Factors to determine the capacity of HVAC system

What factors determine the capacity of HVAC system required :

You should know first the full forms of HVAC. 

• Heating: The amount of thermal energy that needs to be added to the space.
• Cooling: Thermal energy will sometimes need to be removed from a particular space in order to bring down the temperature.
• Humidifying : This process says that increasing the relative humidity through the addition of water vapor into the system.
• Dehumidifying: Process of removing water vapor from the given space.
• Cleaning: Purifying the air by the removal of dust, smoke, pollen and other pollutants.
• Air Movement: By this factor ensuring that there is ample movement of air to keep the inhabitants comfortable.

Turbo direct injection vs common rail

Both common rail and electronic unit injectors are better than the 12 years old technology found in the US as TDI.

Both common rail and electronic injectors are better than TDI because of much higher injection pressure. which results in better atomisation of fuel and giving more power with the lower emission.

Here are some technical difference between TDI, CRDI, and Pressurized injector.

TDI : 

TDi uses a mechanical rotary injection pump its fueling and timing controlled by a computer rather than mechanically. The rotary distributor that distributes the pressure to each injector. A metal pipe feeds the pressure to each injector which opens when the pressure is high enough to overcome a spring mechanism.

CRDI : 

A single pump which develops a high pressure feeds to each injector through a strong pipe (the rail).
The pressure in a pipe is relatively constant.
Each injector opened individually and electronically.

PI :

This type of engine feeds fuel to each injector.
Each injector is pressed by a cam lobe in the cylinder head, which pumps each injector individually and giving very high pressure.

Common rail and high-pressure unit injector are both improvements over our system.
Common rail uses a single fuel rail that is under enormous pressure. The ECU controls the injector individually.

Which one is better Technology for a Diesel Engine?

Yes the TDI is inferior to CRDI because you get more horsepower for same displacement engine size with CRDI. But emission wise, CRDI is much better. Moreover, with CRDI less fuel plumbing is required from the pump to the injectors.

Verdict :

Moving to a verdict about CRDI and TDI.
we come to know CRDI has better performance & efficiency as well due to a reason it is technologically ahead. 
But, CRDI costs more than TDI & CRDI are also bigger in size. 
On the contrary, TDI's are also good engines they offer you value for money and durability with a decent performance & efficiency as well. Moreover, TDI also needs lesser maintenance than CRDI.

Flow and Pressure

There must be a minor difference between flow and pressure. 

Water Flow :
Water Flow is a measurement of how much water is delivered at a particular outlet over a set period of time. For example, if you place a 10 litres bucket under the tap in a sink and it takes 10 seconds to fill the bucket you can see that the flow rate is 1 litre per second.

Water Pressure :
Water Pressure is a measurement of the force exerted by the water. 
We understand it by one example a cold water storage cistern in the attic may be used to supply water to a basin in a bathroom and a basin in a downstairs cloakroom. Assuming everything else is equal you will notice that the pressure at the downstairs tap is considerably more than that at the one upstairs. The increased pressure is due to the height of the cistern in relation to the tap.

Higher pressure will cause greater flow through any given pipe size, but as the flow increases, the pressure will decrease downstream due to friction loss because water velocities increase as well.

For any flow to happen, there is a requirement of pressure gradient and not the pressure. Higher the pressure gradient, keeping all other things (fluid, pipe diameter, length) constant, higher is the mass flow rate. But higher pressure does not reveal anything about the flow.

• The pressure is defined as the force acting perpendicular to the surface of an object per unit area over which the force is distributed.
• In the case of gases, this force is because of the collision of the gas particles with the surface. So, the pressure exerted by the gases in a given environmental condition is more of a statistical average than average value.
• In terms of liquids, the pressure exerted is the weight of the liquid over a surface, acting on that surface.

• The definition of flow is subjective depending on the time and length scales considered. Since we defined flow as the bulk movement of fluid particles.

If we need more water, so increase the pipe size so we don't lose more pressure to friction loss. 

