CNC machining has rapidly dominated the manufacturing industry in recent years due to its high precision and repeatability. With several CNC technologies available today, a basic understanding of CNC machining will help you differentiate their features. One of these advanced technologies is CNC turning.
 

What is turning?

Turning is a machining process in which a lathe is used to rotate metal while a cutting tool moves in a linear motion to remove metal along a diameter, creating a cylinder. The cutting tool can be set at different angles to create different shapes. It can be done by hand or with a CNC lathe. CNC turning is often used when part measurements must be very precise.

CNC turning creates parts by inserting the workpiece into a rotating chuck and removing material with stationary cutting tools. This technology is ideal for producing parts that are symmetrical along their central axis. Turned parts are typically produced faster (and at a lower cost) than milled parts.

Materials used for CNC turning

- Metals

A wide range of metals for CNC machining, with applications in many industries. Ideal for both one-off prototypes and end-use custom parts.
 

• Aluminum: High machinability and ductility, good strength-to-weight ratio.
• Stainless steel: High tensile strength, corrosion resistance and heat resistance.
• Mild steel: High machinability and weldability, high hardness.
• Brass: Low friction, good electrical conductivity, golden appearance.
• Copper: Excellent thermal and electrical conductivity.
• Alloy steel: High strength and toughness, fatigue resistance.
• Titanium: Excellent strength-to-weight ratio, used in aerospace, automotive and medical applications.

- Plastic:

Plastic machined parts are a great alternative to metal parts because they are lightweight, easier to machine, and often less expensive.
 

• POM (Delrin/Acetal): High stiffness, high precision, low friction, easy to machine.
• Nylon: Excellent mechanical properties, heat, chemical, and wear resistance.
• ABS: General-purpose thermoplastic, impact resistant, easy to machine.
• PTFE (Teflon): Low friction, chemical and heat resistant.
• Polycarbonate: High strength, excellent impact resistance, transparent.
• Polyethylene: Excellent strength-to-weight ratio, impact and weather resistance.
• PVC: Excellent chemical and weather resistance, good durability.
• PMMA (Acrylic): Transparent rigid plastic often used as a glass substitute.
• Polypropylene: Excellent chemical resistance. Food grade available.

CNC Turning tolerances

We comply with ISO standards for CNC machining.
 

Advantages of CNC turning

Lathes produce these parts quickly, accurately precision and excellent repeatability. Here are some of the benefits of CNC turning:
 

- High Accuracy

CNC lathes can take precise measurements and eliminate human error by using CAD or CAM files. Professionals can deliver extremely high precision by using advanced machinery, whether for prototype production or completing an entire production cycle. Every cut is precise because the machine used has been programmed. In other words, the final product in the production process is identical to the first one.
 

- Flexibility

Turning centers come in a variety of sizes to suit the versatility of your application. Adjustments are fairly easy because the tasks of this machine are pre-programmed. The operator can perfect your component by making the necessary programming adjustments to your CAM program or even build something completely different. Therefore, you can rely on the same precision CNC machining service company if you need multiple unique parts.
 

- Safety

Manufacturing companies adhere to strict safety rules and regulations to ensure absolute safety. Since the lathe is automated, less labor is required as the operator is only there to monitor the machine. Likewise, the lathe body uses fully enclosed or semi-enclosed protective devices to prevent particles from flying out of the processed item and reduce harm to the operator.
 

- Faster Results

The chances of errors are lower when the specified programmed tasks are performed on a CNC lathe or turning center. This allows the machine to complete the manufacturing process faster without compromising the final output quality. Ultimately, you can get the required components faster than with other options.

Disadvantages of Turning

There are also some disadvantages to consider with turning:
 

- Only Rotatable Components

Since turning requires rotating the workpiece, only rotatable components can be rotated. This means that the size of parts that can be produced by turning is limited.
 

- Parts may require multiple processes and machines

Turning may be just one process used to produce a part. It is often used in conjunction with other processes, meaning that more than one machine is needed to produce the final product.
 

- Expensive Equipment

Lathes can be expensive, especially if they are CNC machines. In addition, turning requires additional accessories and attachments, which increases the cost of the equipment.
 

- Tool wear is significant

Repetitive rotation means that cutting tools are subject to significant wear.
 

- It generates a significant amount of scrap

Like most machining processes, turning generates scrap metal. The metal pieces produced by turning are called chips in North America and in some areas they may be called turnings.
 

What is the CNC Turning process?

The CNC turning process can be quite complex. However, we will provide you with a simplified, step-by-step breakdown of the process, from design to manufacturing.

The general steps of CNC turning are:
 

Step 1: Convert the CAD design file into a CNC program

The first step involves preparing the CAD file for translation into CNC lathe language. This does not involve advanced programming. You must have some 2D drawings of your design available. In that case, you will need to capture these designs electronically using software such as AutoCAD or SolidWorks.

Once you have the electronic design in CAD file format, you can convert it to a CAM program. You can also use the same software tools mentioned above to export the drawing in CAM format. The manufacturing engineer can then use the software to check the manufacturability of the part.
 

