CNC Turning: All You Need to Know

What is CNC Turning?

CNC Turning is a manufacturing process. Metal bars are held and rotated while a tool removes material to create a shape for the CNC-turned components. CNC turning involves holding the workpiece in a horizontally-mounted, adjustable spindle. The piece rotates on a lathe, allowing a computer-controlled turret with attached tooling to cut the material into a specified shape based on programmed instructions. A center with both turning and milling capabilities can stop rotation to allow for milling out of other shapes. Turning parts on CNC turning centers allows for a wide range of complexities, sizes, and material types. The starting material can be round, square, or hexagonal-shaped. Bar length is based on the feeder. The tools in CNC lathes or CNC turning centers are digitally controlled. CNC lathes and CNC turning centers can utilize a variety of processes to create different end results.

How Does CNC Turning Work?

The CNC Turning process involves the raw material being secured and turned by the lathe while a single point cutting tool is moved parallel to the axis of rotation, thereby shaping the material. The exact measurements are fed into a machine via CAD software. Once the computer has read the instructions, it controls the lathe to ensure that the machined parts are manufactured to the exact specifications required. This is different from conventional machining since it is the workstation that rotates rather than the cutting tool. Because of how they operate, CNC turning is typically used to make more cylindrical or oblong-shaped components. The technique is also chosen ahead of CNC Milling and 3D printing because of its ability to produce multiples of the same component quickly and from one single piece of raw material.

The History of CNC Turning

The process of CNC turning is actually based on one of the oldest machining tools in the world, the lathe. In fact, the use of a lathe in manufacturing dates back to Ancient Egypt.

Fast forward several centuries to the late 1940s and numerical controlled (NC) machining was invented by John T. Parsons, who was working in conjunction with the Massachusetts Institute of Technology. Commissioned by the US Air Force, Parsons was tasked with finding the most cost-effective way of producing aircraft parts that fit intricate specifications. Thanks to his efforts, CNC machining soon became the norm in the CNC manufacturing industry.

Then in 1967, the idea of computer-controlled machining first started circulating. A full nine years later, the first 3D computer-aided machining systems became available and within 13 years after that, CNC turning and machining became the industry standard.

Why Choose CNC Turning?

CNC turning is the fastest way to remove extensive material on rounded stock. It’s a type of machining that is also ideal for larger production runs when coupled with an automatic bar feeder that provides an uninterrupted supply of raw material into the machine. CNC turning is the only industrial process to choose when making production volumes of concentric shapes or threaded features. And, because of the rigid construction of a CNC lathe, there is little vibration, which means
turning in machining can offer high levels of dimensional accuracy with excellent surface finishes.

Advantages of CNC Turning

When compared with manual turning, CNC turning offers abundant advantages over traditional manual fabrication methods, including:

  1. Quick Turnaround. CNC turning equipment is pre-programmed and allows the equipment to move more quickly than manual machining.
  2. Superior Precision. Pre-programmed specifications ensure preferable precision and reliability.
  3. Variable Production Sizes. Faster CNC turning allows for larger-scale production with high repeatability.
  4. Material Versatility. CNC turning can be used on a broad range of materials.
  5. Enhanced Worker Safety. CNC turning requires less direct human interaction, thereby reducing the risk of injury to workers.
  6. Cost-Effectiveness. Enhanced speed and reduced labor costs can make CNC turning very affordable in comparison with other manufacturing.

What Kind of Materials Can Be CNC Turned?

Although it is possible to turn any solid, stable material. CNC turned parts manufacturers usually process hard plastics and metals for precision turning parts, such as aluminum, a variety of mild and stainless steel, titanium, magnesium, brass, copper, and other alloys. Note that some tool steel may be too hard to cut on a lathe or mill or else will require special treatment and a longer production time. Soft elastomers or plastics may also be impossible to turn since they cannot be held in a fixed position or would change in shape under the pressure of the cutting tool.

What CNC Turning Parts Can be Made?

CNC Turning is an extremely versatile manufacturing process. While it is mostly associated with the automotive, aerospace, and engineering industries, it can also be used to create objects like pieces of art and ornaments.

The CNC turning parts that are most commonly created can be divided into three broad categories, which are:

Metal Components

CNC Turning parts that are constructed from metal are typically used in the automotive industry. You can manufacture components from materials such as steel, brass, and aluminum.

