What are the Factors Thoughtfully Considered while Designing Machine Elements? An Exploratory Insights from Industrial Practices!

Abstract 

Mechanical engineers need to possess sound understanding of the physics of the design and use of machine elements such as gears, cams, springs, pulleys, joints etc., that are used in engineered components. This design process is deeply enshrined in established design standards/codes that all engineers should be knowledgeable of. Design of Machine Elements is aimed at integrating and applying prior knowledge in fundamental design, materials sciences, statics and dynamics coupled with design strategies and knowledge of machine elements to design various machines. These skills and knowledge help engineers to design, analyse, synthesize and deliver robust engineering solutions. The main learning outcome is the students' acquisition of strong analytical knowledge of machine elements, their design and load carriage/power transmission mechanics. 

The ideal contents of this subject cover but not limited to the following. The courses contents at engineering graduation or Master level are slightly different in order of in depth coverages.

Let's have a look!

Design of Machine Elements - A Perspective

Load Analysis

Engineering Materials

Static Body Stresses

Deflection and Stability

Principal Stresses

Theories of Failure

Fluctuating Loads

Surface Damage

Welded Joints

Threaded Fasteners

Power Screws

Springs

Plain Bearings

Spur Gears

Helical Gears

Bevel Gears

Worm Gears

Rolling Bearings

Shafts

Keys

Couplings

Chain Drives

Wire Ropes, Drums, and Pulleys

Belt Drives

IC Engine Components

Clutches

Brakes

Flywheels

Oil Seals and Gaskets

Pressure Vessels and Rivetted Joints

Gear Boxes and Planetary Gears

Machine Tool Beds and Slideways

Piping

Introduction 

Machine is the devise that comprises of the stationary parts and moving parts combined together to generate, transform or utilize the mechanical energy. All the machines are made up of elements or parts and units. Each element is a separate part of the machine and it may have to be designed separately and in assembly. 

What are Machine Elements?

Complex machines are made up of moving parts such as levers, gears, cams, cranks, springs, belts, and wheels. Machines deliver a certain type of movement to a desired location from an input force applied somewhere else. Some machines simply convert one type of motion to another type, such as rotary to linear. While there is a seemingly endless variety of machines, they are all based upon simple machine elements. The elements discussed here include inclined planes, levers, wheels and axles, pulleys, and screws.

All the machines are made up of elements or parts and units. Each element is a separate part of the machine and it may have to be designed separately and in assembly. Each element in turn can be a complete part or made up of several small pieces which are joined together by riveting, welding etc. Several machine elements are assembled together to form what we call as complete machine, which performs various applications.

Classification of Machines Elements

The machines elements are classified into two main types: general purpose elements and special purpose elements. These have been described below:

1) General purpose elements: The elements which are common to various types of machines serving different applications are called general purpose elements. Examples of these elements are nuts, bolts, keys, axles, shafts, couplings, bearings etc.

2) Special purpose elements: The elements that are used only in the specific type of machine are called as special purpose elements. For instance piston and connecting rods are used in the engines and compressors, while blades are used in the turbines and blowers. Some other examples are cam shafts, push roads, crankshaft, cylinder etc.

Process of designing machine elements 

These are the steps/procedure involved in Machine Design and Design of Machine Elements 

• Identifying the need for the Equipment or a Machine.
• Selecting the possible Mechanisms.
• Analysis of Forces.
• Selection of Materials.
• Design of Elements.
• Modification.
• Detailed Drawings.
• Production.

What are the basic requirements of designing any machine element?

Strength.

Rigidity.

Wear resistance.

Minimum dimensions and weights.

Manufacturability.

Safety.

Conformance to standards.

Reliability.

What are the standards used in machine design?

The following standards are used to all mechanical engineer while design a machine components. Standards for materials, their chemical compositions, mechanical properties and heat treatment. Standards for shapes and dimensions of commonly used machine elements.

Use of standards in machine design

The following standards are used by all mechanical engineers while designing a machine components.

Standards for materials, their chemical compositions, mechanical properties and heat treatment.

Standards for shapes and dimensions of commonly used machine elements.

Standards for fits, tolerance and surface finish of components.

Standards for testing of products.

Standards for engineering drawing of components.

Mainly there are three types of standards used in design.

Company standards

They are used in particular company or group of company.

National standards

National standards are :

IS (Bureau of Indian Standards) 

DIN ( German )

AISI or SAE ( USA )

BS ( UK )

International standard

These are prepared by the International Standards Organization ( ISO )

What are the six things on which machine element design should follow?

The six things on which machine elements should be designed are

1. Strength. Rigidity. Wear.

2. resistance. Min. Dim. And.

3. weight. Manufac- turability.

4. Safety. Conformance. to Standards.

5. Reliability. Maintaina. -bility.

6. Min. Life. cycle. cost.

What are the five basic elements of a machine tool?

The basic elements of machine tools include: chuck, blade, drill bits, socket, spindle, and motor. These components are all important and work together in order to provide the basic functionality that a machine needs in order to perform a specific task.

Advantages of good Design of Machine Elements 

Design principles are fundamental guidelines that help designers create aesthetically pleasing and effective designs. Here are some advantages and disadvantages of using design principles:

Advantages:

1. Consistency: Design principles help maintain consistency throughout a design project. Consistency in design makes the final product more cohesive and easier to navigate for the user.
2. User-Focused: Design principles are focused on the user's needs and preferences, resulting in designs that are intuitive, easy to use, and aesthetically pleasing.
3. Efficiency: Design principles help designers create designs more efficiently by providing a framework for decision-making.
4. Clarity: Design principles can help convey complex information in a clear and concise way, making it easier for users to understand.
5. Versatility: Design principles can be applied across different media, including print, web, and mobile devices, making them a versatile tool for designers.

Disadvantages

1. Limitations: Strict adherence to design principles can limit creativity and lead to predictable designs.
2. Over-Reliance: Over-reliance on design principles can lead to formulaic designs that lack originality.
3. Contextual Factors: Design principles must be adapted to the specific needs of each project and can't be applied universally.
4. Subjectivity: Design principles can be subjective, and what works for one project may not work for another.
5. Changing Standards: Design principles are not static and can change over time as technology and user behavior evolve.

Overall, design principles are an essential tool for creating effective and aesthetically pleasing designs. However, they should be used in moderation, with an understanding that they must be adapted to fit the specific needs of each project.

Conclusions

What constitutes the “basic” principles of design is certainly up for debate. But understanding and implementing the principles covered above is vital to the success of any design project.