Manufacturing Enigineering

Manufacturing Engineering

 Manufacturing Engineering it is a branch of professional engineering that shares many common concepts and ideas with other fields of engineering such as mechanical, chemical, electrical, and industrial engineering. Manufacturing engineering requires the ability to plan the practices of manufacturing; to research and to develop tools, processes, machines and equipment; and to integrate the facilities and systems for producing quality products with the optimum expenditure of capital.

The manufacturing or production engineer's primary focus is to turn raw material into an updated or new product in the most effective, efficient & economic way possible.

Forming processes
Drop forging:-

Upset forging

Upset forging, also known as heading, is a manufacturing process which decreases the length of a workpiece in order to increase the diameter of the material in this area. Upset forging is usually performed in presses.

Press forging

Press forging is a technique that applies gradual pressure on a die holding a work piece. This can be done as an open die or closed die forging process. In an open die press forging process, the metal is surrounded by the die on one side only.

Open die & closed die forging
Open die forging is the process of deforming a piece of metal between multiple dies that do not completely enclose the material. The metal is altered as the dies “hammer” or “stamp” the material through a series of movements until the desired shape is achieved. ... Custom shapes can also be produced with open die forging.

Closed Die Forging is a forging process in which dies (called tooling) that contain a precut profile of the desired part move towards each other and covers the workpiece in whole or in part. The heated raw material, which is approximately the shape or size of the final forged part, is placed in the bottom die.

 Rolling
Rolling is a type of motion that combines rotation (commonly, of an axially symmetric object) and translation of that object with respect to a surface (either one or the other moves), such that, if ideal conditions exist, the two are in contact with each other without sliding.

Working Principle:

Rolling works on same as any other metal forming process. When a compressive force applied by a set of rolls on ingot or any other product like blooms or billets, plastic deformation takes place which decrease its cross section area and convert it into required shape.
Hot rolling

Hot rolling is a mill process which involves rolling the steel at a high temperature (typically at a temperature over 1700° F), which is above the steel's recrystallization temperature. ... Hot rolled steel is used in situations where precise shapes and tolerances are not required.

Cold rolling
Cold rolling is a process by which the sheet metal or strip stock is introduced between rollers and then compressed and squeezed. The amount of strain introduced determines the hardness and other material properties of the finished product.

Application of rolling process:
Hot rolled product such as concrete reinforcing bars, plates, wire rods, sheet and strip, rails, structural. When the plates, sheet and strip products are used to manufacture of piping and tubes, body panels and construction materials. Cold rolled product such as wire sheet and strip.

Extrusion

Extrusion is a process used to create objects of a fixed cross-sectional profile. A material is pushed through a die of the desired cross-section. ... Extrusion may be continuous (theoretically producing indefinitely long material) or semi-continuous (producing many pieces)

Direct extrusion

Direct extrusion, also known as forward extrusion, is the most common extrusion process. It works by placing the billet in a heavy walled container. The billet is pushed through the die by a ram or screw. There is a reusable dummy block between the ram and the billet to keep them separated.

Indirect extrusion

In indirect extrusion, also known as backwards extrusion, the billet and container move together while the die is stationary. The die is held in place by a "stem" which has to be longer than the container length. The maximum length of the extrusion is ultimately dictated by the column strength of the stem.

• Press working

 Press working is a chip-less manufacturing process by which various components are made from sheet metals. It involves the working of a sheet between two die. In press working, the upper die is called a punch. This process is also termed as cold stamping.

Press operations like


Punching 

Punching is a metal fabricating process that removes a scrap slug from the metal workpiece each time a punch enters the punching die. This process leaves a hole in the metal workpiece. ... Its ability to produce economical holes in both strip and sheet metal during medium or high production processes.


Blanking 

Blanking is a steel manufacturing process in which a flat, geometric shape (or “blank”) is created by feeding a coil of sheet metal into a press and die. In this process the blank is punched out from large metal sheet.


Notching

Notching is a metal-cutting process used on sheet-metal or thin bar-stock, sometimes on angle sections or tube. A shearing or punching process is used in a press, so as to cut vertically down and perpendicular to the surface, working from the edge of a work-piece.


