What are the different types of router bits and how are they used in woodworking projects?

Explore the versatility and applications of router bits for various woodworking tasks.Unlocking Precision and Efficiency: A Journey into the World of Milling Cutters

Discover the diverse world of milling cutters and their wide-ranging applications. From end mills to face mills, ball nose cutters to fly cutters, this comprehensive guide explores the different types of milling cutters used in various industries such as manufacturing, woodworking, metalworking, and more. Unleash the potential of milling technology and optimize your cutting processes with the right tool for the job. Learn about the unique features, benefits, and applications of each milling cutter type, and stay ahead in the world of precision machining.

The Origin of Router bits

The milling cutter is a cutting tool with a cylindrical shape and cutting edges on its circumference and bottom, which rotates to perform cutting operations on workpieces. The origin of milling cutters can be traced back to the invention of the plane tool. The plane tool had a cutting edge only on one side, so when it moved back and forth, only one side had a cutting action, wasting time on the return stroke. Additionally, the cutting edge of the plane tool was narrow, resulting in low machining efficiency. In order to overcome these limitations, people improved the tool by mounting it on a shaft and rotating it rapidly, allowing the workpiece to pass underneath slowly. This innovation led to the creation of the original milling cutter, also known as a single-edge milling cutter. Over time and through continuous development, various types of milling cutters have emerged.

router bits type

  1. Cylindrical Milling Cutter: Used for machining flat surfaces on horizontal milling machines. The teeth are distributed around the circumference of the cutter and can be classified as straight teeth or helical teeth. They can also be categorized as coarse teeth or fine teeth based on the number of teeth. Helical teeth with coarse teeth have fewer teeth, higher tooth strength, larger chip space, and are suitable for rough machining. Fine teeth milling cutters are used for precision machining.
  2. Face Milling Cutter: Used for machining flat surfaces, end faces, and contours on vertical milling machines, end milling machines, or gantry milling machines. They have teeth on both the circumference and end face, and can also be classified as coarse teeth or fine teeth. The structure of face milling cutters can be divided into integral type, insert type, and indexable type.
  3. End Router bits: Used for machining grooves and step surfaces. The teeth are located on the circumference and end face of the cutter. It is not fed axially during operation. When an end mill has end teeth passing through the center, it can be axially fed.

Three-flute Milling Cutter: Used for machining various grooves and step surfaces, with teeth on both side faces and the circumference.

Angle Milling Cutter: Used for milling grooves at a specific angle, available in single-angle and double-angle milling cutter types.

Slitting Saw Milling Cutter: Used for machining deep grooves and cutting workpieces, with multiple teeth on the circumference. To reduce friction during milling, there is a secondary relief angle of 15′ to 1° on both sides of the teeth. Additionally, there are keyway milling cutters, dovetail slot milling cutters, T-slot milling cutters, and various form milling cutters.

T-slot Milling Cutter: Used for milling T-slots.

1: Cylindrical milling cutter

  1. Characteristics of cylindrical milling cutter
    High productivity The milling cutter rotates continuously during milling and allows high milling speeds, so it has high productivity. 1.
  2. During continuous cutting and milling, each tooth is cutting continuously, especially in end milling, where the milling force fluctuates greatly, so vibration is inevitable. Vibration is most severe when the frequency of the vibration is the same as or a multiple of the natural frequency of the machine tool. In addition, when high-speed milling, the cutter teeth have to undergo periodic thermal shocks, which are prone to cracks and edge chipping, which reduces the durability of the cutter.
  3. The multi-knife multi-blade cutting milling cutter has many teeth and the total length of the cutting edge is large, which is conducive to improving the durability and productivity of the tool, and has many advantages. But there are also the following two problems: one is that the radial runout of the cutter teeth is prone to occur, which will cause unequal loads on the cutter teeth, uneven wear, and affect the quality of the processed surface; second, the chip space of the cutter teeth must be sufficient , otherwise it will damage the blade
  4. Different milling methods According to different processing conditions, in order to improve the durability and productivity of the tool, different milling methods can be selected, such as up milling, down milling or symmetrical milling, asymmetrical milling Translate this passage into English

Two: face milling cutter
Deflection angle and characteristics of commonly used face milling cutters