PSI:
Pounds per square inch, the standard measurement of pressure in the United States.

Water Velocity:
The accepted standard for water velocity in piping systems is 5 feet per second or less. As flow increases in any given pipe size, the velocity of that water also increases. As velocity and/or flow increases in any given pipe size, the PSI loss also increases. The means of decreasing pressure loss for a given flow is to increase pipe size. (diameter)

Friction Loss:
The PSI loss which results from friction against the interior walls of pipes, directional fittings, valves or any other obstruction to the irrigation water. Once again, as flow increases so do friction loss. Friction loss is synonymous with PSI loss.

GPM, GPH, GPD:
Gallons Per Minute, the standard measure of flow; Gallons Per Hour, often used for low-volume flow such as drip irrigation; Gallons Per Day, a measure of overall water use on a daily basis.

Feet of Head:
Another term for water pressure. The pressure is directly affected by elevation change, and every 2.31 vertical feet of change upwards will decrease pressure by 1 psi in a holding tank. That is why such enormous pressures exist in the deep ocean; enough to crush a submarine as depth increases. Another way to look at it: each 1 foot elevation change equals .433 "feet of head".

Total Dynamic Head:
TDH is a measure of overall head (pressure) loss in a water system. When an irrigation designer or engineer calculates all of the friction (pressure) losses and outlet pressure required for an irrigation system, they will express the number as TDH. If an irrigation system has a maximum TDH of 250, that means that just over 108 PSI will be required to power the system.

Conversion Factors:

Pressure
To Convert From:	Into:	Multiply By:
PSI	Feet of Water	2.307
PSI	Pounds/Sq.Foot	144
PSI	Atmospheres	.06805
PSI	Bars (metric)	.06895
PSI	Inches Water @ 39.2 F	27.681
PSI	Millimeters Mercury @ 0 C	51.715
Feet of Head	PSI	.433501
Bars (metric)	PSI	14.5038
Bars	Feet of Head	33.4883
Bars	Pounds/Square Foot	2089
Bars	Atmospheres	.98692
Bars	Centimeters Mercury @ 0 C	75.0062
Bars	Inches Mercury @ 32 F	29.53

Flow
To Convert From:	Into:	Multiply by:
GPM	Gallons/Hour	60
GPM	Cu. Feet/Second	.002228
GPM	Cu. Feet/hour	8.0208
GPM	Cu. Meters/Second (metric)	.000063
GPM	Cu. Meters/Hour	.2268
GPM	Liters/Second (metric)	.06308
GPM	Liters/Minute	3.7853
GPM	Acre-Feet/Day	.0044192
GPM	Millions Gallons/Day	694.444
Millions Gallons/Day	Acre-Feet/Day	3.0689
Millions Gallons/Day	Acre-Inches/Day	36.8266
Millions Gallons/Day	Gallons/Hour	41,666.667
Millions Gallons/Day	GPM	.00144
Liters/Minute (metric)	GPM	.26418
Liters/Minute	Gallons/Second	.004403
Liters/Minute	Cu. Feet/Second	.000588
Liters/Minute	Cu. Feet/Minute	.0353

Advantages and disadvantages of front wheel drive

Front-wheel drive is mostly small and cheaper cars. Manufacturers like Ford, Honda, Toyota have small cars with front-wheel drive. In front-wheel drive the engine powers the two front wheels which pull the car, and adds to the car's grip of the road. Let us have a deep insight into the pros and cons provided by car with the use of the front-wheel drive. 

Advantages of front-wheel drive :

• It provides good traction control.
• Cheaper than AWD and RWD.
• They are fuel-efficient and more affordable cars.
• Help in making progress in the snow when travelling at a steady pace.
• Increasing the volume available for passengers and cargo because of the single unit contained in the engine compartment of the vehicle.
• Better crosswind stability.
• FWD also helps cut down the car's weight by eliminating the separate transmission and axle assemblies used in RWD cars.
• Lower car weight than other cars.
• It is easier to correct trailing-throttle or trailing-brake oversteer.
• The direct connection between engine and transaxle reduce the mass and mechanical inertia of the drivetrain that allows better fuel economy.
• The powertrain can be often be assembled and installed as a unit, which allows more efficient production.

