Picture below provides a relative size of the plant. Our site plan drawing would indicate where major buildings are located in reference to the site plan, with roads, and piping network lines. What size paper sheet do we use? What scale do we use? Area to be represented is m x m.
The paper sizes available for the task obviously would not be A4, maybe an A3 if the scale is large enough and considering it is legible. Most likely we would be going to the larger size sheets and using the plotter for the output. Remember a set of drawings would all be the same size paper, this also has to be factored in due to various scales used on a project, in this case it could be A1 paper size is used for the whole set of drawings.
Students may try other scales for various paper sizes for the site plan for practise. We are now ready to enter the values for Limits as students have understood the purpose of Unit and Scale Factor. Limits does not have a dialog box it is input as values in the command prompt. Whatever the case, the command to type is Limits. The picture above shows the Command Prompt and type Limits next to the semicolon. The response would be for the input of the coordinate values for the lower left corner and upper right corner of the represented area, or actual area.
We will look at a few examples from our previous work. Example: Room. For the 12m x 6 m room paper size A4 and scale , Unit Millimetres. The lower left corner entry is 0, 0 x - axis, y - axis.
The upper right corner entry is , x - axis, y - axis. Example: Wrench Drawing. Example: Gas Plant Site Plan. Area m x m Scale Unit set in Millimetres. Paper Border Size A2 mm xmm. Drawing border dimension used mm xmm instead of A2 paper edge border x Now we are ready to input the Limits for the A4 drawing sheet of paper for the 12mx6m room at a scale of First enter the lower left corner values which are most likely going to be the reference coordinate point 0,0 for most drawings during the beginning stage of setting up the drawings.
Next the top right corner. Enter , For the Wrench Drawing Scale enter 0,0 then , Students had sized the limits in reference to the paper size. The coordinates are defined within the rectangular area set by the limits command. This boundary as shown below. The printable area margin is small in comparison to the size of the paper. Typical values can be described as follows for portrait orientation of paper and landscape image printout as, left and right margins 17mm, top and bottom 3mm.
It is safe to set the title block border at 5mm and 20mm margins. See picture below. The question mark symbols,? Please note that at this stage students need to realise that we need to actually see the outer boundary in a line form indicated on the computer monitor screen, presently we see the screen blank, the boundary drawn shown in the pictures above is not visible due to there was none drawn.
All we did thus far is set the coordinate points on the x and y axis of the monitor for a specific drawing. What can be suggested for providing a marker on the screen for the paper boundary i.
A rectangle is acceptable but that it does not cause confusion with the Title Block rectangle which will be drawn. One way to differentiate the paper boundary rectangle is to have it shown in a dotted line format and in a different colour than the title block rectangle.
This is left to each CAD department of the business to decide for its requirements. Important: The coordinate point 0,0 should be clearly indicated on the drawing for reference, there could be a small cross hair located at 0,0.
This gives the user a frame of reference on the monitor screen. What we are looking for is something like the sketch below. Title Block The Title Block is a very important section of the drawing as it provides information on the drawing. Project has a start and finish date, and Operations are the daily activities typical throughout the year and continues in the following year. A recommended title block students to start with has to look like the format shown below.
Drawing Area 10 9 8 1 2 6 3 5 7 4 See table below for the above title block numbers description. Description Comments 1 Name of the engineering firm The client company symbol could be located at 10 2 Drawing title 3 Drawing number. Example M1, next drawing Much more than a sequence M2. Architectural drawing A1, next drawing of numbers in the consulting A2.
MPE representing the building services disciplines mechanical, plumbing, and electrical. Where the names of the Dependent on the client a following are noted drawing might have the client 1.
Drawn by representative name included 2. Checked by as client approval which is 3. Approved by also signed. Any others as required At a later point in time when it is time to issue the drawing for construction or manufacture, the above personnel sign on the hardcopy i.
The revision numbering system is set in a logical When a drawing is updated for specific manner so that the office 32 Course: Engineering CAD. Example: Rev. Change of Pipe Size. On the drawing the area where the change is made is indicated with a bubble and a triangle with number 1 inside it to indicate this is Revision 1.
Other revisions follow in sequence - Rev. Students will need to provide title blocks in all the CAD assignments. It is the same standard for both countries. Part 2 of course has exercise where Welding is indicated on components. Apply in CAD drawings as required. The sections in Part Architectural are as follows in the table below. Drawing Shapes. Students know drawing shapes from drawings completed by hand for shapes such as squares, rectangles, circles, ellipse, arcs, triangles, etc.
