Pictorial Techniques for Engineering Components

When using orthographic views, it can be difficult to get a clear picture of how the various views fit together to form the final part. I would say that the main disadvantage of an isometric drawing would be that it can get cluttered more easily than orthographic views. You can use an isometric drawing to show the dimensions, callouts etc. that an orthographic drawing commonly shows, but if you are not careful with their placement, the drawing can get incredibly messy.

This is the advantage of orthographic drawings, that you can break up the technical information among the different views so that no single view gets too cluttered. Overall I'd say that if you're dealing strictly with engineers or technical people, e.g. machinists, then the orthographic views are probably sufficient.

They are used to seeing them so interpretation will not be a problem. If you're dealing with non-technical people, e.g. purchasing, then you may want to go with isometric. It will be easier for them to get a better view of what it is you are looking for. In the drill vice jaw shown in figure 1 multiple views are shown, you can interpret from the views how each side is meant to look like and the size of the product you are making from the drawings.

There are many benefits of using a drawing board as a pictorial technique. One benefit for drawing the particular component free hand and without a computer is that you can observe what you are doing and the whole drawing will look to scale, however if you are using CAD you may not see the whole component as the computer screen may not be big enough to be able to see the whole design or the scale may not be accurate meaning the size of the product will be distorted on the computer screen.

Another benefit of using a drawing board and paper and pencil is that the design cannot be lost or deleted by accident as it could be on CAD, this means that it will be a hard copy therefore it is harder for another person/company to steal the idea. This could be a problem especially if the design is not patented. This is a great benefit as it is 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 is hard to move it to different locations as it is a big piece of paper/ separate pieces of paper and you need to make sure that it does not have folded creases or allow it to be damaged.

To combat this you can put it 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 as a file on a small memory stick that can be easily transferred. CAD designs can also be copied and shared on multiple devices, this is handy if the CAD design is constantly being edited and innovated by multiple designers, which is likely. This is also a limitation as the file could be copied and stolen by someone.

Another limitation of a drawing board is that it is very hard to store as it is very big and it take up a lot of room whereas 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 it out which could potentially leave marks or have to start again. You may also have to keep sharpening the pencil to make sure it is always sharp, the line is consistent depending on the size of the design, and the time is takes to draw it.

Additionally it takes a lot more time and effort than CAD does. You will also have to keep 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 deadline.

To summarize the points above the following benefits and limitations are in the table below.

Limitations

• Very detailed (Easier for the manufacturer to understand.
• Perpendicular lines
• Shows all 3 sides of the drawing, top, side and front
• Can have more than 3 views to show viewable angles on complex designs
• Used by manufacturers in the UK and USA
• Doesn’t take as a long to draw the different views as there is less
• Hard to draw/produce
• Not good for products that are found
• Rear of the object cannot be seen which means some important information could be not be visible.