Lancing 

Lancing is a piercing operation in which the workpiece is sheared and bent with one strike of the die. A key part of this process is that there is not reduction of material, only a modification in its geometry. This operation is used to make tabs, vents, and louvers.

 Different Types of Dies:

The different types of dies used in sheet metal operations are as follows:

Simple Die:

If only one operation is performed in One Stroke and at One Stage is called as Simple Die.

Compound Die:

If more than one cutting operation is performed in one stroke and at one stage called as Compound Die.

Progressive Die:

In this,more than one cutting operation will be performed in one stroke but at different stages and punched out sheet is progressing from one stage to another stage for completing the punching operations so that Blanking will be the last operation.

Combination Die:
If more than one Cutting and Forming operations are combined together and performing one stroke at one stage is called Combination Die.

Forming operation:-


Bending

Bending is a metal forming process in which a force is applied to a piece of sheet metal, causing it to bend at an angle and form the desired shape. A bending operation causes deformation along one axis, but a sequence of several different operations can be performed to create a complex part.

Drawing

Drawing is a metalworking process which uses tensile forces to stretch metal or glass. As the metal is drawn (pulled), it stretches thinner, into a desired shape and thickness. Drawing is classified in two types: sheet metal drawing and wire, bar, and tube drawing.

• Plastic moulding

Plastic moulding is the process of shaping plastic using a rigid frame or mould. ... A popular manufacturing option, plastic moulding techniques are responsible for many car parts, containers, signs and other high volume items.

Properties of plastics:-
Hardness
Density
Tensile
 Strength
Resistance

   Types of plastic:-
    1 – Polyethylene Terephthalate (PET or PETE or Polyester) ...
    2 – High-Density Polyethylene (HDPE) ...
    3 – Polyvinyl Chloride (PVC) ...
    4 – Low-Density Polyethylene (LDPE) ...
    5 – Polypropylene (PP) ...
    6 – Polystyrene (PS) ...

Plastic moulding methods:

Injection moulding 

Injection moulding is a method to obtain molded products by injecting plastic materials molten by heat into a mold, and then cooling and solidifying them. The method is suitable for the mass production of products with complicated shapes, and takes a large part in the area of plastic processing.


Compression moulding

Compression moulding is a forming process in which a plastic material is placed directly into a heated metal mold then is softened by the heat and therefore forced to conform to the shape of the mold, as the mold closes. Once molding is completed excess Flash may be removed.

Vacuum forming

Vacuum forming is a simplified version of thermoforming, where a sheet of plastic is heated to a forming temperature, stretched onto a single-surface mold, and forced against the mold by a vacuum. This process can be used to form plastic into permanent objects such as turnpike signs and protective covers.

Calendaring

Calendering of textiles is a finishing process used to smooth, coat, or thin a material. With textiles, fabric is passed between calender rollers at high temperatures and pressures. Calendering is used on fabrics such as moire to produce its watered effect and also on cambric and some types of sateens.

• Welding

Welding is a manufacturing process that is usually used to join two metal parts together. This process is done by melting the two workpieces and adding filler material. When this molten material cools down, it becomes a strong joint. Different energy sources can be used, but the most common one is the electric arc.




Gas welding

Principle: Gas welding is a most important type of welding process. It is done by burning of fuel gases with the help of oxygen which forms a concentrated flame of high temperature. This flame directly strikes the weld area and melts the weld surface and filler material.

Working:
Gas welding process is quite simpler compare to arc welding. In this process all the equipment are connected carefully. The gas cylinder and oxygen cylinder
connected to the welding torch through pressure regulators. Now the regulate pressure of gas and oxygen supplied to the torch where they properly mixed. The flame is ignited by a striker. Take care the tip of torch is pointing downward. Now the flame is controlled through valves situated in welding torch. The flame is set at natural flame or carburizing flame or oxidizing flame according to the welding condition. Now the welding torch moved along the line where joint to be created. This will melt the interface part and join them permanently.


Application:

    It is used to join thin metal plates.
    It can used to join both ferrous and non-ferrous metals.
    Gas welding mostly used in fabrication of sheet metal.
    It is widely used in automobile and aircraft industries.