Lead Anglecharacteristicapplication
90°The milling force of the 90 “main deviation angle milling cutter is mainly generated in the radial separation of the feed, and the axial component pressure is small. This has positive significance for sharp cutting of low strength structures or pump wall workpieces.Mainly used for sharp cutting of thin-walled parts and parts with poor clamping, and can also be used for occasions requiring right angles and square shoulder sharpness
45°The radial and axial cutting forces of the 45 “main deviation angle milling cutter are close to the same, and the cutting is smooth and requires less machine power. Cutting is lighter at the beginning of the cutting process. When cutting with a large overhang or small shank, the vibration trend will be weakened, and the milling cutter at this angle will reduce the cutting thickness, resulting in a larger feed range of the workbench while maintaining a moderate cutting edge load, improving production efficiency.Milling of sharp and short cutting materials for general purposes
10°A sharp tool with a 10 ° main deviation angle allows cutting at very high cutting parameters, with a very high workbench feed but a small cutting thickness. The cutting force is mainly generated in the axial direction, which can reduce the vibration trend and achieve a high metal removal rate.Mainly used on high feed and milling tools
Circular bladeThe main deviation angle and chip load of the circular blade milling cutter will vary with different cutting depths. This blade has a very sturdy cutting edge that can be rotated multiple times, and has a high workbench feed power, making it an efficient and high metal removal rate machining tool.Most suitable for processing heat-resistant alloys and drilling alloys, as well as processing with large margins and high feed rates

2:Advantages of face milling cutter:

1.High productivity.

2.Excellent rigidity allows for larger feed rates.

3.Multiple teeth can engage in cutting simultaneously, ensuring smooth operation.

4.Adopting an insert tooth structure facilitates easier tooth sharpening and replacement.

5.Extended tool life.

3: End milling cutter
Classification of end mills

  1. Flat end milling cutter: Perform precision or rough milling, milling grooves, removing a large amount of burrs, and fine milling small areas of horizontal planes or contours.
  2. Ball end milling cutter: for semi precision milling of curved surfaces and precision milling: small cutters can be used for precision milling of small chamfers on steep surfaces/straight walls.
  3. Flat end milling cutter with chamfer: can be used for rough milling to remove a large amount of blanks, and can also be used for fine milling of small chamfers on flat surfaces (relative to steep surfaces)
  4. Forming milling cutter: including chamfer cutter, T-shaped milling cutter or drum cutter, toothed cutter, and inner R-cutter.
  5. Chamfer cutter: The shape of the chamfer cutter is the same as that of the chamfer, and it is divided into milling cutters for circular chamfering and oblique chamfering.

. T-shaped cutter: capable of milling T-shaped grooves
. Tooth cutter: milling various tooth shapes, such as gears
. Coarse milling cutter: designed for cutting aluminum copper alloy, capable of rapid machining

·There are two common materials for end mills: high-speed steel and hard alloy. The latter has higher hardness and stronger cutting force compared to the former, which can increase the speed and feed rate, improve productivity, make the tool less obvious, and process difficult to machine materials such as stainless steel/titanium alloy. However, the cost is higher, and the tool is easy to break when the cutting force changes rapidly.

The vibration of the face milling cutter may occur due to the small gap between the cutter and the tool holder. During the machining process, vibration can cause uneven cutting depths on the circumference of the face milling cutter, resulting in increased cutting width deviation from the intended value, which can affect machining accuracy and tool lifespan. However, when the width of the groove being machined is smaller, intentional vibration of the tool can be used to increase the cutting width by enlarging the cutting width deviation. In such cases, the maximum vibration amplitude of the face milling cutter should be limited to below 0.02 mm to ensure stable cutting. In normal machining operations, minimizing the vibration of the face milling cutter is desirable.

When tool vibration occurs, it is recommended to reduce the cutting speed and feed rate. If significant vibration persists even after reducing both parameters by 40%, it may be necessary to decrease the cutting depth. If the machining system experiences resonance, the causes may include excessive cutting speed, insufficient feed rate, insufficient rigidity of the tool system, inadequate workpiece clamping force, or the shape and clamping method of the workpiece. In such cases, adjustments should be made to the cutting parameters and additional measures should be taken to mitigate the resonance.

