Specifications

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The purpose of this page is to share information about how to write quality project specifications. There is a standard, canonical form used in most of the engineering world, and the basic overview of this form is shown below.

Contents

What is a Design Specification Report?

A Design Specification or Needs Assessment is the cornerstone document that any good design is built upon. It clearly outlines the Need that the product must satisfy, as well as define the performance Metrics the product/process must meet in order to be considered successful.

The Design Specification also includes information that describes completely the product desired, as well as fills in background information on the product. It is also important to outline the time schedule that you plan on keeping, as well as the tradoffs between product characteristics. Limiting factors are the characteristics of the finished product that will most affect the design. These need to be included.

What are product design specifications?

Product design specifications fall into four statements about the design problem:

  1. A product characteristic is a description of an attribute or characteristic of a product, typically written as an adjective or adjectival phrase.
  2. A functional requirement is a description of a function the product must provide or something it must do.
  3. A constraint is a hard, quantitative limit placed on the capacity of a product to achieve a certain characteristic or requirement.
  4. A performance metric is a variable decribing a quantifiable measure of the capacity of a product to meet all of the specifications defined in 1, 2, and 3.

The goal of a product design specification is to come up with the structure of a product. A product design specification is a structured description of the purpose, functions, characteristics and other kinds of information that describe the design problem.

Letter of Transmittal

The Letter of Transmittal is a letter sent to your project sponsor, on your official letterhead, that tells the project sponsor what the report you are sending them is about. It should also remind them of your next deadline, so they can be anticipating their next interaction with you.

An example of the layout for a letter of transittal can be found on pages 124 and 125 in Writing as an Engineer by Beer and McMurrey, 2005

Title Page

More or less self explanatory, the title page should contain the name of your project, the names of the project members, and the name of the company sponsoring the project.

Executive Summary

This is what the "executive" or lead engineer will look at when he/she is handed the report. As such it must remind the reader of the basics of the project, and then fill them in on the current status. This summary is divided into two paragraphs. It should be kept to one page for easy copying.

1) Boilerplate Paragraph The boilerplate paragraph is the problem statement of the report. It should give a summary of the current status of the project. For example, if the most recent stage of your project was generating concepts, your most promising or final concept should be outlined here (not too much detail). Specifics of the project should be used (who, what when, where, why, how), that are always repeated.

2) Past, Present, Future Paragraph This paragraph should be a quick history of your project - where you've been, what you are currently doing, and what you plan on doing shortly. If you have already written one spec for your project, the "past" part will be something that you have already told the company you have done or were about to do. The purpose of this is so that the executive is reminded of the remarkable amount of progress you have made so far. Obviously, the "present" part should be a short description of what you are doing when you are NOT writing specs. Remember not to make the "future" section unrealistic; never lie to the company about what you think you can accomplish, as they will be upset (and therefore not likely to hire you) when they find out you did not deliver as expected.

Introduction

A typical introduction for a spec is not quite the same as an introduction you might write for a research paper. The intro here should have a few sentences about who the company is and what they do. Then you should outline the project (perhaps use the project description the company has given you). The intro will be essentially the "story of the project", and should end up being 1.5 - 2 pages, preferably with some pictures or diagrams, and should provide a seamless lead-in to the results and discussion section. In initial specs, the intro probably will not be as long, but you should try to at least produce a page of coherent thought.

Results / Discussion

The first part of your results should be explanations of the tables of interpreted customer needs, metrics, and a breakdown of the "House of Quality". After that, there should be discussion on major design consideration and constraints. There also needs to be a discussion on trade-offs. Once you have a final definition of your project, your results and discussion should be a complete and coherent description of your final thoughts.


Your results portion of your specifications report should include the following:


  • General breakdown in words and explanation of the "House of Quality"
  • Explain the tradeoffs that are in the "Roof" of the "House of Quality"
  • Explain the major design constraints
  • Be sure to include your engineering opinion on decisions and reasoning behind them
  • Explain how your concept will satisfy the project requirements


"Product Design and Development" (see references below) is a very useful book for understanding the basics of creating and optimizing these tables, along with a lot of other relevant information.

Conclusion / Next Steps

This will be very similar to your executive summary, but probably in more detail. The focus should be on what you are going to do next in your project, and some relation should be shown between your most important results and your new direction. Don't make this section too long - remember, if the reader wants more detail, they can go back to the results/discussion section.

Appendices / Schedule

Appendices contain all the supplementary and supporting documentation regarding your project. If you surf a webpage and it adds a piece of information to the pile, archive it on your computer, or print out a copy to include in a report. Most of the tables and charts will be placed in the Appendices. Make sure the schedule is a reasonable one that you can actually keep. Time constraints are important, but the the time required to complete each part of the design process is a factor too.


The House of Quality should be included in the appendix.

Your group should aim for completing the spec report about one week after meeting with your project sponsors, in order for it to be read over by either Dr. Chuck and/or Kelley. Most likely, the report will need to be revised and reworked several times and this may take a few days. By completing a final draft within a week of the meeting, the revisions necessary to create a report that meets all the requirements in full detail can be finished in about 10 days.


Note About Specification Creep

The specification sheet is an essential tool to be used over the course of the project. It is important for your group to remember that you are only required to complete the tasks defined by the spec sheet. This is good to remember when talking to your sponsor, especially if you feel you are being pressured into doing more that you had originally agreed upon. One practice that will help keep the scope of what you need to do is having the spec sheet out, while talking designs with the project sponsor. Keep this in mind when your group is creating your specification and throughout the course of your project. Of course you are free to go above and beyond what is outlined in the spec (tell your sponsor about it though, no surprises!) but remember that you have this valuable tool at your disposal, and use it.

References

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