Mechanical Engineering

Saturday, March 21, 2009
What is Mechanical Engineering?
Mechanical Engineering is an engineering discipline that involves the application of principles of science and mathematics for analysis, design, manufacturing, and maintenance of mechanical systems. The ability in applying these fundamental approaches is aimed to develop economical solutions to technical problems. Mechanical engineering is one of the oldest and broadest engineering disciplines.

What do Mechanical Engineers do?
Many mechanical engineering jobs are available broadly since these engineers are employed in almost every industry. Their work is the link between scientific discoveries and the commercial applications that meet societal and consumer needs. Mechanical engineers do research, design, develop, manufacture, and test tools, engines, machines, and other mechanical devices. Engineers in this discipline work on power-producing machines such as electric generators, internal combustion engines, and steam and gas turbines. They also work on power-using machines such as refrigeration and air-conditioning equipment, machine tools, material handling systems, elevators and escalators, industrial production equipment, and robots used in manufacturing. Mechanical engineers also design tools that other engineers need for their work. In addition, mechanical engineers work in manufacturing or agriculture production, maintenance, or technical sales; many become administrators or managers.

Many engineers develop new products. During this process, they consider several factors. For example, in developing an industrial robot, engineers precisely specify the functional requirements; design and test the robot’s components; integrate the components to produce the final design; and evaluate the design’s overall effectiveness, cost, reliability, and safety. This process applies to the development of many different products, such as cars (electric or hybrid cars), bridges, power plants, aircrafts and helicopters, toys, sports facility buildings and tools. In addition to design and development, many engineers work in testing, production, or maintenance of mechanical systems, and risk based inspection as usually performed in oil and gas industries. These engineers supervise production in factories, determine the causes of component failure and test manufactured products to maintain quality. They also estimate the time and cost to complete projects. Supervisory engineers are responsible for major components or entire projects. Engineers use computers extensively to produce and analyze designs; to simulate and test how a machine, structure, or system operates; to generate specifications for parts; and to monitor product quality and control process efficiency. Nanotechnology, which involves the creation of high-performance materials and components by integrating atoms and molecules, also is introducing entirely new principles to the design process. Most engineers specialize. Mechanical engineering also includes materials engineering such as metallurgical and all about engineering materials selection used for design. Engineers also may specialize in one industry, such as motor vehicles (sand rail or go-karts), or in one type of technology, such as turbines or pipeline materials.


How do Mechanical Engineers solve the problems?
Many design works are directly solved by hand calculating and drawing solutions before it is manufactured and applied to the specific purposes. Modern analysis and design processes in mechanical engineering are aided by various computational tools like finite element analysis (FEA) and computational fluid dynamics (CFD), computer-aided design (CAD) and computer-aided manufacturing (CAM). In system design and controls, a mechanical engineer may apply CAD/CAM systems to feed “instructions" to computer numerically-controlled (CNC) machines such as robots, milling machines, and lathes. In this way the engineer could automate the manufacturing process without the need for intermediate drawings. A mechanical engineer working in thermo-fluid might design a heat sink, an air conditioning system, or an internal combustion engine. Other processes might focus on the fluid itself, such as a fan to cool an electrical system, a turbine to power a submarine, or a spray gun to apply chemical coatings.

What are the requirements to become a Mechanical Engineer?
It requires a solid understanding of core concepts including mechanics, kinematics, thermodynamics, fluid mechanics, energy, and selection of engineering materials. Mechanical engineers use the core principles as well as other knowledge in the field to design and analyze motor vehicles, aircraft, heating and cooling systems, watercraft, manufacturing plants, industrial equipment and machinery, robotics, medical devices and more.


Thursday, March 12, 2009
Dial Torque Wrench
Precision Instruments 0-300 in/lb Torque Wrench (0-25 ft/lb) With ±1% Accuracy
by "Burn" for webBikeWorld.com


This is the torque wrench for those really, really fussy mechanics. Torque wrenches don't get much more accurate than this Precision Instruments 0-25 ft/lb. dial type. It's way too easy to apply too much torque, even with a basic torque wrench, and this goes double for motorcycles, which use soft aluminum just about everywhere.

We have two micrometer type torque wrenches in the webBikeWorld garage in addition to an old beam type torque wrench that we only use for nuts over 75 ft/lbs., but I don't trust them at all.
Some of the cheap torque wrenches don't even list an accuracy figure; others are accurate to within 5% or so. For example, on a 100 ft/lb. torque wrench with 5% claimed accuracy, this would mean that it's only within 5 ft/lbs. when applying 20 ft/lbs. Our Sears Craftsman "Microtork" micrometer torque wrench is supposedly calibrated from 25-250 inch pounds (2 to 20 ft/lbs.) with a plus or minus 4% accuracy at 20% of total capacity, which is 50 inch pounds, or 4.16 ft/lbs.

The micrometer type torque wrenches use an internal spring, and springs are notoriously non-linear in their application of force as they get wound up. The Precision Instruments 0-300 in/lb. dial torque wrench shown here really does look and feel like the precision instrument that it's name implies. The ability to read the dial and the smooth working inner mechanism allow the user to apply a slow, careful application of torque. The 0-300 in/lb. torque wrench is 9-29/32" long overall; 2-11/32" wide and weighs 1 lb., 2 oz. (510 grams). Tool freaks will definitely want this one and the Precision Instruments beam-type torque wrench in their toolbox.

Be Careful Not To Over Tighten Your Lug Nuts!

Monday, March 2, 2009
Be Careful Not To Over Tighten Your Lug Nuts!
By Jason Miller


A common site in your neighborhood auto garage is a mechanic tightening up the lug nuts on your car with an impact wrench. You hear the common screech of the impact wrench as it makes quick work of the lug nuts. You also probably rarely see that same mechanic actually use a torque wrench. Impact wrenches are great tools but they can and will over tighten the lug nuts on your car. At first that doesn’t sound like a bad thing. Tight is good, right? Not necessarily.

Most manufacturers recommend using a torque wrench when tightening lug nuts. They will specify a certain ft/lb to dial in on the torque wrench. This insures the nuts are tightened properly. Over tightening can damage the studs and possibly lead to a failure in the future. Here is what happens. When the nuts are tightened, the studs will stretch. This tension holds the wheels on to the rim. If you over tighten the studs you can damage them and they could fail.
The best approach is to use your impact wrench to snug up the nuts. Then go back with a torque wrench and tighten to the manufacturer specifications. Next time you are having your tires rotated or changed, make sure the mechanic uses a torque wrench and the correct torque. Having the proper tools makes all the difference and will extend the life of your car.

Dial Torque Wrench...!
 
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