Common Methods for Cleaning and Surface Treatment of Die Castings

Cleaning of die casting parts

Methods of removing spures and flash

1) Manual operation: using simple tools such as hammers, files, and pliers to remove the excess parts of die casting parts such as the gating system. The advantage is that it is convenient, simple, and fast, but the disadvantage is that the cut is not neat, and it is easy to damage the castings and cause deformation. It is not suitable for thick gating parts, complex parts, and large castings.

2) Mechanized operation: using edge-cutting machines, punch presses and dies, sawing machines and other mechanical equipment. The advantage is that the cut is neat and it has high efficiency in cleaning large and medium-sized castings.

3) Polishing: selecting steel wheels, nylon wheels, cloth wheels, flying wings wheels, grinding wheels, etc. according to the requirements of die casting parts for polishing treatment.

4) Automatic cleaning process: using robots to clean castings and complete tasks such as removing flash, polishing, and finishing. This achieves clean and efficient production.

Shot blasting cleaning of die casting parts

With the help of shot blasting wheel, shots collide with the surface of castings and absorb the kinetic energy of high-speed moving shots to produce plastic deformation, resulting in residual compressive stress. This improves the surface strength, fatigue strength, and corrosion resistance of die casting parts (China), achieving the purpose of cleaning and strengthening.

Sandblasting cleaning of die casting parts

Using purified compressed air to forcefully spray quartz sand onto the surface of castings to remove impurities such as burrs, oxides, and dirt, etc. from the casting surface through the impact force and friction force, thus cleaning the surface and increasing the surface roughness to improve the adhesion of the coating and the substrate.

Grinding and polishing of die casting parts

Using vibration grinding machines, centrifugal polishing machines, and other equipment, using abrasive stones, grinding agents, water, etc. to friction with the die casting parts in the process of high-speed vibration (rotation) to achieve the effect of removing burrs and polishing the surface.

Correction of die casting parts

When die casting parts are deformed due to solidification shrinkage, top-out deformation or cutting edge deformation, they need to be corrected. The correction needs to be done with measuring instruments and fixtures, manual correction with hammers, or hydraulic correction.

Surface treatment of die casting parts

Electroplating

Die casting parts are plated with a solution containing the desired metal through electrolysis. The casting is the cathode, and the desired metal is the anode. This makes the casting surface a metal film with a strong bond.

Painting

Used for decoration, protection, and marking. By painting, surface defects can be hidden, and surface friction can be increased or decreased. In this process, problems such as orange peel, pinholes, dullness, oil accumulation, and oil dropping may occur on the surface of the castings. Therefore, the paint concentration and amount must be adjusted, and the casting surface must be clean, and operation must be strictly performed according to the operating regulations.

Chemical film formation treatment

Using chromic acid salt treatment to make a tough film on the surface of the castings. It has various colors and can improve the corrosion resistance and surface appearance of the castings. It can also make painting and coloring easier.

Electrostatic spraying

A high-voltage electrostatic field is formed between the spray gun, nozzle, and the die casting parts to make the sprayed paint particles carry a negative charge and fly to the positively charged casting surface to form a uniform coating. This provides a protective layer for the castings and provides a beautiful and smooth surface with good corrosion resistance.

Infiltration treatment

Under vacuum and pressure conditions, the liquid infiltrating agent is made to penetrate into the micro-pores of the casting, and after curing, the pores are sealed to achieve the sealing purpose.