The selection of cutting parameters depends on various factors such as the material of the workpiece, the diameter of the face milling cutter, the machine tool, the tooling system, the shape of the workpiece, and the clamping method. While the cutting speed is primarily determined by the material of the workpiece, the feed rate is influenced by both the workpiece material and the diameter of the face milling cutter. It is important to adjust the cutting speed and feed rate based on the actual circumstances and considerations.

When the priority is given to tool life, it is advisable to decrease the cutting speed and feed rate appropriately. On the other hand, if the chip evacuation is poor, increasing the cutting speed can be considered. The specific adjustments should be made based on the specific conditions and requirements of the machining process. It is important to find the optimal balance between maximizing tool life, achieving good chip formation, and ensuring machining efficiency and quality.

Specifications of straight shank end mills 
specificationsblade length entire length

Rabbeting Router Bits

Rabbeting router bits are versatile cutting tools used in woodworking to create rabbets, which are grooves or recesses cut along the edge or surface of a workpiece. These bits are designed with a bearing or pilot guide that helps control the depth and width of the cut.

With rabbeting router bits, woodworkers can easily create joints, dadoes, and lap joints, as well as add decorative features to their projects. These bits are commonly used for tasks such as creating rabbet joints for cabinet doors, joining boards together, or forming recessed areas for glass panels.

Rabbeting bits come in various sizes and profiles, allowing woodworkers to achieve different depths and styles of rabbets. Some bits feature interchangeable bearings or multiple cutting edges, enabling greater flexibility in creating precise and custom rabbet cuts.

When using rabbeting router bits, it’s essential to follow safety precautions and guidelines. Ensure proper installation of the bit in the router collet and adjust the cutting depth according to the desired rabbet size. Always secure the workpiece firmly and maintain control over the router throughout the cutting process.

With their ability to create strong and visually appealing joints, rabbeting router bits are valuable tools in the woodworking arsenal. Whether you’re a hobbyist or a professional, these bits offer endless possibilities for enhancing your woodworking projects with precision and craftsmanship.

Specifications of straight shank end mills 
specificationsblade length (1-)entire length(2-)

Here are a few examples of vertical milling cutter specifications from different renowned tool manufacturers:

  1. yutools – KSEM Series:
    • Cutter Diameter: 12mm
    • Cutting Length: 40mm
    • Shank Diameter: 12mm
    • Overall Length: 100mm
    • Number of Flutes: 4
    • Material: Carbide
  2. yutools – F2334 Series:
    • Cutter Diameter: 10mm
    • Cutting Length: 30mm
    • Shank Diameter: 10mm
    • Overall Length: 85mm
    • Number of Flutes: 3
    • Material: High-Speed Steel
  3. yutools – HSM D Tool Series:
    • Cutter Diameter: 16mm
    • Cutting Length: 50mm
    • Shank Diameter: 16mm
    • Overall Length: 100mm
    • Number of Flutes: 4
    • Material: Carbide

Please note that these are just examples, and different tool manufacturers may provide their own unique specifications for vertical milling cutters. When making actual selections and purchases, it is advisable to refer to the manufacturer’s product specification sheets for more accurate and detailed information.

4: Three-Flute Milling Cutter

  • Three-flute milling cutters are classified based on tooth type: straight-tooth and staggered-tooth.
  • Straight-tooth milling cutters are used for milling shallow and standard-size grooves, as well as for general slotting, step surface machining, and side surface finishing.
  • Staggered-tooth milling cutters are used for machining deeper grooves.
  • G-Type three-flute milling cutters: Suitable for processing non-ferrous metals and alloys, cast iron, and heat-resistant alloys. They are used for cutting cast iron parts and raw iron, among others.
  • YT-Type three-flute milling cutters: Suitable for processing carbon steel, alloy steel, and steel forgings. They are suitable for cutting carbon steel parts, mild iron, etc.
  • YW-Type three-flute milling cutters: Suitable for processing heat-resistant steel, high manganese steel, stainless steel, and advanced alloy steel, among others.

Please note that the translation provided is based on the information you provided. It’s important to refer to specific industry terminology and standards for accurate translations in a professional context.

