Tungsten inert gas welding

Tungsten inert gas welding is also known as gas tungsten arc welding.

In this process, an inert gas shielded arc welding process using a non-consumable electrode. The electrode may also contain 1 to 2% thoria mix along with the core tungsten or tungsten with 0.15 to 0.40% zirconia. The pure tungsten electrodes are less expensive but also it will carry less current. The thoriated tungsten electrodes carry high current and more desirable because they can strike and maintain a stable at with relative ease. The zirconia added tungsten electrode better than pure tungsten but inferior to thoriated tungsten electrodes.

The process set up :

Tungsten inert gas welding setup is shown in figure it consists of a welding torch at centre electronic inert gas is supplied to the welding zone through the Anil apart surrounding the tungsten electrode to effectively displays the atmosphere Around The World Patel the smaller world tours may not be provided with Anni cooling device for the electrodes but larger ones are provided with circulating cooling water 30 welding process can be used for joining a number of materials through the more aluminium magnesium and stainless steel.

Components used :
  • Power Supply (A.C or D.C)
  • Filler Rod
  • Non-consumable Tungsten electrode
  • Welding Head
  • Inert Gas Supply

Tungesten intert gas welding

Working principle :

TIG welding process is relatively difficult to perform out of another welding process because it normally requires two hands for the process to be performed while other processes require that the welder manually feed a filler metal into the weld area with one hand.

In this process, first of all, strike the welding arc that can be produced by torch. A high-frequency generator provides an electric spark. This spark is a conductive path for the welding current through the shielding gas and it allows the arc to be initiated while the electrode and the workpiece are separated. The inert gas forms a gas shielding around the weld. It protects the weld from the external atmosphere. 

Once the arc is struck, the welder moves the torch in a small circle to create a welding pool, the size of that depends on the size of the electrode and the amount of current then torch moves back and filler metal is added manually to the front end of the weld pool as it needed.
The arc current is often gradually reduced to allow the weld crater to solidify and prevent the formation of cracks at the end of the weld. Thus, this process can be done.

Advantages of TIG welding :
  • It produces high quality and clean welds.
  • No slag is produced so welds are not weakened.
  • The weld is automatically protected by the inert gas during the welding process so welds are corrosion resistance, more ductile, and stronger.
  • This process can apply for any position of welding like wise horizontal, vertical or flat.
  • It can be performed by both automatic and manual technique.
  • It easily applied to thin material and used for a wide range of metal thickness.
  • There is less distortion of work piece because the small heat affected zone.
  • Only the necessary amount of filler metal is added to the welding puddle so there is no spatter or sparks are produced.
  • Use one shielding gas mainly Argon for all applications.
  • In this process finishing process required little or less. Sometimes grinding or preparation before it can be painted.
  • It is the preferred choice in most of the intricate works, where shape of each and every weld joint counts.
Main most common limitations of TIG welding is low deposition rate of the filler and metal per pass so that time increased to completed the welds that's why it is mostly used for thinner metal. More than that it has certain disadvantages we can check it below :

Disadvantages of TIG welding :
  • As we seen it is slow process.
  • More complicated process so that highly skilled labour is required.
  • Less economical than consumable electrode for sections thicker than 3/8 inch.
  • Tungsten inclusion.
  • Welder is exposed to the huge intensities of light.
  • This process is also more expensive.
  • Sensitive to drafts.
Tungsten Inert Gas Welding offers several advantages that account for its popularity and its use in agriculture and many other industries. 
Applications of Tungsten Inert Gas Welding :
  • Stainless steel
  • Alloy steel
  • Aluminium
  • Titanium
  • Copper
  • Magnesium
  • Nickel alloys

Broaching machine

Broaching process is the simplest of all machine tools that can be performed on a broaching machine. It can be consist of a work welding fixture, broaching tools, a drive mechanism and suitable supporting frame. Although the component parts are few, several variations are possible. 

There are two principal types of machine :
  • Horizontal 
  • Vertical 
In addition to these standard types, there are special and continuously operating machines. Both horizontal and vertical types have one or more rams depending on production recruitment. Dual ram models are arranged so that when one ram is on the cutting stroke the other is on the return stroke and the return stroke is performed quickly to gain time, which is used to and load the machine. 

Broaching machines usually pull or push the approach through, or past a work piece that is held in a fixture. On some machines, however, the work piece is moved past that is fixed position. Most broaching machines operated to secure a smooth, uniform cutting action.

Horizontal broaching machine :

Most of all broaching machines at the pull type. They may be used for either internal or external broaching. The horizontal broaching machine consists of a bed or a little more than twice the length of broaching stroke, a broach pilot and the drive mechanism of pulling the brooch. 
It is used in many application especially for broaching keyways, splines, slots, round holes and other internal shapes or contours. They have the disadvantages of taking more floor space than vertical machines. 