Carbon arc welding

Carbon arc welding (CAW) is a process which produces coalescence of metals by heating them with an arc between a non-consumable carbon (graphite) electrode and the work-piece. In carbon-arc welding a carbon electrode is used to produce an electric arc between the electrode and the materials being bonded.


Carbon arc welding Process and its working principle

The carbon arc welding is just similar to metal arc welding. The difference of the both welding electrode are different . In this welding process, the electrode is having carbon material (Carbon rod)and it consist of negative pole and work piece as positive pole. The arc is produced to heat the metal to melt temperature. In this heat temperature in negative electrode as 2800⁰c and positive electrode as 3800⁰c.

The carbon electrode using as negative pole because of low temperature generated on the tip than work piece, and carbon electrode not fuse and mix up with the work piece. If happens, the weld will be rich in carbon, and consequently more brittle and consumed excessively. In this reason DC current used in carbon arc welding AC current not used in the welding because of fixed polarity can be maintained.
The weld is best for joint of two metal melted without of addition of filler metal. If need the filler metal in welding process, the welding rod as in oxyacetylene weld. Sometime, portion gas used in welding process because of protection of molten metal from atmospheric oxygen.



Shielded metal arc welding

The weld is produced by heating with an arc between a covered metal electrode and the work. Shielding is obtained from decomposition of the electrode covering. SMAW is sometimes referred to as stick welding.


 TIG Welding Process

Principle of the process

The TIG process uses the heat generated by an electric arc between the metals to be joined and an infusible tungsten-based electrode, located in the welding torch. The arc area is shrouded in an inert or reducing gas shield to protect the weld pool and the tungsten electrode.

Working of TIG Welding
    In the TIG welding process or Gas Tungsten Arc Welding, the welding torch is connected to a constant current welding power supply and shielding gas source.
    With the help of the constant current supply, the electric arc is produced between the electrode and two metal workpieces which are to be joined.
    A filler metal is used to join the two metal pieces together. As the spark is struck, the filler metal is inserted in the cavity, and due to intense heat, the filler metal melts and fills the cavity between the two metal pieces and forms a strong weld.
    A shielding gas (He or Ar) is used to protect the weld from atmospheric contaminations. As the arc is produced, simultaneously the shielding gas also starts to spread near the weld area and avoids the weld to combine with atmospheric air and protect it from contaminations.
    The welding is performed by a highly-skilled operator. The operator has better control over the weld. He can use both hands to control heat generated and filler metal. From one hand he controls the arc produced and with the other hand he controls the feed of filler metal.


 MIG Welding Process

MIG welding is an arc welding process in which a continuous solid wire electrode is fed through a welding gun and into the weld pool, joining the two base materials together. A shielding gas is also sent through the welding gun and protects the weld pool from contamination. In fact, MIG stands for metal inert gas.

Gas Metal Arc Welding (GMAW) is frequently referred to as MIG welding.  MIG welding is a commonly used high deposition rate welding process.  Wire is continuously fed from a spool.  MIG welding is therefore referred to as a semiautomatic welding process.

Plasma arc welding

Plasma arc welding (PAW) is an arc welding process similar to gas tungsten arc welding (GTAW). The electric arc is formed between an electrode (which is usually but not always made of sintered tungsten) and the workpiece. ... Arc plasma is the temporary state of a gas.

   
Electron-beam welding

Electron-beam welding (EBW) is a fusion welding process in which a beam of high-velocity electrons is applied to two materials to be joined. The workpieces melt and flow together as the kinetic energy of the electrons is transformed into heat upon impact.

Laser beam welding 

Laser beam welding (LBW) is a welding process that produces coalescence of materials with the heat obtained from the application of a concentrate coherent light beam impinging upon the surfaces to be joined. The focused laser beam has the highest energy concentration of any known source of energy.

 Soldering 

Soldering is a process in which two or more metal items are joined together by melting and then flowing a filler metal into the joint—the filler metal having a relatively low melting point. Soldering is used to form a permanent connection between electronic components.

Brazing

 
Brazing is a metal-joining process in which two or more metal items are joined together by melting and flowing a filler metal into the joint, the filler metal having a lower melting point than the adjoining metal. 

 Machining Operations