Milling processing methods and strategies
Milling processing method
The basic processing method of milling:
The end teeth of the cutter mesh to form a flat surface. Tool engagement: ap is small and ae is large.
Machining with tool diameter fully meshed
ae is equal to DC and ap is as high as 1,5 times Dc. The DC depends on the processing strategy used.
Machining through the meshing of the tool side
ap is large and ae is small.
The processing of the engagement of the ball head part of the tool.
ap and ae are very small.
Advanced milling processing methods:
Cavity milling in the Z-axis direction at an angle.
Helical interpolation ramp milling
While the Z-axis ramp milling, the tool makes a circular motion for cavity milling.
Make a partial circular motion on the X or Y axis, and slot by using side milling. (Change the slot milling into side milling).
Push-pull profiling milling
Process a 3D profile by following the contour of the profile.
Use Z-axis drilling to make a deep groove.
A surface is processed by a small amount of drilling or ramp milling on the Z axis, and then the cavity is milled along the X and Y axes.
Move along the Z axis to process a hole.
Definition of milling strategy
It is a general-purpose processing strategy. The ratio of width of cut to depth of cut can vary, depending on the type of process.
Tool characteristics: The tool has a relatively long cutting edge and a small core diameter, and there is no high requirement on accuracy.
Machine requirements: no special requirements.
Application areas: Basic CNC technology, difficult advanced processing methods are not feasible; metal removal rate can only reach a general level; application areas usually include small batches and a wide range of materials.
It is a machining strategy that uses a combination of small radial cutting depth, high cutting speed and feed speed; according to the method used, a high material removal rate and a low Ra value can be achieved. The typical features of this strategy are low cutting force, less heat transferred to the tool and workpiece, reduced burr formation and high dimensional accuracy of the workpiece; under high-speed machining, the use of faster cutting speeds than ordinary machining can achieve high metal Removal rate and good surface roughness.
Tool characteristics: stable (larger core diameter and shorter cutting length), clear and well-shaped chip holding space, which is conducive to good chip removal and coating.
Machine requirements: high-speed CNC control, high speed, fast table feed speed.
Application field: Hardened steel (48-62 HRC) in the mold industry is semi-finished and finished with short delivery time. When using the right tools and advanced processing methods, this technology can also be applied to many other materials.
High performance processing
It is a processing strategy that can achieve a very high metal removal rate. The typical feature of this strategy is that the cutting width is 1 time of Dc, and the cutting depth is 1 to 1.5 times of Dc, depending on the workpiece material; under high-performance machining, a machining method with a much higher chip load than ordinary machining is used. Able to achieve extremely high metal removal rate.
Tool features: The specially developed chip holding structure on the tool chip flute, the tool tip is protected with a 45°, small plane or tip arc, particularly smooth chip space, plating, with or without side shank.
Machine requirements: high stability, high power requirements, high rigidity clamping system.
Application field: In mass production and processing, production efficiency is a key indicator, or single-piece product processing that requires high metal removal rate.
High feed processing
It is a high-feed machining strategy that combines full-edge cutting of the entire tool diameter and small depth of cut. Under high-feed processing, it is possible to achieve high metal removal rate and good surface roughness by using a faster feed rate than ordinary processing.
Tool features: specially developed tool tip, extremely short cutting length, coating.
Machine requirements: high stability, possibility of high feed speed.
Application areas: From mild steel to hardened steel, titanium alloy and stainless steel, it is very good as a pre-processing before high-speed processing, and it can also be used for deep cavity processing. One of the advantages of this technology is that it is very convenient for users to realize simple, safe and fast programming in CAM. Using the so-called contour milling strategy, it is easier to program complex shapes without extensive programming experience.
It is a machining strategy that uses extremely small tool diameters.
Tool characteristics: diameter range from Ø0.1 to 2.0mm, short cutting length, wide range of outer diameter reduction, high precision, coating.
Machine tool requirements: high spindle accuracy, high speed, CNC, thermal stability to prevent spindle extension.
Application areas: various cavity processing on many kinds of materials.
1. Check the power and stiffness of the machine tool to ensure that the diameter of the milling cutter used can be as short as possible in the machine tool overhang;
2. The number of teeth of the milling cutter is moderate to ensure that there are not too many blades that mesh with the workpiece at the same time during processing and cause vibration. When milling narrow workpieces or cavities, there must be enough blades to engage with the workpiece;
3. Appropriate feed per tooth in order to obtain good cutting results when the chips are thick enough to reduce tool wear. The positive rake angle groove type insert is adopted to obtain a smooth cutting effect and the lowest power;
4. The diameter of the milling cutter suitable for the width of the workpiece;
5. The correct entering angle (45 degrees is suitable for general milling);
6. Appropriate milling cutter position;
7. Use cutting fluid only when necessary. Dry milling usually has better tool life.