Vertical broaching machine :

The vertical type may be obtained in either push or pull type. The push-type is more popular. It can be employed in multiple operations, since they are convenient to pass work from one machine to another, and they are more likely to be found doing surface operations. Of the three models available pull-up, pull-down and push down, the pull-up type is most popular. 

Vertical machines require an operator platform or a pit and are economical of floor space than the horizontal type.

Surface broaching machine :

Surface broaching machines have their broaching tools attached to the ram or ram forced in a straight path along with guide ways past the work piece. On some machines, the ram moves horizontally on other vertically. When two rams are used, the machine is called duplex broach. 

Continuous broaching machines : 

For mass production of smart small parts, the highly productive continuous broaching method is used on rotary or horizontal continuous-broaching machines. 

In this machine the work piece is loaded on the table which rotate continuously. During the operation the broach is stationary. 

In the horizontal continuous broaching machine the work piece travel as they are carried by an endless chain. The work piece are loaded into work holding fixture that is mounted on the continuous moving chain. During the operation the broach is stationery as before. Such machines are used for broaching small parts.

Types of belt drive

A belt drive is one of the most common and effective means of transmission of motion from one shaft to another shaft. There are different belt drive used for different applications. Now we can see the different types of belt drive :

Types of belt drive :

According to the power transmitted :
  1. Light belt drive 
  2. Medium belt drive 
  3. Large belt drive 
According to the arrangement of the belt :
  1. Open belt drive
  2. Crossbelt drive
  3. Quarter twist drive
  4. Right angle drive
  5. Stepped pulley drive
  6. Fast and loose pulley drive 
  7. Compound drive 


VTVT and CRDI are the fancy names given to engines from different manufacturers. 

Let us have a deep insight into the difference between VTVT and CRDI. 

VTVT is standing for variable valve timing valve train has ability to independent control of the intake and exhaust valves in an automobile engine on different engine load criteria.

CRDi stands for common rail direct injection is a fuel injection mechanism to supply the requisite amount of fuel at constant pressure and also to maintain a certain amount of pressurized reserve fuel during starting of the engine.

Mostly VTVT technology used for petrol engine while CRDi technology working for a diesel engine.

Application of belt drive

There are different variations of industrial machining application of belt drive that employ a wide range of different types of synchronous timing belt drive systems. 

Application of belt drive :

  • Automobile timing belt 
  • Treadmills
  • Sewing machine
  • Drilling machine with speed cone pulleys
  • An open belt drive in a jig-saw machine
  • Lathe machine with time belt
  • A planner machine with guide pulleys 
  • A flat belt in a circular saw machine  

Belt drive vs Chain drive

Chain and belt drive are both allow locomotive and a transfer of power within a particular piece of machinery. Both are used in many vehicles and other mechanical applications like garage doors. Now we will discuss the difference between both two drive and what is more effective?

Difference between belt drive and chain drive :

  • A chain drive is driven by a chain loop while a belt drive is driven by a belt.
  • A chain drive is made of a metal which makes them more durable and stronger as compared to belt while belt drive is made of synthetic material.
  • A chain can transmit more power and last longer, but typically a belt is quieter.
  • A belt drive gives you lower power transmission efficiency than a chain drive because it will allow higher levels of misalignment between sprockets. Belts are a little more elastic, so they can run tighter to eliminate play or backslash.
  • Replacement of belt is very easy and cheap so it needs little maintenance and has only three moving parts called belt and two pulleys whereas the chain literally consists of hundreds of pieces, side plates, rivets, bushes and rollers.
  • A chain drive is comparatively efficient than belts.
  • If you are using a chain drive in a coastal area with lots of salt in the air, take care of that chain drive. Clean it and keep it lubricated or you will get corrosion which always takes strength away over time which will make you upset.

Conclusion :

The main advantage of a belt is expansion due to a temperature which is minimal and is capable of slipping and also can be used as a safety device. The sounds generated by the belt is minimal so tape recorders use belts. It can absorb vibrations and it is less noisy. It has to be bulkier than a chain to have the same strength so chains are used in some places and belts in other places depending on the desired requirement. There are many different varieties of belts than chains to suit their needs. You can use depending on your requirement.

Belt drive vs Gear drive

belt drive is a system of connecting to wheels by a belt whereas gear drive is two gear is connected with each other as corresponding to both teeth are connect interconnected. Now we will discuss the difference between both two drive and what is more effective?