The Three-Flute Milling Cutter is used for milling stepped surfaces and groove surfaces of medium hardness and strength metal materials. It can also be used for machining non-metallic materials. The Three-Flute Milling Cutter with superhard materials is used for milling stepped surfaces and groove surfaces of difficult-to-machine materials.

5:Angle Milling Cutter Introduction:

Angle milling cutters are used to mill grooves at a specific angle. There are two types of angle milling cutters: single angle and double angle. The specifications include:

  • Outer diameter: 60-160mm
  • Hole diameter: 16-32mm
  • Angle range:
    • Single angle milling cutter: 18°-90°, thickness: 6-35mm
    • Double angle milling cutter: 30°-120°, thickness: 10-45mm
  • Tooth type: Milling teeth, ground teeth
  • Material: Forged M2 (6542), W18, and other high-performance high-speed steels
  • Application: Mainly used for machining various angles or for milling grooves and angle slots.

6:Saw Blade Milling Cutter:

Classification of Saw Blade Milling Cutter: Saw blade milling cutters can be classified into two main categories: small and medium-sized saw blade milling cutters, and large-sized saw blade milling cutters. Classification of Small and Medium-sized Saw Blade Milling Cutters: Small and medium-sized saw blade milling cutters are classified into three types: coarse-tooth, medium-tooth, and fine-tooth. Technical Requirements for Small and Medium-sized Saw Blade Milling Cutters:

  1. The surface of the milling cutter should be free of cracks, and the cutting edges should be sharp without chipping, dullness, or annealing defects that affect performance. Large-sized Saw Blade Milling Cutters: In order to save high-speed steel and facilitate manufacturing, large-sized saw blade milling cutters are generally designed as insert-type structures.


7:T-shaped milling cutter

Features of T-shaped milling cutter: It is a specialized tool for machining T-slots. After milling the straight slot, it can mill a T-slot with the required precision in one pass. The end edge of the milling cutter has a suitable cutting angle, and the teeth are designed as helical or staggered teeth, resulting in smooth cutting with minimal cutting force. · Specification description: The T-shaped milling cutter is generally described by several aspects: the diameter (outer diameter) of the disc and teeth, the thickness (length of the cutting edge) of the disc, the number of teeth (number of cutting edges), the diameter (shaft diameter) of the shank, and the overall length.

Here’s the translation of the T-slot milling cutter specification table

Taper Shank T-slot

In machine tooling, a T-slot with a taper shank refers to a type of T-shaped groove that is designed to accommodate tapered shank tools. The taper shank allows for a secure and rigid connection between the tool and the machine tool spindle, ensuring stability during machining operations.

The specifications of a taper shank T-slot can be described as follows:

Please note that the above specifications are for illustrative purposes and can vary depending on the specific machine tool and manufacturer. It is always recommended to consult the machine tool’s documentation or the manufacturer’s specifications for accurate and precise information on taper shank T-slots.


8: Milling Tool Optimization

When optimizing the milling process, the milling tool plays a crucial role. The number of cutting edges participating in the cutting operation is an important factor. Having multiple cutting edges engaged in cutting at the same time is advantageous, but too many cutting edges can be a disadvantage. Each cutting edge cannot cut simultaneously, and the power required and the number of cutting edges involved are related to the chip formation process, cutting edge load, and machining results. The position of the milling tool relative to the workpiece is also significant.

In face milling, using a milling cutter that is about 30% wider than the cutting width and positioning the milling tool closer to the center of the workpiece results in minimal variation in chip thickness. The chip thickness during entry and exit is slightly thinner compared to cutting at the center.

To ensure an adequate average chip thickness/feed per tooth, it is necessary to determine the appropriate number of teeth for the milling cutter for the specific operation. The tooth pitch of the milling cutter is the distance between effective cutting edges. Based on this value, milling cutters can be classified into three types: close tooth spacing, sparse tooth spacing, and extra-close tooth spacing.

The chip thickness is also influenced by the primary relief angle of the face milling cutter, which is the angle between the main cutting edge of the tool and the workpiece surface. Different primary relief angles, such as 45 degrees, 90 degrees, and circular inserts, result in significant changes in the direction of cutting forces. A milling cutter with a 90-degree primary relief angle mainly generates radial forces acting in the feed direction, which means the workpiece surface will not experience excessive pressure. This is particularly reliable for milling weak-structured workpieces.

