G00 Rapid Traverse

G00  is the basic G-code for CNC programming. It is used to perform rapid traverse

That mean we always want to make a tool to a position that we want fastly

When you finish one cutting on your part is one position, and you need to move you cutting tool to

the next cutting position, you often use G00 to move tool fastly to the place you wanted.

#NOTE:-you can't use G00 when you're cutting the material of your part. G00 is used to save your time not for cutting.its just for positioning your tool in a quick manner.

AMAZING SCIENCE EXPERIMENT

A MUST WATCH VIDEO FOR SCIENCE LOVERS..............................

AUTOMATION AND ITS TYPES CAD/CAM

Automation of production systems can be classified into three basic types:

1. Fixed automation (Hard Automation)

2. Programmable automation (Soft Automation)

3. Flexible automation.

1. Fixed automation (Hard automation): Fixed automation refers to the use of special purpose equipment to automate a fixed sequence of processing or assembly operations. Each of the operation in the sequence is usually simple, involving perhaps a plain linear or rotational motion or an uncomplicated combination of two. It is relatively difficult to accomodate changes in the product design. This is called hard automation.

Advantages:

1. Low unit cost

2. Automated material handling

3. High production rate.

Disadvantages:

1. High initial Investment

2. Relatively inflexible in accommodating product changes.

2. Programmable automation (Soft automation): In programmable automation, the production equipment is designed with the capability to change the sequence of operations to accomodate different product configurations. The operation sequence is controlled by a program, which is a set of instructions coded. So that they can be read and interpreted by the system. New programs can be prepared and entered into the equipment to produce new products.

Advantages:

1. Flexible to deal with design variations.

2. Suitable for batch production.

Disadvantages:

1. High investment in general purpose equipment

2. Lower production rate than fixed automation.

Example: Numerical controlled machine tools, industrial robots and programmable logic controller.

3. Flexible Automation:  Flexible automation is an extension of programmable automation. A flexible automation system is capable of producing a variety of parts with virtually no time lost for changeovers from one part style to the next. There is no lost production time while reprogramming the system and altering the physical set up.

Advantages:

1. Continuous production of variable mixtures of product.

2. Flexible to deal with product design variation.

Disadvantages:

1. Medium production rate

2. High investment.

3. High ‘unit cost relative to fixed automation.

ADVANTAGES AND DISADVANTAGES OF WELDED OVER RIVETED JOINTS

      

 

 

    Advantages:

• The welded structures are usually light in weight compared to riveted structures. This is due to the reason, that in welding, gussets or other connecting components are not used.

• The welded joints provide high efficiency, which is not possible in the case of riveted joints.

• Alterations and additions can be made easily in the existing structures.

• Welded structures are smooth in appearance, therefore it looks pleasing.

• A welded joint has a great strength. Often a welded joint has the strength of the parent metal itself.

• It is easily possible to weld any part of a structure at any point. But riveting requires enough clearance.

• The process of making welding joints takes less time than the riveted joints.

• Shape like cylindrical steel pipes can be easily welded. But they are difficulty for riveting.

• The welding provides very strong joints. which can’t be bended easily. This is in line with the modern trend of providing rigid frames.

• In welded connections, the tension members are not weakened as in the case of riveted joints.

    Disadvantages:

• For making weld joints using weld symbols requires a highly skilled labour and supervision.

• Since there is an uneven heating and cooling in welding process during fabrication, therefore the members may get distorted or additional stresses may develop.

• Since no provision is kept for expansion and contraction in the frame, therefore there is a possibility of cracks developing in it.

• The inspection of defects in welding work is more difficult than riveting work.

DESIGN OF SHAFTS

PURE TORSION

when the shaft is subjected to pure torsional load,the diameter of the shaft may be obtained by using torsion equation


                              τ = T r / J

where,
τ=  torsional shear stress
T= torque acting upon the shaft
r = radial distance of the outermost fibre
J = polar moment of inertia

Note:-

The "Polar Moment of Inertia of an Area" is a measure of a beam's ability to resist torsion. The "Polar Moment of Inertia" is defined with respect to an axis perpendicular to the area considered. It is analogous to the "Area Moment of Inertia" - which characterizes a beam's ability to resist bending - required to predict deflection and stress in a beam.

"Polar Moment of Inertia of an Area" is also called "Polar Moment of Inertia", "Second Moment of Area", "Area Moment of Inertia", "Polar Moment of Area" or "Second Area Moment".