Steel Components

CNC turned components made from steel are extremely economic and strong, though they are often more expensive than their aluminum counterparts. They are mainly used in the aerospace and automotive industries.

Aluminum Components

These precision cnc turning products are primarily used in the high-tech due to the material being both lightweight and strong. It is also extremely resistant to corrosion, meaning aluminum can be used for several applications.

Brass Components

Items made from brass are more commonly associated with electrical contacts and hardware, plus several other commercial products. These are extremely easy to machine and are therefore very cost-effective.

Acrylic Components

Modern acrylic materials are extremely versatile and can be used for a variety of CNC Turning Machine Parts. These range from highly complex machinery components for microfluidic devices, right the way to company logos and signage. Acrylic can also be used for works of art and ornaments for the office or around the house.

Electronic Components

CNC Turning in machining can also be used in the manufacture of printed circuit boards. Because of the increased precision offered by computer-aided manufacturing, the components are extremely electronically efficient.

Types of CNC Turning Processes

There are several types of CNC turning processes, each of which performs different tasks to reach an expected outcome. While none of these CNC turning processes achieve much separately, mixing and matching them all and incorporating computer programming results in high-quality CNC turning parts. Some primary types of turning include:

  1. Straight or cylindrical turning. This type of CNC turning uses a uniform motion to decrease the working diameter to prevent variation of the cut. This process removes large amounts of material from the workpiece before it undergoes more precise cuts.
  2. This CNC turning process creates a narrow cavity by pressing a shaped tool into the material.
  3. Taper turning. Taper turning creates a cylindrical shape with a gradually decreasing diameter.
  4. Often performed on materials that need extra grip, this CNC turning process cuts a serrated pattern into the workpiece.
  5. Spherical generation. This CNC turning process results in a perfect sphere shape by turning the workpiece around a fixed axis of revolution.
  6. This precision turning parts process removes a completed piece from the original stock piece by gouging deeply into the material.
  7. Threading results in helical grooves that can be screwed into other CNC-turned components.

Application Field of CNC Turning

CNC turned parts manufacturers can apply a range of material sizes to create accurate products for many industries, including:

  1. Aerospace. CNC turning is critical to the manufacturing of high-precision parts, engines, and aircraft bodies for the aviation industry.
  2. Medical and dental. Turning produces precise measurements, points, and angles for tools and instruments used in the dental and medical fields.
  3. Automotive. CNC turning quickly creates precise shafts, valves, and other precision turned parts for consumer, commercial, and defense vehicles to keep up with industry demands.
  4. Electronics. CNC turning is capable of producing the highly complex and precise precision turned parts needed to manufacture computers and other electronics.
  5. Military. Turning can machine parts to high standards with precise tolerances for military vehicles, avionics, and other military equipment.

Precision CNC turning is capable of producing precision turned parts, such as screws, motor shafts, and more, for the mechanical industry that meets necessary technical specifications. The highly precise nature of CNC turning also makes it suitable for woodworking, certain electrical applications, and electrical discharge machining (EDM).

CNC Milling vs CNC Turning: All You Need to Know

CNC machining is a rapid manufacturing process that turns digital 3D designs into plastic or metal parts by selectively cutting away material. Many companies require CNC machining services to make precision CNC machining parts and prototypes, and many industries use the versatile technology. But CNC machining comes in various forms. Although all CNC machining technologies follow a similar workflow — software turns the digital design into machine instructions, which instruct the CNC machine to cut material — the hardware for cutting material can differ greatly between machines. In this paragraph we discuss the essential features of CNC milling and CNC turning while also presenting the main advantages of each technology and a selection of common custom machined parts that companies can manufacture using each process.

What is CNC Milling?

CNC milling is one of the most common CNC machining services, and CNC machinists can use it to make a wide variety of CNC machined parts. CNC mills use computer instructions to move a rapidly rotating cutting tool along three or more axes. When the spinning cutting tool makes contact with the workpiece, it removes material in a controlled manner. The cutting tool makes a succession of passes against the surface of the workpiece until the workpiece resembles the desired part. Most CNC mills keep the workpiece stationary, holding it down on the machine bed with a vice. However, multi-axis CNC mills may rock or rotate the workpiece to create a greater number of cutting angles. This allows the machinist to create more complex parts without having to manually reorient the workpiece. YIJIN Hardware is one of the famous CNC milling services Providers provide customers with a one-stop, end-to-end process with short lead times.

