What is a Turning?(how to get rust off chrome rims Willie)

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A turning is a machining operation used to create cylindrical parts on a lathe or turning machine. Turning involves rotating a workpiece while cutting tools remove material to shape the outside diameter. It is one of the most common and fundamental machining processes.
How Does Turning Work?
The turning process utilizes a lathe or turning machine, which consists of a bed, headstock, tailstock, carriage, and cutting tools. The workpiece is securely clamped in the chuck on the headstock, which rotates it at high speeds. The cutting tools are rigidly held on the carriage and fed towards the rotating workpiece to cut away material.
The cutting tools come in various shapes and materials, such as high speed steel, carbide, ceramic, diamond, and cubic boron nitride. The most common is the single point cutting tool, which has a sharp cutting tip angle designed for shearing away material. Other tool types include thread cutting tools, grooving tools, parting tools, and boring bars.
The carriage controls the movement of the cutting tools. It can move transversely across the bed as well as in and out to cut tapers or contours. The tailstock is located opposite the headstock and used to support the free end of long workpieces. Lubricating fluids are often applied to reduce friction and heat.
Types of Turning Operations
There are several fundamental turning operations:
- Facing - Removing material from the face of the part to create a flat surface. This is done before other operations.
- OD (Outside Diameter) Turning - Cutting the external diameter of a cylindrical part. This is the most common operation.
- ID (Internal Diameter) Turning - Also called boring, this involves enlarging existing holes or cutting internal cylindrical forms using boring bars.
- Taper Turning - Machining a tapered diameter by offsetting the tailstock or using a taper attachment.
- Grooving - Cutting grooves or recess into the surface. Useful for splines, threading, and parting.
- Shoulder Turning - Turning down diameters while leaving a rim or shoulder.
- Parting - Cutting workpieces into separate parts using a specially-shaped parting tool.
- Threading - Single-point or tap cutting internal and external threads.
- Form Turning - Shaping complex rotational contours using specially shaped cutting tools.
- Knurling - Creating a pattern of serrated lines or diamonds using a knurling tool. Used for improved grip.
Benefits of Turning
There are many advantages that make turning one of the most prevalent manufacturing processes:
- High production rates possible for cylindrical parts. Complex parts can be completed in a single setup.
- Excellent surface finish and dimensional accuracy and repeatability. Precision ground bars allow tighter tolerances.
- Broad material versatility including all metals, plastics, composites, and woods. New cutting tool coatings expand capabilities.
- Low forces and simple setups reduce machining costs. No special fixturing required.
- Flexible process able to produce various diameters, shapes, threads, tapers, grooves, knurls, etc.
- Ideal for working with cylindrical stock or any axially symmetric part.
- Lends itself to automation and lean manufacturing practices.
- Environmentally cleaner than other machining processes like milling.
Turning Process Variables
There are several important process variables that influence turning operations:
- Cutting speed - The speed at which the workpiece material moves past the cutting tool, measured in surface feet per minute (SFPM).
- Feed rate - The speed at which the cutter advances along the workpiece, measured in inches per revolution (IPR).
- Depth of cut - Thickness of material removed by the tool in one pass, measured in inches.
- Tool nose radius - The rounded cutting edge that impacts surface finish, chip formation, and forces.
- Cutting tool material/coatings - Significantly affects tool life, speeds, finish quality, and work materials.
- Cutting fluids - Coolants or lubricants used to decrease friction, temperature, and chip adhesion.
- Rigidity - Stiffness of the lathe components and setup directly affects achievable tolerances.
By optimizing these parameters, the machinist can maximize productivity, efficiency, and part quality. SFPM and IPR are balanced based on work material, tooling, and surface finish requirements. depths of cut depend on available lathe power, rigidity, and operations performed.
Turning Applications
Turning is utilized across virtually every industry that requires metal parts because of its versatility. Typical applications include:
- Automotive - Engine blocks, transmission cases, axles, driveshafts, brake drums, rotors, hubs
- Aerospace - Missile cones, nosecones, fins, couplings, fasteners, hydraulic components
- Medical - Bone screws, surgical instruments, implants, prosthetics
- Construction/Mining - Shafts, rollers, boring bars, pulleys, gears, sprockets
- Fluid Power - Hydraulic cylinders, valves, connectors, pneumatic actuators
- Transportation - Wheels, axles, rail car/truck components, ship propellers
- Oil/Gas - Pipes, valves, pumps, couplings, tool joints
- Industrial Machinery - Spindles, couplers, cams, bushings, centrifuges
- Consumer Goods - Appliance housings, fittings, sporting goods
Turning remains a staple process due to its simplicity, accuracy, cost-effectiveness, and versatility for round parts. Advances in CNC technology, cutting tools, and automation continue to improve turning capabilities for even more applications. Understanding the fundamentals of turning is key for engineers, machinists, and anyone involved in manufacturing. CNC Milling