How to solve color difference problems in powder coatings? Here are a few methods to help you quickly resolve color difference issues in powder coatings.
1. Improve Control Standards
In powder coating applications, color difference is a key indicator affecting the consistency of product appearance. This is especially true for customers with extremely high color difference requirements (such as those in the electronics and high-end home appliance industries, requiring a color difference ΔE ≤ 0.4), or for products where slight color differences can lead to significant visual changes (such as light-colored powder coatings with red or yellow undertones, which are more sensitive to changes in color difference values, and small deviations are easily noticeable to the naked eye). Therefore, it is essential to further improve quality control standards and strengthen visual inspection. Currently, most powder coating companies control the color difference of general products to ΔE ≤ 1. and some products with slightly higher quality requirements to ΔE ≤ 0.5. However, testing is often conducted under a single light source (such as the D65 standard light source). In actual applications, products are observed under different light source environments (such as natural light, shopping mall lighting, and home lighting). A color difference that is acceptable under a single light source may show significant visual deviations under other light sources, leading to customer complaints. Therefore, to strengthen color difference control, improvements are needed in two aspects: First, the color difference of products under multiple standard light sources (such as D65. TL84. and A light sources) must meet the standard (e.g., ΔE≤0.5) to ensure consistent visual effects in different usage scenarios. Second, a three-level visual inspection mechanism of "inspection - calibration - review" should be established. After the inspectors make a preliminary judgment using instruments, the calibration personnel will verify it under multiple light sources, and the review personnel will make a final confirmation to ensure that the color difference of each batch of products is consistent and qualified, avoiding quality problems caused by differences between instrument detection and visual perception.
2. Increase the batch size of raw material procurement
Color difference between batches of raw materials is one of the important reasons for the instability of powder coating colors. Even for large-scale raw material manufacturers, batch differences are common in their products (especially pigments, whose particle size, purity, and dispersibility are easily affected by the production process). Some powder coating products (such as customized colors and high-saturation colors) are extremely sensitive to pigment color. Even with repeated adjustments to the mixing ratios by on-site color matching personnel, it is difficult to guarantee that the color of a new batch of product will be completely consistent with previous batches. This not only increases labor costs but may also delay delivery. To address this issue, raw material suppliers typically advise powder coating manufacturers to increase their single-batch purchase volume. By purchasing in bulk, they can meet the production needs of multiple batches, reducing the risk of color differences caused by changes in raw material batches from the source. This measure has a significant improvement effect: raw materials from the same batch are more stable in composition and performance, ensuring color consistency across multiple batches of powder coatings. For important clients (such as long-term partners in large automotive and home appliance companies) or critical control products (such as large-volume orders with strict color requirements), adopting the approach of increasing raw material purchase volumes is particularly necessary. It reduces the difficulty of color matching, improves production efficiency, ensures product quality stability, and maintains customer trust.
3. Product Inventory
Coating customers often determine their order quantities based on their workpiece processing batches. Many customers (such as small and medium-sized hardware processing plants and customized furniture factories) place small orders, perhaps only a few tens of kilograms or even a few kilograms of powder coating. These small-batch orders pose challenges to powder coating manufacturers' production and quality control: small-batch production results in high equipment setup costs, low production efficiency, and difficulty in ensuring product performance stability through large-scale production; simultaneously, frequent switching of product types can lead to incomplete equipment cleaning, increasing the risk of cross-contamination. For customers who use the same product year-round and cannot place excessive orders in single batches, powder coating manufacturers can adopt a "small batch, large quantity" production model, based on thorough analysis (such as assessing the customer's historical order volume, usage frequency, and product shelf life), producing a larger quantity of products at once and managing inventory effectively. This approach reduces the cost of small-batch production while ensuring stable product quality; moreover, coating customers generally recommend and welcome this model because sufficient inventory shortens delivery cycles and avoids disruptions to their production schedules due to untimely powder coating supply, achieving a win-win situation for both suppliers and customers.
4. Strengthen Technical Services
While color differences generally require after-sales technical support, pre-sales technical services can significantly reduce their occurrence. Slight color fluctuations are generally acceptable to customers, but persistent fluctuations or widening deviations will lead to strong customer complaints. Regular visits and proactive communication can quickly identify and correct problems. Products with excessive color differences that customers refuse to use should be promptly replaced. When color fluctuations occur in coatings or moldings used by customers, timely communication is crucial to prevent excessive deviations in their standards (many customers will request powder coating colors based on coatings or moldings). Timely visits also allow for continuous understanding of customer needs and proactive product adjustments to meet those needs.
5. Build a Reasonable Pigment Library
The fundamental solution to color differences lies in a complete range of pigments. However, building a comprehensive pigment library requires substantial human, material, and financial resources, and is a long-term, continuous process. Furthermore, it cannot guarantee complete compliance with the company's operational needs, and companies cannot afford to bear the risk of storing entire packages of new pigments for years for a small order. The theoretically unlimited number of pigments in color matching systems is indeed a significant contradiction compared to the limited inventory in reality. The coordination methods are as follows: First, enrich the variety of pigments, such as green pigments including yellowish and bluish shades, and red pigments including orange-red and purplish-red; second, ensure a complete range of specifications, including affordable and high-quality pigments, domestic and foreign pigments, and lead-containing and lead-free pigments; third, prepare special supplies, actively selecting samples for pigments needed for products with high sales volume, high profits, or important customers; fourth, maintain technical reserves, sampling, storing, or testing some special pigments (such as those with high prices, superior quality, special needs, or new varieties).
6. Conclusion
Color matching and quality control are the most basic and important technical tasks in powder coating production. Currently, many companies still use inefficient, purely manual operations. Some have begun to use colorimeters, but the color matching technology of major domestic powder coating manufacturers is only mastered by a few key technical personnel, and their front-line quality inspectors only use visual inspection to fine-tune the product color. However, with the continuous development of powder coating, many managers have gradually realized the high efficiency and quality assurance that colorimeters bring to enterprises. The use of colorimeters will gradually become more widespread. Only by fully combining instrument matching technology with visual judgment and practical experience can technicians truly do a good job in color measurement and control of powder coating products.
