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 vs CRDI

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

A 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.

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.

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.

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.

What is belt drive

Introduction :

To transmit power from one shaft to another pulley are mounted on the two shafts. The pulleys are then connected by an endless belt or rope passing over the pulleys. The connecting belt or rope is kept in tension so that the motion of one pulley is transferred to the other without slip. The speed of the driven shaft can be varied by wearing the diameter of the two pulleys. 

What is belt drive?

Belt the drive is a mechanism in which power is transmitted by the movement of a continuous flexible belt. 

A belt may be a rectangular section is known as a flat belt or of the trapezoidal section known as V-belt. In case of a flat belt, the rim of the pulley is slightly crowned which helps to keep the belt running centrally on the pulley rim. The groove on the rim of the pulley of a V-belt is made deeper to take advantage of the wedge action. The belt does not touch the bottom of a groove. Owing to wedging action V-belt needs a little adjustment and transmit more power without sleep as compared to flat belt also multiple V-belt a system using more than one belt in the two pulleys can be used to increase the power transmitting capacity generally these are more suitable for shorter centre distance. Thus, belt drive works on the law of belting. 

Open belt drive :

An open belt drive used when the driven pulley is desired to be rotated in the same direction as the driving pulley.  

Generally, the centre distance for an open belt drive is 14 to 16 metre. If the centre distance is too large, the belt whips vibrate in a direction perpendicular to the direction of motion. For very short at the centre distance, the belt sleep increasing. Both these phenomena limit the use of belts for power transmission.

Crossbelt drive :

A the crossed-belt drive is adopted when the driven pulley is to be rotated in the opposite direction to that of the driving pulley.

A cross belt drive can transmit more power than an open belt drive as the angle of wrap is more. However, the belt has to be a band in two different planes and it we are out more. 

Advantages of belt drive :

• A belt drive is simple and economical.
• Wide range of speeds is available.
• In belt drive don't need parallel shaft.
• Noise and vibration are damped out.
• Machinery life is increased because load fluctuations are shock-absorbed.
• Less maintenance cost because no lubrication are required.
• Belts permit flexibility ranging from high horsepower drives to slow speed and high speed drives so it is highly efficient in use.
• A flat belt is best for very high-speed drives.
• This drive is very economical even when the distance between the shaft is very large.
• Belts will slip under overload conditions this leads the biggest advantages that preventing mechanical damage to shafts, keys, and other machine parts.
• All the belt drives do not need the pulleys to be maintained at the same height.

Disadvantages of belt drive :

• Operating temperature is restricted up to 80 to 85⁰C.
• Heat buildup occurs.
• Belts can't be used where exact timing or speed is required because of slippage.
• Because of slipping and stretching the angular velocity ratio is not necessarily equal or constant to pulley diameter ratio.
• In belt, drive belts are damaged easily by abrasives or heat or some chemicals.
• Some adjustment of centre distance or use of an idler pulley is necessary for wearing and stretching of belt drive compensation.
• Speed is limited to usually 35 meters per second.
• Power transmission is limited to 370 kilowatts.

Applications of adsorption

Applications of adsorption :

• Activated charcoal is used in gas masks in which all undesirable or toxic gases are observed selectively by charcoal, while purified air passes through its pores. 
• Activated charcoal is used for removing colouring matter of sugar solution and the decolouration of vinegar. 
• Silica and Alumina gels are used as an adsorbent for removing moisture and for controlling humidities of room. Silica Gel has been employed for drying air, used in blast surfaces.
• Charcoal adsorption filters are used for removing organic matter from drinking water.
• Selective adsorption by alumina, magnesia has been used for separating different pigments by adsorption chromatography. 
• During arsenic poisoning, colloidal fabric hydroxide is administered. The letter absorbs the arsenic poison and retails it can thus be removed from the body by vomiting. 
• Fuller's earth is used in large quantities for refining petroleum and vegetable oil due to its good adsorption capacity for unwanted materials. 
• The phenomenon of adsorption is useful in heterogeneous catalysis Example: contact process, Haber's process, hydro generation of oils based on the adsorption process. 
• Adsorption the process is used in the production of a vacuum by using activated charcoal in dewar's flask.
• Lake test for Al⁺ Lake test for Al⁺³ is based upon adsorption of litmus colour by Al(OH)₃ precipitate. 
• Mordants used in Dying cloth, adsorb the dye particles, which otherwise, do not speak to the clothes.

Advantages of gear drive

Gear drive is used to transmitting mechanical power from one place to another, often used to convey power to wheels of the bicycle and motorcycles. It is also used in a wide variety of machine apart from the vehicle. Let us have a deep insight into the advantages of gear drive in this article. 

