CONVENTIONAL MACHINES 

LATHE

A lathe is a machine tool that rotates a workpiece about an axis of rotation to perform various operations such as cutting, sanding, knurling, drilling, deformation, facing, and turning, with tools that are applied to the workpiece to create an object with symmetry about that axis.

Lathe machine is one of the most important machine tools which is used in the metalworking industry. It operates on the principle of a rotating work piece and a fixed cutting tool. The cutting tool is feed into the work piece which rotates about its own axis causing the workpiece to form the desired shape.

Types of lathe machine

·         Center lathe or engine lathe machine

·         Speed lathe machine

·         Capstan and turret lathe machine

·         Tool room lathe machine

·         Bench lathe machine

·         Automatic lathe machine

·         Special lathe machine

·         CNC lathe machine

The main parts of the lathe are

Headstock
The headstock is usually located on the left side of the lathe and is equipped with gears, spindles, chucks, gear speed control levers, and feed controllers.

Tailstock
Usually located on the right side of the lathe, the workpiece is supported at the end.

Bed
The main parts of the lathe, all parts are bolted to the bed. It includes the headstock, tailstock, carriage rails and other parts.

Carriage
The carriage is located between the headstock and the tailstock and contains apron, saddle, compound rest, cross slide and tool post.

Lead Screw

The lead screw is used to move the carriage automatically during threading.

Feed Rod

It is used to move the carriage from left to right and vice versa.

Chip Pan

It is present at the bottom of the lathe. Chip pan is used to collect the chips that are produced during the lathe operation.

Hand Wheel

It is the wheel that is operated by hand to move a cross slide, carriage, tailstock and other parts that have handwheel.

 

MILLING MACHINE

Milling is a process performed with a machine in which the cutters rotate to remove the material from the work piece present in the direction of the angle with the tool axis. With the help of the milling machines one can perform many operations and functions starting from small objects to large ones.

Milling machining is one of the very common manufacturing processes used in machinery shops and industries to manufacture high precision products and parts in different shapes and sizes.

The milling machines are also known as the multi-tasking machines (MTMs) which are multi-purpose machines capable of milling and turning the materials as well. The milling machine has got the cutter installed up on it which helps in removing the material from the surface of the work piece. When the material gets cooled down then it is removed from the milling machine.   

Main parts of milling machine

Column & Base

Knee

Saddle and Swivel Table

Power Feed Mechanism

Table

Spindle

Over Arm / Overhanging Arm

Arbor Support.

Milling Process

The milling machine involves the following processes or phases of cutting:

Surface Finish

Any material put through the cutting area of the milling machine gets regular intervals. The side cutters have got regular ridges on them. The distance between the ridges depends on the feed rate, the diameter of the cutter and the quantity of cutting surfaces. These can be the significant variations in the height of the surfaces.

Gang Milling

This means that more than two milling cutters are involved in a setup like the horizontal milling. All the cutters perform a uniform operation or it may also be possible that the cutter may perform distinct operations. This is an important operation for producing duplicate parts.

Milling Cutters

There are a lot of cutting tools used in the milling process. The milling cutters named end mills have special cutting surfaces on their end surfaces so that they can be placed onto the work piece by drilling. These also have extended cutting surfaces on each side for the purpose of peripheral milling. The milling cutters have small cutters at the end corners. The cutters are made from highly resistant materials that are durable and produce less friction.

 

Types of Milling Machines

The two main configurations of the milling machining operations are the types of milling machines. These are the vertical mill and the horizontal mill. They are further discussed below

Vertical Milling Machines

The vertical mill has a vertically arranged spindle axis and rotate by staying at the same axis. The spindle can also be extended and performing functions such as drilling and cutting. Vertical mill has got two further categories as well: turret mill and bed mill.

The turret mill has got a table that moves perpendicularly and parallel to the spindle axis in order to cut the material. The spindle is, however, stationary. Two cutting methods can be performed with this by moving the knee and by lowering or raising the quill.

The other is the bed mill in which the table moves perpendicular to the axis of the spindle and the spindle moves parallel to its axis.

Horizontal Milling Machines

The horizontal mill is also the similar cutter but their cutters are placed on a horizontal arbor. A lot of horizontal mills have got rotary tables that help in milling in various angles. These tables are called the universal tables. Apart from this all the tools that are used in a vertical mill can also be used in the horizontal mill.

 

Logic gate

Logic gates are the basic building blocks of any digital system. It is an electronic circuit having one or more than one input and only one output. The relationship between the input and the output is based on certain logic. Based on this, logic gates are named as AND gate, OR gate, NOT gate etc.

There are basically seven types of logic gates, lets discuss about them

1.   NOT Gate

2.   AND Gate

3.   NAND Gate

4.   OR Gate

5.   NOR Gate

6.   X-OR Gate

7.   X-NOR Gate

 

NOT Gate

A NOT gate provides a low output when the input is high and high output when the input is low. Because of producing an opposite output as compared to input it is also known as an Inverter.

Inverting NOT gates are single input devices which have an output level that is normally at logic level “1” and goes “LOW” to a logic level “0” when its single input is at logic level “1”, in other words it “inverts” (complements) its input signal. The output from a NOT gate only returns “HIGH” again when its input is at logic level “0” giving us the Boolean expression of:  A = Q.

 

AND Gate

An AND gate is a digital logic gate with two or more inputs and one output that performs logical conjunction. The output of an AND gate is high only when all of the inputs are high. If one or more of an AND gate's inputs are low, then the output of the AND gate will be low.

 

NAND Gate

In digital electronics, a NAND gate (NOT-AND) is a logic gate which produces an output which is low only if all its inputs are high; thus its output is complement to that of an AND gate. A LOW (0) output results only if all the inputs to the gate are HIGH (1); if any input is LOW (0), the result will be a HIGH (1) output. NAND gate is inverse of AND gate.

 

OR Gate

An OR gate is a digital logic gate with two or more inputs and one output that performs logical disjunction. The output of an OR gate is high when one or more of its inputs are high. If all of an OR gate's inputs are low, then the output of the OR gate is low.

 

NOR Gate

The NOR gate is a digital logic gate that implements logical NOR operation. A HIGH output (1) results if both the inputs to the gate are LOW (0); if one or both input is HIGH (1), a LOW output (0) is observed. NOR is the result of the negation of the OR operator.

 

X-OR Gate

XOR gate (sometimes EOR, or EXOR and pronounced as Exclusive OR) is a digital logic gate that gives a true (1 or HIGH) output when the number of true inputs is odd. An XOR gate implements an exclusive or; that is, a true output results if one, and only one, of the inputs to the gate is true. If both inputs are false (0/LOW) or both are true, a false output results. XOR represents the inequality function, i.e., the output is true if the inputs are not alike otherwise the output is false. A way to remember XOR is "must have one or the other but not both".

 

X-NOR gate

The XNOR gate (sometimes ENOR, EXNOR or NXOR and pronounced as Exclusive NOR) is a digital logic gate whose function is the logical complement of the Exclusive OR (XOR) gate. The two-input version implements logical equality, behaving according to the truth table to the right, and hence the gate is sometimes called an "equivalence gate". A high output (1) results if both of the inputs to the gate are the same. If one but not both inputs are high (1), a low output (0) results.