A5 - D1 - Evaluation of Methods of producing Engineering Drawings

Evaluation of Methods of producing Engineering Drawings

More information at:

 http://engineeringlevel3.co.uk/engineering-drawings/evaluating-engineering-drawings

In this document I am going to be evaluating the different methods of producing Engineering Drawings such as CAD and Pictorial Drawings I am also going to be giving the advantages and disadvantages of these drawings which will help me to evaluate the drawings. There are not that many ways to produce an accurate engineering drawing however the most popular of all methods is to hand draw the drawings, using various skills, engineers draw an accurate drawing with a pencil and paper. Meanwhile CAD or computer aided design has been growing massively in popularity since the invention of the program and the computer, it is a computer program which enables you to produce precise scale drawings, this is much more accurate than hand drawing and is also much easier to edit and share the drawing.

The first method that I am going to be talking about for producing engineering drawing is Pictorial Drawing. Pictorial Drawings has many advantages but also it had some disadvantages as you would expect with hand drawing detailed precise drawings. The advantages of using pictorial drawings include, having skilled highly trained engineers that are needed and trained to complete the highly detailed drawings, due to this there is a demand increases for trained engineers, this allows all the skills and tricks of the trade as some people call it to be passed down to the next generations. Another good point or advantage of using pictorial drawings is that the drawing it’s a humans true interpretation of an object, this allows the drawing to have a human element. This is very good and better than CAD because when you use CAD it has a tendency to automatically correct the drawings which means that they might not be a true representation of the object, using pictorial drawings eliminates this problem and computer error meaning that you will be left with a true correct drawing of the object in question.

However there are disadvantages and fall back of using these pictorial drawings, this is defiantly the case when it comes to having to share, copy and store the image/drawing. This is because ALL of the pictorial drawings are on paper and drawn on with pencil and sometime inked in to look better, this means that there is only ever one copy of the drawings unless it get re-drawn, this has it draw back because the two drawings may not be identical so you will have two different size prototypes if it goes onto that stage. However you may be able to photocopy the image so they will be identical but this also has drawn back because the photocopy may have a lose image quality or be pixilate due to the printer you are using. Normally the pictorial drawing in question will be sent out to the manufacture for production, this is normally very easy as the place where the drawing is stored is in the same factory as the producers but sometime this isn’t the case, sometimes the office where the drawing is stored is in a different location than the manufacture. This cases a big problem as the pictorial drawing will now have to be moved and sent safely and securely to the manufacture via a courier service, this is a problem because it can cost the company a lot of money to have to pay the driver also some of the couriers aren’t very reliable and you can’t rely on the to get the drawing to the factory in time for production to start.

The other method that I am going to talk about for the producing engineering drawings is using CAD or computer aided design. With CAD drawings and designs they are much less limitations that using pictorial drawings, this is especially the case when it comes to sharing, copying, viewing and editing the drawing itself. This is because CAD drawing can be stored, viewed and edited on a computer so that they are just ordinary files that can be put onto memory stick and external hardrives. This allows the drawing to be copied and shared easily as you can also email the files. Also because CAD drawings and drawn using a computer programs there are certain automated elements built within the programs with can help with the drawing production as it can be made much faster than using pictorial drawings which saves time and money for the company and the customer. These automated elements also help reduce errors in the drawings by pointing out where mistakes may have been made if it was hand drawn. Using CAD also saves money as mistakes may be built into the final product which could cost the company money in materials, man power, labor costs, waste disposal and also recalls of the actual product after it has gone on sale.

However CAD can also have drawbacks and limitations because as everyone knows all forms of computerized systems whether it be word, Norton or CAD will eventually fail at one point in its use. This is a very big down fall with using the CAD systems because if a company drew all of their designs using the one specific CAD program, such as 2D design, the company who manufactures their products must use exactly the same program to be able to read the drawings and also print the drawings. If the producers of the drawings had to use another company permanently and that company did not use the exact same CAD program one of the participating companies will have to change their systems and CAD program in order to use and view the engineering drawing. This will cost the company changing their system a massive amount of money as they will have to purchase the programs which aren’t cheap. These days sometimes one single manufacturing and designing company can span the entire world and when their computer system crashes the entire company will be brought to a halt which again will cost the company thousands and thousands of pound each day that their systems are down.