The drawing shapes are built by the use of the basic line and forms of lines in different shapes such as arcs. The line is the most commonly used form used in technical drawings. There are more commands in addition to the above, which appear when the downward pointed arrow is clicked, see picture below. Resulting with the drop down shown in picture below.
The commands are depicted as Icons which are drawings that are represented on a button type of shape, which does what the Task the Icon portrays. This is the usual way of applying CAD software. Students need to realise there is customisation in softwares, which allows for shortcuts, for simplifying tasks or reducing the number of clicks. There are sufficient, if not complete, number of commands for completing any technical drawing in CAD.
Students must be able to combine shapes then manipulate the combined shapes to produce the desired shape, using several commands in CAD. For students home use software version and above as made available for students to down load from Autodesk website. Part 2 — Inventor in Computer Room.
Autodesk is the CAD company which develops Inventor. All CAD Softwares available for purchase from AutoDesk are available for educational use by students for a period close to 1 Semester for free. Students should realise by learning, through practice, a CAD software of one CAD developer such as AutoCAD, it will also work almost similarly for other CAD softwares from different developers, and the screen layout of the softwares would be different.
The software supports both 2D and 3D formats. The software is developed and sold by Autodesk, Inc. Version 1. AutoCAD Release 14 February Windows XP. Students know how to use word processing softwares such as MS Word, spreadsheet such an Excel, and there is a need to set select the font type, its size, colour of text, the documents margins, etc. These tasks need to be done once for most operations, similarly in CAD there are such settings as well but more in number.
The aim is for students to familiarize themselves with the Options dialog box. This will make it very user friendly in using the software and making changes as required.
The classroom computers are all connected via a network server, and there are items which cannot be changed due to the hardware environment existing on campus which the IT department is responsible for setting-up for all users at WITT. At home students are using their personal computers and it is known as type standalone system, whereby the user can set the hardware requirements as desired.
Regardless of which version of AutoCAD is used by the student the Options settings will be exactly the same or at most with very minor changes. Click the letter A shown in red at the top left corner. A view as shown below emerges. It has the usual commands on the right from creating New file to Save As, with a few new commands. Option is indicated by the blue arrow. Click Option and the required dialog box appears. It has tabs from Files to Profiles. Students go through each tab by clicking on the tab and reading through each tab requirements.
Click User Preference — See options below. Right Click Customization. This is purely intended for the user to decide how to set the right click. Makes repetitive task easier to execute at times. Insertion Scale should be set per drawing requirements, click to see the options available.
Students will set it at millimetres for this course work. Source means the scale the objects are drawn on the screen or imported into the drawing. Target means the objects are drawn on screen and exported to other drawings at the set unit measure. Set both at millimetres. This has relevance to Blocks command. A block in CAD can be explained as such for now, it is a collection of drawing entities, that make up a representation of an object, example a door, and this door is saved as a mini drawing within the main drawing file.
Whenever there is a need for drawing a door at any new location in the drawing, the mini file can be executed and the exact door placed on the screen. The door is a block in the main drawing. It allows for repeated use of an object that only needs to be drawn once.
Initial Setup. This allows the user to set the CAD screen environment to match the discipline the user is working in. Note at the advanced level there is use of Customisation of the software for the specific needs of the CAD user, this is not covered in the course but students need to be aware of this flexibility. In short it is highly customisable! This also involves recognising the main standard screen in the ribbon format as a new environment since It is only recently becoming the standard among new users and older users.
Prior to this it was the dropdown format with toolbars, and this is still available in or newer versions and is called the Classic menu for the CAD operators who choose to use the older format which was available since the early s!
Click where the arrow points to the downward arrow and the options are presented with Classic indicated. Priority for Coordinate Data Entry. The input is through the keyboard numeric pad. As a drawing is setup it is shown on the monitor the exact coordinates the cursor is at, this is shown on the lower left corner. This takes the guess work out of what the coordinates are. This is found in all CAD softwares. Lineweight Settings. On technical drawings there are lines of different widths and types.
By width it means the thickness of the lines, and type means the lines are drawn in patterns like dots, dashed, etc.
What do these mean? Example a mechanical discipline drawing is showing piping on a site plan, only piping lines drawn are shown thicker, other lines such as building walls are shown thinner. The line types have specific representation for each type, in engineering drawings hidden lines are shown dashed. Lines of the mechanical part not directly visible are shown dashed. Students will learn more on line types from their respective discipline courses, example Technical Literacy. The lines drawn are going to be measured based on millimetres, and technical draughting pencil lead is also sized per millimetres.