A milling cutter with a 45-degree primary relief angle produces roughly equal radial and axial cutting forces, resulting in balanced pressure and lower power requirements for the machine tool. It is especially suitable for milling short chips from brittle workpiece materials.

Circular inserts indicate a continuous change in the primary relief angle from 0 to 90 degrees, depending on the cutting depth. Such inserts have high cutting edge strength. Due to the thin chips produced along the long cutting edge, they are suitable for large feed rates. The direction of radial cutting forces constantly changes, and the pressure generated during the machining process depends on the cutting depth. Modern geometric designs of inserts have made circular inserts advantageous with smooth cutting effects, lower power requirements, and improved stability. Today, they are widely used in face milling and profile milling and are no longer limited to rough milling operations.

Milling Methods

There are two main milling methods: conventional milling and climb milling.

  1. Conventional Milling: In conventional milling, the rotation direction of the milling tool is the same as the feed direction. The milling tool engages the workpiece and cuts the final chip from the beginning of the cut.
  2. Climb Milling: In climb milling, the rotation direction of the milling tool is opposite to the feed direction. Before the cutting starts, the milling tool must slide on the workpiece for a distance, starting with zero cutting thickness and gradually increasing to the maximum cutting thickness.

During face milling, certain profile milling or some slot milling operations, the direction of cutting forces varies. In face milling, where the milling tool is positioned on the outer side of the workpiece, the direction of cutting forces is of particular concern. In conventional milling, the cutting forces push the workpiece against the worktable, while in climb milling, the cutting forces lift the workpiece away from the worktable.

Conventional milling is generally preferred as it provides better cutting results. Climb milling is only considered when there are issues with backlash in the machine or when conventional milling cannot solve the problem.

Ideally, the diameter of the milling tool should be larger than the width of the workpiece, and the centerline of the milling tool should be slightly offset from the centerline of the workpiece. Placing the tool directly on the cutting centerline can result in burrs. The direction of radial cutting forces changes continuously as the cutting edge enters and exits the cut, which can cause spindle vibration, tool breakage, and rough machining surfaces. By slightly offsetting the milling tool from the center, the direction of cutting forces becomes more stable, and the milling tool experiences a preload. We can compare center milling to driving in the center of a road.

Each time the milling tool engages the cut, the cutting edge has to withstand impact loads, which depend on the cross-sectional area of the chip, workpiece material, and cutting type. Proper engagement between the cutting edge and the workpiece during entry and exit is crucial.

When the centerline of the milling tool is positioned completely outside the width of the workpiece, the initial impact force during entry is borne by the outermost cutting edge of the tool tip. This means that the initial impact load is experienced by the most sensitive part of the tool. Similarly, during exit, the cutting forces continue to act on the outermost cutting edge of the tool tip until the impact force is released. When the centerline of the milling tool coincides with the edge line of the workpiece, the maximum impact load occurs during entry and exit when the chip thickness is at its maximum. When the centerline of the milling tool is within the width of the workpiece, the initial impact load during entry is borne by a section of the cutting edge that is further away from the most sensitive tool tip, and the tool smoothly exits the cut during retraction.

It is important to consider how the cutting edge disengages from the workpiece for each individual tool. The remaining material near the end of the cut may reduce the clearance of the cutting edge. When the chip separates from the workpiece, an instant tensile force is generated along the front face of the tool, often resulting in burrs on the workpiece. This tensile force can pose a safety risk to the cutting edge, especially in hazardous situations.

Conventional Milling and Climb Milling:

9: Milling Tool Materials

Milling tools require high hardness and wear resistance: At room temperature, the cutting portion of the tool must have sufficient hardness to penetrate the workpiece and high wear resistance to prevent tool wear and extend its service life.

Good heat resistance: Milling tools generate a large amount of heat during the cutting process, especially at high cutting speeds, resulting in elevated temperatures. Therefore, tool materials should possess good heat resistance, maintaining high hardness at high temperatures to continue cutting. This property, known as heat hardness or red hardness, is essential for tool performance.

