Introduction to CNC Turning(heaviest materials Wilbur)

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CNC turning is a machining process that uses computer numerical control (CNC) to automate the turning operations performed on a lathe. Turning is a form of machining that produces cylindrical parts by rotating the workpiece while a single-point cutting tool is moved linearly against it. The turning operations like facing, boring, grooving, chamfering, cut-off can be performed on a CNC lathe to manufacture rotational, symmetrical and axis-symmetrical components made of metals, plastics, wood etc.
CNC turning centers provide accurate and fast machining by automating the process using CNC programming. CNC machines follow the tool path and machining parameters defined in the CNC program to cut and shape the raw material spun by the chuck precisely and efficiently. CNC turning is widely used in the machining industry including automotive, aerospace, medical, construction industries to produce parts like shafts, bushes, cylinders, discs, and other rotational parts in various batch sizes.
Working Principle of CNC Turning
The working principle of CNC turning is programmable automation of the turning process using computerized controls. It combines the robustness of conventional turning with the precision and repeatability of CNC automation. The programmable system drives the motion of the cutting tool and controls other functions like coordinate system, spindle speed, feed rate, coolant flow etc. according to the CNC program. Here are the key components of a CNC turning center:
- Machine Frame and Base: Provides rigidity and absorbs vibrations during machining operations. Heavy cast iron construction dampens vibrations.
- Headstock: Holds the rotating chuck and spindle which holds the workpiece. Geared AC/DC motors or hydraulics provide the drive for spindle rotation.
- Tailstock: Located opposite of headstock to support the free end of long workpieces with a center or quill. Can be adjustable or fixed type.
- Tool Turret: Holds multiple cutting tools and indexes them into the working position. Can have various tool stations from 4, 8, 12 or more.
- Tool Carousel: Stores large number of tools and automatically changes them into the turret. Enables unattended machining.
- Control Panel: Equipped with CNC controller, program storage, input/output devices, buttons, switches and other controls.
- Bed: Provides mounting surface for headstock, tailstock, slides and other components. Made of cast iron for vibration absorption.
- Ballscrew/Leadscrew Assembly: Transmits motions from the servomotors to the slide for X-axis movements. Recirculating ballscrews predominate modern CNC turners.
- Guideways: Guide the linear sliding motions of the slides. Precision ball bearings with scrappers or box ways used.
- Coolant System: Supplies cutting fluids at high pressure to the tool-workpiece interface for cooling, chip flushing and lubrication.
The machine operates by following the sequential movements commanded by the CNC program. The program is either written manually (G-code programming) or using CAM software that automatically generates the code. The basic sequence in CNC turning includes:
1. Load raw material workpiece in the chuck and ensure stable clamping.
2. Initialize CNC program and various machine parameters like speed, feed etc.
3. Commence automatic operation cycle.
4. The turret indexes the required cutting tool into the working position.
5. The tool approaches the rotating workpiece and engages in machining.
6. Machining operations perform as per program - facing, turning, grooving etc.
7. Cutting tools automatically change for different operations.
8. Finished component is unloaded after completion of program.
Benefits of CNC Turning
CNC turning delivers higher productivity, precision, accuracy, repeatability and automation as compared to conventional turning. Here are some of the major benefits and advantages of CNC turning:
- Faster setup times due to stored tool offsets and work coordinates. Reduces changeover delays.
- Minimal manual intervention leads to consistent machining and reduced rejections.
- Ability to run unattended for mass production. 24/7 unmanned operation possible.
- Complex components can be machined easily with accurate dimensional tolerances.
- Multiple operations like grooving, threading, boring etc. can be performed in a single setup.
- Quick changeover between batches owing to stored programs and tools.
- Easy to integrate with automation like gantry loaders, robotics, conveyor systems etc.
- Advanced software capabilities like simulation, 3D modeling etc.available.
- Minimal scrap loss due to precision programming and machining.
- High degree of data feedback on tool life, cycle time, downtime etc.
- Safer to operate owing to the absence of manual machining.
Thus CNC turning automates the complete turning process and enables mass production of precision machined components, while reducing human efforts. By leveraging CNC, even complex geometries can be produced accurately and efficiently.
Applications of CNC Turning
The applications of CNC turning span across several industries like automotive, aerospace, oil and gas, medical, construction etc. It caters to both high volume production as well as low volume batch requirements. Here are some major applications of CNC turning:
- Automotive: Engine parts, shafts, axles, gears, clutches, valves, turbocharger housings etc.
- Aerospace: Aircraft structural parts, engine components like blisks, disks, impellers.
- Medical Industry: Orthopedic implants, surgical instrument components, prosthetics etc.
- Oil and Gas Industry: Valve bodies, compressor parts like stators, rotors, wellheads etc.
- Construction Industry: Equipment parts like sheaves, sprockets, bearings, gears, shafts, spindles etc.
- Hydraulics Industry: Hydraulic cylinders, pumps, valves and actuators.
- Electrical Industry: Motor armatures, stators, insulators, connectors and transformers.
In summary, CNC turning is a versatile machining process that leverages programmable automation to deliver high precision turned components across many industries. The computer control and stored programs enable fast changeovers between batches, minimal manual intervention and variety of machining operations in a single setup. CNC turning improves productivity, part quality and consistency in comparison to conventional turning. The future will see more widespread adoption of CNC turning for mass production as well as flexible manufacturing of custom components. CNC Milling CNC Machining