Surface treatment of sofa legs, one of the furniture hardware accessories, is processed to meet the requirements of corrosion resistance, wear resistance, decoration, or other special functions of the sofa leg products. Common surface treatment techniques include vacuum electroplating, electroplating, anodizing, electrolytic polishing, pad printing, galvanizing, powder coating, water transfer printing, screen printing, and electrophoretic coating. This article mainly discusses the powder coating and painting processes.

 

 

Sofa Leg Surface Treatment Powder Coating Process

Powder coatings, as 100% solid coatings without any solvents, effectively avoid pollution issues caused by solvents during manufacturing, transportation, storage, and application processes, greatly improving working conditions and posing no adverse health hazards to operators.

 

Powder coatings simplify the painting process. Through the powder coating process, a one-time film can be achieved with only three steps: powdering, curing, and cooling, greatly shortening the production cycle and enabling products to be shipped on the same day. In electrostatic painting, combined with automatic painting machinery and a recovery system, it is possible to achieve automated production, saving energy and resources while increasing production efficiency.

 

Powder coatings also have a high recovery and utilization rate. They can be directly applied to the surface to be coated, forming a coating after baking and curing, and unused powder can be recovered and reused, with a utilization rate of over 95%.

 

Applying powder coatings to sofa leg products results in excellent performance and durability. Prepared from resins that are insoluble in solvents at room temperature or high molecular weight resins that are not easily soluble, they can form high-performance coatings with various functions. Moreover, due to the absence of solvents, the coatings are denser.

 

Powder coatings support one-time coating, allowing for a 50–300μm thick coating in one application, without the sagging or accumulation that occurs with thick paint applications, and have a high edge coverage rate. In contrast, paint generally requires multiple coatings to achieve similar effects.

 

There are certain difficulties and longer cycles in changing colors for powder coatings on sofa legs. Since the color is determined at the factory, changing colors requires adjusting the formula, making it difficult to achieve quick color changes. Additionally, during the electrostatic spraying process, changing colors requires thorough equipment cleaning, especially the transition between dark and light colors, which is more complex.

 

The powder coating process for sofa legs does not easily achieve thin coatings. Due to the limitations of the process, the coating thickness is generally above 50μm, and even under good conditions, the minimum thickness is around 40μm. Forming a coating below 40μm is currently challenging.

 

The appearance smoothness of powder coatings is slightly inferior to that of paint. Due to the high melt viscosity of powder coatings, they can exhibit a slight orange peel effect, affecting the smoothness of the coating.

 

The application of powder coatings also has certain limitations. Their curing temperature is generally above 160°C, limiting their use on heat-sensitive products, such as plastic products. However, there is no problem with applications on furniture hardware accessories like sofa legs. At the same time, electrostatic spraying requires the object to be conductive, which means non-metallic pieces need to be treated for conductivity and heat resistance.

 

Sofa Leg Surface Treatment Painting Process

There is a wide variety of paints, offering users a broad selection. With over a thousand types of paint on the market and new products emerging continuously, users can choose paints based on product performance, purpose, and usage environment to achieve the best coating effects for sofa leg hardware accessories.

 

Painting techniques are diverse and adaptable, including brush painting, dipping, pouring, rolling, scraping, air spraying, high-pressure painting, electrophoretic painting, and electrostatic spraying, among which brush painting, air spraying, and electrophoretic painting are most widely used and can also be applied to sofa leg processing.

 

Air spraying is a widely used construction method in painting factories, especially suitable for medium and small-scale painting operations. Its advantages lie in its simple construction, even, smooth, and flat coating. The required equipment is relatively simple, including a spray gun, air compressor, oil-water separator, and necessary air hoses, etc. Compared with the powder coating process, the one-time investment in equipment is less, the production cost is low, and the capital recovery is fast.

 

The painting process also excels in simplifying pre-treatment processes. Since the primer has excellent rust prevention properties and good adhesion to the substrate and topcoat, it can significantly improve the coating's corrosion resistance and extend the service life of the coating. In practice, only oil removal and rust removal are needed for the object to be painted, without the need for phosphating treatment, which simplifies the pre-treatment process, reduces production costs, and improves production efficiency.

 

The painting process requires high skill from operators. Due to the wide variety of paints, operators need to have an in-depth understanding of the application, performance, scope, construction methods, precautions, and compatibility of various types of paint on sofa legs. In addition, operators also need to have a certain knowledge of color theory to mix the required colors for the object to be painted. During the processing of sofa legs, it is necessary to master the correct painting process to ensure the quality of the coating.

 

The production cycle of the painting process is relatively long, and the comprehensive cost is also high. This is mainly because there are many painting processes, requiring the use of various materials such as primer, putty, thinners, and topcoat, and drying time is needed between each process. Some paints cannot be air-dried and require heat curing. In terms of material consumption, energy consumption, and labor costs, the comprehensive cost of the painting process is higher than that of the powder coating process.

 

In terms of environmental friendliness, the painting process has certain issues. Since the paint contains organic solvents, it is easy to volatilize into the air during construction and curing, posing a risk to human health. When using air spraying, a large amount of over-spray mist is also produced, which has adverse effects on operators. Therefore, operators processing sofa leg hardware accessories need to be equipped with protective measures such as gas masks.

 

The fire hazard of the painting process is also higher than that of the powder coating process. This is mainly because the paint contains easily volatile organic solvents, which can easily cause combustion and explosion when in contact with an open flame. Powder coatings do not contain organic solvents, so the risk is lower.

 

The ignition point, flash point, and ignition energy of paint are all lower than those of powder coatings, and the combustion spread rate is faster than that of powder coatings. When using air spraying to paint workpieces, whether it is ventilation equipment, construction environment, or operating procedures, it is inferior to the powder coating process, so the risk of fire is higher. However, it should be noted that once a powder coating explodes, its explosive strength and destructive power will be much greater than that of liquid coatings.