Advantages of gear drive :

• It is very compact and needs less space.
• Most convenient for very small centre distances.
• The velocity ratio will remain constant throughout and any velocity ratio up to 60:1 can be obtained.
• It has very high efficiency which is very useful in transmitting motion.
• It will be possible to transmit the power if the axes of the shafts are not only parallel, but even when the axis of the shaft is nonparallel, intersecting, non-intersecting and coplanar or non-coplanar by using different types of gears.
• They can be used conveniently for transmission of low, medium and high power.
• It is a reliable service that is a very good advantage.
• Gears are employed for a wide range of applications like in watches, precision measuring instruments, machine tools, gearboxes fitted in automobiles, aero engines, etc.
• Gears may be cast integral with the shafts if required. 
• In a wide range of metallic and non-metallic materials, gears can be cast.
• It provides a large range of speed and torque for same input power. 
• It is compact and needs less space.

Disadvantages of gear drive

Gear drive is used to transmitting mechanical power from one place to another, often used to convey power to wheels of the bicycle and motorcycles. It is also used in a wide variety of machine apart from the vehicle. Let us have a deep insight into the disadvantages of gear drive in this article. 

Disadvantages of gear drive :

• It is very difficult to manufacture the gears because in manufacturing gears the specials equipment are needed which is costly so they are not economical.
• They are not suitable for very large centre distances of shafts.
• They always require proper lubrication.
• If there may any error during manufacturing then it may cause a big accident.
• If a large number of gear wheels used in gear trains that increases the weight of the machine.
• Noise and vibrations will be more at high speeds. 
• Use of a large number of gear wheels in gear trains increases the weight of the machine.

Disadvantages of chain drive

A chain drive is positive drives, so the velocity ratio remains constant and no-slip occurs, making it suitable mainly for the shorter centre distance. The chain drive is a way of mechanical power transmission mainly used in a motorcycle. Let us check some disadvantages of a chain drive in this article. 

Disadvantages of a chain drive : 

• It is heavier as compared to belt drive.
• In chain drive, both driving and driven shafts are perfectly inclined.
• It requires accurate mounting and good lubrication.
• Higher initial cost because production cost for the chain is high.
• Weight of a chain is high and if the chain is dry it becomes noisy.
• Lubrication of its parts is required.
• There are gradual stretching and an increase in the length of chains. Some of its links need to be removed from time to time.

Advantages of chain drive

A chain drive is positive drives, so the velocity ratio remains constant and no-slip occurs, making it suitable mainly for the shorter centre distance. The chain drive is a way of mechanical power transmission mainly used in a motorcycle. Let us check some advantages of a chain drive in this article. 

Advantages of a chain drive :

• Positive and non-slip drive.
• Efficiency is high for a shorter distance.
• It is used generally up to 3 meters but some special cases it is up to 8 to 10 meters also.
• Permits high-velocity ratio up to 8:1 because of no-slip takes place in this drive.
• Transmit more power than belt drive.
• Maintenance is low.
• Chains are made up by metal so chain occupies lesser space than belt drive and rope drive.
• It permits higher speed ratio of 8 to 10 in one step.
• It can be operated under any atmospheric conditions.
• It has the ability to transmit motion to various shafts by only one chain.
• Easy to install and repair.
• Good service life.
• Lesser loads are put on the shafts.

Advantages and disadvantages of belt drive

A Belt drive is one of the most common and effective devices of transmitting motion from one shaft to another by means of a thin, in-extensible band running over the two pulleys. It is generally used to employed the rotary motion is to be transmitted between the two shafts. 
So for the above reason belt drive has more advantages. Let us check it out one by one below.

Advantages of belt drive :

• A belt drive is simple and economical.
• A wide range of speeds is available.
• In belt drive don't need parallel shaft.
• Noise and vibration are damped out.
• Machinery life is increased because load fluctuations are shock-absorbed.
• Less maintenance cost because no lubrication is required.
• Belts permit flexibility ranging from high horsepower drives to slow speed and high speed drives so it is highly efficient in use.
• A flat belt is best for very high-speed drives.
• This drive is very economical even when the distance between the shaft is very large.
• Belts will slip under overload conditions this leads the biggest advantages that preventing mechanical damage to shafts, keys, and other machine parts.
• All the belt drives do not need the pulleys to be maintained at the same height.

Disadvantages of belt drive :

• Operating temperature is restricted up to 80 to 85⁰C.
• Heat buildup occurs.
• Belts can't be used where exact timing or speed is required because of slippage.
• Because of slipping and stretching the angular velocity ratio is not necessarily equal or constant to pulley diameter ratio.
• In belt drive, belts are damaged easily by abrasives or heat or some chemicals.
• Some adjustment of center distance or use of an idler pulley is necessary for wearing and stretching of belt drive compensation.
• Speed is limited to usually 35 meters per second.
• Power transmission is limited to 370 kilowatts.

Advantages and disadvantages of V-belt drive

The V-belt drive is also called a friction drive. The shape of the V-belt is somewhat trapezoidal. The pulleys also have tapered sides forming v groove in which the belt sits thus V-belt does not get many possibilities to slide away from the pulleys. Let us have a deep insight into the pros and cons of V-belt drive in this article. 

