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Mastering CNC G Codes for Turning – A Comprehensive Guide


CNC turning is a versatile and precise machining process that relies on the use of G codes to create intricate designs and achieve the desired level of accuracy in the final product. In this comprehensive guide, we will explore the basics of CNC G codes for turning, their applications, and tips to help you get the most out of your CNC turning projects. Whether you are new to the world of CNC machining or a seasoned veteran, understanding G codes will take your turning skills to the next level.

Getting Started with CNC G Codes for Turning

G codes, or preparatory functions, are essential in CNC programming for providing specific commands to the machine. In the CNC turning process, these codes instruct the machine on how to move, at what speed, and in which direction. The use of G codes ensures consistent and repeatable results regardless of the machinist's skill level. Some commonly used turning G codes include:

G00: Rapid positioning

G01: Linear interpolation (straight line motion)

G02: Circular interpolation (clockwise)

G03: Circular interpolation (counterclockwise)

G70: Finishing cycle

G71: Rough turning cycle

G72: Rough facing cycle

G90: Absolute positioning

G91: Incremental positioning

Understanding G Code Parameters for Turning

To successfully execute a turning operation, G codes must be accompanied by parameters that provide specific information about the required action. Parameters often include coordinates (X, Y, and Z), feed rates (F), spindle speed (S), and tool selection (T), among others. By understanding the meaning and use of these parameters, operators can create highly tailored programs that deliver exceptional results.

Tips for Efficient and Accurate CNC Turning

Once you have a solid understanding of G codes and their accompanying parameters, honing your CNC turning skills will involve refining your approach and workflow. Here are some general tips to help improve efficiency, precision, and overall quality.

Plan your turning sequence:Before starting your CNC program, plan your turning operations in a logical order to prevent unnecessary machining steps and reduce idle time.

Use canned cycles:Canned cycles are pre-programmed G code sequences that can perform common machining tasks such as drilling, tapping, and more. Utilizing canned cycles can significantly reduce the amount of manual programming required.

Verify your program:Always simulate your CNC program using software before running the actual machining operation. This helps identify any discrepancies, potential collisions, and other problems that may lead to costly mistakes.

Prioritize tool rigidity:Always opt for the most rigid cutting tools and holders to limit deflection, improve surface finish, and achieve tighter tolerances.

Advanced G Code Techniques for Turning

As operators gain experience and confidence with basic G codes and parameters, they can begin to explore advanced programming techniques that enhance precision, versatility, and productivity. Some advanced turning G codes worth investigating include:

G40, G41, G42: Cutter radius compensation (used to automatically adjust the toolpath based on the tool's diameter)

G92: Spindle speed programming (allows the operator to control spindle speed throughout the turning process)

G76: Threading cycle (for programming complex thread profiles, including single-point and multi-start threads)

By incorporating advanced G codes and techniques, operators can tackle more complex turning projects while delivering consistently high-quality results.

Frequently Asked Questions

Below are some frequently asked questions related to CNC G codes for turning:

Q1: What is the difference between G90 and G91?

G90 is an absolute positioning command, meaning that the coordinates specified are in relation to the machine's origin (also called the machine home position). On the other hand, G91 is an incremental positioning command, where the coordinates specified are relative to the current position of the tool.

Q2: How can I improve surface finish in CNC turning?

Optimizing surface finish in CNC turning involves multiple factors, including the selection of suitable cutting tools, proper tool geometry, tool path programming, and adjusting cutting parameters such as spindle speed, feed rate, and depth of cut.

Q3: Can G codes be reused in a CNC program?

Yes, G codes can be reused in a CNC program by utilizing subroutines or loops. These programming techniques allow for the repetition of specific turning operations or entire sections of the program without manual duplication.

Delving Deeper into CNC G Codes for Turning

Gaining in-depth knowledge of CNC G codes and their applications represents an excellent investment for any machinist or programmer looking to maximize the versatility and precision of their turning projects. By understanding the fundamentals, advancing towards more complex techniques, and practicing good machining practices, the boundaries of what you can accomplish with CNC turning will expand exponentially.

May this comprehensive guide serve as a helpful starting point on your journey towards mastering CNC G codes for turning. Remember, practice, experimentation, and continuous learning are the keys to success in CNC machining. Happy turning!

cnc g codes turning

What is CNC Turning

CNC turning is a process that involves using computer numerical control (CNC) machines to shape and finish various materials, such as metals and plastics, into desired shapes and sizes.
This process is typically used in the manufacturing industry to produce precision parts and components for a wide range of applications, including automotive, automation, aerospace, medical, machinery, and industrial.

CNC Turning service

Asianstar Professional CNC Turning Service

Asianstar CNC turning Service offers precision machining for a wide range of materials, including metals, plastics, and composites. With high level facilities and skillful operators, we can produce high-quality parts with tight tolerances and intricate designs.

Our CNC turning capabilities allow us to produce parts with diameters ranging from 0.5 mm to 480mm and lengths up to 450mm. We offer both single and multi-axis turning, as well as live tooling options for added complexity and accuracy.

