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What Should be Paid Attention to when Cold Rolling Forming Machine is Rolled?

Feb. 28, 2020

Rolling processing refers to the relative rolling between the rubber cylinder of the offset press and the plate cylinder or the impression cylinder under pressure. It is a kind of chip-free processing. At normal temperature, the plastic deformation of the metal is used to make the micro unevenness of the surface of the workpiece smooth, so as to change the surface structure, mechanical characteristics, shape and size. Therefore, this method can simultaneously achieve two purposes of finishing and strengthening, which cannot be achieved by grinding. No matter what kind of processing method is used, there will always be fine convex and concave tool marks on the surface of the part, and there will be staggered peaks and valleys. The following Door Roll Forming Machine Supplier will come to tell you what you need to pay attention to when rolling roll forming machines.

Door Roll Forming Machine

Door Roll Forming Machine

At present, the processing methods according to the external force transmitted to the rolling tool can be divided into three types: mechanical, rolling and spring. According to the nature of processing, it can be divided into two categories: light finishing and enhanced processing. Through experiments with different materials, we found:

(1) Whether the selection of rolling pressure is correct has an impact on the surface roughness, size and accuracy after rolling. In general, the rolling pressure increases and the surface roughness increases. However, the rolling pressure is increased to a certain extent, and the surface roughness is no longer improved. If it continues to increase, the rolling surface begins to deteriorate and even cracks appear.

(2) The surface roughness of the workpiece is improved, and the rolling effect is the best. When the pre-processing roughness reaches Ra1.6, as long as the interference amount is appropriate, the roughness can reach Ra0.2 or more. However, when the pre-processing roughness is only Ra6.4 ~ Ra3.2, and the machining surface has vibration and irregular cutting patterns, then the deeper cutting patterns cannot be rolled and polished, which can only be increased by increasing the interference amount. If the ovality and taper of the hole are too large, the above defects still exist after rolling and the roughness is large. Therefore, the pre-machined surface is preferably smaller than Ra3.2, the geometric accuracy is above one or two, and it can obtain small roughness, which is the ideal accuracy.

(3) The material is soft, plastic and easy to be rolled. As plasticity decreases and hardness increases, the amount of permanent deformation decreases. Generally, the rolling effect of steel and copper is better, and the effect of cast iron is poor. The rolling effect of malleable iron and nodular cast iron is better than gray cast iron. When casting cast iron, when the hardness of the material of the casting is not uniform, defects (holes, trachoma, etc.) on the surface being rolled will be immediately exposed. Therefore, when the casting surface has more defects and the quality is poor, the rolling process should not be used.

(4) The amount of rolling interference has a great impact on surface roughness and geometric accuracy. It is known through experiments that the most reasonable rolling interference is 0.027 to 0.036 mm, and the surface roughness obtained at this time is the smallest. The maximum interference amount is affected by various factors, so the determination of the optimal interference amount should be determined based on multiple tests under specific conditions.

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

(6) Do not roll too many times. The rolling effect is the most significant, and can reduce the roughness by 2 to 3 levels. Two or three times.

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

(8) Rolling tools usually include balls, cylindrical rollers, conical rollers, rollers, etc. However, the use of balls as deforming members can reduce the cost of the entire rolling tool. In addition, the ball has high precision, high hardness, small contact surface with the workpiece, with a smaller rolling pressure, a smaller interference amount can obtain higher pressure and smaller roughness. And the ball has a long service life, is not easy to wear, is cheap, and easy to replace.

The above are the matters needing attention when the cold roll forming machine introduced by Cold Roll Forming Machine Manufacturer.