Carbide milling cutters are widely used in CNC machining centers, CNC engraving machines and ordinary milling machines to process planes, grooves, steps, etc. Common types include end mills, slot milling cutters, saw blade milling cutters, spiral drill milling cutters, etc.
Carbide milling cutters are mainly divided into: integral carbide end mills, carbide straight shank slot milling cutters, carbide saw blade milling cutters, carbide end mill spiral drill bits, carbide machine reamer milling cutters, carbide end mills, carbide ball head milling cutters, etc.
Uses of Carbide Milling Cutters
Carbide Cylindrical Milling Cutters
Carbide cylindrical end mills are mainly used for horizontal milling machines to process planes, and their teeth are distributed on the circumference of the milling cutter. According to different tooth shapes, they can be divided into straight teeth and spiral teeth. According to different tooth numbers, they can be divided into coarse teeth and fine teeth. Spiral tooth coarse tooth milling cutters have fewer teeth, high tooth strength, and large chip space, which are suitable for efficient rough processing. Fine-tooth milling cutters have more teeth, smoother cutting, and are suitable for finishing to obtain higher surface quality.
Carbide Face Milling Cutters
Carbide face milling cutter bits are suitable for plane processing of vertical milling machines, end milling machines and gantry milling machines. The teeth are distributed on the end face and circumference, and can be divided into two categories: coarse teeth and fine teeth. According to different structures, face milling cutters can be divided into three types: integral type, insert type and indexable type, which are suitable for different processing needs.
Carbide End Milling Cutters
Carbide end milling cutters are mainly used for processing grooves, step surfaces, etc., and their teeth are distributed on the circumference and end faces. Generally, end mills cannot be fed axially during processing. Only when their end teeth extend to the center can axial feeding be achieved, thereby improving processing flexibility.
Carbide Three Sided Milling Cutters
Carbide three-sided milling cutters are mainly used for processing various grooves and step surfaces, and their teeth are distributed on the circumference and both sides. Compared with ordinary end mills, it can participate in multi-faceted cutting at the same time, improve processing efficiency, and is suitable for milling tasks that require high precision and high efficiency.
Carbide Angle Mmilling Cutter
Carbide angle milling cutter is used to mill grooves at specific angles. According to different structures, it can be divided into single-angle end mill and double-angle milling cutter. Single-angle milling cutter is suitable for processing grooves on one side of the bevel. Double-angle milling cutter is used to process symmetrical V-shaped grooves or other compound angle structures at the same time to improve processing efficiency and precision.
Carbide Saw blade Milling Cutter
It is used to process deep grooves and cut off workpieces, and there are more teeth on its circumference. In order to reduce friction during milling, there are 15′~1° secondary deflection angles on both sides of the teeth. In addition, there are keyway milling cutters, dovetail slot milling cutters, T-slot milling cutters and various forming milling cutters.
Carbide Milling Cutter Milling Method
Carbide milling cutters have the following two main milling methods relative to the feed direction of the workpiece and the rotation direction of the end mill. The first is down milling, where the direction of rotation of the milling cutter is the same as the feed direction of cutting. When cutting starts, the milling cutter bites the workpiece and cuts off the last chip. The second is reverse milling, where the direction of rotation of the milling cutter is opposite to the feed direction of cutting. The milling cutter must slide on the workpiece for a period before starting cutting, starting with a cutting thickness of zero and reaching the maximum cutting thickness at the end of cutting.
In down milling, the cutting force presses the workpiece against the worktable, and in reverse milling, the cutting force causes the workpiece to leave the worktable. Since down milling has the best cutting effect, down milling is usually the first choice. Reverse milling is only considered when there is a thread clearance problem on the machine tool or there is a problem that down milling cannot solve.
Every time a carbide milling cutter insert enters the cutting, the cutting edge is subjected to an impact load, the load size of which depends on the cross section of the chip, the workpiece material and the cutting type. Ideally, the milling cutter diameter should be larger than the workpiece width, and the milling cutter axis should always be slightly away from the workpiece centerline. Burrs are very likely to occur when the tool is placed directly opposite the cutting center.
The direction of the radial cutting force will change constantly when the cutting edge enters and exits the cutting, the machine tool spindle may vibrate and be damaged, the blade may break and the machined surface will be very rough. The carbide milling cutter deviates slightly from the center, the direction of the cutting force will no longer fluctuate, and the milling cutter will obtain a preload.
Carbide End Mill Selection
Except for end mills and some end mills and carbide as milling cutter materials for milling stainless steel, all other types of milling cutters are made of high-speed steel, especially tungsten-molybdenum series and high-vanadium high-speed steel, which have good effects, and their tool durability can be increased by 1 to 2 times compared with W18Cr4V.
The spray cooling method has the most significant effect, which can increase the durability of the milling cutter by more than double; if the general 10% emulsion is used for cooling, the cutting fluid flow should be ensured to achieve sufficient cooling. When the carbide milling cutter mills stainless steel, take Vc=70~150m/min, Vf=37.5~150mm/min, and make appropriate adjustments according to the alloy grade and workpiece material.
Stainless steel has strong adhesion and melting properties, and chips easily adhere to the milling cutter blade, which worsens the cutting conditions; when reverse milling, the blade first slides on the hardened surface, increasing the tendency of work hardening; the impact and vibration during milling are large, which makes the milling cutter blade easy to break and wear.
When milling stainless steel, the cutting edge must be sharp and able to withstand impact, and the chip groove must be large. Large helical angle milling cutters (cylindrical milling cutters, end mills) can be used, and the helical angle b increases from 20° to 45° (gn=5°), and the tool durability can be increased by more than 2 times. Because at this time the working front angle g0e of the milling cutter increases from 11° to more than 27°, milling is light. However, the b value should not be larger, especially for end mills, b≤35° is appropriate, so as not to weaken the cutter teeth.
The use of corrugated edge end mills to process stainless steel pipes or thin-walled parts is light and fast, with little vibration, fragile chips, and no deformation of the workpiece. Good results can be achieved by high-speed milling with carbide end mills and milling stainless steel with indexable end mills.
When milling stainless steel, down milling should be used as much as possible. Asymmetric down milling can ensure that the cutting edge is smoothly cut off from the metal, and the chip bonding contact area is small. It is easy to be thrown off under the action of high-speed centrifugal force, so as to avoid the chip impacting the front cutting surface when the cutter teeth re-cut into the workpiece, resulting in peeling and chipping, thereby improving the durability of the tool.
Stainless steel materials are widely used and can be encountered in turning, milling, drilling and tapping. However, because stainless steel has different characteristics from other general materials, processing stainless steel has become a big problem for technicians!