Although CAD systems and programs can crash, fail and have compatibility errors, their range of features such as 3D rendering/viewing and computerized product testing makes them far superior than having to us pictorial drawings and having to hand draw all the objects in question read for manufacturing. This is because hand drawing models are just an accurate drawing of the object on a single sheet of paper rather than a complex drawing that can be manipulated and rendered in many different way whenever they are needed and where ever they are needed unlike pictorial drawings will have to be redrawn and kept in one place apart from being able to be sent all over the world.

Engineering is moving on, and so are we, come and join us at our new home

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Dominic Clifford 

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A5 - M2 - Engineering Drawing Report

Evaluation of Methods of producing Engineering Drawings

In this document I am going to be reporting on an engineering drawing. I am going to be giving reasons why it is suitable for its intended audience or in other words its intended user. I am also going to be saying how the drawing communicates information effectively and provide a good analysis of this engineering drawing.

In this engineering drawing you can clearly see that it is a first angle projection and that it is an orthographic drawing or a wall attachment adapter. I can tell this because it has the first angle projection symbol in the bottom right corner box which is below the title and also the way that the drawing is laid out. This type of drawing and this drawing itself will be used by the manufacturer to produce a product  for a customer, this drawing will first be given to an engineer to interpret it and then the product will be produced by either using machinery or humans, this will be the final product. All of the information that giving’s you on the drawing is everything that you will need to know to be able to produce this product e.g. the dimensions and radius and the drawing lines are given. In this particular drawing the construction lines are used for the dimensions. This particular engineering drawing is very well laid out and the drawing is in the centre or the page and all of the important information such as the scale and size/date are all presented neatly in the bottom left corner so it is easy to read and also easy to spot where it is rather than all spread out over the page, also the text is a good size as it is readable and mostly consistent, this all makes it much easier to interpret the drawing. This is CAD designed product and not a pictorial hand drawn drawing, this makes it much easier to share as it is a computer file and can be sent via email, however it cannot be shared by posting it which also makes it safer and less likely to me damaged. This however make it harder to make changes to the drawing as you can’t just get a pencil and do it quickly you have to go through the hassle of having to log on, open the file and the change it and also it may be harder to get the author’s permission to change the drawing. In the manufacturing process there may be more than one drawing that is required to make the product, this is so that the manufacture can have a full understanding of the drawing and product that they are producing, this allows it to be accurately make to the correct specification. When the product is complex this is often what happens as there are too many parts and components to be able to fit on one sheet and make it much easier for the author and the manufacturer to use, this also make it much more accurate use as it shows that all the parts will be able to together to make the final product correctly. When the engineering drawing arrives at the manufacture there are many manufacturing methods used, the British method which is when an engineer uses several different machines and the own skills to produce the final product.

This drawing will be interpreted to make a prototype by the manufacture and is essential that the drawing is 100% accurate or there may be a problem in the production of the product. The drawing is basically meant to be a paper copy of the product therefore all the dimensions must be correct in order to be made the correct specification. If the drawing is not produced properly or is interpreted wrong there are many problems that it can use such as the product in this cause the wall attachment adapter not working when it is tested and therefore the drawing must be re-made to make sure that the prototype will work when they test it again. When this happens there are many problems and issues it causes to the manufacture and the company making the product the include; the waist or man power, waist of factory hours where other products could have been produces, waste or materials to make the prototype, Labor cost meaning that the company will have to pay the staff to do the job again to make sure it correct and also the image of the company, people will know that there has been a mistake when making a product as it must be published by the company by law and therefore this can damage the image or the company and people may lose faith in the company and think that they shouldn’t use the company in case this happens to their prototype of with the want to make and use. Along with this if there is an issue with making the prototype it means that the will be a delay in it getting to the customer which will cause the costumer extra problems because they may need it urgently.

Engineering is moving on, and so are we, come and join us at our new home

http://engineeringlevel3.co.uk/engineering-drawings/drawing-report

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Dominic Clifford 

Twitter - @clifford_96

A4 - P8 - Test you Knowledge

Test your knowledge by answering the following questions.

• An isometric drawing is a true 3D representation. True or false?