Mechanical pencils are sized 0. When drawing in CAD set the line thickness based on the suggestion in the following table: No. The Hidden Line 0. Typically by Layer. This will be practiced in lessons and briefly explained now. One sheet is used for drawing the building structural floor plans, on this sheet all the drawing is going to be light grey in colour ie the line colour is light grey, the line is drawn continuous, with a thickness of 0.
Next sheet is going to have its building walls drawn its going to have the walls thickness in straight lines drawn in blue brown colour, with a thickness of 0. The plastic sheet for structural is a Layer and it can be given a name, example Structural Ground Plan. Then the wall layer is given a name Walls Ground Plan. The physical plastic in the software is a cyberspace Layer!
This gives the user control on the drawing. A layer has associated with it Colour, Linethickness, Linetype, etc. Edit Scale List.
This dialog box provides for scales not typical to be created. It show all the available scales based on the unit selected. As we had set it to metric the metric scales are shown. The screen has a rectangle already drawn. Screen view below is presenting the cross hair present on the screen when no point has been picked, it shows the cross hair coordinates at the location of the screen.
We want to draw the line below without coordinate input. For obtaining the exact location on the screen of an objects point, it only requires that the objects relative information be the target of the point to be selected. Example a line has end points, a circle has centre, and quadrants, also a line has a midpoint, a line has a perpendicular reference to it, etc. Students only need to click on the highlighted points and the exact coordinate is automatically selected! This is known as using the Object Snap method of drawing, and it is extensively used.
Finally the line is drawn using Object Snap. Now for some of the most used tools on the status bar for draughting. See below. These icons are tools for assisting in the draughting process. Hover the pointer over the button and its name is highlighted.
Students will learn these tools from practice and initial trials and errors. All these buttons can be called Drafting Settings and are used extensively. See the picture below for the name of each button in the draughting settings, the functions of each button is what it is called by name.
The tutorial book in class will provide the practice for these settings. Remember the names and where they are located and how to make the settings. How to make the settings? Click on the button and its colour is brightened, this tells the student it is enabled. Right click on the button and a pop-up screen appears, click settings. A dialog box appears.
Apply as required. The next tab in Options is Drafting. This relies tab requires that the draughting settings are known. The settings on Drafting set the mode of operation for the drafting settings. An introduction to this dialog box will be provided by the Tutor. Remember hover over a button and its brief description is provided, wait a few seconds an expanded description is provided, and by pressing F1 a help document appears providing detailed explanation on the use of the tool.
There is a dialog box for defining the behaviour of object snaps which students will see soon. Now we can proceed to the next Tab — Drafting. Shown Below. The above dialog box is important in 2D and 3D draughting. Through practice students will gain a solid understanding of these settings.
The key is in understanding a few terms not known yet and the rest is plain English terms association to it! The setting on how Object Snap is to behave on the screen is set in this dialog box. Use this method to guide along the way in the beginning, with practice students will become familiar. This is for student information.
Stay with the default settings for except for the screen background colour which can be set to black as most students prefer, and is also the case in the work place. Looks a whole lots better now on the screen if it was not set to black to begin with! CAD working space area then looks as below. This is the screen in the real world CAD environment. Now to Selection Tab. Click each selection to get acquainted to where these settings are located. An article that appeared on the internet magazine inc.
It is also an introduction to computer aided manufacturing. The term geometrical data relates to geometrical modelling which can be explained as follows; Geometric modeling is an area of mathematics and computational geometry that studies methods and algorithms for the mathematical description of shapes. The shapes studied in geometric modeling are two- or three-dimensional.
Most geometric modeling is done with computers and for computer-based applications. Two-dimensional models are important in computer typography and technical drawing. These models typically appear on a computer monitor as a three-dimensional representation of a part or a system of parts, which can be readily altered by changing relevant parameters. CAD systems enable designers to view objects under a wide variety of representations and to test these objects by simulating real-world conditions.
Computer-aided manufacturing CAM uses geometrical design data to control automated machinery. These systems differ from older forms of numerical control NC in that geometrical data are encoded mechanically. Since both CAD and CAM use computer-based methods for encoding geometrical data, it is possible for the processes of design and manufacture to be highly integrated.
These developments were pioneered by the General Motors Research Laboratories in the early s. One of the important time-saving advantages of computer modeling over traditional drafting methods is that the former can be quickly corrected or manipulated by changing a model's parameters.
The use of computer modeling to test products was pioneered by high-tech industries like aerospace and semiconductors.