        τ=16T/πd^3

∵      J= (π/32)*d^4

         r=d/2




FOR HOLLOW SHAFT JUST REPLACE D^4 WITH [d⁴₀-dᵢ⁴]

where ,

d⁴₀ =outer dia
dᵢ⁴ = inner dia

Calculating the section modulus

To calculate the section modulus, the following formula applies:

An equation: Z = I /y.  

where I = moment of inertia,
           y = distance from centroid to top or bottom edge of the rectangle, here d/ 2. 

For symmetrical sections the value of Z is the same above or below the centroid.

For asymmetrical sections, two values are found: Z max and Z min.

To calculate the value of Z for a simple symmetrical shape such as a rectangle:

An equation: Zxx = I xx/y.  where An equation: Ixx = bd3/12 mm4.

and y=d/2

This gives the formula for  Z = bd2/6 mm3.

PLASTIC EXTRUSION AND MOULDING

EXTRUSION MOULDING
Extrusion is a manufacturing process used to make pipes, hoses, drinking straws, curtain tracks, rods,and fiber. The granules melt into a liquid which is forced through a die, forming a long 'tube like' shape.The shape of the die determines the shape of the tube.The extrusion is then cooled and forms a solid shape.The tube may be printed upon,and cut at equal intervals.The pieces may be rolled for storage or packed together.Shapes that can result from extrusion include T-sections,U-sections,square sections,I-sections,L-sections and circular sections.One of the most famous products of extrusion moulding is the optical fiber cable.
Everyday examples of extrusion can be seen when toothpaste is squeezed out of a tube, icing is pushed out of an icing bag and "Play do" shapes are made. Extrusion moulding of plastics is used to make any long shape that has a constant cross section. Pipes, gutters, window sections and decorative trims can all be made using the process.,

Typical extrusion material-
• PVC (polyvinylchloride), 
• LDPE (low-density polyethylene, or polythene), 
• HDPE (high density polyethylene) and 
• PP (polypropylene) 

Thermoplastics are pliable when they are heated but form a rigid shape once cooled. Perhaps most common plastic extruded is PVC. Hard, "unplasticised" PVC can be used in pipes for water, sewage and gas.


Working principle
The extrusion process begins with the plastic polymer in a granule or powder form. A funnel, or hopper, feeds this into the heating chamber of the extruder. The polymer melts as it is heated to temperatures typically above 200ºC
 Once molten, a screw-mechanism pushes the melted polymer through the shaped "die head" which forms the plastic into shape. As it leaves the extruder, the plastic is cooled by water or air to give the final form. Flexible products, like tubing, may be coiled whilst rigid plastics, such as window-frame sections, will be cut to length.

Parts of plastic moulding machine-

Hopper
The hopper is a large funnel that holds the raw plastic in either granular or pellet form. The hopper sends a continuous stream of raw plastic into the heating barrel of the extrusion machine.


Heated Barrel
The heated barrel of a plastic extrusion machine is a long, horizontal cylinder. The cylinder is heated internally through the use of a heating jacket. As the plastic is fed into the cylinder by the hopper, the plastic melts from the heat 

Die and Mandrel
 A water-cooled die is located at the end of the heated barrel. The intended shape of the plastic is cut into the die. Water passes along the metal die to cool the plastic as it passes and harden it into shape. A mandrel may also be located after the die to produce a hollow shape.
Screw design:-

Most screws have these three zones:
• Feed zone (also called the solids conveying zone): this zone feeds the resin into the extruder, and the channel depth is usually the same throughout the zone.
• Melting zone (also called the transition or compression zone): most of the polymer is melted in this section, and the channel depth gets progressively smaller.
• Metering zone (also called the melt conveying zone): this zone melts the last particles and mixes to a uniform temperature and composition. Like the feed zone, the channel depth is constant throughout this zone.


Compound extrusions
Compounding extrusion is a process that mixes one or more polymers with additives to give plastic compounds. The feeds may be pellets, powder and/or liquids, but the product is usually in pellet form, to be used in other plastic-forming processes such as extrusion and injection molding. As with traditional extrusion, there is a wide range in machine sizes depending on application and desired throughput. While either single- or double-screw extruders may be used in traditional extrusion, the necessity of adequate mixing in compounding extrusion makes twin-screw extruders all but mandatory

Application:-

• Insulated coating for wires and cables.

