In the early stage of development, powder coating was mainly used for metal corrosion protection. With the continuous progress of powder coating production and application technology and the strengthening of environmental protection awareness and regulations all over the world, the application scope of powder coating has been expanding, and the decorative and beautifying effect of powder coating has attracted more and more attention, The assembly line processing and assembly of modern enterprises (such as refrigerators, air conditioners, instruments and meters, metal doors and windows, aluminum profiles, electromechanical equipment and other manufacturers) requires a high degree of stability in the internal and external quality of coating products. The consistency of coating color between batches has become an important requirement of customers.

Measuring instrument
Color measuring instruments mainly include color difference instrument and spectrophotometer. The color difference meter is cheap and easy to carry. It can measure and compare colors conveniently and quickly. It can also provide data reference for color matching personnel, but the error is large, and it is impossible to directly carry out color matching operation. There are two types of spectrophotometer. One is portable, similar to the color difference instrument, but the measurement is more accurate. It can also measure the reflection spectrum curve, output the system data, and can be used with the color matching software; The price of a desktop color analyzer is higher than that of the other. At present, color difference meter and portable spectrophotometer are widely used, but the color matching software is expensive, and only a small number of large-scale powder coating enterprises apply it. However, with the development of domestic color measuring instrument manufacturers, Hangzhou CHNSpec technology took the lead in developing the first spectrophotometer in China. Its product data can be comparable with imported products, but the price is lower than imported instruments.

Figure 2 - CHNSpec spectrophotometer

Measurement operation
Step 1: take the CHNSpec cs-660 as an example for the following measurement, prepare the powder coating sample to be measured (as shown in Figure 3), and press the surface to be uniform and flat with a powder former;

Figure 3 - powder sample to be measured

Figure 4 - powder pressed into a cake

Step 2: turn on the instrument, set various parameters and formulas according to the instructions, and conduct black-and-white calibration;

Figure 5 - black and white calibration

Figure 6 - standard sample test results

Step 4: after the above standard sample is measured and saved, press the "menu" key to enter the "sample measurement" interface under the standard sample. Align the sample with the test hole according to the standard sample measurement method, press the "test" key for measurement, and complete the color difference measurement after "dripping" sound, and then the measurement result can be obtained (as shown in Figure 7).

Figure 7 - sample measurement results

According to the measurement results, customers can carry out color matching, which greatly reduces the time cost and labor cost.
Color blending and quality control are the most basic and important technical work in powder coating production. At present, many enterprises are still using low-efficiency pure manual operation, and some have begun to use the assistance of color difference instrument. However, the color matching technology of major domestic powder coating manufacturers is only mastered by a few key technicians, and the quality inspectors on the production line 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 brought by spectroscopic color matching instrument to enterprises, and the use of spectroscopic color measuring instrument will be gradually popularized. Only by fully combining the instrument matching technology with visual evaluation and practical experience, can technicians really do a good job in the color measurement and control of powder coating products.