From DDL Wiki

Revision as of 23:23, 5 October 2009

Client Comments on Report 1

We received your report, and we have some comments and questions. Some sections appear to be incomplete, and the missing executive summary makes your big-picture conclusions and recommendations difficult to assess. Please respond point by point to the items below. We are looking forward to seeing your ideas in Report 2.

• Executive Summary: Missing - please provide.
• Stakeholder Needs: Good identification of stakeholders and nice list. Please list out needs as a bullet list - for example, if "easy to integrate into design" and "flexible" are different needs, list them as such - each need is of the type "the product should..." - listing this way will help with next phases. It seems that there are quite a few missing needs like reliability, resistance to wear, corrosion, dirt, avoidance of pinch points or grease to contact driver, gear ratio to provide low enough force on driver and also avoid need for large angles of motion and switching hands while turning, low weight, low cost, etc.
• Use: Clear description. For phase 2 you should observe the car being driven by members not on your team, and interview them.
• Assembly: Clear diagram, but it is not clear how the extensions are secured to the rack. An exploded view would help.
• Mechanical Function: Clear. A picture of the tie rod connection with the wheel suspension would be helpful. What component provides the stop if the user attempts to turn the wheel too far, and how is the rack mounted to the frame?
• Mechanical Analysis: You seem to be doing two useful analyses but please explain further what design implications they have and what you can conclude from your analyses.
  • On your graph, please label both of the axes, make the text larger for readability, and instead of having a legend you could provide a figure caption that explains what we are looking at, since there is only one line.
  • How do you interpret this graph? The relationship looks essentially linear, but you mention that it is nonlinear in what might be an important way - is the nonlinearity significant?
  • In your second analysis, please provide a clearer free body diagram. It is somewhat ambiguous how the parts that you have drawn fit together, and whether some of the drawings are the same part shown from different angles. You might be able to clarify by showing an exploded view of the assembly and/or orthographic projections of one or more of the parts, but please label clearly which part is which in the drawing(s). Also, please show the equations you are using and define your notation before plugging in the numbers. What is your conclusion from this analysis?
• Bill of Materials: Good list. Why is a steel pinion matched with an aluminum rack? It is okay that a few sub-assemblies were not fully dissected to avoid destruction, but please identify every individual component in your bill of materials (how many bushings in sub assembly 001, and are they all identical? What material and manufacturing process, and what assembly process? Is the rear pinion bushing identical to the front?)
• DFMA: Good observations - since this product is manufactured at low volume, optimizing the process, particularly assembly, is less critical.
• FMEA: The FMEA appears to be only a table. What are your conclusions and recommendations? What are the failure modes associated with the increased slop in the system that you noted in the user study?
• DFE: Nice analysis breaking down production into components. How did you estimate the cost of each grouping? The assessment of difference between primary and secondary aluminum is insightful, since this is the largest impact. However, you didn't comment on the implication of a CO2 tax. Also, use phase emissions would include those associated with additional gasoline consumption to carry the weight. While this may dominate production emissions for mass produced vehicles driven daily, it is likely small in your application, but you should state this assumption. Please replace your figure number placeholders with actual numbers.
• If any of your images, figures, or text were taken from another source, please be certain to provide proper attribution.

Response To Client Comments

• The Executive Summary has been added per request