Wednesday, October 7, 2009

Technical Drawings

I've always found well done mechanical drawings interesting. A lot of it may have to do with the fact that even though I've taken courses in drafting, I can still barley make a passable drawing by hand if my life depended on it. Recently, thanks to the wonderful developments of computer aided design programs I can now make drawings that are completely precise and show each component in perfect location and size to one another. While CAD technology was still developing mechanical drawing that were more of an illustration of the device were still necessary but with the ability of computers to render textures quickly and in greater detail this too is a task that has been digitized. This recent ability to create drawings so effectively is almost a shame. Drawings created using software are one of the best examples of how technology can sterilize what was once an art.
Designs by Da Vinci

Originally technical drawings were just used to convey an idea, showing the basic way a device would be constructed, parts were shown to an approximate scale but no exact measurements were given. Notes on the drawing were critical to its understanding, giving an explanation to way the device was intended to function. It was then up to the designer and manufacturer to collaborate to assemble a working version of the device. Artists and designers such as Da Vinci pioneered the use of specific geometric views display an idea in a way that was easy to visualize.

18th and 19th Century Technical Drawings

Up until the 20th century technical drawings would remain at the level of a sketch, usually accompanied with a wooden model to demonstrate the main principles. This wooden model was often used as the main template for actual manufacture. With the development of standardized and interchangeable parts the role of the technical drawing became a much more important one. Before the advent of a interchangeable parts a manufacture would simply create a part that worked or fit for the application and then just keep replicating that part. Now with standardized screws, nuts, bolts, springs and shafts being manufactured on a large scale which made them cheaper to buy than producing an individual batch yourself engineering drawings were needed to call which standardized part was supposed to be used were. Also with the standardization of technical drawings themselves a drafter could send a drawing out to a manufacturer who would know what all of the symbols and nomenclature meant and he would be able to a return a finished product just as the drafter has intended.

19th century Technical Drawings

Recently there has been a separation of manufacturing oriented drawings and educationally oriented drawings. Most technical drawings used are simple wire frame views of a component that show dimensions and other information for productions but contain little information on the function of a product. Technical illustration is a term that is now used to describe the colored and shaded drawings of a product that often show a cut away section revealing the operating mechanisms. I remember fondly seeing these types of pictures in the way things works books and issues of popular science. I will probably make another post with pictures of some pretty hilarious patents that I have seen floating around.

1 comment:

  1. At one point I tried to put together a folder of my favorite crazy patents, but after a while I gave up. Taking a deeper look into certain industries, you would be amazed at how few technical drawings/specifications exist and how much of the "engineering" that goes on is trial and error with physical templates and a handful of tribal knowledge. As a contract engineer, I usually get brought into projects and design tasks after the tribal knowledge or technical proficiency of some department has been exhausted. I always make sure to spend as much time as I need to develop the appropriate documentation because I have seen what happens when it doesn't exist. The technical drawing (and GD&T) are a dying art form (and one that I have obsessed over ever since I was introduced to their intricacies and beauty) with the advent of newer technology and the ability to pull manufacturing geometry/dimensions/features directly from a 3D cad model. I have also found that while machinists are able to program complicated parts in less time, they are paying less and less attention to the drawings that relay the design intent and critical features of the part/device which are being called out. Ok, rant over. Just wanted to let you know that I share an appreciation for technical doodles.