Short Answer:

Mechanism synthesis is the process of designing a mechanism that can perform a desired task or motion. The steps in mechanism synthesis help engineers move from problem definition to the final design of a working mechanism. These steps include identifying the problem, selecting the type of mechanism, determining dimensions, analyzing motion, and testing the final design.
Each step ensures that the designed mechanism performs its function smoothly, efficiently, and reliably. Proper synthesis helps in achieving the desired motion or output while maintaining strength, accuracy, and ease of operation.

Detailed Explanation :

Steps in Mechanism Synthesis

Mechanism synthesis is a systematic process that allows engineers to create mechanisms that fulfill specific motion or functional requirements. It involves several well-defined steps, from understanding the problem to validating the final design. The goal is to develop a mechanism that accurately delivers the required motion, path, or function.

1. Problem Identification and Task Definition
   The first and most important step in mechanism synthesis is identifying the problem clearly. Engineers must understand what motion or function the mechanism needs to perform. This includes defining input, output, and the relationship between them. For example, a windshield wiper mechanism must convert rotary motion into oscillating motion.
   During this stage, constraints such as space, speed, load, and accuracy are also identified. A clear definition of the task ensures that the following steps are directed toward solving the correct problem.
2. Type Synthesis (Selection of Mechanism Type)
   Once the task is defined, the next step is to decide what type of mechanism will best perform the required motion. Type synthesis involves choosing a suitable mechanical structure such as a four-bar linkage, slider-crank mechanism, or cam-follower system.
   Each type of mechanism has its own advantages and limitations. The choice depends on factors like simplicity, strength, available components, and cost. For example, if linear motion is needed from a rotating shaft, a slider-crank mechanism might be ideal.
3. Number Synthesis (Determination of Links and Joints)
   After selecting the type of mechanism, the next step is to determine the number of links and joints required. This step is called number synthesis. It involves applying Gruebler’s equation or mobility criteria to ensure the mechanism has the right number of degrees of freedom.
   For instance, a four-bar linkage typically has one degree of freedom, meaning one input motion produces one predictable output motion. Correct determination of links and joints is essential for achieving the desired motion without unnecessary complexity.
4. Dimensional Synthesis (Determination of Link Lengths and Angles)
   In this step, the actual dimensions of the mechanism are determined. Dimensional synthesis focuses on calculating the lengths of links, angles, and pivot positions that will produce the required motion.
   This step often uses analytical, graphical, or numerical methods. For example, Freudenstein’s equation is commonly used in four-bar linkage synthesis. Proper dimensional synthesis ensures smooth operation and accurate motion transfer in the final mechanism.
5. Motion and Path Analysis
   After dimensions are decided, motion analysis is performed to verify that the designed mechanism provides the required output. This includes checking the path traced by points, the velocity, and acceleration of moving parts.
   If the motion is not as desired, link lengths or joint positions may need to be adjusted. The goal is to ensure that the motion generated by the mechanism meets the design requirements accurately.
6. Function Analysis and Refinement
   At this stage, the mechanism’s ability to perform its function is tested under expected conditions. Function analysis helps in evaluating how effectively the mechanism converts input to output and whether it meets performance requirements such as speed, accuracy, and smoothness.
   Engineers may modify link lengths or orientations to optimize performance. The mechanism is also checked for reliability and durability to ensure long-term operation.
7. Prototype Development and Testing
   Once the analysis shows satisfactory results, a physical or computer-simulated prototype is developed. The prototype allows engineers to test the mechanism under real or simulated working conditions.
   Testing helps in identifying any mechanical interference, excessive vibration, or material failure. After successful testing, the design is finalized for manufacturing.
8. Documentation and Implementation
   The final step is to prepare complete documentation, including drawings, material specifications, and assembly instructions. Proper documentation ensures that the mechanism can be reproduced and maintained effectively.
   Implementation involves manufacturing the mechanism and integrating it into the machine or system where it will perform its intended task.

Conclusion

The steps in mechanism synthesis provide a clear and logical approach to designing mechanical systems. From defining the task to final implementation, each step ensures that the mechanism is efficient, accurate, and reliable. A well-synthesized mechanism performs its function smoothly and helps improve the overall performance of the machine. Understanding and following these steps carefully is essential for successful mechanical design and innovation.