Engineering Problems

Question 1

Failures of the Beer can

Answer 1

→ However, ballooning was a problem for the can, especially when shipping
→ The solution to this is the “inwardly dished bottom”
→ A way had to be found to open the can
→ This was first dealt with using church key openers, however it was inconvenient to carry around
→ Pop tops were the next solution, however people would just take them off and throw them on the floor
→ Pop tops only work with the correct depth of scoring of the can. Too deep weakens the can, too shallow makes it hard to open.
→ The final solution was the non-detachable pop top, which shows there was lots of room here for trial and error leading to incremental improvement
→ Another problem is the fact that, to minimize the manufacturing cost and the price to the beverage companies buying the cans there is an interest in minimizing the amount of aluminum used in a can. This objective has to be pursued without increasing the risk of can failure.
→ They tried fluting the sides of the can, but it was rejected by consumers
→ Final solution for accomplishing this was the tapered top

Question 2

The Paper Clip

Answer 2

→ The key to paper clips is the springiness of the metal from which they’re made
→ Before the invention of the paper clip other objects were used to hold paper together - for example, clothespin-like objects, as well as pins, the use of which was also made possible by springiness.
→ There would have been no reasons to move from pins to wire paper clips had there not been relative disadvantages in using pins. These were:
→ It was hard to put a pin through more than a few sheets of paper
→ The pin leaves holes in the paper
→ Pricked fingers are likely
→ The thickening of the papers pinned together at a corner complicates the stacking of pinned-together paper.
→ When paperclips were introduced to the market, they weren’t widely used because they were too expensive
→ No infrastructure to build them
→ Paperclips weren’t patented because it involves divulging information to competitors
→ You need to justify your patent
→ The firm who had the most dominant design (The Gem) chose to patent the machine that made paperclips as opposed to the paperclip itself
→ Without a machine to reduce manufacturing costs the paper clip could not have outcompeted pins

Question 3

Problems with the Comet

Answer 3

→ Investigation showed that changes in pressure caused metal fatigue was the source of the problem
→ Comet engineers wrongly assumed that because the number of aircraft take-offs and landings is rather modest (compared to cycles of use of factory machinery) metal fatigue would not be a problem
→ However Jet aircraft were subdued to extreme conditions, which changes the circumstances
Jet aircraft also consumed lots of fuel, and there is a strong incentive to minimized fuel consumption. This can be accomplished by flying high, where there is less resistance. But flying high requires cabin pressurization and, consequently, variability in the external pressure on the fuselage around the cabin. It was these shifts in the external/internal pressure balance of the cabin that caused the metal fatigue.

Question 4

Differences in the design processes of the 747 and 777

Answer 4

747:
→ Groups of engineers worked individually or in teams to design parts and subsystems, however the parts wouldn’t always fit together
→ This created a dependence on physical mock-ups, which was very expensive
→ At the point of assembly, many parts didn’t quite fit, requiring shims, however they added a lot of extra weight
777:
→ CATIA: Computer Aided Three-Dimensional Interactive Application
→ However it required a very large amount of computer power

	→ The Clash program produced a red flashing light when separate designs produced ‘interferences’. 
	→ CATIA-man: Avatar that tells you if there is enough space for workers to continue manufacturing with existing design
		→ They created CATIA-man to detect manufacturing problems The result was very successful, the need for shims in manufacture was greatly reduced

Question 5

Lessons from these cases

Answer 5

1. Improving productivity requires addressing the fundamental engineering problem of failure
   → Sometimes failure happens after the product is developed and put to use (the Comet, the environmental failure associated with detachable pop tops)
   
   2. Development costs for some products can be very high indeed. There are incentives to find economies in the design process.
   3. Intellectual property (patents) are sometimes an important part of the innovation process, however what is patented is a matter of commercial strategy.
   4. Sometimes innovators decide not to patent in order to keep inventions secret. it may be better to secure first mover advantages while not disclosing the information to potential competitors that patent registration necessarily involves.
   5. Regulatory threat can provide an incentive to innovation
   6. Large savings in the cost of manufacturing (which mean productivity increases) can be produced through small reductions in the amount of materials used in each item produced.