Disadvantages of front-wheel drive :

• In low traction condition, the front wheels lose traction that makes steering ineffective.
• Traction can be reduced while attempting to climb a slope in slippery conditions such as snow or ice-covered roadways.
• Lack of weight shifting will limit the acceleration of a front-wheel-drive vehicle.
• They can't compete in the sport of drifting this is not a big deal to car manufacturers.
• In FWD the front axle typically supports around 2/3rd of the weight of the car quite equal to half weight this factor in the tendency of FWD cars to understeer.
• Torque steer is the tendency for some high power FWD cars to pull to the left or right under hard acceleration. 
• The driveshafts may limit the amount by which the front wheels can turn, they are generally unable to make the same U-turn as a similar-sized rear-wheel driver car.
• FWD cars simultaneously put power to the road and steer the car.
• CV tend to need replacing more frequently than in a rear-wheel-drive vehicle.
• High wear because of CV joints.

Advantages and disadvantages of Wankel engine

The Wankel engine is an internal combustion engine type that uses an eccentric rotary design to convert pressure into rotating motion. In contrast to the common reciprocating piston engine, which has pistons instantly and rapidly changing 180 degrees direction, all parts rotate in one direction. Let us have a deep insight into the pros and cons of the Wankel engine in this article. 

Advantages of the Wankel engine :

• The Wankel engine is considerably lighter, simpler.
• There are no valve or complex valve trains.
• There are no connecting rods. 
• There is no crankshaft.
• It has higher volumetric efficiency and a lower pumping loss.
• High reliability.
• A smooth flow of power, and a high power-to-weight ratio.
• It is very quick to react to throttle changes.
• The Wankel engine generally has smaller frontal area than a piston engine of equivalent power allowing a more aerodynamic nose to be designed around it so mostly used in remotely piloted aircraft.
• The simplicity of design and smaller size allows for saving construction costs.
• Due to a 50% longer stroke duration compared to the four-cycle engine, there is more time to complete the combustion This leads to greater suitability for direct injection.

Disadvantages of Wankel engine :

• It consumes a lot of fuel.
• Rotary engine produces very less torque.
• The spare parts are very costly.
• There is incomplete combustion of the air-fuel mixture. so the emission is heavy.
• The rotor seals don't last as long as piston seals.

Advantages of turbocharger

A turbocharger is the mechanical device that increases the flow of air in the engine, runs on waste exhaust gasses or we can say that it derives its energy from exhaust gasses that usually get wasted in the naturally aspirated engine. Let us have a deep insight into the advantages provided by the turbocharger. 

Advantages of the turbocharger :

• The most obvious advantage of getting a turbocharged engine in your vehicle is that you are going to have a much faster, much more powerful ride.
• The maximum power of the engine with a great turbocharger increased by 40% or more compared with a supercharger system without the turbocharger.
• Turbochargers can spin much faster.
• Superchargers are parasitic, they eat parts of power produced by an engine.
• Most turbochargers are electronically driven to eliminate turbo lag.
• Turbochargers recycle energy produced by engines by transforming more exhaust gas energy into power output with lower thermal and frictional losses.
• Turbochargers supplied more air mass into the engine's combustion chamber so the combustion is easier, plain and also emission is lower. As a result, the turbocharged diesel engines have about 50 per cent lower CO2 and NOx emissions compared to naturally aspirated engines.
• Turbochargers delivered more power output, which transforms in improvement vehicle’s performance on a road and makes driving enjoyable.
• The turbocharger itself acts as an additional silencer.

Advantages of rear wheel drive

The most common layout for a rear-wheel-drive is the car mounted longitudinally with the engine and transmission at the front of the car. Some other rear-wheel-drive car layouts include front-mid, rear-mid and rear engines. Let us have a deep insight into the advantages of cars mounted with real wheel drive. 

