To see an animated version of this tutorial, please see the Drawing and Drafting section in MIT's Engineering Design Instructional Computer System. (EDICS)

Drawing Handout Index

PPT theme featuring mechanical engineering - industrial drawing detail and several background and a light blue colored foreground Amazing slides having the engineer of mechanical backdrop and a lemonade colored foreground. Microsoft PowerPoint - Engineering Drawings Lecture Dimensioning Author: Paul Created Date: 5/28/2014 12:15:11 AM. PPT theme featuring mechanical engineering - industrial drawing detail and several background and a light blue colored foreground PPT theme having technical background - drawings of the engineer background and a sky blue colored foreground. What is a “Section View”? A section view is a view used on a drawing to show an area or hidden part of an object by cutting away or removing some of that object. The cut line is called a “cutting plane”, and can be done in several ways. Ensured that,the drawings being used are the latest issues. Old drawings that have been on MEC076 Engineering Drawing Interpretation 1 Resource Package December, 1995-10 the bench, under the bench or in drawers for months or years pose a real threat to industry. All this can be overcome by a simple phone call to the drawing office in most cases.

Introduction

One of the best ways to communicate one's ideas is through some form of picture or drawing. This is especially true for the engineer. The purpose of this guide is to give you the basics of engineering sketching and drawing.

We will treat 'sketching' and 'drawing' as one. 'Sketching' generally means freehand drawing. 'Drawing' usually means using drawing instruments, from compasses to computers to bring precision to the drawings.

This is just an introduction. Don't worry about understanding every detail right now - just get a general feel for the language of graphics.

We hope you like the object in Figure 1, because you'll be seeing a lot of it. Before we get started on any technical drawings, let's get a good look at this strange block from several angles.

Figure 1 - A Machined Block.

Isometric Drawing

Mechanical engineering basics ppt

The representation of the object in figure 2 is called an isometric drawing. This is one of a family of three-dimensional views called pictorial drawings. In an isometric drawing, the object's vertical lines are drawn vertically, and the horizontal lines in the width and depth planes are shown at 30 degrees to the horizontal. When drawn under these guidelines, the lines parallel to these three axes are at their true (scale) lengths. Lines that are not parallel to these axes will not be of their true length.

Figure 2 - An Isometric Drawing.

Any engineering drawing should show everything: a complete understanding of the object should be possible from the drawing. If the isometric drawing can show all details and all dimensions on one drawing, it is ideal. One can pack a great deal of information into an isometric drawing. However, if the object in figure 2 had a hole on the back side, it would not be visible using a single isometric drawing. In order to get a more complete view of the object, an orthographic projection may be used.

Orthographic or Multiview Drawing

Imagine that you have an object suspended by transparent threads inside a glass box, as in figure 3.

Figure 3 - The block suspended in a glass box.

Then draw the object on each of three faces as seen from that direction. Unfold the box (figure 4) and you have the three views. We call this an 'orthographic' or 'multiview' drawing.


Figure 4 - The creation of an orthographic multiview drawing.


Figure 5 - A multiview drawing and its explanation.


Which views should one choose for a multiview drawing? The views that reveal every detail about the object. Three views are not always necessary; we need only as many views as are required to describe the object fully. For example, some objects need only two views, while others need four. The circular object in figure 6 requires only two views.

Figure 6 - An object needing only two orthogonal views.


Dimensioning

Figure 7 - An isometric view with dimensions.


We have 'dimensioned' the object in the isometric drawing in figure 7. As a general guideline to dimensioning, try to think that you would make an object and dimension it in the most useful way. Put in exactly as many dimensions as are necessary for the craftsperson to make it -no more, no less. Do not put in redundant dimensions. Not only will these clutter the drawing, but if 'tolerances' or accuracy levels have been included, the redundant dimensions often lead to conflicts when the tolerance allowances can be added in different ways.

Repeatedly measuring from one point to another will lead to inaccuracies. It is often better to measure from one end to various points. This gives the dimensions a reference standard. It is helpful to choose the placement of the dimension in the order in which a machinist would create the part. This convention may take some experience.

Sectioning

There are many times when the interior details of an object cannot be seen from the outside (figure 8).

Figure 8 - An isometric drawing that does not show all details.

We can get around this by pretending to cut the object on a plane and showing the 'sectional view'. The sectional view is applicable to objects like engine blocks, where the interior details are intricate and would be very difficult to understand through the use of 'hidden' lines (hidden lines are, by convention, dotted) on an orthographic or isometric drawing.

Imagine slicing the object in the middle (figure 9):


Figure 9 - 'Sectioning' an object.


Figure 10 - Sectioning the object in figure 8.

Take away the front half (figure 10) and what you have is a full section view (figure 11).