We use proven processes and quality control measures to ensure that every part we produce meets our clients' specifications and expectations.

Whether you need a single prototype or high-volume production runs, our CNC turning service can provide the precision and reliability you need to get your project completed on time and on budget.

CNC Turning service

Components Sizes of Asianstar CNC Turning Service

Unit (mm) Min Max
Out Diameter 0.5 480
Inner Diameter (Hole) 0.3 465
Length 1.0 450
Groove Diameter 0.4 above
Thread M1.2 above

Components Tolerance of Asianstar CNC Turning Service

Unit (mm) Tolerance according to sizes
Height Tolerance Diameter Size 0.5 to 3 3 to 6 6 to 30 30 to 120 120 to300 300 to480
Tolerance ±0.003 ±0.010 ±0.020 ±0.030 ±0.035 ±0.040
Length Tolerance Length Size 0.5 to 3 3 to 6 6 to 10 10 to 20 20 to 30 30 above
Tolerance ±0.010 ±0.020 ±0.250 ±0.250 ±0.030 ±0.035

Components shape and position tolerance of Asianstar CNC Turning Service

Tolerance Class followed Tolerance (mm)
Straightness and Flatness Verticality Symmetry
10 10 to 30 30 to 100 100 to 300 300 to 1000 1000 to 3000 to 100 100 to 300 300 to 1000 1000 to 3000 to 100 100 to 300 300 to 1000 1000 to 3000
H ±0.015 ±0.02 ±0.03 ±0.05 ±0.10 ±0.15 ±0.02 ±0.025 ±0.03 ±0.035 ±0.02 ±0.03 ±0.04 ±0.05

Capability of Asianstar CNC Turning Service

Type of Turning Machine Diameter Size (mm) Length Size (mm) Productivity (PCS/Month)
Auto Turning Machine Simple Turning Machine Multi Turning Machine Pin Turning Machine Min 0.5 Max 480 Min 1.0 Max 450 200’000/Item


Multiple Machining Processes

Multiple Machining Processes

Asianstar has various machining processes to support different types of components from client, we can choose the best suitable manufacturing solution to carry result in perfect performance and cheap cost

Flexible Custom Service

Flexible Custom Service

With skillful machining technologies, Asianstar is flexible to support clients on different materials and different structures of the components, we also flexible on the components quantities and even assembly

Create Designing for Clients

Create Designing for Clients

Not only producing according to clients drawings, Asianstar also propose the better designing to clients, supporting clients to buildup improved designing or even new generation components

Standard Procedures

Standard Procedures

Asianstar production, as experienced by many years, is strictly following internal Standard Operating Procedures, to make sure the production schedule is smooth and plans are well carried out well without accidents

Standard Procedures

Standard Procedures

Asianstar strictly controlling product quality by system. We start QC controlling from production plan once setting up, to production process by monitoring QC checking and until the final Inspection before packing

Fast Lead-Time Delivery

Fast Lead-Time Delivery

Asianstar strictly control the production processes, teams keep the plan moving ahead according to the procedures, we have internal time management schedule which mostly bring earlier lead-time of delivery

Asianstar: Professional CNC Machining Supplier

From year of 2005, Asianstar Company establish the CNC Machining Factory in Guangdong Province, China.
We mostly provide CNC Turning, Milling, Drilling, Grinding, and Multi Machining processes service on various materials.
With the Belief of becoming a key supplier in the supply-chain of Precision Components, we strictly control our product quality, keep high precision on our components production, buildup the whole-process QC System and submit the satisfaction for every order.
By long term development, we have buildup partnership with world-wide clients, supporting our partners in Designing, Optimizing, Producing and Testing on each type of components.


CNC Turning Service

CNC Turning Service

Our CNC Turning Service provides different sizes of roll shape work-pieces, the diameter range is from 0.5mm to 480mm, reaching tolerance +/-0.003mm.

CNC Milling Service

CNC Milling Service

Our milling machines and CNC centers are able to produce complicated structure part, five-axis devices produce multi-sides at one-time jag which bring high precision result

Sheet Metal Fabrication

Sheet Metal Fabrication

Our Sheet Metal Fabrication provides slicing, punching, bending, welding, painting and assembling for set products, unique tooling for each project to raise production efficiency

Aluminum Extrusion

Aluminum Extrusion

Our Aluminum Extrusion brings clients various shapes of aluminum parts, high efficiency for mass quantity, our precision extrusion mold control tolerance within 0.01mm

Forging Service

Forging Service

For some steel serious products, we apply Forging Service to make out their outer shape and them use CNC devices to start drilling, forming, rolling, cutting, etc.

Finishing Service

Finishing Service

Our Surface Finishing Service uses chemical or electro post-treatments after machining tasks are finished, normally includes Oxide, Anodizing, Passivation, E-Plating, Painting,etc.


  • Q1.Do you support ODM/OEM?

    Yes, we support ODM/OEM, we provide custom-made service for clients or even support clients on designing or improving

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