What is a Turning?(corrosion resistant Kitty)
- source:BREDA CNC Machining
How Does Turning Work?
The turning process utilizes a cutting tool called a turning tool that is held rigidly in a tool holder, which is secured to the machine’s tool post. As the cylindrical workpiece rotates, the cutting tool feeds into it axially along its length to remove material. The depth of cut is set by adjusting the tool’s radial position. The speed and feed rates of the rotation and axial movements are precisely controlled to achieve the desired dimensions and surface finish.
Types of Turning Operations
There are several basic types of turning operations, including:
- Facing - Machining the end surface of a cylindrical part perpendicular to its axis. This produces flat faces.
- Straight turning - Machining the outside diameter of a cylindrical part with a single point cutting tool. This reduces the diameter to precise dimensions.
- Taper turning - Machining a tapered section on the outside diameter by adjusting the angle of the cutting tool.
- Grooving - Cutting a groove in the part by moving the tool perpendicular to the axis. Used to cut threads and grooves.
- Undercutting - Machining an enlarged section below the existing diameter, often for threading purposes.
- Parting - Severing a part from the stock by cutting radially with a specially shaped tool.
- Boring - Enlarging and smoothing holes by feeding a single point tool radially into the bore.
- Drilling - Creating a round hole in the center of a part by drilling axially into the face.
- Form turning - Using a shaped cutting tool to machine complex profiles.
Equipment Used in Turning
Turning operations are performed on specialized machine tools called lathes. There are several types of lathes, including:
- Engine lathe - The most common, used for a wide range of turning jobs. The workpiece rotates between two centers or in a chuck.
- Turret lathe - Has multiple cutting tools mounted on a turret that can be automatically indexed. Used for high production.
- CNC lathe - Computer numerical control (CNC) allows programming automated machining operations. Offers precision and complexity.
- Vertical turning lathe - Oriented vertically for convenience machining large diameter parts. The cutting forces are downwards.
- Multi-axis turning centers - CNC machines with multiple spindles and turrets allowing simultaneous multi-axis turning.
The appropriate lathe is selected based on the dimensions of the part, types of features required, precision needed, and production volume. Tooling, setup, programming, and fixturing must also be considered.
Turning Tools and Inserts
There is a wide variety of single point turning tool bits and inserts that can be used for different materials and applications. Common tool materials include high speed steel, carbide, ceramic, diamond, and cubic boron nitride. The tools come in many standardized shapes like round, square, triangular, and diamond form tools. The appropriate tool geometry depends on factors like feed rate, depth of cut, heat generation, and desired finish. The cutting edges are either ground for sharpening or use indexable inserts that can be replaced as they wear down. Advanced coatings like titanium aluminum nitride can extend tool life. The tools are secured into tool holders on the machine's turret or tool post.
Turning Process Parameters
There are several key process parameters that must be set correctly during turning operations:
- Cutting speed (surface feet per minute)
- Feed rate (inches per revolution)
- Depth of cut (inches radial)
- Cutting fluid - coolant or lubricant used
These parameters directly impact the forces, temperatures, tool life, surface finish, tolerance accuracy, and other outcomes. They must be applied appropriately for the workpiece material, tooling used, desired quality, and equipment capabilities. Parameters are often determined from reference charts and calculations. During cutting, they can be adjusted to optimize the process.
Applications of Turning
Turning is an extremely common manufacturing process used across virtually all industries. Typical applications include:
- Reducing the diameters of round bars into bolts, pins, axles, shafts, bearings, and bushings
- Machining circular and cylindrical components like rolls, pulleys, disks, and sleeves
- Producing precision parts like gears, cams, journals, pistons, and rollers
- Creating screw threads, undercuts, and grooves for functionality
- Smoothing and dimensioning drilled holes and inside diameters via boring
- Fabricating parts that will be used in automobiles, engines, appliances, machinery, aerospace components, and more
Turning remains one of the most essential and widely-used machining processes, valued for its versatility, efficiency, and ability to produce precision cylindrical components. Continuous improvements in machine tools, cutting tools, automation, and other technologies will ensure turning remains critical for modern manufacturing. CNC Milling CNC Machining