CNC Machining of Roller Die of N95 Mask Machine
A series of cutting test data about the aluminum alloy parts of the mask machine (the embossed roller of the mask) at high speed, ultra-high speed and low cutting force, milling, etc. And referring to foreign cnc processing data, the selection principles of each cutting amount are summarized as follows:
(1) The milling speed v, the cutting speed of machining aluminum alloy is not limited. In theory, using a higher cutting speed can increase productivity, reduce or avoid the formation of built-up edge on the front of the tool, which is beneficial to the discharge of chips. The increase in milling speed will undoubtedly increase tool wear. However, the increase in milling speed can effectively increase the metal removal rate per unit time and unit power, and at the same time can improve the surface processing quality of the workpiece within a certain range of high-speed cutting speeds. For a large number of parts of embossed rollers of masks, the cutting speed is selected based on the cutting force. When the embossed roller is high-speed cutting, the radial cutting force remains basically unchanged with the speed under the condition that the radial milling depth ae remains unchanged. This means that the range of milling and cutting speeds that can be selected is wide, and according to the existing CNC equipment, the speed can be selected at 12000-22000rpm.
(2) The feed rate fz for milling. Increasing the feed rate fz will undoubtedly increase the milling force, which is obviously detrimental to the CNC machining of the die roller of the mask. For the CNC finishing of the mask roller, do not choose a large fz. But too small fz is also harmful, because if fz is too small, extrusion replaces cutting, which will generate a lot of cutting heat, aggravate tool wear, and affect machining accuracy. Therefore, when milling the die rollers of masks, a moderate feed rate should be selected, generally between 0.1mm/z and 0.2mm/z.
(3) Axial milling depth ap and radial milling depth ae. No matter from the perspective of force, or considering factors such as residual stress and milling temperature, it is obviously advantageous to adopt a small axial depth of cut ap and a large radial depth of cut ae. This is the principle of selection of cutting parameters under high-speed milling conditions. For the processing of the side wall of the die roller of the mask, the radial force generated under the condition of small ap is obviously small. And in the case of small ap, the increase of ae within a certain range will not increase the deformation of the die roller of the mask, so that a larger ae can be used for milling processing; For the gear hobbing of the die roller of the mask, the use of a large ap for the last cut can increase the rigidity of the processing system and reduce the deformation of the pressure teeth of the die of the mask. Therefore, when processing the roller teeth of the mask, a larger ap should be selected for processing. In general, the axial milling depth ap can be selected from 2 to 10 mm, and the radial milling depth ae can be selected from 0.5 to 0.9D.
The amount of milling should be tailored to different processing objects. The programmer is required to select a reasonable tool motion trajectory, optimize the cutting amount, and select the appropriate cutting speed according to the needs. Only in this way can the advantages of high-speed cutting technology be truly utilized. After several years of exploration and research, through a large number of milling experiments, a cutting parameter database that meets the characteristics of CNC equipment, tools, and products has been established. It has been well applied in CNC machining such as the outsourcing project of embossing roller die of mask machine.
