For many manufacturing companies, balancing high precision and cost control is always a major problem when machining workpieces. However, the CNC turning machining I introduced today can solve this problem well, and the machining technology is also good at completing various types of parts processing. And this article will tell you everything about CNC turning in detail.
What is CNC Turning?
So, what exactly is CNC turning? Turning, a common machining process, is a specific subtractive machining process. During the machining process, the workpiece or material will rotate at high speed, and the cutting tool will remove the excess material according to the computer program settings, so that the product can gradually form the desired shape and size.
CNC Turning Steps
After talking about the interpretation of the process, I will introduce you to the specific working steps of the turning process, which are roughly divided into three stages: preparation stage, processing stage and follow-up processing.
1. Preparation Stage
（1）Design and Programming
First of all, the first step in all your work is to carefully study the part drawings and understand their geometric shapes, dimensional tolerances, surface roughness requirements, materials and other technical information.
Next, you need to write the CNC program according to the machining process formulated. During this period, you need to use computer-aided design (CAD) software to create a 3Dl model of the parts, set the tool path and cutting parameters (such as spindle speed, feed speed, cutting depth), and then convert the design into a G code, which is the control language of CNC machine tools.
（2）Preparation
You need to choose the right processing materials (such as metal, plastic, etc.) according to the requirements of the parts. And you must also choose the appropriate cutting tools to ensure that the tools can complete the work well.
（3）Clamping Workpieces
As for the workbench, you need to install the workpiece on the spindle of the lathe to ensure stability and avoid vibration or displacement during the machining process. At the same time, it is also necessary to pay attention to the center of the workpiece aligned with the lathe spindle to ensure machining accuracy.
（4）Set Up The Machine Tool
The last step in the preparation stage is to set up the machine tool. This means that you need to enter the set processing parameters on the CNC control panel, such as cutting speed, feed rate, etc. And in terms of tools, you should also pay attention to determining the starting position of the tool through measuring tools.
2. Processing Stage
（1）Start The Program
At this point, the processing process officially begins. After running the CNC program, the lathe will automatically execute your preset cutting path.
During this period, you also need to monitor the operating status of the machine tool, listen to whether the sound is normal, check the surface finish of the parts, and regularly conduct random inspections on the machined parts to understand tool wear and other problems.
（2）Processing Is Completed
After the machining is completed, you can stop the CNC program and be careful to take out the finished parts to avoid damage to the parts.
3. Follow-Up Processing
（1）Inspection and measurement
After the part is machined, you first need to measure its dimensions and tolerances, which requires the use of professional measuring tools, such as calipers, micrometers, etc. At the same time, you should also pay great attention to surface quality to ensure that the surface finish of the parts meets technical requirements.
(2) Post-Processing
Next, the cleaning work. You can use an air gun or detergent to remove chips and coolant from parts. If there are sharp burrs on the edges of the part, you also need to use a file, scraper or a special deburner to remove the burrs. In short, this step is to ensure that the final part is free of any flaws.
（3）Surface Treatment & Packaging
If the drawing has requirements, you also need to send qualified parts for subsequent processing, such as anodizing, electroplating, heat treatment, painting, etc.
After all machining processes are completed, you can anti-rust treatment and properly package the parts, and then prepare them for storage or shipment.
CNC Turning Tools
Now, are you very curious about what tools are specially used for material turning processing of CNC lathes? I will introduce it to you in detail below.
1. Tool Type
（1）External Turning Tool
This is the most basic and most commonly used tool in CNC turning. It can be used to cut the outer cylindrical surface, conical surface or curved surface of a workpiece, and common ones are turning tools and inserts.
（2）Facing Tool
It is usually used to cut the end face of the workpiece to flatten it and reach a specified length dimension. External turning tools with a large main declination angle can be used for face turning.
（3）Internal Turning Tool
A tool specially used to process the inner holes of the workpiece. The internal turning tool can expand or finish existing holes on the workpiece (such as holes drilled by the drill bit), thereby achieving accurate inner diameter dimensions and surface finish.
（4）Grooving Tool
The tool can turn grooves of various shapes on the outer circle or inner hole surface of the workpiece, such as retraction slots, sealing ring grooves, etc.
(5) Cut-off Tool
Cut off the finished parts from the bar. The blades of this tool are usually narrower, which is also to prevent material waste.
