Milling Processing Methods
1) Basic milling processes include: plane milling, slot milling, side milling, and profile milling.
2) Advanced milling processes include: ramp milling, thread interpolation, cycloidal milling, push-pull profile milling, plunge milling, contour milling, and drilling.
02 Definition of Milling Processing Strategies
(1) General machining is a general-purpose machining strategy. The ratio of cutting width to cutting depth can vary, depending on the type of process.
1) Tool characteristics: The tool has a relatively long cutting edge and a small core diameter, and does not have high requirements for accuracy. 2) Machine tool requirements: No special requirements. 3) Application areas: With basic CNC technology, high-difficulty advanced machining methods are not feasible; the metal removal rate can only reach a general level; the application areas usually include small batch sizes and a wide range of materials.
(2) High-speed machining is a machining strategy that combines a small radial cutting depth with a high cutting speed and feed rate; depending on the method used, a high material removal rate and a low Ra value can be achieved. The typical characteristics of this strategy are low cutting forces, less heat transferred to the tool and workpiece, reduced burr formation and high dimensional accuracy of the workpiece; under high-speed machining, using faster cutting speeds than ordinary machining, high metal removal rates and good surface roughness can be achieved.
1) Tool characteristics: stable (large core diameter and short cutting length), clear and well-formed chip space, conducive to good chip evacuation, coating. 2) Machine tool requirements: high-speed CNC control, high speed, fast table feed speed. 3) Application areas: semi-finishing and finishing of hardened steel (48-62 HRC) in the mold industry with short delivery time. When using the right tools and advanced machining methods, this technology can also be applied to many other materials.
(3) High-performance machining is a machining strategy that can achieve very high metal removal rates. The typical characteristics of this strategy are that the cutting width is 1 times Dc and the cutting depth is 1~1.5 times Dc, depending on the workpiece material; under high-performance machining, a machining method with much higher chip load than ordinary machining can achieve extremely high metal removal rates.
1) Tool characteristics: specially developed chip structure on the tool chip groove, the tool tip is protected by 45°, small flat surface or tool tip arc, particularly smooth chip space, coating, with or without side lock handle. 2) Machine tool requirements: high stability, high power requirements, high rigidity clamping system. 3) Application areas: in mass production, production efficiency is a key indicator, or single-piece product processing requires high metal removal rate.
(4) High feed machining is a high feed machining strategy that combines full cutting of the entire tool diameter and small cutting depth. Under high feed machining, high metal removal rate and good surface roughness can be achieved by using a faster feed speed than ordinary machining.
1) Tool characteristics: specially developed tool tip, extremely short cutting length, coating. 2) Machine tool requirements: high stability, possibility of high feed rate. 3) Application areas: from soft steel to hardened steel, titanium alloy and stainless steel, it is very good as a pre-processing before high-speed machining, and it can also be used for deep cavity machining. One of the advantages of this technology is that it is very convenient for users to implement simple, safe and fast programming in CAM. Using the so-called contour milling strategy, complex shapes can be programmed more easily without extensive programming experience.
(5) Micromachining is a machining strategy that uses extremely small tool diameters.
1) Tool characteristics: diameter range from Ø0.1 to 2.0mm, short cutting length, wide range of external diameter reduction, high precision, coating. 2) Machine tool requirements: high spindle accuracy, high speed, CNC, thermal stability to prevent spindle elongation. 3) Application areas: various cavity machining on a wide variety of materials.
03 Milling parameters and calculation formula
Cutting parameter calculation formula:
04 Milling summary
1) Check the power and rigidity of the machine tool to ensure that the diameter of the milling cutter used can be as short as possible when the machine tool uses the tool overhang; 2) The number of teeth of the milling cutter is moderate to ensure that there are not too many blades engaging with the workpiece at the same time during processing to cause vibration. When milling narrow workpieces or cavities, there must be enough blades and workpieces to engage; 3) Appropriate feed per tooth to obtain good cutting results when the chips are thick enough to reduce tool wear. Use positive rake groove inserts to obtain smooth cutting results and minimum power; 4) The milling cutter diameter is suitable for the width of the workpiece; 5) The correct main deflection angle (45 degrees is suitable for general milling); 6) Appropriate milling cutter position; 7) Use cutting fluid only when necessary, dry milling usually has a better tool life.