Advantages of rear-wheel drive :

• Better weight balance and distribution.
• Better acceleration.
• Better mass distribution front to rear axles.
• Better road holding and stopping.
• No torque steer.
• Better ride and feel.
• Better serviceability.
• Costs are reduced because manufacturing is simple as compared to FWD. 
• Steering and traction are not through the same front wheels thus better tire life. 
• Traction capacity increases as you accelerate because the rear wheel is the dynamic weight transfer.
• RWD car accelerates faster than an FWD.
• Less costly and easier maintenance.
• Rear-wheel drive puts the wheels which are pulling the load closer to the point where a trailer articulates, helping to steer, especially for large loads.
• Better handling in dry condition.
• More predictable steering in low traction condition. 
• Possible to turn them further than would be front-wheel drive resulting in a smaller steering radius. 
• Weight transfer during acceleration. 

Advantages of diesel engine

The diesel engine is an internal combustion engine in which air is compressed at a high temperature and ignite the fuel which is injected into the combustion chamber, where a piston is actuated by combustion and expansion thus transforms the chemical energy into mechanical energy that used in various automobile vehicles. Let us have a deep insight into the advantages provided by a diesel engine. 

Advantages of diesel engine :

• The diesel engine offers the best class mileage. 
• A diesel engine has 25 to 30 % better fuel economy than a petrol engine.
• The engine is stronger and offers more horsepower. 
• Less pollution.
• Diesel is better efficient available fuel and it is energy-dense and durable than petrol fuel.
• Diesel engine free to spark plug it helps in avoiding the elimination of ignition tune-ups.
• Can use alternative fuel like bio diesel.
• It is much safer in accidents because diesel does not evaporate as easy as petrol. 
• Carbon monoxide and unburnt hydrocarbons do not form in the crevices of the cylinder wall because the diesel engine only compresses air. 
• Produce maximum torque at low engine speed. 
• Easier to turbocharge and supercharge a diesel engine. 
• No sparking as the fuel auto-ignites thus no spark plugs or spark wires required. 
• They can be run on synthetic fuel easily. 

Advantages of petrol engine

A petrol engine is an internal combustion engine made for converting heat into mechanical energy which is generated by spark ignition of petrol. Generally, petrol and air are usually mixed after compression stroke. There are four strokes in two revolutions of the piston such as suction, compression, expansion and exhaust. Let us have a deep insight into the advantages provided by the petrol engine. 

Advantages of a petrol engine :

• The petrol engine is cheaper than the diesel engine to purchase.
• Less noise and vibration and service and maintenance cost are less too.
• The engine works smooth its light and easy to drive.
• Power output is good.
• It can be easily retrofitted for alternative fuel like CNG and LPG.
• Low emissions hence environment-friendly engine.
• The petrol has a higher energy density than almost any other form of energy.
• Despite its explosiveness and flammability, it’s relatively easy and safe to store and easily carry around in cars.

Advantages and disadvantages of hot rolling

Rolling is classified by the temperature of the metal rolled. The hot rolling process is only done when working at extremely high temperatures, hence the name is "hot rolling". It is used to break down imperfections from flat-rolled steel coils such as billets and ingots. Following the process, the hot coils can either be sold immediately as is or moved to the next cold rolling process due to technology advances.

The hot rolling process begins at high-temperature ranges and is generally used for the development of large deformations. As opposed to cold rolling mills which are processed with four vertical oriented rolls, hot rolling is done with two vertical rolls. The pressure and fast speed and high temperature are applied between these two rolls to reduce the material and make it stronger. Unfortunately, dimensions are not accurately obtained to the way this process occurs. Here, in this article, you can check it out the pros and cons of the hot rolling process one by one below.

