Electrochemical polishing of titanium rods and titanium alloy rods

Titanium rod polishing is a process where the part and the abrasive are rotated together in a solution containing an emulsifier (or corrosion inhibitor) and weak acid or weak alkali, thereby achieving a smooth surface. It is suitable for processing small parts and those that are difficult to polish or finish. Choosing the correct polishing standard can improve productivity and quality.

(1) Shape of the roller
The roller shapes include circular, hexagonal, and octagonal, among which the polygonal shape is more practical. This is because the radius of the barrel wall from the axis is not equal, and there is a certain angle, so the rotating parts can easily change their positions, the chance of collision increases, the grinding is uniform, the efficiency is high, and thus the polishing time can be shortened.

(2) Size of the roller
The diameter is usually 50mm - 100mm, and the length varies depending on the number of grooves. One type of roller has a length of 600 - 800mm; the other type is 800 - 1500mm. It is usually better to choose the larger one. This is because the pressure and friction force on the part in the roller are greater, so the cutting amount also increases. However, for those parts that are afraid of pressure and prone to deformation, a small roller can be used and the length of the roller can be increased.

1) Materials for the roller
The rotational speed of the roller and the amount of material removed from the part have a direct relationship within a certain range. That is, the faster the speed, the greater the amount of material removed from the metal surface. However, when the speed exceeds a certain limit, it will decrease. This is because when the speed is too fast, the centrifugal force of the part in the roller increases, reducing the friction force. Generally, it is advisable to control the speed at 45r/min.

2) Abrasives and solutions for polishing
The polishing abrasives include floating stone, quartz, granite chips, shells, iron filings, and ceramic fragments, etc. The size of the abrasive particles should be larger or smaller than the holes of the part. The amount of material in the roller is also an important factor affecting the surface quality of the part. The amount of material usually should occupy 70% of the volume of the roller. For heavier titanium parts or threaded parts, the amount should be controlled at 80% - 90%. The solution in the roller should be filled to about 95% of the volume of the roller (note: when adding acidic solution to the roller, add water first, then add acid to avoid corrosion of the part during polishing. During the polishing process, due to the increase in time, the concentration of the contained solution gradually decreases and may even lose its effect. Therefore, it is necessary to check the change in solution concentration and replace it every certain period. The polishing time should not be too long, otherwise the part will be damaged. That is to say, use a brush to remove the burrs, oxides, residual oil stains and corrosion sludge on the part surface, and make the part have a certain luster. It must be pointed out that elastic, rigid or thin-walled parts should be removed from the roller immediately after polishing, otherwise it is easy to cause hydrogen penetration or local over-corrosion.