ME 491: Notes

Supplemental Notes

This page provides links to supplemental notes for in-class lecture. The notes are listed here so that it will be easier to find by topic, than by digging through lectures sequentially.. Click on the note heading or the "Continue ..." link to get the full content for the lecture.

Big Ideas in Engineering and Product Design

The big ideas in design are themes that connect the skills and knowledge we seek to develop in the Capstone course sequence. The big ideas are:

Engineering design is only one aspect of design
Design requires creativity
Design is iterative, messy and accepts multiple solutions
Design requires a clear understanding of your client's needs
Design requires teamwork and planning
The design process cannot be reduced to a foolproof recipe
Standards are very important

Some of the big ideas, like design requires creativity and design requires teamwork and planning, are superficially obvious. However, putting these ideas into practice requires skills and understanding that are not taught in many engineering courses. Experienced engineers know that non-technical skills and knowledge can be equally or even more important than engineering analysis when solving practical problems.

The big ideas are motivation for the learning activities in the Capstone course sequence. If you find yourself asking, "Why are we doing this?", check in on the list of big ideas. If the connection is not obvious, ask me.

Bill of Materials

A Bill of Materials (BOM) lists the components, sources for the components, and costs of components in a device or a sub-assembly of a device. Items in a BOM will include fasteners, fittings, mechanical components, entire assemblies and electrical parts that are purchased from vendors. A BOM can also include raw materials used to fabricate the device or sub-assembly. The raw material specification would be especially important if particular material properties are required for a part.

Brainstorming and Its Variations

Brainstorming is a technique used by a group to generate ideas without evaluating those ideas. Brainstorming is relatively simple to do, and can be fun. However, there is a fair amount of research literature that suggests that both the quality and quantity of ideas created by group brainstorming is less than the quality and quantity of ideas created by having the individuals in the group work alone. See below.

In addition to the notes presented here, refer to the Brainstorming section in Part II of the textbook by Mattson and Sorenson. (pp. 200-201 in the 4th edition).

Creativity

Engineers are urged to be innovative. Innovation requires creativity. How do you define creativity? What can you do to increase your creative ability?

Design As Learning

If we think of design as a learning process, we orient our thinking toward curiosity, discovery, and development of mastery.

Design Process

Design is the intentional arrangement of artifacts or ideas or processes in order to have a desired effect. We all practice design.

Engineering design is the application of design to problems that require training in one of the many fields of engineering. Although engineers can work in isolation on problems of limited scope, most engineering design work involves teams of people. Often those teams consist of people with training in different engineering disciplines and in related disciplines such as industrial design, manufacturing, and business.

Engineering design usually involves complex devices and processes and often requires a large investment in time and resources. Because of the cost and societal (environmental, economic, cultural) impact of engineering, the engineering design process has been studied and organized into several explicit procedures.

Functional Decomposition

Functional decomposition is a technique for dividing a larger task into smaller tasks. During decomposition, the team focuses on the inputs and outputs of each task and uses generic descriptions of the process achieved by the task. The decomposition process is usually applied recursively until the design team can readily envision ways of achieving each of the sub-tasks. Functional decomposition is also called functional analysis, top-down design, or logical decomposition.

Functional decomposition can be applied to many engineering tasks. For our purposes, i.e. in ME 491-493, we use functional decomposition as a tool in the conceptual design phase. During conceptual design, the team uses functional decomposition to explore solutions to a given problem without overly constraining the choices for implementing those solutions. That is consistent with the "conceptual" part of Concept Design. Implementation details are workout out in the Subsystem Engineering phase (to use the terminology of Mattson and Sorenson).

A functional decomposition for a design goal is linked to a specific design concept. One should not expect one-and-only-one functional decomposition for a given objective. Since the design team will need to choose among competing conceptual designs, the team should expect to develop more than one functional decomposition. For example, consider the task of making coffee. Different functional decompositions would be needed to describe the a drip coffee maker, an espresso machine, or a machine that dispenses coffee made from "instant" powdered coffee.

Also remember that design will require iteration and refinement as the team's knowledge improves as the design evolves. Therefore, initial attempts at functional decomposition will likely need to be revised or even discarded altogether. The goal is greater understanding, not checking a box in some recipe for the design process.

Sections

The Basic Idea
Separating Function from Implementation
Example: Automated Pencil Sharpener – Version 1
Flow of Material, Energy and Information
Use Verb-Noun pairs to define functions
Example: Automated Pencil Sharpener – Version 2

Meeting with Sponsors

When you interact with project sponsors please pay attention to the following.

First and foremost, remember that you are representing PSU and the MME Department, as well as yourself. It is not too hard to leave a good impression. It can be very hard to recover from a bad impression.

Controlling DC Motors

Knowing how to control a simple DC motors will help you complete your lifting device for the design competition. This web page will point you toward resources that will help you power the motors in your printer kits.

Other resources

TB6612 breakout product page at Adafruit
TB6612 hook-up guide
Slides showing a Demo apparatus made with a repurposed inkjet printer

TB6612 Wiring and Usage Guide

This page provides information on hooking up a TB6612 breakout board from Adafruit, Sparkfun or Pololu.

Motor Pong on a Hacked Printer

A hacked inkjet printer is used to demonstrate electromechanical control of small DC motors. The system responds to limit switches and uses a TB6612 breakout board to drive the printer's motors. The electrical circuit and software is implemented with an Arduino UNO microcontroller.

To follow along on this example you probably want to download these files:

motor_pong.ino Arduino program that uses the MME Motor Library
MMEmotor library (zip archive) provides an object-oriented interface to the TB6612 breakout board. Refer to the Arduino documentation for instructions on installing a library.
Our local TB6612 wiring guide

Project Planning

Project planning and project management are important supporting processes in engineering design. The textbook by Mattson and Sorenson does not cover project management explicitly, though the ideas of teamwork, coordination of effort, analysis of dependencies (design networks in the textbook) are discussed throughout the book. This web page summarizes ideas about project planning and management to supplement the textbook.

Prototyping

Refer to the section on Prototyping in the Product Development Reference of the textbook by Mattson and Sorenson, who write

Prototyping is the act of physically constructing an approximation of a product or part of a product

also refer to the local resources listed on this page.

Requirements matrix

The purpose of the requirements matrix is to identify the links between the market requirements and performance measures. Market requirements describe the features that will make the design desirable. Performance measures guide the engineering decisions used to make the design real (tangible).

Refer to the Requirements matrix section in part 2 of the textbook.

Concept Screening and Scoring

After after generating ideas, use a variety of tools to analyze and filter the ideas to end up with those worth pursuing in more detail. These techniques can be applied iteratively as new ideas emerge or as existing ideas are refined.

Software for Teams

There are many software tools to aid in the design process. For the sake of exposition, we can organize these tools into categories

Engineering Analysis
Designing and Manufacturing Parts
Business Analysis and Project Management
Collaboration tools

Teamwork

Teamwork skills are important in engineering, business and life.

On your projects, teamwork is important in the allocation and coordination of tasks. Your team will also need to make decisions that, sooner or later, will require you to figure out how to resolve differences of opinion.