Figure 11 - Sectioned isometric and orthogonal views.

The cross-section looks like figure 11 when it is viewed from straight ahead.

Drawing Tools

To prepare a drawing, one can use manual drafting instruments (figure 12) or computer-aided drafting or design, or CAD. The basic drawing standards and conventions are the same regardless of what design tool you use to make the drawings. In learning drafting, we will approach it from the perspective of manual drafting. If the drawing is made without either instruments or CAD, it is called a freehand sketch.


Figure 12 - Drawing Tools.

'Assembly' Drawings

An isometric view of an 'assembled' pillow-block bearing system is shown in figure 13. It corresponds closely to what you actually see when viewing the object from a particular angle. We cannot tell what the inside of the part looks like from this view.

We can also show isometric views of the pillow-block being taken apart or 'disassembled' (figure 14). This allows you to see the inner components of the bearing system. Isometric drawings can show overall arrangement clearly, but not the details and the dimensions.


Mechanical Engineering Drawing Pdf Download

Figure 13 - Pillow-block (Freehand sketch).


Figure 14 - Disassembled Pillow-block.

Cross-Sectional Views

A cross-sectional view portrays a cut-away portion of the object and is another way to show hidden components in a device.

Imagine a plane that cuts vertically through the center of the pillow block as shown in figure 15. Then imagine removing the material from the front of this plane, as shown in figure 16.


Figure 15 - Pillow Block.


Figure 16 - Pillow Block.


This is how the remaining rear section would look. Diagonal lines (cross-hatches) show regions where materials have been cut by the cutting plane.

Figure 17 - Section 'A-A'.


This cross-sectional view (section A-A, figure 17), one that is orthogonal to the viewing direction, shows the relationships of lengths and diameters better. These drawings are easier to make than isometric drawings. Seasoned engineers can interpret orthogonal drawings without needing an isometric drawing, but this takes a bit of practice.

The top 'outside' view of the bearing is shown in figure 18. It is an orthogonal (perpendicular) projection. Notice the direction of the arrows for the 'A-A' cutting plane.


Figure 18 - The top 'outside' view of the bearing.

Half-Sections

A half-section is a view of an object showing one-half of the view in section, as in figure 19 and 20.

Figure 19 - Full and sectioned isometric views.


Figure 20 - Front view and half section.


The diagonal lines on the section drawing are used to indicate the area that has been theoretically cut. These lines are called section lining or cross-hatching. The lines are thin and are usually drawn at a 45-degree angle to the major outline of the object. The spacing between lines should be uniform.

A second, rarer, use of cross-hatching is to indicate the material of the object. One form of cross-hatching may be used for cast iron, another for bronze, and so forth. More usually, the type of material is indicated elsewhere on the drawing, making the use of different types of cross-hatching unnecessary.

Figure 21 - Half section without hidden lines.


Usually hidden (dotted) lines are not used on the cross-section unless they are needed for dimensioning purposes. Also, some hidden lines on the non-sectioned part of the drawings are not needed (figure 12) since they become redundant information and may clutter the drawing.

Sectioning Objects with Holes, Ribs, Etc.

The cross-section on the right of figure 22 is technically correct. However, the convention in a drawing is to show the view on the left as the preferred method for sectioning this type of object.

Figure 22 - Cross section.

Dimensioning

The purpose of dimensioning is to provide a clear and complete description of an object. A complete set of dimensions will permit only one interpretation needed to construct the part. Dimensioning should follow these guidelines.

  1. Accuracy: correct values must be given.
  2. Clearness: dimensions must be placed in appropriate positions.
  3. Completeness: nothing must be left out, and nothing duplicated.
  4. Readability: the appropriate line quality must be used for legibility.

The Basics: Definitions and Dimensions

The dimension line is a thin line, broken in the middle to allow the placement of the dimension value, with arrowheads at each end (figure 23).


Figure 23 - Dimensioned Drawing.


An arrowhead is approximately 3 mm long and 1 mm wide. That is, the length is roughly three times the width. An extension line extends a line on the object to the dimension line. The first dimension line should be approximately 12 mm (0.6 in) from the object. Extension lines begin 1.5 mm from the object and extend 3 mm from the last dimension line.

A leader is a thin line used to connect a dimension with a particular area (figure 24).


Figure 24 - Example drawing with a leader.

A leader may also be used to indicate a note or comment about a specific area. When there is limited space, a heavy black dot may be substituted for the arrows, as in figure 23. Also in this drawing, two holes are identical, allowing the '2x' notation to be used and the dimension to point to only one of the circles.

Where To Put Dimensions

The dimensions should be placed on the face that describes the feature most clearly. Examples of appropriate and inappropriate placing of dimensions are shown in figure 25.


Figure 25 - Example of appropriate and inappropriate dimensioning.

