Eight Common Machining Processes in the CNC Field

When it comes to manufacturing, machining processes are an indispensable aspect. These processes involve transforming raw materials into desired shapes, dimensions, and surface finishes, encompassing a variety of precision machining methods to meet the requirements of different components. Below is a detailed introduction to eight common machining processes:

 

When it comes to manufacturing, machining processes are an indispensable aspect. These processes involve transforming raw materials into desired shapes, dimensions, and surface finishes, encompassing a variety of precision machining methods to meet the requirements of different components. Below is a detailed introduction to eight common machining processes:

01. Turning

Turning is a process in which the workpiece is secured on a rotating fixture while a cutting tool gradually removes material from the workpiece to achieve the desired shape and size. This machining method is well-suited for producing cylindrical parts, such as shafts and sleeves. The method of turning and the choice of cutting tools significantly influence the final product's geometry and surface roughness.

Turning can be categorized into various types, including external turning, internal turning, face turning, and thread turning.

• External Turning: Primarily used for machining shapes such as shafts, cylinders, and cones.
• Internal Turning: Involves inserting the cutting tool into the inner bore of the workpiece to machine the inner diameter and surface to the required size and precision.
• Face Turning: Typically used to produce flat surfaces, such as the base or end face of a component.
• Thread Turning: Achieved by moving the cutting edge of the tool relative to the surface of the workpiece to gradually cut a thread profile. This includes both internal and external threads.

02. Milling

Milling is a machining process where a rotating cutting tool removes material from the surface of a workpiece. By controlling the movement of the tool, it is possible to produce complex parts such as flat surfaces, contours, gears, and more. Milling includes various techniques such as face milling, vertical milling, end milling, gear milling, and profile milling, each tailored to specific machining needs.

• Face Milling: The cutting edge of the tool removes material from the workpiece surface to create a flat surface.
• Vertical Milling: Commonly used for machining grooves and holes along the height of the workpiece.
• End Milling: Involves cutting on the sides of the workpiece, often used for machining contours, slots, and edges.
• Gear Milling: Employs specialized cutting tools with edges designed to shape the teeth of gears.
• Profile Milling: Used for machining intricate curves or contour shapes, with the tool path precisely controlled to follow the desired profile.

03. Drilling

Drilling is a machining process that uses a rotating drill bit to cut material and create holes of specified diameters and depths. It is widely employed in manufacturing, construction, and maintenance industries. Drilling can be classified into several types, including conventional drilling, center drilling, deep-hole drilling, and multi-axis drilling.

• Conventional Drilling: Uses a drill bit with helical cutting edges, typically for smaller holes and general drilling needs.
• Center Drilling: Involves creating a small pilot hole on the workpiece surface before using a larger drill bit, ensuring precise positioning of the larger hole.
• Deep-Hole Drilling: Designed for machining deeper holes, requiring specialized drill bits and cooling techniques to maintain accuracy and quality.
• Multi-Axis Drilling: Employs multiple drill bits at various angles to perform simultaneous drilling, ideal for machining multiple holes in one operation.    

04. Grinding

Grinding is a machining process that removes material from the surface of a workpiece using abrasive tools, achieving the desired shape, dimensions, and surface quality. It is commonly employed for parts requiring high precision and fine surface finishes, such as molds, precision mechanical components, and tools.

Grinding is categorized into surface grinding, external cylindrical grinding, internal cylindrical grinding, and profile grinding:

• Surface Grinding: Used to machine flat surfaces of a workpiece, providing smooth finishes and precise dimensions.
• External Cylindrical Grinding: Applied to the outer cylindrical surfaces of components like shafts and pins.
• Internal Cylindrical Grinding: Used to machine the inner surfaces of holes, such as bores and shaft holes.
• Profile Grinding: Designed for machining intricate contour shapes, such as the edges of molds and cutting tools.

05. Boring

Boring is a machining process used to enlarge and refine existing internal circular holes in a workpiece by cutting material with a rotating tool. Unlike drilling, which creates holes by cutting into the surface of the workpiece, boring involves inserting the tool into an existing hole to achieve precise dimensions and flatness.

Boring can be classified into manual boring and CNC boring:

• Manual Boring: Suitable for small-batch production and straightforward machining tasks.
• CNC Boring: Utilizes programmed instructions to control cutting paths, feed rates, and rotational speeds, enabling automated, high-precision machining.

06. Planing

Planing is a machining process where a planer tool removes material from the surface of a workpiece to achieve a flat surface, precise dimensions, and desired surface quality. It is commonly used for machining large workpieces with flat surfaces, such as bases and machine beds. The process ensures the surface is smooth and suitable for assembly with other components.

Planing typically involves two stages:

• Rough Machining: The planer tool removes material at a greater cutting depth to quickly reduce the size.
• Finishing: The cutting depth is reduced to achieve a higher surface quality and dimensional accuracy.

Planing can be categorized into manual planing and automated planing:

• Manual Planing: Ideal for small-batch production and straightforward machining tasks.
• Automated Planing: Uses automated machine tools to control the movement of the planer tool, ensuring a more stable and efficient machining process.

07. Shaping

Shaping is a machining process that uses a shaping tool to gradually deepen cuts and create intricate internal contours. It is commonly used for machining contours, grooves, holes, and other complex shapes on workpieces. Shaping can achieve high precision and excellent surface quality, making it ideal for parts requiring accuracy and smooth finishes.

Shaping is typically divided into the following types:

• Flat Shaping: Used to machine flat surfaces on workpieces, providing smooth surfaces and precise dimensions.
• Contour Shaping: Designed for machining intricate contours, such as those required in molds and complex parts.
• Groove Shaping: Used to machine grooves and channels, with the cutting edge entering the workpiece and cutting along its surface.
• Hole Shaping: Involves machining the internal contours of holes, with the cutting edge entering the hole and shaping its inner surface.

 

 

08. Electrical Discharge Machining (EDM)

Electrical Discharge Machining (EDM) uses electrical arc discharge to cut and machine conductive materials, achieving high precision and complex shapes for parts such as molds and tools. It is commonly used in the manufacturing of molds, plastic injection molds, aircraft engine parts, medical devices, and other fields. EDM is typically employed to process materials that are difficult to cut using traditional machining methods, such as hard, brittle, or high-hardness materials like tool steel, carbide, and titanium alloys.

Key features of EDM:

1. Non-contact cutting: Unlike traditional mechanical cutting, EDM is a non-contact machining method. There is no direct physical contact between the tool and the workpiece; instead, material is removed through electrical arc discharge.

2. High precision: EDM can achieve high precision machining, typically reaching sub-micron level dimensional accuracy. This makes it suitable for manufacturing molds, models, and other precision parts that require high accuracy.

3. Complex shapes: Since EDM is a non-contact method, it can be used to process very complex shapes, including internal contours, small holes, slots, and more.

4. Applicable to high-hardness materials: EDM is suitable for materials with high hardness because it does not rely on the tool hardness required by traditional cutting methods.  

These are the eight common machining processes. Each process has its specific application areas and advantages. Choosing the appropriate process depends on the material, shape, size, and surface requirements of the part.