High strength and good toughness: Milling tools must withstand significant impact forces during the cutting process. Therefore, tool materials need to have high strength to resist fracture and damage. Additionally, due to the impact and vibration experienced by milling tools, they should also possess good toughness to prevent chipping and fracturing.

Commonly used milling tool materials include:

High-Speed Steel (HSS): Also known as high-speed tool steel or cobalt steel. It is available in general-purpose and special-purpose varieties.

Characteristics of High-Speed Steel for Milling Tools:

  • High content of alloying elements such as tungsten, chromium, molybdenum, and vanadium, resulting in a quenching hardness of HRC62-70. It can maintain high hardness even at temperatures as high as 600°C.
  • Good edge strength, toughness, and vibration resistance, making it suitable for manufacturing tools used at moderate cutting speeds. Even on machines with poor rigidity, high-speed steel milling tools can still perform well.
  • Good processability: High-speed steel is easy to forge, machine, and grind. It can also be used to manufacture tools with complex shapes.
  • Compared to cemented carbide materials, high-speed steel has lower hardness, poorer red hardness, and lower wear resistance.
  • Cemented Carbide: It is made through powder metallurgy processes using metal carbides, such as tungsten carbide, titanium carbide, and a metal binder, mainly cobalt.

Characteristics of High-Speed Steel for Milling Tools:

  • High content of alloying elements such as tungsten, chromium, molybdenum, and vanadium, resulting in a quenching hardness of HRC62-70. It can maintain high hardness even at temperatures as high as 600°C.
  • Good edge strength, toughness, and vibration resistance, making it suitable for manufacturing tools used at moderate cutting speeds. Even on machines with poor rigidity, high-speed steel milling tools can still perform well.
  • Good processability: High-speed steel is easy to forge, machine, and grind. It can also be used to manufacture tools with complex shapes.
  • Compared to cemented carbide materials, high-speed steel has lower hardness, poorer red hardness, and lower wear resistance.
  • Cemented Carbide: It is made through powder metallurgy processes using metal carbides, such as tungsten carbide, titanium carbide, and a metal binder, mainly cobalt.

Characteristics of Cemented Carbide for Milling Tools:

  • High-temperature resistance: Cemented carbide maintains excellent cutting performance at temperatures around 800-1000°C, allowing for cutting speeds 4-8 times higher than those used with high-speed steel.
  • High hardness at room temperature and good wear resistance.
  • Low bending strength and poor impact toughness, resulting in less resilience to bending forces and a tendency for the cutting edge to become blunt over time.

10:The main functions of different geometric angles in milling tools are as follows:

  1. Rake angle: It is the most important angle on the cutting tool. Increasing the rake angle results in a sharp cutting edge, reduces deformation of the metal being cut, and decreases the frictional resistance as the chips flow over the rake face. This leads to lower cutting forces and cutting heat. However, increasing the rake angle excessively or too little can reduce the tool’s lifespan. The optimal value of the rake angle is primarily determined by the workpiece material. For metals with low strength, hardness, and high plasticity, a larger rake angle is preferred. For metals with high strength and hardness, a smaller rake angle is recommended. Due to the lower bending strength and brittle nature of cemented carbide, the optimal rake angle for cemented carbide tools is usually smaller than that for high-speed steel tools under the same cutting conditions.
  2. Relief angle: The relief angle primarily reduces the friction between the relief surface and the workpiece and affects the strength of the cutting teeth. Since the milling tool’s cutting thickness per tooth is relatively small, the relief angle is generally larger than that of turning tools to reduce friction on the relief surface. When rough milling or machining workpieces with high strength and hardness, a smaller relief angle is preferred to ensure sufficient strength of the cutting teeth. However, when machining workpieces with high plasticity or elasticity, the relief angle should be appropriately increased to avoid excessive frictional contact between the relief surface and the workpiece due to the elastic recovery of the machined surface.

It’s important to note that the specific values of these angles depend on various factors such as the workpiece material, cutting conditions, tool material, and machining requirements. Optimal angle selection is crucial for achieving desired cutting performance and tool life.

