How to choose between CNC turning and milling in practical applications?

In actual production, facing complex parts processing requirements, have you ever been confused: Should I choose CNC turning or milling? Which processing method is more suitable for your production needs? CNC turning and milling are the two most commonly used processing methods in modern manufacturing, each with its own unique advantages and applicable scenarios.

In practical applications, how to choose CNC turning or milling according to processing requirements is a key issue to improve processing efficiency and ensure product quality. This article will discuss in detail how to choose CNC turning and milling in practice from the aspects of processing principles, selection factors, and practical application cases, to help you make a more informed decision.

1. Basic principles and characteristics of CNC turning and milling

(1) CNC turning

CNC turning is a processing method that mainly rotates the workpiece. The tool moves along the axial or radial direction of the workpiece to complete the processing of features such as the outer circle, inner hole, and end face. Its characteristics include:

1) Applicable parts: Rotating parts, such as shafts, discs, and sleeves.

2) Processing efficiency: high, suitable for mass production.

3) Surface quality: good, especially suitable for high-precision rotating body processing.

The advantages of CNC turning are its efficiency and stability. For simple rotating body parts, turning can complete a large number of processing tasks in a short time, with high processing accuracy and good surface quality.

For example, in automobile manufacturing, CNC turning is usually used for the processing of parts such as drive shafts and bearing rings. In addition, turning can further improve processing efficiency through multi-turret and multi-spindle technology, which is suitable for mass production.

(2) CNC milling

CNC milling is a processing method with tool rotation as the main motion. The workpiece is fixed or moved, and complex geometric shapes are processed through multi-axis linkage. Its characteristics include:

1) Applicable parts: complex shape parts, such as planes, curved surfaces, slots, holes, etc.

2) Flexibility: high, suitable for small batch and multi-variety production.

3) Processing capacity: can achieve high-precision processing of complex geometric shapes.

The advantages of CNC milling are its flexibility and versatility. For parts with complex shapes, milling can achieve high-precision processing through multi-axis linkage.

For example, in mold manufacturing, CNC milling is usually used to process the cavity of injection molds.

In addition, milling can also achieve the processing of complex curved surfaces through five-axis linkage technology, which is suitable for high-precision parts manufacturing in aerospace, medical equipment and other fields.

2. Key factors for choosing CNC turning and milling

In practical applications, the following factors need to be considered comprehensively when choosing CNC turning or milling:

(1) Part geometry

1) Applicable scenarios for turning: rotating parts, such as shafts, discs, and sleeve parts. For example, automobile drive shafts, bearing rings, etc.

2) Applicable scenarios for milling: complex-shaped parts, such as boxes, molds, blades, etc. For example, engine cylinder blocks, injection mold cavities, etc.

(2) Material properties

1) Applicable materials for turning: suitable for processing materials with moderate hardness and easy cutting, such as low-carbon steel, aluminum alloys, copper alloys, etc.

2) Applicable materials for milling: Suitable for processing materials with high hardness or complex shapes, such as titanium alloys, high-temperature alloys, composite materials, etc.

(3) Processing accuracy and surface quality

1) Advantages of turning: High-precision machining of rotating bodies with good surface quality. For example, machining of precision shaft parts.

2) Advantages of milling: High-precision machining of complex shapes, multi-axis linkage can achieve high surface quality. For example, machining of high-precision structural parts in the aerospace field.

(4) Processing efficiency

1) Advantages of turning: Suitable for rapid machining of large quantities of simple parts. For example, mass production of standard parts.

2) Advantages of milling: Suitable for efficient machining of small quantities of complex parts. For example, machining of customized molds.

(5) Equipment and cost

1) Turning equipment: Usually low cost, suitable for simple parts machining.

2) Milling equipment: Multi-axis CNC milling machines have high cost and are suitable for complex parts machining.

3. Selection strategy in practical application

(1) Processing selection of rotating body parts

CNC turning is usually selected for rotating body parts (such as shafts, discs, and sleeves). For example, the processing of automobile transmission shafts:

1) Processing requirements: high-precision outer circle, inner hole and end face processing.

2) Reason for selection: Turning can efficiently complete the processing of rotating parts with good surface quality.

(2) Processing selection of complex shape parts

CNC milling is usually selected for complex shape parts (such as molds, boxes, blades). For example, the processing of injection mold cavities:

1) Processing requirements: high-precision processing of complex geometric shapes.

2) Reason for selection: Milling can realize the processing of complex shapes through multi-axis linkage and has high flexibility.

(3) Choice of composite processing

For parts that require both rotating body processing and complex shape processing, turning and milling composite processing can be selected. For example, the processing of complex structural parts in the aerospace field:

1) Processing requirements: combination of rotating body parts and complex geometric shapes.

2) Reason for selection: Turning and milling composite machine tools can reduce the number of clamping times and improve processing accuracy and efficiency.

4. Collaborative application of CNC turning and milling

(1) Advantages of milling-turning machine tools

Milling-turning machine tools combine the functions of turning and milling and can complete multiple processing tasks on one machine tool. Its advantages include:

1) Reduce the number of clamping times: improve processing accuracy and reduce errors.

2) Improve efficiency: reduce process conversion time and shorten production cycle.

3) Reduce costs: reduce equipment investment and floor space.

(2) Collaborative application cases

1) Case 1: Processing of engine cylinder

Turning is used for hole processing, and milling is used for plane and groove processing.

Through milling-turning processing, efficient and high-precision processing is achieved.

2) Case 2: Processing of turbine blades

Turning is used for rotating parts, and milling is used for complex curved surfaces.

Through milling-turning processing, integrated processing of complex parts is achieved.

5. Summary

In practical applications, CNC turning and milling each have their own advantages. When choosing, comprehensive consideration should be given to factors such as part characteristics, material properties, and processing requirements.

For simple rotating parts, turning is an efficient choice; for parts with complex shapes, milling is more flexible; and for parts that require both rotating body processing and complex shape processing, turning and milling combined processing is the best choice.