False - An isometric drawing has only two dimensions, width and height. The appearance of depth is an illusion

• Oblique cabinet projection produces a distorted representation of the object that it portrays. True or false?

False - Because we shorten the receding lines, the image produced gives a better representation of the object we are drawing.

• Sketches are drawn to strict standards. True or false?

False - We draw to strict standards when producing ‘drawings’

• A diameter is half the radius of a circle. True or false?

False - A radius is half the diameter, conversely, a diameter is twice the radius.

• Circles that are said to be concentric always share the same centre. True or false?

True

• Dimension values should be readable from:

1. a) all sides of the drawing
2. b) the top and bottom sides of the drawing
3. c) the bottom and left-hand sides of the drawing
4. d) the bottom and right-hand sides of the drawing.

‘D’

• State which A-size paper for drawings having the following widths and heights (all dimensions are mm):

1. a) 420 × 297                        A3
2. b) 594 × 420                        A2
3. c) 297 × 210                        A4
4. d) 841 × 594                        A1

• Identify the following abbreviations that may appear on drawings.

1. a) CL             Centreline
2. b) DIA           Diameter
3. c) NO            Number
4. d) PCD         Pitch-circle diameter

• Only one of the two following statements is true; which is it?

1. a) In first angle projection, the view as seen by the observer is projected onto a plane behind the object.
2. b) In first angle projection, the view as seen by the observer is projected onto a plane in front of the object.

• A length of bar has the linear dimension 85.5 ± 0.01. What are the maximum and minimum acceptable lengths for the bar?

The acceptable size would lie between 85.49 and 85.51 mm

1. A drawing of a component on a circuit board, the scale of which is given as 5:1, has a line representing one side of a rectangular component drawn to a length of 50mm. What is the actual length of the side of the rectangular component?

5:1 means that the object has been drawn five times larger than the real object. The actual length of the side of the component will therefore be 10 mm.

• On a second drawing that shows the layout of a turbine house, and with the scale given as 1:50, a line representing one side of the turbine house has been drawn to a length of 500mm. What is the actual length of the side of the turbine house?

The scale 1:50 means that lines on the drawing will be 1/50th the size of the actual component. A line of 500 mm length will represent 50 × 500 mm or 25000 mm.

• Hatching is used on drawings to:

1. a) show where an object has been sectioned
2. b) indicate where the dimensions should be placed
3. c) enhance the appearance of the drawing
4. d) help the CAD program run efficiently.

• When the snap feature is used in CAD drawings:

1. a) the program will close by pressing the Ctrl key
2. b) lines will only be drawn either horizontally or vertically
3. c) a series of dots will be displayed on the screen
4. d) the cursor will move in incremental steps.

• In CAD drawing, a circumscribed polygon is one in which:

1. a) a polygon shares the same centre as a circle of the same size
2. b) a polygon is drawn around the outside of a circle
3. c) a polygon is drawn and then a circle is drawn on its inside
4. d) a polygon cuts the circumference of a circle an even number of times.

http://engineeringlevel3.co.uk/test-your-knowledge

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Dominic Clifford 

Twitter - @clifford_96

A2 - P3 - Orthographic drawings

Orthographic drawings

More information at:

http://engineeringlevel3.co.uk/engineering-drawings/orthographic-drawings

This show the diameter of the bigger circle as the arrows point in at the two far edges of it. By using calculations you can discover the diameter of the bigger circle and also the smaller circle within. This shows the diameter of the inner, smaller circle as it has the two arrows pointing at the two far edges of the inner circle. This line shows as section parts because it cuts straight through the circle, we know it’s not hidden detain because it’s not a consistent dash line it’s only partly broken and not a full line. This shows the 3^rd angle projections. This shows the Angular and Linear measurements of the drawing. This is hatching. I know this because the area has multiple lines such as on hatching. We use hatching to show bits of the object with will be cut out and removed in the production.

THERE IS NO HIDDEN DETAIL

This line shows as section parts because it cuts straight through the circle, we know it’s not hidden detain because it’s not a consistent dash line it’s only partly broken and not a full line. This shows the date it was made. This shows the scale. This shows hidden detail as it is a consistent dashed line, all the other consistent dashed lines are also hidden detail. This line shows as section parts because it cuts straight through the circle, we know it’s not hidden detain because it’s not a consistent dash line it’s only partly broken and not a full line. This is 3^rd angle projection.