（6）Threading Tool
A thread turning tool can be used to process external or internal threads on the workpiece. This insert has a specific angle that matches the thread profile (e.g. 60° or 55°).
2. Tool Material
- High-speed steel (HSS): This steel has good toughness and wear resistance, and is suitable for processing soft and non-metallic materials.
- Corded carbide: high hardness, strong wear resistance, suitable for processing hard metal materials
- Ceramic tools: high temperature resistant and wear-resistant, very suitable for high-speed cutting, but have high brittleness.
- Polycrystalline diamond (PCD): suitable for machiningnon-metallic and hard materials, with extremely high wear resistance.
CNC Turning Materials
1. Metal Material
- Aluminum Alloy: Lightweight, easy to cut, strong corrosion resistance
- Stainless Steel: high strength, corrosion resistance, high temperature resistance
- Carbon Steel: high strength and high hardness, very suitable for high-strength cutting
- Titanium Alloy: high strength, light weight, good corrosion resistance
2. Non-Metallic Materials
- Plastic: lightweight, easy to process, good corrosion resistance
- Composite materials: Combine the advantages of multiple materials. Composite materials have high strength and light weight characteristics.
3.Special Materials
- Cemented Carbide: extremely wear-resistant, suitable for high-efficiency cutting
- Ceramic Material: high temperature resistant, wear-resistant, suitable for high-speed cutting
What Is CNC Turning Used For?
It can be said that the CNC turning process has been used in all walks of life, providing high-quality services to these industries. So, what industries are there? And you just need to continue reading.
1. Precision Parts Manufacturing
- Aerospace Components: key components of manufacturing aircraft and spacecraft, such as fuselage, engine components, etc.
- Auto Parts: produce high-precision auto parts such as engine components, transmission shafts, and wheel hubs.
- Specific Types Of Parts: shaft parts (such as drive shafts, motor shafts, piston rods, etc.), flange parts (such as flanges, pulleys, gear blanks, etc.), sleeve parts (such as: stainless steel bushings, bearing seats, pipe joints, etc.).
2. Medical Devices
It can manufacture medical products that require high precision such as surgical instruments and implants (such as joint replacements and dental implants).
3. Electronic Products
CNC turning can be used to machining the shells and internal components of electronic products such as mobile phones and computers.
4. Tools and Molds
- Cutting tools: Can produce various cutting tools, such as tools, drill bits, etc., suitable for various turning needs
- Mold manufacturing: used to manufacture injection molds, die-cast molds, etc., and is widely used in plastic and metal molding.
5. Oil & Gas
CNC turning can be used to make valves, joints, drilling tool parts.
CNC Turning Advantages And Disadvantages
Having introduced so much content about CNC turning, you must be curious about what its advantages and disadvantages are? Don’t worry, the answer will be told below.
1. CNC Turning Advantages
（1）High Efficiency
CNC turning is a completely automated process. The automated operation of the machine tool reduces human intervention, and the processing speed is fast enough, which is very suitable for mass production. In addition, automatic tool change, optimized cutting speed and feed rate also shorten the machining cycle of a single part.
（2）High Precision
CNC machine tools are precisely controlled by computer programs and can process parts with extremely high accuracy. These finished parts are very accurate in size and have very small tolerances. As long as the program and tool settings remain unchanged, every part produced is almost identical and has extremely high consistency.
（3）Complex Shape Processing
Through the precise linkage between the X-axis and Z-axis of the machine tool, you can make complex contoured parts according to the drawings, which can easily complete complex geometric shapes and multi-axis machining.
（4）Strong Flexibility
The production flexibility of the CNC turning process is excellent. If you want to switch from the production of one part to another, you usually only need to change machine programs, tools, and blanks. This fast switching mode saves time and is also very suitable for mass production.
（5）Reduce Manual Errors
Since the machine tool is program-controlled, this undoubtedly reduces errors and quality problems caused by human operation.
（6）High Safety
The area of CNC turning is completely enclosed. The protective doors effectively block splashing chips and coolant, and also isolate the operator from the tool processing area, which greatly reduces the risk of work-related injuries.
（7）Save materials
Precise machining reduces material waste well, which also increases cost-effectiveness.
