Assignment that prepared by our group

Sunday, June 29, 2008

Introduction and 1) Operational Principal



Introduction and Background Information and Lathe Machines

A lathe is most probably most primitive machine tool that have been used to turn round or conical parts which are symmetrical about it's own central axis. The most primitive lathe machine had two centers, a rope to turn the wooden piece, a tool rest and a rope to impart rotary motion. Most significant advancement was made by an Englishman, Henry Maudslay, in 1797, when he conceptualized the idea of having a lead screw to synchronize the part and tool motion to cut threads. This invention, in my mind, was the key invention that gave rise to lathes that we see today. Until now, no further advancements have been made to turn the corner in a very significant way. Most of the present advancements are some sort of variations of this crucial idea invented by Mr. Maudslay. A lathe can machine metals, plastics and combination of these materials. It is designed to perform operations such as turning, boring, drilling, reaming, threading, knurling, grooving, facing and taper turning. Some advanced lathes can also perform milling, hard turning, grinding and broaching operations depending on the specially designed attachments that a machine has. In next few paragraphs, we will try to get a brief explanations about these operations. Such machines can produce one part or several look alike parts using either mechanical devices or CNC (Computer Numerically Controlled) programs that are very much in use in today's world. Figure 1 shows one of such lathe machines offered by Smithy Company. A conventional lathe or CNC lathe can perform both external and internal machining operations in a repetitive fashion. In most of these machining operations, specially designed tools might be required to suit the dimensions and accuracy required for each part. It will not be too much out of place if it is told that many ideas for next generation machines such as machining centers, milling machines, drilling machines, grinding machines etc, stemmed out of his basic concepts of a lathe machine. In the same note, lathe operations normally require very basic skills which could be used for other machines also without any major difficulties. Hence, a basic understanding of the principles of lathe machine and its operations is very much essential for further learning on operations of other machineries. Knowing the background, let's turn towards knowing and getting familiar with recent generation of lathes with many advanced features that make such equipment highly flexible and versatile for turning operations.

Operational Principal
The engine lathe is the most versatile machine tools; with proper setups and accessories it can perform such machining operations as facing, straight, and taper turning, drilling, threading, milling, grinding, boring, forming, and polishing.
All operations performed on the engine lathe remove metal in essentially the same manner; that is, the cutting tool is fed against the work and shapes the workpiece, which securely mounted and rotating.



A turning operation is an operation in which a rotating work piece is turned against a cutting tool so that required amount of material (chip) can be removed from the work piece to give the required shape and size




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