THERE IS NO HATCHED AREAS, NO DIAMETER OR RADIUS and NO ANGULAR AND LINEAR MEASUREMENTS.

This shows the Angular and Linear measurements of the drawing. This is 3^rd angle projection. This line shows as section parts because it cuts straight through the circle, we know it’s not hidden detain because it’s not a consistent dash line it’s only partly broken and not a full line. This shows hidden detail as it is a consistent dashed line, all the other consistent dashed lines are also hidden detail. This is hatching. I know this because the area has multiple lines such as on hatching. We use hatching to show bits of the object with will be cut out and removed in the production.

THERE IS NO DIAMETER OR RADIUS ON THIS DIAGRAM

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Dominic Clifford 

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A1 - P2 - Benefit & Limitations or pictorial techniques

Benefit & Limitations or pictorial techniques

More information at:

http://engineeringlevel3.co.uk/engineering-drawings/benefits-limitations

A pictorial technique is when you use a device such as a drawing board, CAD (computer aided design) or CAM (computer aided manufacturing). The main aim of a pictorial device is to add you when you are creating and image/object that you or a manufacturer will use to create. You use a pictorial technique when you want to give precise measurements of an object, It may also give a scale (1:2, 3:1) which enables you to see than you need to increase or decrease the size of the object on the paper when in making.

A case study for a pictorial technique is a drawing board which is used to get precise measurements and angles for a diagram which will later be used to create an object, You can create many diagrams using this technique such as Isometric, Oblique drawing which give u all angles and dimensions of the object.

There are many benefits of using a drawing board as a pictorial technique. A benefit for drawing the diagram free hand and without a computer is that you can see what you are doing and how it looks other than if you are using CAD you may not see the whole thing as the computer screen may not be big enough to be able to see the whole design. Another benefit of using a drawing board and paper and pencil is that the design cannot be lost or deletes as it could be on CAD, this means that it will be safe also it means that it is harder for another person/company to steal the idea meaning it’s a great benefit as it cannot be copied and there for unique to the company/manufacture.

Just like the benefits there are limitations to using a drawing board and paper and pencil. One of the big limitations is moving and trying to keep the drawing safe and secure, with the drawing it will be hard to move it from place to place as it is a big piece of paper and you need to make sure that it is not folded over or damages, although you can put in in a portfolio or a rolling tube however even with these they are still quite big and hard to move around unlike CAD which is easy as you can have it on a small memory stick that can fit in a pocket. Also with using a drawing board it is very easy to damage or destroy the diagram as when it is out or being drawn it is liable to have food and drink spilt on it and also for it to be ripped or other object falling and damaging it from shelves ect.. Another Limitation of a drawing board is that it is very hard to store a it is very big and take up a lot of room where as with CAD it takes up little room and memory making it much better and easier to store. Other Limitations include; if you make a mistake you have to rub out leaving marks or have to start again, you must keep sharpening the pencil to make sure it’s always sharp and the line is consistent, takes a lot more time and effort than CAD, you will keep having to  changing equipment such as set squares and triangles, and also always having to switch to a roller to get the precise measurement and finally if you need to eat or drink you will have to move out the area to have food or drink which may waste time and may mean you miss the dead like. Another limitation of using a drawing board is not being able to show perspective as with the drawings you are unable to show it in that much detail, this could cause problems as when the project is produced you will not be able to see if the object gets smaller when you look at it and it goes into the distance, unlike with CAD you will be able to show this perspective enabling a better drawing for the user to read off. Also with the engineering drawing you will not be able to see 3D and move it around you just have one image on paper without being able to move it where as if you use CAD you have the ability to move the object to see all dimensions and sides.

 The drawing can be improved by using a different type of pictorial technique such as CAD which amends most of the limitations outlines and improves some of the benefits that I have also outlined, however like every pictorial technique it will always have limitation although some will have less than others such as CAD has some of the lowest limitations whereas using a drawing board has the most limitations compared to other pictorial techniques.

Engineering is moving on, and so are we, come and join us at our new home

http://engineeringlevel3.co.uk/engineering-drawings/benefits-limitations

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Dominic Clifford 

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