When it comes to the surface treatment of sofa legs, there are a few key points you need to keep in mind.

 

When it comes to furniture hardware accessories processing, some common surface treatment methods we use include mechanical polishing, chemical treatment, surface heat treatment, and spray coating. Surface treatment is essentially about cleaning, sweeping, deburring, degreasing, and removing oxidation from the surface of the sofa leg workpieces.

 

During the processing, transportation, and storage of sofa leg workpieces, the surface often accumulates oxidation, rust, residual molding sand from casting, welding slag, dust, and other dirt and oil.

 

To ensure that the coating can firmly adhere to the surface of the sofa leg workpieces, it's crucial to clean the surface before painting. Otherwise, it will not only affect the binding force between the coating and the metal and the anti-corrosion performance, but it can also lead to further corrosion of the base metal even with a protective coating, causing the coating to peel off and affecting the mechanical performance and service life of the workpiece. Therefore, the surface treatment before painting is an important guarantee and measure to obtain a high-quality protective layer and extend the service life of the product.

 

Here are a few things to pay attention to for a good surface treatment on sofa leg workpieces:

1. No oil or moisture

2. No rust or oxides

3. No adhering impurities

4. No residues of acids or bases

5. The surface of the sofa leg workpiece has a certain roughness.

 

Surface treatment methods include:

Manual treatment: Such as scrapers, wire brushes, or grinding wheels. Manual methods can remove rust and oxidation from the surface of the workpieces, but they are labor-intensive, have low production efficiency, poor quality, and may not be thorough.

 

Chemical treatment: Mainly involves using acidic or alkaline solutions to react chemically with the oxides and oil on the surface of the workpieces, dissolving them in the solution to remove rust, oxidation, and oil. Then, using nylon brush rolls or 304# stainless steel wire brushes (made to withstand acid and alkali solutions) to clean the surface will achieve the desired result.

 

Mechanical treatment methods: Mainly include wire brush roll polishing, shot blasting, and sand blasting. Polishing with a brush roll involves the brush roll rotating at high speed in the opposite direction of the workpiece under the drive of an electric motor, brushing away the oxidized iron scale. The brushed-off iron scale is washed away by a closed-loop cooling water flushing system. Shot blasting is a method of rust removal and cleaning that uses centrifugal force to accelerate the shot and then projects it onto the workpiece.

 

Sand blasting and shot blasting: Sand blasting for surface treatment has a strong impact and clear cleaning effects. However, shot blasting can easily cause deformation of thin plate workpieces, and the impact of steel shot on the workpiece surface (whether shot blasting or sand blasting) can cause deformation of the metal substrate. Since Fe304 and Fe203 have no plasticity, they will break off after impact, and the oil film deforms with the material, so shot blasting and sand blasting cannot completely remove oil from workpieces with oil.

 

Sand blasting roughness:

This is what is commonly referred to as roughness. The sand particles impact and rebound from the surface, creating indentations on the surface that are a few thousandths of an inch deep, known as the base pattern. The rebound can cause some parts of the surface to protrude outward by a few thousandths of an inch, with the lower parts called "valleys" and the higher parts called "peaks." Each sand particle impact on the surface will create a "valley" and a "peak," which is the cause of the base pattern (the reason for the formation of roughness). It is expressed in mill (mil), where one mil is 1/1000 of an inch.

 

The base pattern value formed should be 30% of the total coating system and should not exceed 1/3 of the dry film coating thickness, generally between 50-70 (microns) for anti-corrosion. 1 micron (um) = 0.001 millimeters (mm), 1 mil = 0.001 inches = 0.0254 millimeters (mm).