Difference between belt drive and gear drive :

  • Belt drive has lesser life as compared to that of the gear drive.
  • Belt drive requires more maintenance as compared to gear drive but maintenance cost if less in belt drive.  
  • Belt drive system does not require lubrication while in case of gear drive required lubrication on a regular interval.
  • Safety is less in belt drive as compared to the gear drive.
  • A belt drive is quieter in operation than that of the gear drive.
  • A belt drive is less efficient than gear drive due to more frictional loss. 
  • In a belt-drive, there exists some slip between the two pulleys while transmitting power However, in gears the slip does not occur as it is a positive drive. 
  • Gear drive is having higher transmission efficiency than belt drive.
  • Higher speeds efficiency of belt drive is very low as compared with gear drive.

Conclusion :

  • If you want a quiet vibration operation then you choose belt drives and if an operation requires ruggedness and efficiency then go for gear drives. 
  • For shorter distances, gear drives are best and longer distances belt drives.
  • To gain higher torque and power gear drive is used.

Broaching process

Introduction :

Broaching is one of the most precise and productive processes in metalworking areas. In this process removal of a layer of material of desired width and depth usually in one stroke by a slender rod or bar type cutter having a series of cutting edge. It can be performed on a broaching machine.

The broaching term may have derived from ancient Roman word braces, which meant an object having projecting teeth. The operation itself dates only to the 1850s when broaching tools, then called "drifts" were hammered in blacksmith shops through the work or pushed through with an arbour process.

Basic principles of broaching :

Broaching is a process of machining in which removal of a layer of material of desired width and depth usually in one stroke by using a slender rod or bar type cutter. This rod or cutter having a series of cutting edges with gradually increased protrusion. Broaching and shaping are similar processes while in shaping, attaining full depth requires a number of strokes to remove the material in thin layers step by step by gradually in feeding the single point tool. Whereas, the broaching process can remove the whole material in one stroke by using a bar type cutter is called broach. 

By using the broaching process various forms of holes and various size of the section, internal and external through straight or helical slots or grooves or external surfaces of different shapes can be made. Teeth of external and internal splines and small spur gears are also been made by broaching.

Broaching process

Construction And Operation of Broaching :

Construction of any cutting tool is characterized mainly by :
  • Configuration
  • Material 
  • Cutting edge geometry
  • Configuration of the broaching tool

Pull and push-type broaches both are made in the form of slender rods or bars of the varying section having along with one or more rows of cutting teeth with increasing height. But push-type broaches are subjected to compressive load and therefore they are made shorter in length to avoid buckling.

Broaching tool configuration

The essential elements of the broach are following below :

  • Pull end for engaging the broach in the machine.
  • The neck of shorter diameter and length.
  • The front pilot for initial locating the broach in the hole.
  • Roughing and finishing teeth for metal removal.
  • Finishing and burnishing teeth.
  • Rear pilot and follower rest or retriever.

Broaches are designed mostly pull-type to facilitate alignment and avoid buckling. 

The length of the broach is mainly depended on :
  • Type of the broach ( Pull or Push type ).
  • Number of cutting edges.  
  • Pitch depending upon the work material. 
  • The maximum thickness of the material layer to be removed.
  • Nature and extent of finish required.
Broaches are generally made from solid rod or bar. The broaches of large section and complex shape are made by separate sections or inserting separate teeth.

Cutting motion of broaching

The material of broach :

In broaching process for cutting broaches are used. That is made of materials having the usual cutting tool material with high hardness, strength, toughness and good heat and wear resistance properties.

For ease of manufacture and resharpening the complex shape and cutting edges, broaches are mostly made of HSS (high-speed steel). Nowadays cemented carbide segments or replaceable inserts are used especially for stronger and harder work materials like steels and cast iron. TiN-coated carbides provide much longer tool life in broaching.

Broaching operation :

Broaching operation can done by a series of following sequential steps :
  • Selection of broach and broaching machine
  • Mounting and clamping the broach in the broaching machine
  • Fixing workpiece in the machine
  • Planning tool - work motions
  • Selection of the levels of the process parameters and their setting
  • Conducting machining by the broach.
Methods of broaching process :

  • Pull broaching :
In this type of broaching the work is held stationary and the brooch is pulled through the work. broaches are usually long and are held in a special head. Pull broaching is used mostly for internal broaching but it can do some surface broaching.
  • Push broaching :
In this type of broaching the work is held stationary and the broach is pushed through the work hand and hydraulic arbor press are popular for push broaching, this method is used mostly for sizing holes and cutting key ways. 
  • Surface broaching :
In this type of broaching either the work or the broaching tool moves across the other. This method has rapidly become an important for surface finishing. Many irregular or intricate shapes can be broached by surface broaching, but the tools must be specially designed for each job.
  • Continuous broaching : 
In this type of broaching the work is moved continuously and the broach is hell stationery. The path of moment maybe the straight horizontal or circular. This method is very suitable for broaching number of similar works at a time.

