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(1) Whether the rolling pressure is selected correctly will affect the surface roughness, size and accuracy after rolling. In general, as the rolling force increases, the surface roughness increases. However, when the rolling force increases to a certain level, the surface roughness no longer increases. If it continues to increase, the rolling surface will begin to deteriorate and even cracks will appear.

(2) To improve the surface roughness of the workpiece, rolling processing has the best effect. When the pre-machining roughness reaches Ra1.6, as long as the interference amount is appropriate, the roughness can reach more than Ra0.2. But when the pre-machining roughness is only Ra6.4~Ra3.2, and there are vibration and random knife marks on the machined surface, then the deeper knife marks cannot be rolled out, and the only way is to increase the interference and roll again. If the ovality and taper of the hole are too large, the above defects will still exist after rolling, and the roughness will be large. Therefore, the pre-processed surface is preferably less than Ra3.2, and the geometric accuracy is above level one or two, so that small roughness and ideal accuracy can be obtained.

(3) The material is soft, highly plastic and easy to be rolled and polished. As the plasticity decreases and the hardness increases, the amount of permanent deformation decreases. Generally speaking, the rolling effect of steel and copper is better, and the effect of cast iron is worse. Malleable iron and ductile iron have better rolling effect than gray cast iron. When rolling iron castings, when the material hardness of the castings is uneven, defects on the rolled surface (pores, blisters, etc.) will be immediately exposed. Therefore, when there are many defects on the surface of the casting and the quality is poor, the rolling process should not be used.

(4) The size of rolling interference has a great influence on surface roughness and geometric accuracy. Through experiments, it is known that the most reasonable rolling interference is 0.027~0.036mm, and the surface roughness obtained at this time is the smallest. The maximum interference amount is affected by many factors, so the optimal interference amount must be determined through multiple tests based on specific conditions.

(5) The rolling speed has little effect on the surface roughness, so we can increase the rolling speed to improve production efficiency.

(6) The number of rolling times should not be too many. One-time rolling has the most significant effect and can reduce the roughness by 2 to 3 levels. Second or third time.

(7) The feed amount should be determined according to the diameter of the ball. The smaller the feed, the smaller the surface roughness. The optimal feed rate should be determined experimentally.

(8) Rolling tools usually include balls, cylindrical rollers, conical rollers, rollers, etc. However, using balls as deformation members can reduce the cost of the entire rolling tool. Moreover, the ball has high precision, high hardness, and a small contact surface with the workpiece. With a smaller rolling force and a smaller interference amount, higher pressure and smaller roughness can be obtained. Moreover, the balls have a long service life, are not easy to wear, are cheap and easy to replace.

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