Advantages of hot rolling :

• Hot rolling can reduce energy consumption and costs considerably.
• Hot rolling can improve the processing performance of metals and alloys because coarse grains during foundry are broken, the cracks are healed, casting defects are reduced and eliminated hence, cast microstructure is transformed into a deformed structure to improve processing properties. 
• Hot rolling not only improves the efficiency of production but also creates conditions for increasing rolling speed and achieving continuous and automated rolling.
• A porosity of metal is considerably minimized. 
• Flow stresses are low so forces are relatively lower. 

Disadvantages of hot rolling :

• Non-metallic inclusions inside the steel are pressed into thin sheets after hot rolling, causing delamination that deteriorates the tensile properties of the steel in the direction of thickness. 
• The hot-rolled steel of various sections has residual stress caused by uneven cooling that has some influence on the performance of steel member under external force. Such as stability, deformation, fatigue and other aspects may have adverse effects.  
• Hot rolling does not accurately control the mechanical properties required for the product, and microstructure and properties of the hot rolled product are not uniform. 
• The strength index is lower than that of the cold working products and higher than fully annealed products. The plastic index is higher than cold working products and lower than fully annealed products. 
• The thickness and dimension of the hot rolled product are difficult to control therefore, hot rolled products are generally used as blanks for cold rolling. 

Advantages of all wheel drive

An all-wheel-drive vehicle is one with a powertrain that can supply power to all its wheels, whether full-time or on-demand. Let us have a deep insight into the advantages provided by car used to all-wheel drive.

Advantages of all-wheel drive :

• Excellent traction in all kinds of weather.
• For transmitting driving forces, AWD vehicles have twice the grip available.
• Stability and degree of driver control are greater than RWD and FWD.
• Easily the most versatile drive train arrangement.
• Most AWD systems primarily deliver power to one set of front or rear wheels. The power is diverted to the other axle when slippage is detected at one axle.
• AWD is Entirely automatic driver does not need to manually engage four-wheel drive.
• Best choice for inclement weather and also works well on dirt and mud.
• It provides improved handling and better tire grip in sudden panic swerves.

Milling machine lubrication

Lubrication is necessary for all the machine for the long life of the machine. Here we can see that the lubrication system of the milling machine and various lubricants use in the different parts of milling machine.

Maintaining your milling machine is one of the keys to prolonging its life as well as maintaining good finishes. Although lubricating the machine can take up a bit of time, the cost savings are will pay off in the long run as it is very expensive to fix a milling machine due to a lack of preventative maintenance.

List of lubricants following below :

longevity is largely determined by the lubrication of milling machine lubrication. 

Lubricants must be in strict accordance with the requirements of milling lubrication, the oil should be clean, no acid, no water and durum and so on. Recommended N46 oil. 

Vertical milling machine should be lubricated three times per months and one time per half a years after the use of 3 years.

Guideway ball screw, etc should be lubricated 4 times per day, done by every shift in the day and night.

Other parts required lubrication is equipped with oil cups, filling each class at least four times per day.

Read related posts:

1. Milling machine introduction
2. Difference between turning and milling
3. Working principle of milling machine
4. Milling machine safety precautions
5. Milling machine parts
6. Types of milling cutter
7. Uses of milling machine
8. Milling machine uses
9. Milling machine operation

Milling machine parts

• Base

The base is made of grey iron casting accurately machined on its top and bottom surface and serves as a foundation member. It gives support and rigidity to the machine and also acts as a reservoir for the cutting fluids.

• Column 

The column is the main supporting frame mounted vertically on the base. The top of the column is finished to hold an overarm that extends outward at the front of the machine.

• Knee 

The knee is a rigid casting mounted on the front face of the column. The knee moves vertically along the guideways and this movement enables to adjust the distance between the cutter and the job mounted on the table. The adjustment is obtained manually or automatically by operating the elevating screw provided below the knee. The top face of the knee forms a slideway for the saddle to provide cross travel of the table.

• Saddle

The saddle rests on the knee and constitutes the intermediate part between the knee and the table. The saddle moves transversely, i.e., crosswise (in or out) on guideways provided on the knee.

