Introduction A computer that reads machine code instructions in order to control a machine tool is known as a Computer Numerical Controller. Computer Numerically Controlled, (CNC), Machine tools are usually used for machining raw material stocks into completed designs by carrying out a series of such instructions. CNC Lathes are probably the most commonly known application of this technology. They rotate a piece of material so it can be cut, sanded, drilled or polished, with the result being a completed three-dimensional product. Essentially, CNC lathes are basically the same as a standard turret lathe, but operating under computer control.

History

Electric motors started to become commonly available in the early 20th century, which inevitably led to many standard lathes being converted to electric power. It was the initial stage in automating the milling or turning process, It continued rapidly during the last century as producers and industrialists increasingly wanted to improve efficiency and minimize manufacturing costs.

Constituent Parts / Components

Today's CNC lathes combine a computer with a lathe machine and a controller to convert each digital program instruction into the desired action at the cutting tip. Specialized software is first used to create the required design that needs to be replicated physically on metal, wood, etc. The work piece is next fitted on the chuck and rotated at slow or high speeds depending on the material and the type of cut or centering required. The computer then controls the cutting action of the lathe as required in order to produce the finished product. Modern lathes can have multiple spindles so that multiple transformations can be carried out on the end product without having to stop and reload it in a different orientation.

CNC lathes are usually fitted with three jaw hydraulic chucks. Work holding is accomplished with hard jaws or bored soft jaws. Lathes may also have a collet chuck. This allows for variable size and precision holding without the need for soft jaw boring. When equipping a lathe with a collet chuck, it may be necessary to modify or change the draw bar connecting the actuator to the chuck.

The tool pieces that are required to cut through steel are usually made of titanium carbide, tungsten carbide, and other hard alloys depending on the material that needs to be cut. The tool bits are utilized until the tolerance levels are maintained after which they are either sharpened where possible, or replaced with a new bit.

A skilled operator is still required for a CNC lathe, despite all the advances in computer technology. In the past this would have required one or two operators for the actual physical work, so there is still a saving in both time and manpower. A developer is also required to compile the program commands needed to instruct the equipment in the first place.

Programming a CNC lathe firstly requires a blueprint of the item to be created. After the blueprint is analysed, the programming of the cutting tools required for making each part can then be started. Every move is programmed in extremely fine detail so that the required engineering tolerances can be achieved. A lot of skill and quality review is required at this stage to ensure no problems occur once the program is running in the live environment.

Practical Applications of CNC Lathes

CNC lathes were primarily designed for cutting hard materials spinning at high speed. They are also frequently used for boring precise holes into such hard materials. Modern lathes are also often used on other materials such as plastic and wood. They are commonly used in light, medium and heavy engineering shops for creating many of the objects we see in everyday use. There is still a place for more traditional manual and electric lathes however. Usually this is where craftsmanship is a key part of the finished product, or where low production volume does not warrant the cost of a CNC lathe.

Advantages / Benefits

As a percentage of the market share, CNC lathes have quickly established their dominance. They provide a more rapid turn-round time for complex one-off parts and ensure consistency in quality control and design tolerances. They are designed to use modern carbide tooling and fully utilize modern processes. Three further benefits are reduced production time, reduced inventory and reduced set up times. With the general rise in production levels, automated CNC lathes ultimately offer higher production volumes, with greater precision and fewer errors.

Summary

CNC lathes bring real benefits to the general population and are a perfect example of man's technological achievements being put to practical use. Goods today can be produced faster, more accurately and at a cheaper cost than previously due to their extensive use.