System Design Cycle or Machine Design Cycle: Prototype Building and Testing

What is Prototype Building and Testing

In the previous step of the detailed design all the details of the product or the machine were worked out. In the next stage of prototype building and testing (see fig below) all the details, the subassemblies, and assembly drawings including the materials and part list, the completed design is sent to the prototype or the model shop for fabrication. The prototype is the model of the machine developed as per the detailed design.

Before carrying out the mass production of the machine or product the prototype is manufactured to test if it performs as per the specifications and requirements and also to check if the design of the product is correct. Say for instance if the new airplane is designed, its mass production is not done immediately, rather its prototype is made for testing the performance of the airplane in different conditions and at different loads. Prototype building is an important and essential part of almost all the designs.

In most of the cases the size and the capacity of the prototype is exactly similar to the final machine that is to be manufactured. In other cases like ships, the prototype is comparatively smaller than the actual machine which is to be manufactured.

The manufacturing of the prototype is carried out in a manner similar to the final product that has been designed. The parts which can be manufactured in-house are manufactured and other commercial parts are purchased from the market. All the parts of the machine are assembled together to form a prototype machine which is ready for evolution and testing.

Benefits of Prototype Testing

The prototype can be considered to be the actual machine which is eventually to be manufactured on large scale basis. The prototype is developed for testing the machine that has been designed recently so as to remove all the faults and shortcomings from the machine before carrying out its production and sending it to the market.

Let us see how the testing of prototype can help:

1) Prototype helps producing acceptable performance.

2) It helps establishing the physical reliability of the system and the components.

3) The prototype helps verify design hypothesis.

4) The prototype helps generating new design information, if any.

5) It helps finding the flaws in the machine.

6) After testing, better design concepts can be developed.

7) The prototype exposes all the difficulties that may have been overlooked in the theoretical design of the product.

8) The test results from the prototype provide convincing evidence.

9) The prototype testing increases the validity of the results.

After carrying out prototype testing the results may be either satisfactory or not satisfactory. If the results are not satisfactory the design is sent back to the preliminary or detailed design stage for feedback to carry out the changes in the design or the specifications and the requirements of the product (see the fig below). The newly designed product is again sent for prototype testing and the results are analyzed. This process of making continuous revisions and improvements to the design will be repeated until the designer is satisfied that the performance specifications are met. Thereafter the designs are sent to the production department for manufacturing the product or machine.

System Design Cycle or Machine Design Cycle


Book: Machine Design by Dr. P. C. Sharma and D. K. Aggarwal

This post is part of the series: System Design Cycle or Machine Design Cycle

Whenever the new product or the machine is to be design there is a cycle of the steps that are followed. The sequence of the events in the machine design cycle or system design cycle have been codified Asimow, who is considered to be the father of system design or machine design. Here they are:
  1. System Design Cycle
  2. System Design Cycle: I) Recognition of a Need
  3. System Design Cycle: II) Specifications and Requirements
  4. System Design: III) Feasibility Study
  5. System Design Cycle: IV) Creative Design Synthesis
  6. System Design Cycle: V) Preliminary Design and Development
  7. System Design Cycle: VI) Detailed Design
  8. System Design Cycle: VII) Prototype Building and Testing
  9. System Design Cycle: VIII) Design for Production and IX) Product Release