• Table

The table rests on ways on the saddle and travels longitudinally. 

The table rests on guideways in the saddle and provides support to the work. 

The table is made of cast iron, its top surface is accurately machined and carriers T-slots which accommodate the clamping bolt for fixing the work. 

A leadscrew under the table engages a nut on the saddle to move the table horizontally by hand or power.

The worktable and hence the job fitted on it is given motions in three directions:

Vertical (up and down) movement provided by raising or lowering the knee.

Cross (in or out) or transverse motion provided by moving the saddle in relation to the knee.

Longitudinal (back and forth) motion provided by hand wheel fitted on the side of the feed screw.

For universal milling, machine table may also swivel 45° to either side of the centre line and thus fed at an angle to the spindle.

• Overarm

The Overarm is mounted at the top of the column and is guided in perfect alignment by the machined surfaces. The Overarm is the support for the arbor. The arm is adjustable so that the bearing support may be provided nearer to cutter.

• Front Brace 

The front brace is an extra support that is fitted between the knee and overarm.

The front brace is slotted to allow adjustment of the height of the knee relative to the overarm.

• Spindle 

The spindle of the machine is located in the support part of the column and receives power from the motor.

• Arbor support 

The arbor support is fitted to the Overarm and can be clamped at any location on the Overarm. Its function is to align and support various arbors. The arbor is a machined shaft that holds and drives the cutters.

• Elevating screw

The upward and downward movement to the knee and the table is given by the elevating screw that is operated by hand or an automatic feed.

Read related posts:

1. Milling machine introduction
2. Difference between turning and milling
3. Working principle of milling machine
4. Milling machine safety precautions
5. Lubrication used in milling machine
6. Types of milling cutter
7. Uses of milling machine
8. What is a milling machine?
9. Milling machine uses
10. Milling machine operation 

Advantages and disadvantages of using plastic bags made from polyethene

A plastic bag, polybag, or pouch is a container type made from thin, flexible, plastic film, nonwoven fabric, or textile plastic. Plastic bags are used to contain and carry goods such as food, manufacture, powder, ice, magazines, chemicals and waste. It is a common packaging form. Let us have a deep insight into the pros and cons of using plastic bags made from polyethene. 

Advantages of polythene :

• Polyethene is useful properties like water-resistant and having a low density.
• The polymer can be also reused once it used as shopping bags.
• Polyethene can be burned to provide a source of energy as heating for buildings.
• Polyethene bags can be recycled.
• Extremely impact resistant.
• Extremely safe to handle and no sharp edges, no exposed metal staples, no slivers from wood.
• Polyethene will not react chemically with core samples.
• The poly box is 5 pounds and wooden box 10 pound nearly equal to half of the weight of wood box it causes easy shipping.
• Nesting ratio of 3.2:1 for polyethene. 
• Remains cool to the touch in high temperatures.
• Structural integrity is unaffected by UV rays.

Disadvantages of polyethene :

• The polymer takes a long time period of time to break down in landfill sites.
• Polyethene is made from crude oil, which is a now renewable fossil fuel.
• Large amounts of energy are required to produce the polymer.
• Polythene is not biodegradable, and if dumped in the soil causes harm to the plant life.
• Polythene threatens life in the water bodies. 
• The chemicals in polythene affect the survival of flora and fauna of the aquatic and marine ecosystems. 
• Polythene is also likely to clog the drains causing problems in the water flow of the pipes.
• In most households poly bags are used to preserve food items. It has been found out, the colourful poly bags contains lead and cadmium which are toxic and cause adverse effects to human health. 

Advantages of glass reinforced plastic

Reinforced plastic has more strength and high resistance against weather, thus finding its use in outdoor applications and other many applications so it allows many advantages. Let us have a deep insight into the advantages of glass-reinforced plastic.