In order to get the feel of what dimensioning is all about, we can start with a simple rectangular block. With this simple object, only three dimensions are needed to describe it completely (figure 26). There is little choice on where to put its dimensions.


Figure 26 - Simple Object.

We have to make some choices when we dimension a block with a notch or cutout (figure 27). It is usually best to dimension from a common line or surface. This can be called the datum line of surface. This eliminates the addition of measurement or machining inaccuracies that would come from 'chain' or 'series' dimensioning. Notice how the dimensions originate on the datum surfaces. We chose one datum surface in figure 27, and another in figure 28. As long as we are consistent, it makes no difference. (We are just showing the top view).

Figure 27 - Surface datum example.


Figure 28 - Surface datum example.

In figure 29 we have shown a hole that we have chosen to dimension on the left side of the object. The Ø stands for 'diameter'.


Figure 29 - Exampled of a dimensioned hole.

When the left side of the block is 'radiuses' as in figure 30, we break our rule that we should not duplicate dimensions. The total length is known because the radius of the curve on the left side is given. Then, for clarity, we add the overall length of 60 and we note that it is a reference (REF) dimension. This means that it is not really required.


Figure 30 - Example of a directly dimensioned hole.

Somewhere on the paper, usually the bottom, there should be placed information on what measuring system is being used (e.g. inches and millimeters) and also the scale of the drawing.

Figure 31 - Example of a directly dimensioned hole.

This drawing is symmetric about the horizontal centerline. Centerlines (chain-dotted) are used for symmetric objects, and also for the center of circles and holes. We can dimension directly to the centerline, as in figure 31. In some cases this method can be clearer than just dimensioning between surfaces.

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Seminar Topics for Mechanical Engineering with ppt (2021)

A cruise control system is developing by two companies to make adjustments in the speed of a car automatically to maintain a safe distance, is known as Adaptive Cruise Control. This inventive technology uses RADAR for looking forward, which is installed behind the grill of a vehicle and keep an eye over the speed and distance of the vehicle.

It is a computer-aided design program used for 2D as well as 3D design and drafting by engineers, architects and professionals in the field of construction. It was developed by Autodesk Inclusive and the very first program that can be operated on personal computers. At the initial stage, it supports only polygons, circles, lines, arcs and text whereas, in the later update, it enables to support custom objects with the help of C++ application programs interface.

It is an instrument which is using the optics to measure the small angles with extremely high sensitivity. Autocollimator can be applied in precision alignment, monitoring the angles for long time and detection of movements of angles. Two types of autocollimator are there, named as Digital and Visual. The aim is to measure the straightness of a beam and able to conclude about an error in straightness with the help of graphical methods.

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It is used to switch on the light on the entrance or gate at night automatically with the presence of a person or object by using sensors. Moreover, it also sounds an alarm to indicate the presence of a person. Two units of transmission and receiving are there in this circuit. It is good for security purposes.

It is a procedure to measure the performance of the products as well as services towards the other business firms which are regarded as best in the market. It helps an organization to identify areas, systems or processes for improving, either it can be a continuous improvement or dramatic improvement.

It is a new concept in the field of mechanical engineering. It draws attention to the basic concepts of different fields such as biology, mechanics, electronics and mechanical engineering. The term deals with the interaction of organs of the human body with the electro-mechanics systems or devices. For instance, it is used in pancreas pacemakers for diabetes, electronic muscle stimulator and so on.

These are two pioneering technologies of the electronic field, named as CMOS and Bipolar. The elements fabricated from the CMOS technology dissipate low power with a smaller margin of noise and the particles are smaller. On the other side, the bipolar technology fabricates the components at a high speed, switch quickly and provide good noise.

It is a short form for Computer Numerical Control and it works according to the information fed into the controller unit of the machine. It consists of the mini-computer or microcomputer that works as a controller unit of the machine. In this machine, the memory of the computer has different programs and the programmer can straightforwardly write the codes and do editing in the programs as per the requirements.

These are in a tube shape and containing the molecules of pure carbon that are long as well as thin, of about 1-3 nanometers in diameter and the length of the tube is hundreds to thousands of nanometers. These nanotubes are a hundred times stronger than steel and the weight is of one-sixth of it.

The word “Cryogenic” means a very low temperature. Moreover, the term refers to the technique used to pulverizing the spices as well as herbs at a very low temperature, even at sub-zero temperature (-17.78℃). It helps to preserve the essential oils of a herb and it increased the capacity of production as well as less wear and tear of the tools.

This is a system that uses s set of gears that provide the definite number of speed and it has two-variable diameter pulleys. As compared to the traditional automatic transmission, CVT avails with more useable power, better economy for fuel and great driving experience. It is a kind of automatic transmission.

