The main cutting edge of the END MILLS is on the cylindrical surface and the cutting edge on the end face is the secondary cutting edge. The cutting edge on the end face is the secondary cutting edge. It is not possible to make a feed movement along the axial direction of the milling cutter during operation. End mills can be used for side machining, grooving, curved surfaces, etc. There is a wide range of end mills available for various machining forms.
In the past, HSS monolithic end mills were commonly used, but nowadays, with the advancement of coating technology and tool material technology, coated carbide monolithic end mills and indexable end mills are becoming popular and are widely used in mould and die machining, high hardness material machining and other fields.
Helix angle: The larger the helix angle of the end mill, the longer the contact line between the workpiece and the cutting edge, the smaller the load applied to the unit length of the cutting edge, thus contributing to a longer tool life. But on the other hand, the helix angle increases, the cutting resistance of the axial direction of the force also increases, making the tool easy to fall out of the toolholder, so, with a large helix angle of the tool processing, requiring good rigidity of the toolholder. 0 ° helix angle is called a straight edge, the shortest contact line.
The choice of helix angle: stainless steel is a hard-to-cut material with low thermal conductivity, which has a large impact on the tool tip. High hardness materials with the increase in hardness, cutting resistance increases, it is appropriate to choose a large spiral angle of the end mill. For thin plate processing and other workpiece rigidity is low, it is appropriate to use a small helix angle of the end mill.
The core thickness is an important factor in determining the rigidity of the end mill and the chip holding tank. The core thickness of an integral end mill is generally 60% of the outer diameter. If the core thickness increases, the cross-sectional area increases and the rigidity increases, but the chip tank is reduced and the chip evacuation performance becomes worse; conversely, the core thickness decreases and the rigidity decreases, but the chip evacuation performance is enhanced.