Different Types of broaches and their applications :

Broaching is widely used machining process, wherever feasible, for high productivity as well as product quality. There are different types of broaches have been developed and are used for wide range of applications.
Broaches can be broadly classified in several aspects such as 

Type of operation :
  • Internal broaching 
  • External broaching 
Method of operation :
  • Push type 
  • Pull type
Type of construction :
  • Solid
  • Built-up
  • Inserted tooth 
  • Progressive cut 
  • Rotor cut 
  • Double jump or overlapping tooth
Function :
  • Surface
  • Keyways
  • Round hole 
  • Splint
  • Spiral 
  • Burnishing 
Broaching of inside surfaces is called internal broaching or hole broaching and of outside surfaces, external or surface broaching. Internal broaching tools are designed to enlarge and cut various contours in holes already made by casting, forging, rolling, drilling, punching etc. It offers a combination of a high degree of accuracy and excellent surface finish, combined with high output rate and low downtime.

A push Broach is one that is designed to be pushed through the workpiece by special press or a push broaching matching. Because of tendency to band under compressive loads the push broach must be short and stocky, which means fever teeth are in broach and less material can be removed for each pass of the tools.

In a pull broach the tool is entirely in tension and long slender broaches are possible having a large number of teeth, consequently more stock can be removed for each pass.

When a brooch is made is one piece, it is called solid broach. Internal broaches are usually of the solid type. Broaches are sometimes build up of several sections and sometime made up of a series of teeth inserted in a block of steel. 

Surface broaches are usually of the build up or inserted tooth type. 

Progressive cut broaches have teeth a part of which are of the same height and have different width. In progressive cut broaching, metal is removed in thick layers by each tooth from only part of work-surface. The last teeth of a progressive cut broach remove a thin layer over the entire profile of work surfaces in ordinary cut broaching. 

Rotor cut broaches are used for removing large amount of materials in holes where forging or castings where a primary cutting operation is not desired. Teeth are staggered around the periphery at different sections so as to shear the work and allow cheap clearance. This would be an ideal tool to use for making a square hole from around cast one. 

A burnishing process makes a glazed or finished surface in steel, cast iron or nonferrous hole. Burnishing teeth are round and do not cut but compress and rub the surface metal. The amount of stock left for burnishing should not exceed 0.025 mm.

Advantages of broaching :
  • Very high production rate. Mainly higher than milling, planing, boring etc.
  • High dimensional, high accuracy and high class of surface finish of the product is possible.
  • Roughing and finishing in single stroke of the same cutter.
  • Needs only one motion of cutting, so design, construction, operation and control are simpler.
  • Extremely suitable and economic for mass production.
  • Expertise not needed.
  • Remarkable finished face.
  • Short cycle time with high accuracy.
  • Little skill is required to perform a broaching operation. In most cases the operator merely loads and unloads the work piece.
Limitations of broaching : 
  • Only through holes and surfaces can be machined.
  • Usable only for light cuts.
  • Cutting speed cannot be high.
  • Defects or damages in the broach severely affect product quality.
  • Design, manufacture and restoration of the broaches are difficult and expensive.
  • Economic only when the production volume is large.
  • Very large work piece can't be broached.

Advantages and disadvantages of broaching

Broaching is one of the most precise and productive processes in metalworking areas. In this process removal of a layer of material of desired width and depth usually in one stroke by a slender rod or bar type cutter having a series of cutting edge. It can be performed on a broaching machine. Let us have a deep insight into the pros and cons of the broaching process. 

Advantages of broaching :

  • Very high production rate higher than milling, planing, boring etc.
  • High dimensional and form accuracy and surface finish of the product.
  • Roughing and finishing in a single stroke of the same cutter.
  • Needs only one motion of cutting, so design, construction, operation and control are simpler.
  • Extremely suitable and economical for mass production.
  • Expertise not needed.
  • Remarkable finished face.
  • Short cycle time with high accuracy.
  • Little skill is required to perform a broaching operation.
  • Broaching can be used for either internal or external surface finishing.
  • A tolerance of +-0.0075 mm and a surface finish of about 0.8 microns can be obtained in this process.
  • Cutting fluid may be readily applied where it is most effective because a broach tends to draw the fluid into the cut.

Disadvantages of broaching : 

  • Only through holes and surfaces can be machined.
  • Usable only for light cuts.
  • Cutting speed cannot be high.
  • Defects or damages in the broach severely affect product quality.
  • Design, manufacture and restoration of the broaches are difficult and expensive.
  • Separate broach has to be procured and used whenever size, shape and geometry of the job changes.
  • Economic only when the production volume is large.
  • A very large workpiece can not be broached.
  • High tool cost.
  • Broaching can not be used for the removal of a large amount of stock.
  • Parts to be broached must be capable of being rigidity supported and must be able to withstand the forces that set up during cutting.