Machine Design
Machine design is defined as the use of imagination, scientific principles and engineering techniques to create a machine or structure economically, in order to satisfy the requirements of a customer.
Machine design is the first step involved in creation of a machine.
Basic requirements of machine
Elements
The machine element should satisfy the following basic requirements-
1- Strength
2- Rigidity
3- Wear Resistance
4- Minimum dimensions and weight
5- Manufacturability
6- Safety
7- Conformance to standards
8- Reliability
9- Maintainability
1- Strength:- A machine part should have sufficient strength to avoid failure either due to fracture or due to general yielding.
2- Rigidity:- A machine component should be rigid, i.e. it should not deflect or bend too much due to forces or moments that act on it.
3- Wear Resistance:- There are different types of wear such as abrasive wear , corrosive wear and pitting . Surface hardening can increase the wear resistance of the machine components such as gears and cams.
4- Minimum dimensions and weight:- A machine part with minimum possible dimensions and weight will result in minimum material cost .
5- Manufacturability:- The shape and material of the machine part should be selected in such a way that it can be produced with minimum labour cost.
6- Safety:- The shape and dimensions of the machine parts should ensure safety to the operator of the machine.
7- Conformance to standards:- A machine part should confirm to the national or international standards covering its profile , dimensions, grade and material .
8- Reliability:- The probability that a machine part will perform its intended functions under desired operating conditions over a specified period of time.
A machine part should be reliable , i.e., it should perform its function satisfactorily over its lifetime .
9- Maintainability:- It is the ease with which a machine part can be serviced or repaired.
Factors influencing machine
Design
There are following various factors that influence the machine design -
1- Cost
2- High output and efficiency
3- Strength
4- Stiffness or Rigidity
5- Operational safety
1- Cost :- The best machine design is the one which helps to get the finished product with all the major functionalities and highest possible quality at the lowest possible cost .
2- High output and efficiency:- The machine design must have a high output and efficiency .
3- Strength :- The machine design should be strong enough to sustain all the forces it is designed for so that it is not damaged or permanently deformed during its life time .
4- Stiffness or Rigidity:- The machine design should be rigid enough so that under the effect of applied forces for which it is designed there is no deformation of the machine or machine element beyond the specified limits.
5- Operational safety:- For the safety of the operator of the machine, the hazard producing things from the machine should be eliminated and the design should confirm to the safety codes.
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