Understand sandblasting and shot blasting! Popular science on industrial surface treatment technology, enterprises can avoid detours when selecting products｜Yichuan
Sandblasting is a powerful tool for finishing
Sandblasting is achieved by impinging abrasives on the workpiece at high speed under the impetus of compressed air. This process focuses on the intensity that can be controlled , how long it takes to paint after sandblasting and rust removal , and the direction that can be changed at will by human will. The operator can hold the spray gun and aim it at the workpiece's dead ends, inner cavities, threads and other complex parts to make fine adjustments and handle them properly without causing damage to the surface of the precision parts.
Sandblasting is most suitable for processing molds, aluminum parts, and small workpieces that require high surface quality. It can effectively remove burrs and scale and then adjust the surface roughness of the workpiece to standard values, laying a good adhesion foundation for subsequent spraying and electroplating.
Shot blasting is the trump card for mass production
The centrifugal impeller generates centrifugal force due to its high-speed rotation, and relies on this centrifugal force to evenly eject steel shot to the surface of the workpiece. A shot blasting machine can process several tons of steel structural parts per hour, and its efficiency is several times that of sandblasting. Moreover, the shot blasting machine can be recovered and recycled, which has significant cost advantages in the long run.
Shot blasting is particularly suitable for large-volume products such as steel structures, steel plates, castings and automobile chassis parts. It can not only quickly remove rust and oxide scale, but also strengthen the surface condition of the workpiece with its own impact force, resulting in an increase in the hardness of the part and an extension of its fatigue life, achieving the effect of killing two birds with one stone.
Choosing the wrong process is very costly
In order to save costs, many factories directly purchase cheaper sandblasting machines to process large objects. Because its processing efficiency cannot match the order, the construction period is delayed or even delayed to the point of requiring compensation. On the contrary, some people use shot blasting machines to process precision small workpieces that must be painted within a long time after sandblasting and rust removal . Eventually, the workpieces will deform or even be punctured, and the entire batch of workpieces will have to be scrapped and remade.
For example , how long does it take to paint after sandblasting and rust removal ? In 2023, a hardware factory in Zhejiang used shot blasting to process 0.5 mm thick aluminum alloy brackets. However, the final result was that the deformation rate exceeded 30%, causing a loss of more than 100,000. After switching to the sandblasting process, the scrap rate was suddenly reduced to less than 2%. This is the actual value of choosing the right process.
Pay attention to the time of painting after rust removal
After the sandblasting and rust removal operation is completed, the metal surface will quickly react with moisture and oxygen in the air to form an oxide layer again. According to industry standards, in an environment with a relative humidity of less than 50%, the cleaned surface after sandblasting must be primed within four hours.
If the air humidity exceeds 70%, or the workshop temperature is below five degrees, then this window period will be reduced to less than two hours. Many factories ignored this rule and waited until the next day to start painting operations, which resulted in a lack of adhesion of the coating and blistering and peeling off in just half a year.
In actual operations, we must pay close attention to the environment
During the rainy season in the south, where the humidity often exceeds 80%, after sandblasting and rust removal, the surface must be dried immediately with a hot air blower, and the painting must be completed within two hours. In the northern winter, if the workpiece is transported into the workshop from outside, there will be condensation on the surface, which must be dried with compressed air before sandblasting.
It is proposed that a thermometer and hygrometer be installed in the sand blasting workshop to record the environmental data after the rust removal is completed. If the humidity exceeds the standard, you can use a dehumidifier to reduce it to less than 50%, or preheat the workpiece to more than three degrees higher than the dew point and then spray paint, so that the coating adhesion will be guaranteed.
Choose the right equipment to get twice the result with half the effort
Sandblasting and shot blasting are not substitutes, but complementary solutions. For small batches of precision parts, choose sandblasting for small batches of precision parts, and for batches of coarse and heavy parts, choose shot blasting. This is the basic principle. If the factory has both small precision parts and large steel structure parts, it can be equipped with two types of equipment at the same time and switch as needed. Are the punctuation marks correct? If not, I'll change them.
Yichuan Automation, which has been engaged in sandblasting and shot blasting technology research for fifteen years, can provide customized solutions based on the specific types of products and output conditions that customers can provide. If your workpiece has rust removal requirements on the one hand, hardness enhancement on the other hand, or very strict standards in terms of coating adhesion, then you are welcome to come to the factory for trial testing.
What type of workpieces does your factory currently mainly process? Have you ever encountered any quality accidents caused by choosing the wrong process? Welcome to share your experience in the comment area, and give it a like so that more colleagues will discover this useful article.
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