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This is a part of the mechanism of the hydraulic braking system and consists of the brake disc and a calliper, having two brake pads. Two types of the braking system in Vehicles are used such as a disc brake system and drum brake system. The disk brake system is superior to drum brake system and the response of disc brakes are more predictable at high temperature and in any conditions.

It is also known as digital radio, which is an innovative system for broadcasting and receiving radio stations. To accomplish the CD quality, the signals are received in digital form. Alongside the audio, it also allows the transmission of texts and pictures to enhance the experience of listening.

It is an embedded system which is a blend of hardware as well as software and forms a dedicated computer system that can do some definite and pre-defined tasks and encapsulate with the device it manages. It has sophisticated functionalities, low cost of manufacturing, low power and operations in real-time.

Fractals are never-ending matters which are formed by repeating the same process again and again. So, the fractal robots are the objects comprises of bricks with some electronics in them. These are useful for bridge building, fire fighting, defence technology, medical applications, space applications, earthquake applications and so on.

This term is related to the Formula 1 car racing where hi-tech car tracks provide the driver to run their cars at an excess of 320 kilometres per hour safely with no or zero injuries in case of any crash or accident. These tracks are highly safe and use the CSAS (Circuit and Safety Analysis System) and also do barrier crash test to make it more secure and thrilling to watch.

It comes from the sub-surface of the earth and is a kind of heat. Beneath the earth’s crust, it is contained in the rocks as well as fluids. Well, are dug into the underground reservoirs to touch the steam and hot water to produce the geothermal energy which is useful to drive the turbine linked to the electricity generators.

It stands for Global System for Mobile Communication and is a digital cellular technology used for the transmission of mobile voice as well as data services. This concept is based on the cell-based mobile radio system and most probably used in Europe and Asia. This standard is widely accepted in the field of telecommunications and it is applied on a global basis.

It is a wireless communication based on the packet system and it provides rates of data ranges from 56 up to 114 kbps. Moreover, it avails the continuous connectivity of the internet for mobile phone as well as the users of the computer. Higher the data rates enable the user to take part in video conferences and get in touch with multimedia websites.

This is a device to transfer heat from a fluid (a liquid or a gas) to another fluid (gas or liquid) with no mixing of two fluids or they never meet together. Overall efficiency and size of the system influences the heat exchanger and must maintain the balance between the heat exchanger effectiveness and pressure drop to accomplish the wanted tradeoff efficiency and size in the system.

These are devices used to transfer heat and it is hollow cylindrical with a small amount of working fluid to produce the heat by the process of evaporation. To exemplify, it is useful for the Air Conditioning as well as refrigeration application. It is normally used to transfer heat from heat injection to its destination with minimum differences in temperature.

It is a fabrication and formation of metals process which enables the shaping of the metals such as stainless steel, aluminium, copper, steel and brass. The process is cost-effective and uses specialized kind of die moulding that utilizes extremely pressurized fluid to create metal. It has two classifications such as sheet hydroforming and tube hydro-forming.

It is a technology that is commonly known as “HT technology” allows the processor to manage two threads or two sets of instructions at the same time. This technology is developed by Intel Corporation and used in certain Pentium 4 processor as well as Intel Xeon processor. As it works together on two tasks, so it has two separate processors to do a couple of instructions at the same time.

Mechanical Engineering Drawing Ppt

The term is closely related to the robots having overall appearance based on the body of the human. To resemble a male human, Androids are human robots and Gynoids are to resemble a human female. These are useful to help in the real world and not in research labs only.

A hovercraft is a vehicle that is one part boat, one part aeroplane and other one is a helicopter and it traps the air cushion underneath itself and then floats along on top of it. It looks like a boat, it can move across water and however, similar to the plane also and pushes via the air with the help of propellers.

This is a device that is supporting the rotor of the compressor with no mechanical link with the help of magnetic attraction and active control with sensors, electric magnets, power supply unit, controllers and power amplifier. It is a bearing system without any oil and uses the forces of electromagnetic to maintain the position of a rotor to a stator
This type of machining is used in manufacturing industries as it evolves less heat in the process and it is cost-effective. This is an Ultrasonic impact grinding which is an operation that comprises of a vibrating tool varying the frequencies of ultrasonic to remove the material from the piece of work.

It works on Newton’s third law of motion: “For every action, there is an equal and opposite reaction”. It is a kind of reaction engine and provides thrust by expelling a reaction mass. Air-breathing, gas turbine engines and axial flow are some of the most used jet engines.

These are man-made nanoscale crystals used to transport the electrons. When the UV rays put on these crystals, then it will emit light of different colours. It has a separate quantized energy spectrum. It contains a small number of conduction band electrons, valence band holes or the finite number of elementary electric charges.

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