The Workpiece Is Slow To Remove Rust And Has Poor Adhesion? Special Shot Blasting Machine Solves Surface Pretreatment Problems In One Move

The workpiece is slow to remove rust and has poor adhesion? Special shot blasting machine solves surface pretreatment problems in one move

The surface rust removal of riveted weldments slows down the progress of the project, and the coating begins to peel or even fall off not long after the plastic spraying is completed. These two problems make many factories very distressed. As long as you choose the correct shot blasting pretreatment equipment, the efficiency of rust removal and the life of the coating can be greatly improved at once.

Why does traditional rust removal get worse the more you use it?

In the workshop, people use sandpaper to perform manual grinding work. A relatively skilled worker can only handle sixty or seventy medium-sized rivet weldments in a day. When peak season orders arrive directly, the products will be directly stacked in the warehouse to remove the rivet weldments . The degree of polishing depends entirely on the feel of the hand, and local rust cannot be cleaned. During the post-painting stage, bulging will occur as soon as it is heated.

On the surface, pickling and rust removal appear to be quite fast, but for the treatment of hydrochloric acid waste liquid, even if it only takes one year, the cost will be as high as hundreds of thousands of yuan, and then you will have to find units with corresponding qualifications to remove the waste liquid.

When the workpiece is immersed in acid, hydrogen atoms will enter its lattice structure, which will cause the toughness of the metal part as the base material to decrease. As a result, subsequent spraying operations will still face the problem of shedding, which is actually equivalent to performing a rust removal operation in vain.

How does the shot blasting machine remove rust?

Inside the equipment, the high-speed rotating impeller, which rotates at more than 3,000 revolutions per minute, will throw out steel shot with a diameter ranging from 0.8 mm to 1.2 mm, causing their impact speed to reach 50 meters per second to 80 meters per second. In this way, the rust, oxide scale and welding slag are physically peeled off layer by layer. In this entire process, no chemical agents are used at all.

Because the steel shot has been repeatedly slapped and hit, many densely packed small pits appear on the metal surface, which are generally called anchor lines in the industry. Paints and powder coatings can both capture this texture. In this way, their adhesion will increase from the original level of only two or three MPa to a level as high as more than five MPa? Will the workpiece be slow to remove rust and have poor adhesion? The special shot blasting machine solves the problem of surface pretreatment in one move, thus basically completely avoiding peeling or falling off.

Different workpieces with different machine models

Transformer shells and regular steel structural parts use closed shell shot blasting machines. The projectiles can cover the surface from multiple directions and clean the corners, so the uniformity of the cleaning is relatively stable. Products such as small screws or small stamping parts are loaded using crawler rollers. One thousand, two to three hundred items can be processed in one hour. Sand blasting, rust removal, shot blasting and surface treatment of riveting and welding parts . It is enough to arrange for one person to watch the operation of the machine.

The mass of large castings and heavy forgings can easily be two to three hundred kilograms. They are so heavy that people cannot move them, and they are not securely fixed when hung on ordinary brackets.

In order to solve this problem, some people use a hook-type shot blasting machine. This machine can hang heavy workpieces with hooks and let them rotate 360 ​​degrees in the air. This can ensure that there are no dead corners to clean and remove all the thick and stubborn rust on the surface. In Jiangsu and Shandong, many factories engaged in heavy industry foundry work are using this specific cleaning program.

When choosing equipment, don’t just focus on the unit price.

That general-purpose shot blasting machine looks like it can cost tens of thousands of yuan. However, if the size, material and monthly production capacity of the workpiece do not match, the adjustment of the projectile angle and flow rate will not be accurate. The cleaning effect will be 30% off.

In Weifang City, Shandong Province and Taizhou, Jiangsu Province, there are a number of shot blasting factories that support the service of incoming samples. If the three-dimensional drawing of the workpiece and the monthly production volume are reported, then the quotation will be more reliable.

From 2025 to now, environmental inspections have become more and more stringent, and open sandblasting workshops have basically been stopped. Only closed shot blasting plus cyclone dust removal and bag filtration are considered compliant. When selecting a model, you should take the dust recovery system into consideration. Don't wait until the equipment is installed before spending 100,000 yuan on environmental protection.

How much can you save by doing some accounting?

By changing the manual polishing process to shot blasting, the overall speed of rust removal has been increased by three to four times. Posts that originally required five people to be jointly responsible for now only need one person to guard the machine. This saves personnel costs and social security expenses of about 150,000 to 200,000 yuan a year. The rhythm of the production line has also been fully matched, and the subsequent spraying steps will not be blocked or delayed due to the slow speed of the rust removal link.

The life span of the coating has been extended from the original two to three years to five to eight years. The rework rate for repairs, which was originally 15%, has now been reduced to less than 3%.

There is also the loss of raw materials and the maintenance costs required for after-sales visits. These two expenses were directly cut in half and became half of the original ones. The site adopts a closed operation method, and the dust in the air can be recycled and processed centrally. The money required for environmental protection rectification is also saved because of the above measures.

Only if the preprocessing is done correctly will the later stages be stable.

The three necessary processes of rust removal, oil cleaning, and deburring must be carried out, and no omissions can be made in each process, so that the surface roughness is strictly controlled within the range of Ra6 to Ra12, so that peeling and bulging will not occur after spraying, and the appearance quality when leaving the factory can withstand the test. Use a hundred-grid tool to draw a grid standard of five millimeters by five millimeters for testing, so that the peeling area of the coating is kept within the prescribed five percent limit. This enables customers to pass the inspection in one go.

As time comes to 2026, for new materials and new coatings, the requirements for base materials are becoming higher and higher. If aluminum-magnesium alloy parts and riveted welding parts of galvanized sheets still have to be polished by old-fashioned sandpaper, the adhesion between the coating and the base material will definitely not meet the current new standards. It is much more cost-effective to update the pre-treatment equipment before orders enter the peak season than to wait until the peak season to temporarily rework.

What are the specific methods you use to remove rust from riveted welded parts in the factory? And within this year, what is the total amount of money spent on rework operations and environmental rectification? Everyone is welcome to interact and communicate in the comment area.

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