In milling processing, milling amount is also an important parameter in processing. Milling amount is the amount of milling that makes full use of the cutting capacity of milling cutter and machine tool performance to obtain high production efficiency and low processing cost on the premise of ensuring processing quality. Then, how to choose the milling quantity?
1、 Selection principle of milling quantity
The selection of milling parameters has a close relationship with the machining accuracy of milling, the improvement of machining surface quality and the improvement of productivity. The four parameters are: milling speed, feed rate, milling width and milling depth.
Milling speed: the linear speed of the selected point on the cutting edge in the main motion during milling.
Feed rate: it includes three aspects: feed rate per revolution, feed rate per tooth and feed rate per minute. Feed per revolution: the displacement of the milling cutter relative to the workpiece in the feed direction every revolution. The feed rate of each tooth is the displacement of each tooth of the milling cutter relative to the workpiece in the feed direction. Feed per minute, the displacement of the milling cutter relative to the workpiece in the feed direction every minute of rotation.
Milling width: the dimension of the milling layer measured in the direction perpendicular to the axis of the milling cutter and the feeding direction of the workpiece.
Milling depth: the dimension of the milling layer measured in the direction parallel to the axis of the milling cutter.
The principle of selecting milling quantity is to maximize the product of milling width (or depth), feed rate and milling speed on the premise of ensuring processing quality, reducing processing cost and improving productivity. At this time, the cutting time of the process is the least.
During rough milling, under the condition that the machine tool power and process system rigidity allow and have reasonable milling cutter durability, the milling amount is selected and determined according to the sequence of milling width (or depth), feed rate and milling speed. Among the milling parameters, the milling width (or depth) has the least influence on the durability of the iron knife, followed by the feed rate, and the milling speed has the greatest influence. Therefore, when determining the milling amount, we should choose a larger milling width (or depth) as far as possible, then choose a larger feed per tooth as allowed by the process equipment and technical conditions, and finally choose the allowable milling speed according to the durability of the milling cutter.
During finish milling, in order to ensure the requirements of machining accuracy and surface roughness, the width of the cutting layer should be milled out at one time as far as possible; The depth of cutting layer is generally about 0.5mm; Then select the appropriate feed rate per tooth according to the requirements of surface roughness; Finally, the milling speed is determined according to the durability of the milling cutter.
In the actual production process of the factory, we can't only superstitious about the choice of these milling methods, but also need to choose according to experience and by looking up tables.