Step 2: Prepare the CNC Lathe

The next step is to set up the machine. Although most of the processes are automated, an operator is still required. To prepare the CNC lathe effectively, you should follow these steps:
 

• Make sure that you turn off the power. CNC machining can get quite dangerous. So, you should be extra careful and check the power switches.
• Fix the part to the block. The chuck is responsible for holding the part in place during the turning process. Not loading it properly can be dangerous and can result in parts that are the wrong size.
• Load the tool turret. Several tools are involved in the turning operation, so you must ensure that you are selecting the right tool for your particular finishing operation. The turret will help to hold as many tools as possible at once to help you operate smoothly.
• Ensure proper calibration. You must set up the tool and workpiece properly to ensure that the results are satisfactory.
• Upload the CNC program. The final step before starting the operation is to load the CNC code into the machine.

There are two variables to keep in mind at this stage. The first is the rotational speed (how fast the workpiece rotates). The second is the feedrate (how fast the cutting tool moves along the rotating workpiece).
 

Step 3: Making CNC Turned parts

The final step is to produce your desired part. There are a number of different turning operations you can choose from, depending on the result you want. Additionally, the complexity of the part will determine how many cycles you will have. Calculating the cycle time will help you know the final time spent on the part, which is important for calculating costs.

Typically, the turning cycle time will include:
 

• Loading time. Although this is part of the setup process, a cycle may require another means of loading the workpiece into the machine.
• Cutting time. This is the time it takes to cut the workpiece. Feedrate and depth of cut are factors that affect cutting time.
• Idle time. Any activity that is not related to cutting is idle. For example, changing the setting of the turning center, moving the tool, etc.
• The result of the manufacturing process will depend on the raw material used. A plastic part will be different in function and surface roughness than a metal part.

Machining methods of CNC turning

There are many types of turning tools available for CNC turning. As a result, you can perform a number of operations on the workpiece. These operations are classified into external operations and internal operations. External operations help change the outside diameter of the part. On the other hand, internal operations change the inside diameter.
 

- Turning

In this process, a single-point turning tool moves along the surface of the workpiece to remove material and form different parts. The features it can create include tapers, chamfers, steps, and contours. Machining these features usually occurs at small radial depths of cut, with multiple passes being made to achieve the final diameter.

Taper turning involves creating conical surfaces by gradually reducing or increasing the diameter of a cylindrical workpiece.
 

- Hard Turning

This type of turning is performed on materials with a Rockwell C hardness greater than 45. Heat treatment of the material is essential before performing this process. Hard turning is intended to limit or replace traditional grinding operations. It competes favorably with rough grinding when used for material removal purposes. However, it may not be suitable for operations where size and form are important.
 

- Facing

In this process, a single-point turning tool moves along the end of the material. In this way, it removes thin layers of material, resulting in a smooth flat surface. The depth of the surface is usually very small and the machining can take place in a single pass.
 

- Grooving

This operation also involves a radial movement of the single-point turning tool into the workpiece. Thus, it cuts a groove with a width equal to the cutting tool. It is also possible to make multiple cuts to form grooves larger than the width of the tool. Similarly, some manufacturers use special tools to create grooves of various shapes.
 

- Drilling

Drilling removes material from the internal parts of a workpiece using a standard drill bit. These drill bits are fixed in the turret or tailstock of a turning center.
 

- Threading

This operation uses a single-point threading tool with a 60-degree tip. The tool moves along the face of the workpiece to cut threads into the outer surface of the part. Machinists can cut threads to a specific length, while some threads may require multiple passes.
 

- Bending

This process involves cutting a serrated pattern into the surface of the workpiece using a specialized knurling tool. The pattern acts as a visual elevation or handle.
 

- Reaming

This sizing operation removes a small amount of metal from the drilled hole. It helps create internal holes with precise diameters. For example, when you make a 6mm hole with a 5.98mm drill bit, you can easily read the exact dimensions.
 

Applications of Mechanical Turning

CNC turning and machining processes are very beneficial to various manufacturing sectors. Below we will look at the applications of CNC turning operations.
 

- Automotive Industry

CNC turning operations are quite common in the production of automotive parts that improve the functionality of the vehicle. This process is compatible with the production of metal components such as cylinder blocks and plastic components such as dashboard components.
 

- Electrical Industry

CNC turning is suitable for creating circuit boards, among other electrical components. Since it is an extremely precise machining process, the product has a high electronic performance, meeting all requirements and specifications.
 

- Aerospace Industry

The aerospace industry requires a process like CNC turning and machining because it has high dimensional accuracy. They are suitable for designing steel parts for space shuttles, aircraft fasteners and internal components.
 

Intech Company CNC machining fast, accurate, on demand

Turning is one of the most important parts of the manufacturing industry, delivering precise results for a wide range of components. Its versatility and production capabilities ensure large-scale production with identical results.

Intech prides itself on cutting-edge technologies and advanced lathes to help you upgrade your custom machining experience. We also combine the knowledge and expertise of our technicians with rigorous quality control and quality assurance to provide you with high-quality parts that meet your requirements.

If you are considering CNC turning, contact us to learn more about your options for products manufactured using our efficient, high-precision CNC turning process.

• Hotline: 0966 966 205
• Address: Lot 6, Lai Xa Industrial Park, Tay Tuu Ward, Hanoi City
• Email: sales@intech-group.vn