatment stage, the electrostatic powder spraying stage, and the high-temperature curing stage.
The pre-treatment stage is responsible for "washing the steel clean and letting it hold the powder." The common process is degreasing—water rinse—conditioning—phosphating (or ceramic conversion)—drying. The phosphate film forms a micron-scale crystal layer on the steel surface, the foundation for powder adhesion; if skipped or shortchanged, the later paint film sits on an oil film and falls off at a touch. Many small workshops shorten pre-treatment to save cost; the surface looks clean but actual powder-holding power is already greatly reduced.
The electrostatic powder spraying stage consists of a spray booth, automatic spray guns (rotary bell or electrostatic gun), and a powder recovery system. The workpiece is grounded, and negatively charged powder is attracted to the surface; coverage and film-thickness uniformity depend on gun distance, voltage (usually 60–90 kV), and gun travel rhythm. Only manufacturers with automatic lines plus manual touch-up avoid easy "bare spots" at edges and recesses; purely manual spraying highly depends on the worker's feel, with obvious batch-to-batch variation.
The curing stage is a high-temperature oven tunnel where powder melts, levels, and cross-links into a film at 180–200°C; oven-temperature uniformity and chain speed decide the leveling quality. Small workshops use batch box ovens, large ones use continuous through-type curing ovens; a few points of temperature difference control make one surface matte and another glossy, not necessarily visible to the eye, yet half a year later their stain and scrub resistance differ vastly.
Judging spraying quality, the first gate is not good looks but how firmly it holds. The industry's common quick test is the "cross-cut method" (hundred-grid test, per GB/T 9286): score a grid on the film, stick tape and rip hard; the smaller the detached area the higher the grade, with grade 0 meaning no detachment at all and grade 1 allowing very slight edge flaking. For display cabinets—frequently moved and bumped by props—acceptance should require at least within grade 1.
Adhesion roots in two points: whether pre-treatment is adequate and whether curing is sufficient. Too-thin phosphate film or incomplete degreasing means a "false bond" between powder layer and substrate; insufficient curing temperature or time leaves powder not fully cross-linked, the film soft and poorly scratch-resistant. Some manufacturers lower oven temperature and speed up the chain to go faster—hard to see by eye, but a hard fingernail scrape leaves a white mark, and a 48-hour salt spray test blisters.
Shengqilin Display Cabinet Manufacturer has a complete spraying line after sheet metal, executing pre-treatment and curing parameters per standard process cards, precisely so display cabinets can withstand handling and wiping during long-term store use. The one-stop process linkage also avoids the industry's chronic ailment of "boards shuttling back and forth, responsibility unclear" when outsourcing spraying.
"I wanted champagne gold, you made me earthy yellow." Color-difference disputes rank in the top three of display cabinet customization. There are three sources of color difference: different powder batches, uneven film thickness, and fluctuating baking temperature.
Powder coating itself is batch-colored; the same formula in different production batches has ΔE (color difference) fluctuation, so compliant manufacturers do "batch retention + color matching before production," using a colorimeter to keep ΔE within 1.5 (basically imperceptible to the eye). Uneven film thickness also shifts color—same color, thicker looks deeper, thinner looks lighter—so gun trajectory and powder volume must be stable, with target film thickness generally at 60–80 µm.
Fluctuating baking temperature makes the same batch of powder show different gloss and hue; a continuous oven paired with an oven-temperature recorder is basic practice. When the purchaser inspects goods at the factory, they can bring a sealed color sample panel and spot-check by comparison or simple colorimeter to avoid "same under the lamp, different in the store." For chain projects needing multi-store replication, the sealed sample and color-difference acceptance standard must go into the contract, or ten stores yield ten shades of gold.
In early years display cabinets mostly used oil-based paint, releasing large amounts of VOCs (volatile organic compounds) during application—pungent and unfriendly to workers and store environments. The advantage of electrostatic powder coating is near-zero VOCs and high utilization (unabsorbed powder is recovered and resprayed, over 95% utilization), a clear green direction for the industry and aligned with malls' increasingly strict environmental entry requirements.
But powder coating also has environmental-side requirements: the curing oven emits a little smoke at high temperature, so compliant lines need waste-gas collection and treatment (e.g., catalytic combustion or activated-carbon adsorption). Malls and stores demand ever higher environmental standards and often require coating environmental test reports and in-plant waste-gas treatment documentation before entry. When choosing a factory, it is worth asking "which powder do you use, and do you have an environmental test report"—this often screens out non-compliant small workshops and reduces the risk of odor complaints after store opening.
Surface treatment is the display cabinet's "invisible competitiveness." The same design—whether pre-treatment is standard, the spray gun stable, curing sufficient, color difference controllable—all ends up written into the texture at the moment the store lights up. By shifting the factory-audit focus from "looking at drawings" to "looking at the spraying line," purchasers can save much later rework and wrangling. For display cabinet customization solutions, visit the Shengqilin Display Cabinet Manufacturer official website at www.tyw0086.com.