What is CNC Turning?

CNC turning is a form of CNC machining that machinists use to make rounded, cylindrical, and conical parts. Although it is less versatile than CNC milling, it is one of the most popular CNC machining services and rapid prototyping services. Machines that carry out CNC turning are called CNC lathes or CNC turning centers. They are different from CNC mills in that they rapidly rotate the workpiece in a chuck but do not rotate the cutting tool. The cutting tool, affixed to a turret, moves towards the spinning workpiece under computer instructions and removes material where necessary. A CNC lathe can cut the outside of the workpiece or bore through the inside to create tubular CNC machined parts. The turret of the machine may have multiple cutting tools that can be individually engaged as required.

Advantages of CNC Milling

CNC mills offer numerous advantages to manufacturers and prototype companies. Unlike lathes, mills are versatile machines capable of creating a range of different shapes. Furthermore, a variety of cutting tools can be used to serve different operations such as roughing and end-milling. Although they are CNC manufacturing machines in their own right, mills are also useful for post-machining. For example, they can be used to add details to turned, molded, or 3D printed parts. CNC milling is also fast, repeatable, and inexpensive in low volumes — partly because it does not require tooling. It is therefore found among manufacturing services and rapid prototyping services.

Advantages of CNC Turning

The biggest advantage of CNC turning is its ability to create round profiles. It is much more difficult to achieve perfect roundness using other CNC machining services like CNC milling or CNC routing. CNC turning is also highly accurate, which makes it a valuable technology for boring holes of precise dimensions with set tolerances. CNC milling and CNC turning can be combined to reap the benefits of both processes. In most cases, CNC turning takes place first, allowing the machinist to mill further (asymmetrical) details on the part.

Parts Made with CNC Milling

Example CNC milling parts include:

  • Fittings: Milled fittings connect two or more parts together
  • Enclosures and housings: Electrical devices and other products can use custom-milled enclosures to protect internal components
  • Brackets: Milled brackets can contain custom threads and holes and may be more complex than sheet metal brackets
  • Gears: CNC milling can produce straight and spiral gears for mechanical devices
  • Mold tooling: Milled tooling, made of steel or aluminum, allows for rapid prototyping of molded parts
  • Engine parts: Automotive engineers use CNC milling for engine blocks and other parts
  • Medical devices: CNC mills can produce implants, surgical instruments, and other medical devices
  • Water pumps: Multi-axis mills can create reliable impellers for hydraulic equipment
  • Forming punches: CNC mills can create other manufacturing equipment, such as forming punches for sheet metal fabrication

Parts Made with CNC Turning

Example CNC turning parts include:

  • Rollers: CNC lathes can fabricate rollers with tight tolerances for industrial use
  • Ball joints: CNC turning is ideal for rounded connective devices like ball joints
  • Nuts and bolts: The accuracy of turning makes it suitable for tolerance-critical items like nuts and bolts
  • Shafts: Shafts with rounded profiles are highly suited to CNC turning
  • Flanges: CNC turned flanges can strengthen beams and pipes
  • Nozzles: Nozzles are typically cylindrical or conical with hollow insides, making them suitable for CNC turning
  • Turbines: CNC turning can produce round turbine blades for the energy industry
  • Firearms: A CNC lathe can produce the tubular shape required for a firearm barrel

Which Should You Choose?

Generally speaking, CNC turning is best for parts with round, cylindrical, or conical profiles, and CNC milling is best for everything else. If you require CNC turning parts or components, YIJIN Hardware can help. We are dedicated to providing the highest quality precision-engineered products for a wide range of industries.

That be honest, CNC milling and CNC turning can be combined to good effect. If a part has a predominantly round shape but also requires asymmetrical cuts or features, CNC milling can follow CNC turning in sequence. And although it is less common, CNC turning can also follow CNC milling — if a boxy or irregular-shaped part requires a large hole bored through its center, for example. Finally, sometimes you don’t have to choose: CNC milling-turning centers integrate both technologies into a single production device.


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