Fit By Design
Or Design To Fit |
Mechanical Drafter Designer
Applications of Mathematics 10 |
Lesson Idea by: Van McPhail, Okanagan Mission Secondary
There's hardly any object in your home or school that hasn't been created thanks in part to a mechanical drafter designer.
A mechanical drafter designer is the person who takes an idea and turns it into a drawing. It's this drawing that allows the object to be made.
In recent years, computer-aided design (CAD) has changed the face of the occupation. CAD allows drafters to create a drawing on a video screen at computer workstations. This means those in the occupation don't have to draw as well as they once did. Plus, the computer also handles much of the mathematical requirements.
Even so, good drawing and math skills are still required of top-notch workers.
A big part of working in the mechanical drafting field is being comfortable with numbers, says Tom Gilbert of T.G. Consulting in Winfield, B.C. That's because numbers are the language used by drafter designers, and everyone they work with, from engineers, machinists and suppliers.
Numbers allow everyone involved in designing and building something to "speak the same language." For instance, every part in a motor has to be designed and built. And every part in that motor has to fit with and work with all the other parts. You can't just say, "This part should be as big as an apple." Everyone has a different idea about how big an apple is. So, that's why numbers are used. Numbers are precise and mean the same thing to everyone.
Once a mechanical drafter designer has calculated the numbers, the numbers must be interpreted. That is, the mechanical drafter designer has to decide, "Is this number the right number?" Once that judgement is made, the design and drafting process can continue.
Mechanical drafter designers use computers to help them do many of their calculations. For instance, Gilbert uses the CAD system to check stress and strain, to calculate distances, and conduct other types of analyses. Still, it's very important for Gilbert to understand how the calculations were done and to work them out himself. That's because it's sometimes much easier to calculate a distance or angle by hand than it is to draw it in CAD.
"By the time I draw it on the machine, I could have easily done the calculation either by hand or calculator," he says. Many of the technicians that graduate from schools today don't have the ability to do this. Instead, they rely heavily on the computer, adds Gilbert.
"It limits them! Yes, you have to be able to use the computer, but as a tool," states Gilbert emphatically. For his business, he needs drafters who are flexible and can work in a variety of situations. For example, much of his company's work involves "fabrication drawings." These are the drawings used in fabrication, or in other words, manufacturing. When Gilbert is called out to the factory, he doesn't want to lug around his laptop computer -- especially into a dusty, dirty environment.
In these cases, Gilbert does many of the calculations right on the spot, either in his head or on a simple calculator.
With your classmates, name 10 things in your classroom that a mechanical drafter designer may have designed.
Discuss the following:
- What type of measurements and calculations would be involved during the design process?
- What design decisions would be made based on these mathematical calculations? (For example, too much material, not strong enough, item not balanced)
In small groups, perform the following series of measurements using a carpenter's square, a piece of string, and a protractor. Record these numbers on the Student Worksheet below. (If you don't have a carpenter's square, you can improvise one using two metre-sticks placed at a 90 degree angle to each other.)
a) Hold a piece of string so it crosses both legs of the carpenter's square. Label the long leg of the square "a" and the short leg "b."
b) Measure the distance between the 0 point and where the string crosses the carpenter's square. Take the measurements from the carpenter's square.
c) Using a protractor, measure the angles formed by the string and the carpenter's square. Record these measurements as angle A and angle B.
d) Using the carpenter's square, measure the length of string between the two points on legs a and b. (You can do this by grasping the string where it crosses the square, then holding the string against one of the legs of the square to measure it.)
e) Move the string to create a new triangle. Take the measurements as set out above. Record these on the worksheet.
f) Create three more triangles, again taking the measurements and recording the results. Altogether, you will have created and measured five triangles.
