1. 4th Edition
Chapter 26
Design Step #6:
Manufacturing & Testing

2. What You Will Learn How to interact with people with practical skills
How to evaluate the use of hand tools
Design for Manufacture Assessment
Exploring Engineering

3. Manufacturing
This chapter is the heart of the “Hands-on” section of this text
Engineers often work in front of their computers but to be successful many kinds of engineers also need practical experience
Where can you get help?
Exploring Engineering 3

4. Manufacturing & Testing Strategies
Get Help!
Talk to a machinist. Professional machinists are partners in the design process. What they lack in formal engineering and analysis, they make in manufacturing and practical experience. A practicing engineer will consult with a machinist before finalizing a detailed design.
Don’t delay in getting started. Begin manufacturing immediately. Only then does the team gain a realistic sense of the manufacturing timeline.
Divide up responsibilities so team members work in parallel on different subassemblies. If not the team stands around waiting for the same glue joint to dry.
Exploring Engineering 4

5. Manufacturing
Keep detailed drawings up to date. If they are not up to date, only one person knows what the actual design looks like. That one person ends up doing most of the manufacturing, while the other team members watch. With accurate drawings, team members can work in parallel.
Set and enforce intermediate deadlines. Manufacturing can span several weeks. The instructor sets the big deadlines through the milestones; the teams should set the little ones in between.
Exploring Engineering 5

6. Materials
Exploring Engineering 6

7. Joining Materials
In general engineers don’t use many tools in their jobs but they communicate with those who do. So engineers need to know some “how-to’s”
Exploring Engineering 7

8. Adhesives
Stick it to ‘em …
Exploring Engineering 8

9. Useful Hand Tools
The text describes 15 hand tools for measuring, cutting, drilling, screwing, tightening, hammering, wiring and grabbing. There are lots more.
Hand tools are to machine tools as kites are to airplanes – they both fly but the comparison stops there!
Exploring Engineering 9

10. Design Milestone: Design for Manufacture Assessment 1
Assignment: Make as much progress as possible toward completion of manufacturing and testing of your design.
Grading
Teams should bring their materials and a detailed drawing of their machine to the next design studio. Grading will be based on the amount of progress made.
100 points = Manufacturing is more than 50% completed
80 points = Manufacturing is between 25% and 50% completed
60 points = Some progress made but less than 25%
0 points = No progress
Exploring Engineering 10

11. Design Milestone: Design for Manufacture Assessment 2
Assignment
Get all subfunctions working by the assigned due date.
Performance Test defined by the instructor.
Grading
Team grades are based on the level of functionality demonstrated in the best of three trials and computed as follows:
If manufacturing is 95% completed, then
si = 1 (if the subfunction worked) and si = 0 if not
Exploring Engineering 11

12. Design Milestone: Design for Manufacture Assessment II
More on grading
Grade = Assigned grade on a scale of 100 points
B = Base grade (typically B = 70 points)
Wi = Number of grade points associated with the ith subfunction and defined such that
I =Total number of subfunctions being evaluated
Exploring Engineering 12

13. Manufacturing If manufacturing is less than 95% completed, then
Grade = f B Grade = Assigned grade on a scale of 100 points
B = Same base grade as previously
f = Fraction of manufacturing that was completed
Exploring Engineering 13

14. Design Competition Tips
Team members must work in parallel on different aspects of the design to accelerate progress.
From here on, the design project is a race to begin testing. Teams with the most testing time tend to win competitions.
Exploring Engineering 14

15. Summary
Usually engineers interact with machinists and others with practical skills
Need to know how to evaluate practical skills
Lots of hand tools for specialized purposes
Need to make material selections and decide how to assembly design.
Exploring Engineering 15