2. CNC Turning Disadvantages
（1）High Initial Investment Cost
The purchase price of a CNC machine tool is quite expensive. What’s more, you also need to invest in CAM software, tool systems, fixtures and related operator training, so the early expenses are still very large.
（2）Complex Operation
Operators need professional programming and equipment operation skills, and each brand new part needs CNC programming and machine tool setting (detachment, setting coordinate system, etc.). Therefore, the preliminary preparation stage is still quite time-consuming.
（3）Higher Maintenance Costs
CNC turning machine tools are complex equipment that integrates mechanical, electrical, hydraulic, pneumatic and computer control. Therefore, in addition to requiring professional technicians for later repair and maintenance, the cost of replacement spare parts is also relatively high.
Types Of CNC Turning Machine
Finally, I will introduce you to the types of CNC turning machine tools, which is probably what you want to know very much.
1. Horizontal Lathe
The most common type of CNC machine tool, the spindle is parallel to the ground, and the structure is mature, easy to operate and program, which is very suitable for processing various shaft and disc parts.
2. Vertical Lathe
The workpiece is mounted on a horizontally rotating workbench. The vertical lathe spindle is perpendicular to the ground, and this lathe is very suitable for machining large diameter, heavy duty, but shorter length parts (such as flywheels, flanges, gear blanks), and covers a small area.
3. Double Spindle Lathe
This machine tool is equipped with two spindles, which can process two parts simultaneously or complete complex parts processing. The most important feature is that it can improve production efficiency and is very suitable for mass production.
4. Multi-Axle Lathe
The machine tool is equipped with multiple machining shafts (such as X-axis, Z-axis, Y-axis), which can realize the machining of parts in complex geometric shapes. Moreover, the characteristic of multi-axle lathe is high flexibility, so it is suitable for the production of high-precision parts.
5. Automatic Lathe
The most important feature of automatic lathes is automation, which can automatically feed and process, reducing manual intervention and reducing human errors.
6. Skateboard Lathe
This machine tool is equipped with a slider structure, which can be used to machining long shaft parts and can machining slender parts with high precision.
7. Turn-Mill Center
A very powerful high-end machine tool. Based on CNC lathes, it adds Live Turret and C-axis functions. In addition to turning capabilities, the Turn-Mill Center can also perform machining such as milling, drilling, and tapping on the ends or sides of the workpiece. So this machine tool can complete most or even all the processes of the part in one clamping
8. Hard Turning Machines
This machine tool is specially designed to process hard materials (such as hardened steel) and can replace the grinding process, thus saving time and cost well.
Conclusion
In summary, in the machining industry, CNC turning is an indispensable processing technology. It has produced many precision parts of different shapes for customers. I believe you are also very interested in this technology. Our DSR company is a professional manufacturer with 14 years of machining. We can provide customers with advanced CNC turning services. If you have any needs for this, please contact us immediately!
FAQ
Q1: How to use G41 and G42 in CNC turning?
A: G41 and G42 are instructions for tool radius compensation in CNC programming. They are mainly used to correct tool paths to make the processed parts meet the design dimensions.
G41 represents the tool left compensation, which is suitable for the tool moving along the left side of the path; G42 represents the tool right compensation, which is suitable for the tool moving along the right side of the path. When you use it, you need to define the tool radius value in the tool compensation table, activate the compensation through instructions such as G41 Dxx or G42 Dxx, and cancel the compensation through G40 after processing.
During this period, you should pay attention to the correct use of compensation instructions to correct the tool path and avoid dimensional errors. At the same time, you should also pay attention to the accuracy of direction selection and tool radius setting.
Q2: What is the difference between cnc milling and turning?
A: When it comes to the difference between CNC turning and CNC milling, it is mainly divided into the following points.
CNC milling mainly cuts fixed workpieces through rotating tools, so it is very suitable for processing complex planes, curved surfaces and asymmetric shapes; while CNC turning is cut by rotating workpieces, which can be used to process cylindrical or rotatably symmetrical parts, such as stainless steel shaft and stainless steel sleeve.
In terms of suitable parts, CNC milling is very suitable for processing non-circular parts, while CNC turning is more suitable for rotary symmetrical parts.
As for tool movement, during CNC milling, the workpiece is usually fixed and the tool will move around the workpiece; while CNC turning is completely different, the workpiece will rotate, and the tool is usually fixed or moved along the axis.