• Monofilament: for rope, bristles and synthetic textile fibres.

• Flat plastic sheets for signs, refrigerator interiors, glazing and lighting applications.

• Pipes and tubing used for hoses, water, gas, sewers and drains.

 Advantages of Plastic Extrusion

      3 of the major advantages of plastic extrusion are as follows.

• Low Cost: Compared to other molding processes, plastic extrusion molding has a low cost and is more efficient. The extrusion molding process uses thermoplastics and they undergo repeatedly melting and hardening, this allows the waste to be reused rather than be discarded. Raw material and disposal costs are lowered. 

• Better Flexibility: Extrusion molding will provide considerable flexibility in the products being manufactured with a consistent cross section. As long as the cross section stays the same, the extrusion molding can produce complex shapes

• After Extrusion Alterations: Plastics remain hot when they are removed from the extruder and this allows for post-extrusion manipulations. Many manufacturers will take advantages of this and use a variety of roller, shoes and dies to change the shape of the plastic as needed.

 Disadvantages of Plastic Extrusion

Plastic extrusion has also some disadvantages.

• Expansion: Once the hot plastic is removed from the extruder it will many times expand. This is called die swell. It is problematic to try and predict the exact degree of expansion. Because it is hard to predict the exact expansion, manufacturers often accept significant levels of deviation from the dimensions of the product.

• Product Limitations: Extrusion plastic molding does place limits of the types of products that can be manufactured. There are alternatives that require an investment in a different type of extrusion equipment.

DIFFERENCE BETWEEN FRANCES AND KAPLAN TURBINE


1. Type of Turbine
      France Turbine is radially in ward or mixed flow Turbine
      Kaplan Turbine is partially axial flow


2. Disposition of shafts

      France Turbine disposition of shaft is in vertical or horizontal direction
      Kaplan Turbine disposition of shaft is only in vertical direction


3. Number of vanes

     France Turbine has very large number of blades 16 to 24
     Kaplan Turbine has very small number of blades 3 to 8


4. Adjustment of runner vanes 

     France Turbine Runner vanes are not adjustable
     Kaplan Turbine Runner vanes are adjustable

5. Resistance to over come

     France Turbine very large resistances have to be over come
     Kaplan Turbine very less resistances have to be over come
6. Head

     France Turbine medium head is required
     Kaplan Turbine very low head is required
7. Flow Rate

     France Turbine medium flow rate is required
     Kaplan Turbine very large flow rate is required
8. Specific Speed

     France Turbine 50 to 250
     Kaplan Turbine 250 to 850
9. Type of generator

     France Turbine regular generator is required
     Kaplan Turbine heavy duty generator is required

CHANGING LOCATION IN TINDER WITHOUT PAYING FOR IT

YES U HEARD IT RIGHT now you can fake your location in tinder app without paying for it thus you will have the power to explore and find a perfect match for you sitting at home 

Requirements:-

1. fake GPS app(play store link)
2. An android mobile phone
3. Data pack 

 NOTE:- This tutorial will not work with a wifi connection.

STEP 1 -  Turn on your mobile data 2G,3G or 4G


STEP 2- Download the above fake GPS app and install it on your phone and open it now you will see a search box there search your desired location and then tap the green circular button having white triangle inside it located at the lower right end of your phone screen.
now the app will automatically close showing a notification with a pause button the latitude and longitude of that fake location(we don't have to do anything with this ).

STEP 3- Now open your tinder app now it will ask you to turn your wifi on press ok and allow it 

STEP 4- Now a home screen with tinder default layout will open written as 'finding people near you'

Hola now tinder will search people near your fake location and you will find people around that fake location

How to change the location 2nd time??
After using first time above method  to change your location again turn off your mobile data and force stop both tinder app and fake gps app and clear cache now repeat the above MENTIONED steps enjoyyy 

DIFFERENT FORMS OF IRON BASED ON CARBON CONTENT

HERE ARE SOME BASIC BUT VERY IMPORTANT TERMS EASILY EXPLAINED FOR YOU RELATED TO PIG IRON,CAST IRON,WROUGHT IRON......etc

'Iron is an element, found in chemistry labs'

Pig iron:- It is iron as cast after smelting from ore. It is so called because it used to be a very simple casting made by scooping roundish depressions in a row along a runnel. Add red-hot iron, and the visual effect resembles piglets feeding from a sow. Pig iron has 5% carbon by weight or more.

