Topic: CNC Turning: Process, Machines, and Advantages
CNC turning
CNC turning is a fundamental machining process used to produce cylindrical shapes from workpieces. The mechanism utilizes a CNC system to control the tool movement and remove material from the rotating workpiece.
A CNC turning lathe machine, or CNC turning centre, is at the core of the turning process. You can use turning to make a wide variety of parts and products, from power transmission shafts to hydraulic cylinders and aircraft’s landing gear components.
What is CNC Turning?
Turning mechanism
CNC turning is a subtractive manufacturing process that involves computer-controlled system to rotate work and move the stationary tools to shape cylindrical items. The CNC system controls tool path, feed, speed, and othe auxiliary function for repeatiablity and accuracy.
CNC turning machining creates shafts, bushing, bores, grooves, threads, stepped geometries, and custom cylindrical contours from workbar. It can machine differen materials with tolerances ±0.01 mm or better.
CNC lathes or turning cenetrs uses single-point cutters, insets, boring bars, live tooling, etc. It depends on the design shape you are machining and required operations for it.
Types of CNC Turning Machines
Types of turning machines
According to industry practices, CNC turning machines can be classified into three types: CNC lathes, turning centers, and Swiss turning machines.
Let’s take a look at them:
CNC Lathe Machines
These are the standard turning machines that can produce simple cylindrical to intricate multi-feature parts. Lathes typically come in 2, 3, 5, and 7 axes capabilities. As the machine has higher axes, it can produce more complex and precise parts.
There are two types of CNC lathes: Horizontal and vertical, based on whether the machine works by mounting the workpiece horizontally between the head and tailstock or vertically.
CNC Turning Centers
The turning centers integrate the milling and some other capabilities in the turning manufacturing process. Typically, they come in higher axes and are well-suited for turning, threading, boring, and contouring.
Turning centers are ideal for complex and multifeature parts, such as engine shafts, orthopedic pins, and hydraulic cylinders.
Swiss Turning Machines
CNC Swiss turning machines are used for micro-sized machining with tight tolerances, typically for parts with diameters of 0.3 to 32 mm. They can also machine the high length-to-diameter ratio. Unlike lathes, Swiss machines include a guide bushing mechanism located close to the cutting tool. It holds the wokbar to minimize deflection & vibration.
Advantages of CNC Turning
Turning is an accurate machining process that offers benefits like material flexibility, customization, repeatability, and safety.
Let’s look at the key advantages:
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- Accurate Machining: The rigid CNC machine components allow for stable material removal and can deliver parts as accurate as ±0.005mm.
- Custom Shapes: The diversity in turning operations allows for custom shapes with various geometrical features. It also gives more freedom to designers.
- Material Flexibility: You can use metals, plastics, composites, rubbers, and other materials in the turning process, except for some very hard materials.
- Repeatability: The CNC automation runs the same program & tool path. This consistency results in identical CNC turning parts, even in large volume production.
- Safety: The automation and other protective devices in the lathe allow for safety precision CNC turning parts and eliminate accidental risks to the operator.
Types of CNC Turning Operations
turning operations
Several types of CNC turning operations are used for both internal and external machining, such as straight turning, facing, taper turning, knurling, grooving, parting, drilling, boring, threading, and chamfering. Meanwhile, each of them might require a specific CNC turning tool type.
These operations can make parts from simple shafts to complex parts with detailed profiling. Consequently, the number of operations required to create a turned part depends on the complexity of the design.
The table below further explains the turning operations:
| Operation | Function | Tool type |
| Straight turning | Reduce the outer diameter to size or profile | Single-point turning tool |
| Facing | Create a flat face at the end of the part | Facing tool/carbide insert |
| Taper turning | Produce a conical surface or angle | Taper or angled insert |
| Parting | Separate the finished part from the bar stock | Parting cutter |
| Grooving | Cut narrow radial or axial grooves | Grooving insert or form tool |
| Threading | Cut external or internal threads | Threading tool and profile insert |
| Boring | Enlarge/finish internal bores | Boring bar |
| Drilling | Create holes along the axis on the lathe | Drill held in the tailstock/turret |
| Knurling | Form grip patterns on OD | Knurling wheel |
| Chamfering | Break edges, add lead-in/out | Chamfer tool |
What Are the CNC Turning Applications?
CNC turned parts
The use of CNC turning process ranges from general-purpose machining to highly sophisticated applications like robotics and luxury watches. Other industries like automotive, medical, and aerospace also rely on turning for various components.
Let’s take a look at the application examples;
- General Machining: Roughing of cylindrical workbar for surface preparation, simple shafts, etc.
- Automotive: Precise automotive parts, such as gear shafts, gear blanks, pistons, bushings, and suspension system components.
- Electronics: Fittings for electronics housing, small connectors, pins, EV parts, etc.
- Medical: Custom medical device components, bone screws, surgical tools, orthopedic pins, personalized implants.
- Aerospace: High precision components for aircraft, drones, and rockets. E.g., landing gear components, turbine shafts, and custom interior parts.
Conclusion
Overall, turning has extensive range of uses, from general machining tasks to intricate components for industries. With the use of right turning machine and tooling, you can perform CNC turning machining on metals, plastics, composites, etc.
If you are outsourcing the CNC turning services, you need to consider the capabilities and expertise of cnc turning machining supplier. So, you can get the parts exact to design specifications.
FAQs
What is a CNC turning job?
It is a machining process that involves a rotating workpiece and a stationary cutter to remove the material and create cylindrical components.
What is the difference between CNC milling and CNC turning?
The main difference is that CNC milling moves a rotating cutting tool against a stationary workpiece, turning rotates the workpiece against a stationary tool for material removal.
What are the basics of CNC turning?
CNC turning uses programmed commands to rotate material at set speeds while cutting tools shape it with simultaneous operations.
