01 Milling Machining Methods
1) Basic Milling Machining
Includes: Plane milling, slot milling, side milling, and contour milling.
2) Advanced Milling Machining
Includes: Incline milling, thread interpolation, cycloidal milling, push-pull contour milling, plunge milling, contour milling, and drilling.
02 Definition of Milling Machining Strategies
(1) General Machining
This is a general-purpose machining strategy. The ratio of cutting width to cutting depth can vary depending on the type of operation.
1) Tool Characteristics: The tool has a relatively long cutting edge and a small core diameter, with no high precision requirements.
2) Machine Tool Requirements: No special requirements.
3) Application Areas: Basic CNC technology is required; advanced machining methods with high difficulty are not feasible; metal removal rate can only reach a general level; application areas typically include small batch sizes and a wide range of materials.
(2) High-Speed Machining
This is a machining strategy that combines small radial depth of cut with high cutting speed and feed rate. Depending on the method used, it can achieve very high material removal rates and low Ra values. Typical characteristics of this strategy include low cutting forces, less heat transferred to the tool and workpiece, reduced burr formation, and high workpiece dimensional accuracy. High-speed machining, using faster cutting speeds than conventional machining, can achieve high metal removal rates and good surface roughness.
1) Tool Characteristics: Stable (larger core diameter and shorter cutting length), clear and well-formed chip space, conducive to good chip removal and coating.
2) Machine Tool Requirements: High-speed CNC control, high-speed table, and fast feed rate.
3) Application Areas: Semi-finishing and finishing of hardened steel (48~62HRC) in the mold industry, with short delivery times. When using the correct tools and advanced machining methods, this technology can also be applied to many other materials.
(3) High-Performance Machining
This is a machining strategy that can achieve very high metal removal rates. The typical characteristics of this strategy are a cutting width of 1 times Dc and a cutting depth of 1 to 1.5 times Dc, depending on the workpiece material; under high-performance machining, using a machining method with a much higher chip load than ordinary machining, extremely high metal removal rates can be achieved.
1) Tool characteristics: Specially developed chip-collecting structure on the tool chip flute, 45°, small plane or tool tip arc protection, particularly smooth chip-collecting space, coating, with or without side retaining shanks.
2) Machine tool requirements: High stability, high power requirements, and a high-rigidity clamping system.
3) Application areas: Mass production machining where production efficiency is a key indicator, or single-piece product machining requiring high metal removal rates.
(4) High feed machining
This is a high feed machining strategy that combines full-cutting across the entire tool diameter with a small depth of cut. Under high feed machining, high metal removal rates and good surface roughness can be achieved by using a faster feed rate than ordinary machining.
1) Tool Characteristics: Specially developed tool tip, extremely short cutting length, coating.
2) Machine Tool Requirements: High stability, high feed rate capability.
3) Application Areas: From mild steel to hardened steel, titanium alloys and stainless steel, it is excellent as a pre-machining process 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 achieve simple, safe and fast programming in CAM. Using the so-called contour milling strategy, it is relatively easy to program complex shapes even without extensive programming experience.
(5) Micromachining
This is a machining strategy that uses extremely small tool diameters.
1) Tool Characteristics: Diameter range from φ0.1~2.0mm, short cutting length, wide range of outer diameter reduction, high precision, coating.
2) Machine Tool Requirements: High spindle precision, 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 Formulas
Cutting Parameter Calculation Formulas
04 Milling Summary
1) Check the machine tool's power and rigidity to ensure the milling cutter diameter has the shortest possible overhang on the machine tool;
2) Use a suitable number of teeth on the milling cutter to ensure that not too many inserts are simultaneously engaged with the workpiece during machining, causing vibration. Sufficient insert engagement is necessary when milling narrow workpieces or cavities;
3) Use an appropriate feed per tooth to achieve good cutting results with sufficiently thick chips, thus reducing tool wear. Use positive rake angle inserts for smooth cutting and minimal power consumption;
4) Use a milling cutter diameter suitable for the workpiece width;
5) Use the correct lead angle (45 degrees is suitable for general milling);
6) Use appropriate milling cutter position;
7) Use cutting fluid only when necessary; dry milling generally results in better tool life.