Cast iron:- It is pig iron remelted (or even, these days, shipped directly to a foundry in molten form) and cast into something useful. It still has 5% or more carbon, and the carbon separates out into flakes. This reduces the tensile strength, but not the compressive strength, so it is used where compression is important. Machine tool bases are often cast iron.

Take out all but 0.25% of the carbon, add a little manganese and silicon, and you have mild steel. This is the steel that you see the most of. It works relatively easily, has good tensile and compressive strength, and is cheap. Car and appliance bodies are mild steel sheet. Coat the sheet with zinc to prevent corrosion, and use it for roofs and ducts. Most modern "wrought iron" railings are really mild steel, so you need to keep them painted. This is what most people are thinking of when the say just "steel" with no qualifiers.

Take out just about all the carbon and you have wrought iron, easy to shape on a forge and weather resistant - it rusts a lot more slowly than other steels. It is almost pure iron. Rarely seen these days.

carbon steel:-Leave in just the right amount of carbon, around 1%, and you have carbon steel. This is useful in springs, knives, and high-tensile wire rope. Its big feature is that you can change its properties from soft via springy to hard and brittle by simple heat treatment. Also sometimes called tool steel, though this tends to be used for more complex alloys.

To get stainless steel you remove the carbon and add a lot of chromium, at least 10.5%. It is capable of taking a moderately good edge, (not as good as a tool steel) but it will not rust, provided it is exposed to air so that it can form a protective oxide layer. Great for cutlery and cooking gear, but not so good for bolts, which rust out fast where you can't see them, because there is no free oxygen there.

ENGINEERING MECHANICS BY EGOR.P. POPOV

                                   INTRODUCTION 

In the world of virtuality everything is digitalised, no one bother to carry books that matches our pillows, these books are like warnings to you "hey you cant change your place while reading me" 

And everyone of us carry a electronic device capable of handling pdf,docs,xps etc files there are too many i can not mention here and as a GATE exam seeker SOM one of the vary important topic asked in this competitive examination.I am giving you what you need.

Till now we have talked about e-reading now the most popular question ever asked is "which book is best or say good for SOM" i am not just discussing about this subject it is for all but to answer the current question i am here providing you the pdf of one of the most popular books available for SOM 

(cover page)

download your book here

HOW TO DOWNLOAD

It is simple as cutting a cake you just have to click on the "download your book here" and yup you will be redirected on my google drive page where again download option will appear kindly download from there IF YOU FEEL ANY PROBLEM WHILE DOWNLOADING PLEASE LEAVE A COMMENT BELOW 

REVIEW

lets review this book this book consist of point to point basis concepts means you may have to go through the texts 2-3 times but you will surely going to crystal clear your concepts.this book covers the whole syllabus with a good variety of solved and unsolved questions and it is one of the first preferred book in PU (Punjab university) syllabus so a PU student must have this book.So finalizing the review i will give this book 4 out of 5 stars which is much worth so folks give it a try and just i said you may got frustrated on the first read but be patient and keep reading .

SUBJECT WISE GATE PREVIOUS YEAR QUESTIONS FOR MECHANICAL

                                  

                                  hey GATE folks

You are at right place for what you are searching yes subject wise question papers lots of people around us including you don't bother to solve and separate questions from a combined previous year question papers we all need a direct hit what i mean to say if we are studying SOM then we want to clear all those concepts and for that we need problems to challenge our concepts and keeping that target in my mind i am presenting here the most you need all you have to do is download this papers and start solving i am solving too and do share your questions i will help to short them out 



here are the links to download

1. engineering mathematics
2. engineering mechanics 
3. fluid mechanics
4. heat transfer
5. industrial engineering
6. machine design
7. manufacturing engineering
8. refrigeration and air conditioning
9. strength of materials(som)
10. theory of machines(TOM)
11. THERMODYNAMICS   

so please do comment and share my post so other people can get it easily 

                                                    !!thank you!!

LUBRICATION SYSTEM OF INTERNAL COMBUSTION (I.C) ENGINE

INTRODUCTION

we stand and walk on our feet due to friction but coin has two sides similarly friction is our friend and enemy both.wherever relative motion takes place friction come into consideration 

and this happens in our engines

The frictional force developed in an I.C.Engine which consists of no. of sliding & rotating components like bearings, pistons, valve gears etc may be so large that it may cause excessive wear & tear due to which replacement of components is very necessary. A large amount of the power developed by the engine may also be used to overcome this force of friction. Due to friction, heat is also generated. Due to generation of heat, the temp. of various components may rise to so high a value that a complete seizure of the engine components may take place.
Therefore, in order to overcome these difficulties, a thin film of a suitable lubricant is interposed where the metal-metal contact takes place. This thin film reduces the friction considerably by keeping the two metal surfaces apart from each other and thus wear, tear & temp. developed are also reduced greatly.