Advantages of glass-reinforced plastic :

• Glass can be easily drawn into the fibre from the molten state.
• Glass is cheaper and readily available.
• Glass fibre is relatively strong.
• In terms of plastic matrix materials, glass is chemically inert.
• One of the main reasons for using glass-reinforced is the fact that it does not conduct electricity.
• Resistant to corrosion.
• In its weight-to-potency ratio, glass-reinforced plastic is found.
• High strength plays a vital role when it comes to designing man load-bearing structures and glass-reinforced fulfils this need.
• Compared to other corrosion-resistant materials like titanium and stainless steel, it is very affordable.
• Glass-reinforced plastic has a high strength to weight ratio and high flexural strength making it an attractive lightweight material that builds strength into almost any finished component or product.
• The unique physical properties of glass-reinforced plastic make it extremely flexible meaning that almost any specifications can be easily tooled, moulded and manufactured.
• It probably won't corrode so you may not even have to finish it by painting it, just have the plastic producer dye it for you.
• It does not expand or contract anything like steel does.
• Glass-reinforced plastic will weight half the weight of aluminium and seventh of steel.
• Low transport cost.
• Long effective service life.
• Variety of joint system.
• Better hydraulic performance.

Advantages and disadvantages of ultrasonic machining

Ultrasonic machining also called ultrasonic vibration machining is a machining process in which, in the presence of abrasive particles, the material is removed from a part's surface by low amplitude and high-frequency vibration of a tool against the material surface. Let us have a deep insight into the pros and cons of ultrasonic machining in this article. 

Advantages of ultrasonic machining : 

• Ultrasonic machining can be used to drill circular or non-circular holes on very hard materials like stones, carbides, ceramics and other brittle materials.
• Machining of non-conducting materials like glass, ceramics and semi-precious stones easily.
• The cost of metal removal is low.
• As there is no heat generation in this process, there is no change in the physical properties of the job during machining.
• There are no residual stresses in the machined workpiece.
• This machining method produces highly accurate profiles and good surface finishes.
• The operation of the equipment is quite safe and noiseless.
• Free from burrs and distortions.
• Good surface finish and structural integrity.

Disadvantages of Ultrasonic Machining :

• The major limitation of the ultrasonic machining process is its comparatively low metal cutting rates. 
• Power consumption is high. 
• The depth of cylindrical holes is presently limited to 2.5 times the diameter of the tool. 
• Wear of tool increases so sharp corners become rounded. 
• The grain size and abrasive slurry are also the correct dimensions. 
• Periodic replacement of slurry is necessary for efficient cutting operations.
• The choice of tool metal is one of the most important decisions making for optimization of metal removing and tool cost.
• Replacement of tool is required for accurate machining as the high wear rate of the tool results in poor dimensional accuracy.
• Initial machining and tooling costs are very high.
• This process is not suitable for heavy metal removal operations.
• Softer materials give much difficulty in machining.
• Limited sized cavities are produced by this machining process.
• Minimum depth of the hole is achieved.

Engine nomenclature plate

The letters and numbers that make up an engine's model number are a series of codes to tell you the engine family, the number of cylinders, the emissions standard, the type of ignition, the capacity, the type of aspiration, and the generator set rating.

The Model Number :

It is easiest to demonstrate with a particular engine model a 1206E-E66TAG for instance.

• The first two digits – 12 – tell you the engine family, in this case, the 1200 Series.
• The next two digits – 06 – tell you the number of cylinders, in this case, six.
• The next letter – E – confirms the engine meets EU Stage IIIB/U.S. EPA Tier 4 Interim.
• The E after the hyphen says it has electronic fuel injection. If there were no letter, it would have a mechanical injection.
• The next two digits – 66 – give you the engine capacity in decilitres, in this case, 6.6 liters
• The following letters give their type of aspiration. In this case, T means it is turbocharged, and A says it is air-to-air charge cooled. W would mean it was water-to-air charge cooled, and if there were no letters, it would be naturally aspirated.
• The G in brackets gives the engine’s generator set rating.

You can also check out Engine nomenclature