Advantages of V-belt drive :

• Positive drive as slip between belt and pulley is negligible.
• No joint troubles as V-belt are made endless.
• Operation is smooth and quiet.
• High-velocity ratio up to 10 can be obtained.
• It can be easily installed and removed.
• Due to wedging action in the grooves, limiting ratio of tensions is higher and thus, more power transmission.
• It may be operated in either direction with a tight side at the top or bottom.
• Multiple V-belt drives increase the power transmission manifold.
• Slip between the belt and the pulley is negligible.
• The axis can be vertical or horizontal or inclined.
• They can dampen vibration.

Disadvantages of V-belt drive :

• It can not be used for large centre distances.
• In V-belt construction of pulleys is not simple.
• V-belt is not as durable as a flat belt.
• It costlier as compared to the flat belt.
• V-belt drive can't be used for long distances due to a greater weight per unit of length.
• It may be not applicable to synchronous machines because they are not free from creep.
• The centrifugal tension prevents the use of belts at speeds below 5 m/s and above 50 m/s.

Difference between laser and electron beam welding

What is laser beam welding?

A welding technique used to join pieces of metal or thermoplastics through the use of a laser is called laser beam welding. 

What is electron beam welding?

Electron beam welding is a fusion welding process in which a beam of high-velocity electrons is applied to the material and thus welding is done. 

Electron beam welding and laser beam welding are two very popular methods used for welding. Let us have a deep insight into the difference between both of welding process.

Difference between laser and electron beam welding : 

• EBW is performed in a high vacuum environment, which is most suitable for titanium, refractory metals and flammable metals. while LBW is not performed under a vacuum environment it usually performed with shielding gas such as argon or nitrogen.
• EBW is usually narrower than the laser weld. The LBW weld is particularly suited for high volume application. 
• EBW cost is higher than the LBW.
• In EBW X-rays is generated while not generated in LBW.
• Size of the workpiece is limited because of vacuum size in EBW while LBW can weld any size of workpieces.
• The power efficiency of EBW is 80 to 90 % and 7 to 10 % is for LBW. 
• Penetration is deep in case of EBW while lake penetration in LBW.

Electron beam welding advantages and disadvantages

Electron beam welding is a powerful beam welding process. The heat source in electron beam welding for melting joints is a focused beam of high-velocity electrons. The electron beam upon impinging on the workpiece releases the necessary heat by converting its kinetic energy. 

Electron beam welding is a fusion welding process in which a beam of high-velocity electrons is applied to two materials to be joined. It is often performed under vacuum conditions to prevent dissipation of the electron beam. Let us have a deep insight into the pros and cons of electron beam welding in this article. 

Advantages of electron beam welding :

• No gas contamination.
• Deepest weld penetration.
• The depth-to-width ratios between 10:1 to 30:1 can be easily realized with electron beam welding.
• It is done in a vacuum environment so clean welding environment is guaranteed.
• Small heat affected zone similar to laser beam welding.
• It allows welding of titanium, refractory metals and flammable metals.
• Widely used in many industries.
• Filler metal or flux are not needed to be used in this process of welding.
• No additional processing is required.
• The process can be used at higher welding speeds, typically between 125 to 200 mm/s.
• It is also possible to closely control this penetration by controlling the accelerating voltage, beam current and beam focus. 
• The heat liberated is low and also is in a narrow zone. Thus, the heat-affected zone is minimal as well as weld distortion is eliminated.

Disadvantages of electron beam welding :

• Due to vacuum enclosure, high initial set up cost.
• Size is restricted by a vacuum chamber only small to medium size items can be welded.
• Sometimes this process required complex tooling.
• X-rays generated during welding.
• Longer cycle time than laser beam welding so this process is time-consuming.

Electron beam welding applications

Electron beam welding process is done under the vacuum, the welds are clean and free from oxides and nitrides so this process posses various application.

Application of electron beam welding : 

• High depth-to-width ratio eliminates multiple-pass welds. Penetration is 0.001 to 2 inches.
• Welds up to 95% of the strength of the base material.
• By using this process welds in close proximity to heat-sensitive components because of minimizes shrinkage and distortion.
• Precise control and repeatability at speeds from 1 to 200 inches per minute.
• This process permits welding of refractory and dissimilar metals not weldable with another conventional welding process.
• Electron beam welding is ideal for sealing of pre-evacuated housings and electrical components.
• In power generation, vacuum system and medical field. 
• In aerospace sensors like jet engine components, transmission components, parts of structures.
• In space sensors like titanium tanks.
• In automotive industries gears, transmission part, parts of a turbocharger.
• Welding of metals with dissimilar melting points for example - steel to nickel alloys, copper to nickel alloys, copper to steel, tantalum to tungsten.