Lathe Operations: Facing

Facing Operations Facing is the process of removing metal from the end of a workpiece to produce a flat surface. Most often, the workpiece is cylindrical, but using a 4-jaw chuck you can face rectangular or odd-shaped work to form cubes and other non-cylindrical shapes.

When a lathe cutting tool removes metal it applies considerable tangential (i.e. lateral or sideways) force to the workpiece. To safely perform a facing operation the end of the workpiece must be positioned close to the jaws of the chuck. The workpiece should not extend more than 2-3 times its diameter from the chuck jaws unless a steady rest is used to support the free end. Cutting Speeds

If you read many books on machining you will find a lot of information about the correct cutting speed for the movement of the cutting tool in relation to the workpiece. You must consider the rotational speed of the workpiece and the movement of the tool relative to the workpiece. Basically, the softer the metal the faster the cutting. D…

Structure of Materials

It should be clear that all matter is made of atoms. From the periodic table, it can be seen that there are only about 100 different kinds of atoms in the entire Universe. These same 100 atoms form thousands of different substances ranging from the air we breathe to the metal used to support tall buildings. Metals behave differently than ceramics, and ceramics behave differently than polymers. The properties of matter depend on which atoms are used and how they are bonded together.

The structure of materials can be classified by the general magnitude of various features being considered. The three most common major classification of structure in increasing size, are:

Atomic Structure. It includes features that cannot be seen, such as the types of bonding between the atoms, and the way the atoms are arranged.

Microstructure, It includes features that can be seen using a microscope, but seldom with the naked eye.

Macrostructure, It includes features that can be seen with the naked eye.

The atomic structure primarily affects the chemical, physical, thermal, electrical, magnetic, and optical properties. The microstructure and macrostructure can also affect these properties but they generally have a larger effect on mechanical properties and on the rate of chemical reaction. The properties of a material offer clues as to the structure of the material. The strength of metals suggests that these atoms are held together by strong bonds. However, these bonds must also allow atoms to move since metals are also usually formable. To understand the structure of a material, the type of atoms present, and how the atoms are arranged and bonded must be known.


Popular posts from this blog

Lathe Operations: Step Turning

Lathe Operations: Plain Turning

What Is Capstan Lathe Machine?