The development of CAD and CAM and particularly the linkage between the two overcame traditional NC shortcomings in expense, ease of use, and speed by enabling the design and manufacture of a part to be undertaken using the same system of encoding geometrical data. This innovation greatly shortened the period between design and manufacture and greatly 57 Course: Engineering CAD.
Computers are also used to control a number of manufacturing processes such as chemical processing that are not strictly defined as CAM because the control data are not based on geometrical parameters. Using CAD, it is possible to simulate in three dimensions the movement of a part through a production process.
This process can simulate feed rates, angles and speeds of machine tools, the position of part-holding clamps, as well as range and other constraints limiting the operations of a machine.
The continuing development of the simulation of various manufacturing processes is one of the key means by which CAD and CAM systems are becoming increasingly integrated. This is of particular importance when one firm contracts another to either design or produce a component. CAD systems have no means of comprehending real-world concepts, such as the nature of the object being designed or the function that object will serve.
CAD systems function by their capacity to codify geometrical concepts. Thus the design process using CAD involves transferring a designer's idea into a formal geometrical model. Efforts to develop computer-based "artificial intelligence" AI have not yet succeeded in penetrating beyond the mechanical—represented by geometrical rule-based modeling.
Other limitations to CAD are being addressed by research and development in the field of expert systems. This field is derived from research done in AI. One example of an expert system involves incorporating information about the nature of materials—their weight, tensile strength, flexibility, and so on—into CAD software.
By including this and other information, the CAD system could then "know" what an expert engineer knows when that engineer creates a design. The system could then mimic the engineer's thought pattern and actually "create" more of the design.
Expert systems might involve the implementation of more abstract principles, such as the nature of gravity and friction, or the function and relation of commonly used parts, such as levers or nuts and bolts. Such futuristic concepts, however, are all highly dependent on our abilities to analyze human decision processes and to translate these into mechanical equivalents if possible. One of the key areas of development in CAD technologies is the simulation of performance.
Among the most common types of simulation are testing for response to stress and modeling the process by which a part might be manufactured or the dynamic relationships among a system of parts.
In stress tests, model surfaces are shown by a grid or mesh, that distort as the part comes under simulated physical or thermal stress. Dynamics tests function as a complement or substitute for building working prototypes. The ease with which a part's specifications can be changed facilitates the development of optimal dynamic efficiencies, both as regards the functioning of a system of parts and the manufacture of any given part. Simulation is also used in electronic design automation, in which simulated flow of current through a circuit enables the rapid testing of various component configurations.
The processes of design and manufacture are, in some sense, conceptually separable. Yet the design process must be undertaken with an understanding of the nature of the production process. It is necessary, for example, for a designer to know the properties of the materials 59 Course: Engineering CAD. The conceptual overlap between design and manufacture is suggestive of the potential benefits of CAD and CAM and the reason they are generally considered together as a system.
As defined by SearchSMB. There is as much as possible where the task is similar to use the common words to describe the task. Example cut and paste, format command, and how to highlight and make changes.
Students will feel at home in this respect, and the learning curve is made shorter! When an engineering software for whatever application becomes well known for its results produced by one of its features it becomes a trend for other software developers to develop similar features.
As the first technical software to learn and practice it is certainly a stepping stone for learning other softwares.
Technical Literacy Course Topics Applied In This Course This course is taught with the criteria students are taking technical literacy in this semester or had taken it in prior semesters, or had completed such prior study elsewhere and validated by the Engineering Department.
The subject matter of the Technical Literacy course will provide the theory and engineering drawing fundamentals lessons. The Engineering CAD course will concentrate on progressing with using computer hardware and software to produce final drawings which are printed on paper.
He also likes to write articles related to the mechanical engineering field and tries to motivate other mechanical engineering students by his innovative project ideas, design, models and videos. Your email address will not be published. Save my name and email in this browser for the next time I comment. This site uses Akismet to reduce spam. Learn how your comment data is processed. Re: Best Books for AutoCad full notes free pdf download nice 1 very helpfull. Re: Best Books for AutoCad full notes free pdf download i like this site which give every solution related to engineering.
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This site uses Akismet to reduce spam. Learn how your comment data is processed. Introduction to Pressure Vessels Vessels, tanks, and pipelines that carry, store, or receive fluids are called pressure vessels. A pressure vessel is defined as a container with a pressure Knuckle Joint A knuckle joint is used to connect two rods which are under the action of tensile loads.
However, if the joint is guided, the rods may support a compressive load.
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