Workpiece material (MPA)High speed steel milling cutterCarbide milling cutter
cast iron5°~15°-5°~5°
Back Angle Selection:
During milling, the wear of the milling cutter primarily occurs on the back face. Using a larger back angle can reduce wear. When using a larger negative rake angle, the back angle can be increased appropriately. Specific values can be referred to in the table.
Type of milling cutterRear corner value
High speed steel milling cutterCoarse teeth12°
Fine tooth16°
High speed hacksaw blade milling cutter
Coarse and fine teeth20°
Hard alloy milling cutter
Coarse teeth6°~8°
Fine tooth12°~15°

Selection of Rake Angle
·The rake angle, represented by the helix angle β for end mills and cylindrical milling cutters, is the angle at which the outer circumference of the cutter spirals. This allows the teeth to gradually engage and disengage with the workpiece, improving the stability of milling. Increasing the helix angle can increase the effective rake angle, making the cutting edges sharper and facilitating chip evacuation. For narrow milling cutters, the increase in helix angle β may not have significant benefits, so it is common to use a small or zero value for B.
The specific values of the helix angle can be referred to in the table.
Milling cutter typeSpiral tooth cylindrical milling cutterEnd MillThree sided and two sided milling cutters
Helix angle45°~6025°~30°30°~45°15°~20°
·Selection of Lead Angle and Secondary Lead Angle ·The primary lead angle in face milling cutters has the same function and impact on the milling process as the primary lead angle in turning tools. Common values for the primary lead angle are 45°, 60°, 75°, and 90°. When the machining system has good rigidity, a smaller value is chosen, while a larger value is chosen otherwise. The secondary lead angle is usually around 5° to 10°.
·Cylindrical milling cutters only have primary cutting edges and do not have secondary cutting edges, thus they do not have a secondary lead angle. The primary lead angle for cylindrical milling cutters is typically 90°.

·Cutting Zone Parameters and Cutting Layer Thickness h: ·The cutting layer thickness, h, refers to the perpendicular distance between two adjacent machined surfaces. The thickness varies continuously during the cutting process. For turning operations with a straight cutting edge: h = f · sin(K), where f is the feed rate and K is the rake angle. The cutting width, b, is the measurement of the cutting layer size along the machined surface. The contact length between the primary cutting edge and the workpiece in the cutting layer is given by b/a · sin(K), where a is the cutting edge length. ·Cutting Area A: ·The cutting area, A, refers to the cross-sectional area of the cutting layer within the base surface. It is calculated as A = h · b · f · ap, where ap is the axial depth of cut.

Twelve: Milling Forces and Milling Power

Milling forces and milling power are influenced by the motion and direction of the cutting tool and the milling process. They can be categorized as follows: (1) main cutting force Fc, (2) feed force Fp, (3) axial force Fa.

  1. Cutting Forces
  • Vertical Force (Fv): The force exerted by the cutting tool in the vertical direction, perpendicular to the worktable.
  • Transverse Force (Fe): The force exerted by the cutting tool in the transverse direction, perpendicular to the cutting direction.
  • Longitudinal Force (Ff): The force exerted by the cutting tool in the longitudinal direction, parallel to the cutting direction.
  1. Milling Power Milling power refers to the power consumed during the milling process. It is the energy transformation and utilization in the milling process.

2: Milling Power

The effective value of milling power refers to the average power consumed during the milling process. It represents the actual power utilized for material removal and is calculated based on the cutting parameters, such as feed rate, cutting speed, and specific cutting force. The milling power is an important parameter to consider in optimizing machining efficiency and tool performance.

Thirteen: Applications of milling cutters

Applications of single-edge and double-edge milling cutters: These cutters are used for applications involving materials such as acrylic, PC plastic, PVC, aluminum-plastic panels, softwood, aluminum panels, and others. Cutting characteristics: They are made of hard alloy materials and employ unique edge mirror grinding technology and high-capacity chip flutes, which provide features such as chip non-sticking, low heat generation, and high surface finish during high-speed cutting.

Materials: Tungsten steel, high-speed steel, and hard alloy can be used.

Difference between single-edge and double-edge milling cutters: Single-edge milling cutters have lower cutting efficiency because they have one less edge at the same rotational speed. However, they can achieve better surface finish. On the other hand, double-edge milling cutters have higher cutting efficiency, but the two edges may have differences in cutting angles and cutting heights, resulting in slightly poorer surface finish.