LUBRICATION
To supply lubricating oil between the moving parts is simply termed as “lubrication”.
Purpose of Lubrication
1. To reduce friction between the moving parts to a minimum value, thereby to reduce power loss due to friction.
2. To minimize wear of moving parts as far as possible.
3. To provide cooling effect by acting as a cooling medium & remove heat from various parts.
4. To form an effective seal between the piston rings & cylinder walls and thus prevent the escape of gases from the cylinder and avoid power loss.
5. To keep the engine parts clean by washing off and carrying away the impurities from the engine parts.
6. To provide cushion (protection) to the engine by absorbing the shocks developed by sudden application of load and instant combustion of fuel in the cylinder of the engine.
7. To reduce noise by absorbing shocks between the bearings and engine parts.
8. To prevent metallic components from corrosive attack by the acid formed during the combustion process.

TYPES OF LUBRICANTS:

Lubricants are at following three types.1. Solid: graphic, mica etc2. Semi solid: grease3. Liquid: mineral oil, vegetable oil, animal oil etc.

•  Graphite is often mixed with oil to lubricate automobile spring. Graphite is also used as a cylinder lubricant.
•  Grease is used for chassis lubrication.
•  Mineral oils are almost used for engine lubrication.

Properties of Lubricant

1. high boiling point and low freezing point (in order to stay liquid within a wide range of temperature)
2. high viscosity index.
3. thermal stability.
4. hydraulic stability.
5. demulsibility.
6. corrosion prevention.
7. high resistance to oxidation.

Engine Lubrication System: Engine lubrication system is mainly of following types.

1. Splash system
2. Pressure system
3. Petroil system or mist lubrication

splash system:-In this system of lubrication the lubricating oil is stored in an oil sump. A scoop or dipper is made in the lower part of the connecting rod. When the engine runs, the dipper dips in the oil once in every revolution of the crank shaft, the oil is splashed on the cylinder wall. Due to this action engine walls, piston ring, crank shaft bearings are lubricated.

pressure system:- In this system of lubrication, the engine parts are lubricated under pressure feed. The lubricating oil is stored in a separate tank (in case of dry sump system) or in the sump (in case of wet sump system), from where an oil pump (gear pump) delivers the oil to the main oil gallery at a pressure of 2-4 kg/cm2 through an oil filter.

The oil from the main gallery goes to main bearing, from where some of it falls back to the sump after lubricating the main bearing and some is splashed to lubricate the cylinder walls and remaining goes through a hole to the crank pin. From the crank pin the lubricating oil goes to the piston pin through a hole in the connecting rod, where it lubricates the piston rings.
For lubricating cam shaft and liming gears the oil is led trough a separate oil line from the oil gallery.
The oil pressure gauge used in the system indicates the oil pressure in the system. Oil filter & strainer in the system clear off the oil from dust, metal particles and other harmful particles.

petroil system:-

This type of lubrication is used for two stroke cycle engines. The lubrications oil (2 to 3 percent) is mixed with petrol in the fuel tank. The oil and fuel mixture is inducted through the carburetor. Petrol gets evaporated and the oil lubricates the main parts of the cylinder.

The fuel -oil ratio used is important for good performance. the optimum fuel -oil ratio used is 50:1.

ADVANTAGE

• Separate lubricating system is not needed.
• No maintenance cost for lubriction system.
• Weight of engine is reduced by avoiding separate lubricating system.

DISADVENTAGE

• If oil is less there is chance for seizure of engine.

More oil makes excess smoke in the exhaust.

CONCLUSION:

We often think that the function of lubricating oil is only to lubricate the engine parts so that the power loss due to friction is minimum. But a lubricating oil has many other functions which are explained before.
Lubrication must be done properly and right type of lubricant should be used. Improper or inadequate lubrication of engine will cause serious trouble such as scored cylinders, worn or burnt out bearing, misfiring cylinders, dirty spark plug, stuck piston rings, engine deposits and sludge and excessive fuel consumption.