Thursday, October 10, 2013

Knowledgeable unskilled Engineers...

As mentioned in one of my earlier posts, mechanical engineers are rarely taught ( in Indian engineering colleges ) during their graduate or undergraduate programs on certain skills they need the most. My quick list is as follows:

  • Hand calculation - Eg: To calculate the power required to drive a machine
  • Reading engineering drawings  and understand the various notations (like GD&T)
  • Knowledge of materials and their selection
  • Knowledge of manufacturing processes and their limitations (practical aspects)
  • Selecting various elements like motor, gearbox, servo, sensors, actuators etc.
  • Understanding how parts are assembled and their implications
  • How to make engineering judgement from measurements and results. 
Even though mechanical engineers are taught on doing calculations like finding the force, torque etc. it is not taught in a practical application point of view where in they get to apply their knowledge of calculating forces on a given engineering problem. If a fresh mechanical engineer is asked to find the motor power required to drive a conveyor carrying a load of 100 kg at 15 m/min, I have serious doubts how many could actually attempt doing this. However if you ask them to find the power for a given torque and speed they will do this in minutes. The problem actually lies in the habit of finding results based on "given" data. Engineers are not trained in assuming, building hypothesis, approximation etc. In fact this is the skill that differentiates an engineer from a technician. 

I am reminded of a good old story where an expert was called to fix a leaking boiler. He inspected the boiler, found the cause  and location of leak and asked his technician to do the repair to arrest the leak. Finally he charged  $100. The company official who was supposed make the payment asked : "You mean $100 for just arresting a leak?" The expert replied: " Arresting the leak costs only $ 2, while finding the cause of leak costs $ 98 ! " 

The grim reality of our engineering education is that none of our engineers (includes me when I too passed out as a fresh engineer) get a mental picture of what they are supposed to do in an industrial setting. Very few actually have to derive differential equations and do matrix multiplication as part of their day to day job, unless they are into core design and engineering research. However they should be able to manage resources, find the right vendors, select and order engineering goods like motor, gearbox etc., do some quick calculations, choose a suitable manufacturing process and so on. All these skills are for mechanical engineers who manage production and projects. 

The very engineering faculty who are supposed to teach this do not get a chance or rather do not get trained in doing such calculations during their career. The same reason applies to all the important skills I have listed.

The last point, engineering judgement is probably the most important skill, not only for mechanical engineers, but for any engineer. For a mechanical engineer this skill is required for him to be able to anticipate whether a given system can or might fail and under what circumstances. This skill differentiates a skilled engineer from a knowledgeable engineer. 

To summarize, I would say that fresh engineers are knowledgeable, but not skilled enough. They know how to do calculations for some given quantities. They learn some facts, pass exams, earn a degree. For example, they know what drilling is. But may not know how to choose a pilot drill. They also might not know that drilling process usually produces a larger hole than the one it is intended for. Eg. A 10 mm drill produces a 10.1 mm or 10.2 mm  hole. They might have learned about induction motor, how to start a motor in lab, etc. but might not know how to choose a motor for a given application. These highlight one important drawback in our education system, we create knowledgeable engineers who are not skilled enough! Of course these skills can only be attained through experience. About a decade ago we had the luxury to wait to get an engineer trained on the job till he/she acquires the skill. In these days when the world goes so fast and is well connected industry needs everything faster and earlier which means engineers need to be imparted some of these skills during their undergraduate program itself. 

Any possible solution?

Train the engineering faculty to further train the students so that they become reasonably skilled enough for a job. Teachers to be trained not on theory but on practical engineering skills. I shall put in my thoughts on how this training can be implemented in practice.

Wednesday, October 09, 2013

Concept of Force

If we are trying to pedal a bicycle gently, we require a particular amount of effort which all of us intuitively know. However if we need to move it at a higher speed, we need to “push” it hard. Now, if we have pillion rider on the bicycle we need to put in more effort. Thus we find that the “push” is related (read proportional) to the mass as well as the increase in speed ( change is speed per unit time or acceleration ). Now the question is why we multiply mass and acceleration. Whenever we need to bring in the effect of two or more quantities simultaneously, we multiply them. We need to bring the effect of both mass and acceleration simultaneously. We also multiply things when they are related. If one (mass or acceleration) is more the other has to be proportionately less for the same force. Hence we multiply mass and acceleration to quantify our “push” and we call this quantity as a Force.

We define force,F = m * a, where m is the mass of the body and a the linear acceleration of the body on a plane.

Please be forewarned that forces exist even if there is no motion associated with it. A bridge is permanently applying a force by way of it's weight on the columns. However there is no visible motion. There will be a separate post on stationary forces.