Double edge milling cutter

Single edge milling cutter

Three-flute milling cutters and four-flute milling cutters ·Processing range: Aluminum parts, plastics, castings, copper parts, aluminum alloys, titanium alloys, nickel alloys, copper alloys, stainless steel molds, alloy steels, 45# steel, etc. ·Main applications: Milling flat surfaces, side surfaces, and grooves. ·Characteristics: Heat resistance, high concentricity of the milling cutter. ·Materials: Tungsten steel, high-speed steel, and hard alloy for three-flute and four-flute milling cutters.

·Milling Cutter Usage ·To achieve optimal cutting surfaces and extend tool life, it is important to use high-precision and high-rigidity milling cutters.

  1. Before using the tool, please check for tool runout. If the tool runout exceeds 0.01mm, correct it before cutting.
  2. It is preferable to have a shorter length of tool protruding from the tool holder. If the tool protrusion is too long, please reduce the spindle speed, feed rate, or cutting depth accordingly.
  3. If abnormal vibration or noise occurs during cutting, reduce the spindle speed and cutting depth until the situation improves.
  4. For steel materials, the best cooling method is through spray or air jet cooling to maximize the effectiveness of high-aluminum titanium. For stainless steel, titanium alloys, or heat-resistant alloys, it is recommended to use non-water-soluble cutting fluids.
  5. The cutting conditions may vary depending on the workpiece, machine, and software. Once the cutting conditions stabilize, gradually increase the feed rate by 30% to 50%.

Application of Grinding Heads ·Applications: Hole drilling in mobile phone glass, processing optical glass, window glass, precision ceramics, PCD and PCBN materials, stone materials, magnetic materials, semiconductors, jewelry, and other industries. ·Uses: Beveling, chamfering, grinding, corner cutting, hole drilling, and other operations. ·Characteristics:

  1. Used for hole drilling, expansion, cutting, beveling, chamfering, grinding, and corner milling in mobile phone glass processing. It can be completed in one step, ensuring precise product dimensions and high production efficiency.
  2. The diamond particles have a wide range of grain sizes, and the products are available in single-grit, double-grit, and multi-grit options to meet various processing needs. The products have high precision, sharpness, wear resistance, long service life, ease of use, and low production costs.

Diamond grinding head

Material: Diamond ·In the GB/T6405-94 standard, there is a clear specification (see the table below) that some varieties of synthetic diamond are only used for tool production and not for abrasives.

The selection of grit size in grinding wheels is a measurement of the abrasive grain size. Grit size refers to the classification marking of the abrasive grain size according to standards. When indicating the characteristics of superhard abrasives, grit size refers to the grit number. In the use of superhard abrasives, the selection of grit size is generally determined based on the surface roughness requirements of the workpiece, grinding efficiency, process requirements, and the type of abrasive bond. The following two tables can be used as references.

Concentration Selection:

The concentration of superhard abrasives refers to the mass of abrasive material containing in the working layer of the abrasive tool per unit volume. It is a unique characteristic of superhard abrasives. Internationally, it is universally agreed that when there is 0.88 grams of superhard abrasive material per cubic centimeter of volume, the concentration is referred to as 100% and designated as 100. The commonly used concentrations are shown in the table below:

25%0.22 g/cm³
50%0.44 g/cm³
75%0.66 g/cm³
100%0.88 g/cm³
125%1.10 g/cm³
150%1.32 g/cm³
175%1.54 g/cm³
200%1.76 g/cm³
225%1.98 g/cm³
250%2.20 g/cm³
275%2.42 g/cm³
300%2.64 g/cm³
325%2.86 g/cm³
350%3.08 g/cm³
375%3.30 g/cm³
400%3.52 g/cm³
425%3.74 g/cm³
450%3.96 g/cm³
475%4.18 g/cm³
500%4.40 g/cm³
525%4.62 g/cm³
550%4.84 g/cm³
575%5.06 g/cm³
600%5.28 g/cm³
625%5.50 g/cm³
650%5.72 g/cm³
675%5.94 g/cm³
700%6.16 g/cm³
725%6.38 g/cm³
750%6.60 g/cm³
775%6.82 g/cm³
800%7.04 g/cm³

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