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Client Comments on Report

We received your report. Your summary suggests that your findings are only (1) that the DFA has no room for improvement, and (2) that disassembly can be improved (but how specifically?). Are these the only significant findings?

Specific comments follow:

• You include significant discussion on general relationships with our suppliers or shop practices such as stocking backup tooling. This is not necessary - suppliers need only meet our specs and would not be subject to product liability if they fulfill their specs. We would like you to focus on your product. The stakeholder needs more specific to the product itself are more critical, and here you seem to be missing some important ones: safety, durability / life, stable, flexible mounting, flexible lighting, does not damage surfaces, etc. Please revise to focus on specifics for this product, and please provide a bullet list of needs for the customer and other significant stakeholders with specific needs.
• Please provide a picture or diagram to support understanding of your system function descriptions.
  • Images have been added in the Function section.
• In the mechanical analysis, you suggest that there is a "balance between how robust the joints are and the weight they can support". What do you mean?
  • The mechanical analysis has been edited to further explain this statement.
• You state that your mechanical analysis will "show what the optimal material combination is". Where is this determined?
  • This is a remnant from a previous assumption that the plates used in the joints were made of metal in the base and plastic in the top. The statement has been removed.
• Your mechanical analysis does not appear to examine a worst-case scenario. Why do you think the case you tested is most relevant?
  • We were not testing so called 'worst-case scenarios' but rather the supportive moment supplied by the joint. For this reason, there are no real worst case scenarios. I the next design, we will make the lamp with stops on it such that the user may only move the lamp into what we will call 'stable' positions where the moment supplied by static friction is great enough to hold the payload in place.
• Your component list lacks introductory text. What are the findings?
• We are surprised that so many of the parts, particularly the fasteners, are made from aluminum because it is quite soft. How do you know this is the material. Similarly, why is the spring brass rather than spring steel?
• You mention that "DFM optimizes the manufacturing of a product". We understand DFM to be about optimizing a product for manufacturability, quite a different thing. Please comment.
  • We admit that our wording was confusing and perhaps misleading. It has been rewording.
• What is "DSA"?
  • A careless error on our part, it should be "DFA".
• You suggest that the lamp materials have very little value at end of life; however, aluminum does have value and can be sold for recycling.
  • A good point. However, it is painted which makes it much harder to recycle.
• The sector you identified for EIOLCA seems to be representative of manufacturing; however you didn't examine the use phase. Is the manufacturing phase significant compared to use?
  • The use does in fact consume more energy and cause the emitance of more MTCO2. However, there is little Initech can do to control which light bulbs the users chose to put in the lamp.
• You suggest that the best ways to reduce GHGs is redesigning manufacturing or trucking processes, but these are outside of our control. What are the aspects of the product itself that contribute to these (e.g.: more operations required? more space required in trucking?)?
  • Those have been added.
• Your FMEA suggests that the friction knob is the most critical failure mode. What suggestions do you have for improvement?
  • On reconsideration, we left out a much more critical failure mode: that of the base disconnecting to the lamp as a whole. Suggestions for improving this have been added.

We look forward to seeing your research results and new ideas in the next report.

Client comments on the Mechanical Analysis

The mechanical analysis provides useful information for the weight support in the lamp linkage. My few comments are:

• If the torque tests were done when the lamp set was in vertical, the joints would be preloaded due to component weights. On the other hand, if the tests were performed when the lamp set was laid horizontally on desktop, then there would be no preload. Therefore please indicate how the tests have been done in the assumptions.
  • The additional moments due to loads were subtracted out. This has been noted in the assumptions at the beginning of the analysis.
• Since the analysis shows that the arm linkage is able to carry a maximum weight of 1.5 lb, I would like to know the design safety factor based on the current lamp weight. Also, if a user decides to replace the traditional bulb with a compact fluorescent bulb (heavier) for energy saving, how the design factor will be changed?
  • The measurements were all taken without the bulb as a payload and the weight of the light bulbs are unknown. Also, calculating an actual ‘safety factor’ for the lamp is nearly impossible as it changes with position of the lamp and is dependant on the coefficient of dynamic friction which was not calculated in this experiment and is additionally very difficult to calculated. If a user were to attempt to use a compact fluorescent bulb in this lamp and extend it to an awkward position, it would slowly descend and the user would readjust it to a stable position where the effective torque arm on both joints is short enough that the supporting moment is able to hold the light in the given position.
• I would like to see more conclusion in the end of the analysis. For example, please express how you think about the design - are the joints over-designed?
  • The conclusion has been properly adjusted to explain more of what was learned. Note that though they were not over designed for the given application, the are under designed for what we hope to use them for.