Milling cutter refers to a rotary cutter with one or more teeth used for milling processing. When working, each cutter tooth cuts off the margin of the workpiece in sequence and intermittently. It is mainly used for processing planes, steps, grooves, forming surfaces and cutting the workpiece on the milling machine.
Features of milling cutter
1. Each cutter of the milling cutter participates in intermittent cutting.2. What is the material thickness of each tooth in the cutting process.
3. The feed per tooth αf (/tooth) means the relative millimeter displacement of the performance link of each tooth of the milling cutter.
Type of milling cutter
1. Cylindrical milling cutterIt is used to process planes on horizontal milling machines. The cutter teeth are distributed on the circumference of the milling cutter. According to the tooth shape, they are divided into straight teeth and spiral teeth. According to the number of teeth, there are two types: coarse teeth and fine teeth. The helical coarse-tooth milling cutter has few teeth, high tooth strength and large chip holding space, which is suitable for rough machining; fine-tooth milling cutter is suitable for fine machining.
2. Face milling cutter
It is used to process planes on vertical milling machines, face milling machines or planer milling machines. There are cutter teeth on the end face and circumference, as well as coarse and fine teeth. Its structure has three types: integral type, insert type and indexable type.
3. End mill
It is used for processing grooves and stepped surfaces, etc. The cutter teeth are on the circumference and end surface, and cannot be fed along the axial direction when working. When the end mill has end teeth passing through the center, it can feed axially.
4. Three-sided edge milling cutter
It is used to process various grooves and stepped surfaces, and there are cutter teeth on both sides and the circumference.
5. Angle milling cutter
It is used for milling grooves at a certain angle, and there are two types of single-angle and double-angle milling cutters.
6. Saw blade milling cutter
It is used for processing deep grooves and cutting off workpieces, with more teeth on the circumference. In order to reduce the friction during milling, there are 15'~1° secondary deflection angles on both sides of the cutter teeth. In addition, there are keyway milling cutters, dovetail milling cutters, T-slot milling cutters and various forming milling cutters.
7. T-shaped milling cutter
Used to mill T-slots.
The basic requirements of the milling cutter to cut some materials:
(1) High hardness and wear resistance: Under normal temperature, the cutting part of the material must have sufficient hardness to cut into the workpiece; with high wear resistance, the tool will not wear and extend the service life.(2) Good heat resistance: The tool will generate a lot of heat during the cutting process, especially when the cutting speed is high, the temperature will be very high. Therefore, the tool material should have good heat resistance, even at high temperatures. It can still maintain high hardness under high temperature and has the ability to continue cutting. This property of high temperature hardness is also called hot hardness or red hardness.
(3) High strength and good toughness: In the cutting process, the tool has to withstand a great impact, so the tool material must have high strength, otherwise it is easy to break and damage. Because the milling cutter is subject to impact and vibration, the milling cutter material should also have good toughness so that it is not easy to chip and chip.
Commonly used materials for milling cutters:
1. High-speed tool steel (referred to as high-speed steel, front steel, etc.), divided into general and special high-speed steel. It has the following characteristics:(1) The content of alloying elements tungsten, chromium, molybdenum, and nickel may corrode the fire characteristic HRC62-70. At 6000C, it can still maintain health.
(2) The cutting edge strength is good, and the vibration resistance is strong. It can be used to manufacture tools with general tool speed. For the machine tool of steel pulley, high-speed steel milling cutters can still be cut smoothly.
(3) Good craftsmanship, young, easy to process and sharpen, and it can also manufacture tools with more complex shapes.
(4). Compared with cemented carbide materials, the appearance, low hardness, red hardness and wear resistance and other shortcomings.
2. Cemented carbide: It is the advantage of metal carbon undecorated, tungsten carbide, titanium carbide and metal catalyst made of cobalt through powder and metallurgical processes. Its main features:
It can be high temperature, the material performance is excellent at about 10000C, and the material speed is 4-8 higher than that of steel. 8 times lower than normal temperature, good abrasion resistance. Bending strength and impact strength are maintained, poor. The blade is not easy to sharpen and is very sharp.
Types of milling cutters
1. According to the material of the cutting part of the milling cutter:(1) High-speed steel milling cutter: This type is used for more complex cutters.
(2) Hard alloy milling cutters: mostly welded or mechanically clamped to the cutter body.
2. According to the purpose of the milling cutter:
(1) Milling cutters for processing planes: cylindrical milling cutters, end milling cutters, etc.
(2) Milling cutters for processing grooves (or step tables): end mills, disc milling cutters, saw blade milling cutters, etc.
(3) Milling cutters for special-shaped surfaces: forming milling cutters, etc.
3. According to the structure of the milling cutter
(1) Point-tooth milling cutter: The cut-off shape of the tooth back is a straight line or a broken line, which is easy to manufacture and sharpen, and the cutting edge is relatively sharp.
(2) Relief tooth milling cutter: The cut-off shape of the tooth back is an Archimedes spiral. After sharpening, this type of milling cutter will not change the rake angle and the tooth profile, so it is suitable for forming milling cutters.