Talk:Cordless drill

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First Report

We received your report on the cordless drill and were impressed with your work. It is clear that you looked deeply into some areas, although the documentation of product functionality was not sufficient for us to fully understand how the drill functions. The text you provided in section 4.2 was helpful, but it was difficult to relate this to your BOM. A picture of the assembly with labeled components would be a big help. We were unable to tell, for example, how the heat sink attaches to the motor or how the clutch break works – much of the internal functionality is still a mystery to us. A diagram or labeled assembly would be a big help here. Your analyses results are interesting, and we appreciate your initial ideas for improvement. Detailed comments follow:

  • Your identification of environmental factors affecting use is interesting. We see this as one possible area of opportunity. For example, you identified limitations for use in wet spaces – is this a need that our customers might have?
  • The need for “decent hand strength” is an important opportunity. We designed the second handle into the drill specifically to address this issue. Is there anything we can do to improve here and broaden our market appeal? You identified some opportunities for addressing users with special needs. If you choose to go this direction, make sure you involve some representative users in the process. Your opportunity of difficulty working in tight spaces is interesting – this could be a useful road to pursue.
  • Your analysis mentions the “transfer speed to power”. I’m not a mechanical engineer, but I thought that power = torque times speed. I’m not sure what you mean here.
  • We found some incomplete sections of the report: You left the text “[Insert more extensive introduction to product dissection here]”, and some photos on the BOM were not available. Was the report you submitted complete?
  • We are surprised that you couldn’t find more DFMA opportunities for improvement since there are quite a few parts; although the commonization of fasteners is something we can look into. You didn’t talk about assembly much – mostly your dissection experience – might there be some opportunities here?
  • You discuss the clutch break, but I don’t see it in your parts list. What is it – how does it work?
  • Your FMEA analysis is interesting, but which recommended actions should we pursue, and how? For example, how might we “redesign brake for longer life”?
  • One major DFE concern of ours is that customers want to have the drill ready to use when needed. As a result they either leave the battery on the charger at all times, which wastes energy, or they find that sometimes the battery has an insufficient state of charge at the time they plan to use the product, and the customer is dissatisfied. What can we do here?
  • Also, please include a free body diagram and mechanical analysis to help us understand the product more quantitatively: Either a mechanical analysis of the forces a user places on the drill during use for an ergonomic study or an analysis of the gear reductions on speed and torque input/output, depending on which is more appropriate for your analysis.

Additional Comments

It might be useful if the preface to the parts list had a bit more information about the overall characteristics of the parts. There appears to be a contradiction between the manufacturing section of the Executive summary as compared to the DFE with respect to the different number of screws, and the manner in which they can be consolidated.

Letter of Response

Dear Cordless Drill Executives,
Thank you for your comments on our preliminary report. We found them extremely helpful and implemented them in our current report and presentation. Through extensive market research and product analysis we have been able to identify key areas for improvement and generate some ideas for how to address these areas. The contents of this letter will outline where you can find the answers to your questions in our report.

We apologize for the minor glitches there was a slight oversight in the final editing of our report. The exclusion of the photos of minor parts was done purposely because we felt they were not necessary for understanding how the cordless drill works. However these have since been added because in order to have a thorough understanding of the cordless drill pictures of all parts are necessary. These can be found in Section 5 in addition to an exploded view to help identify where the different parts our located in the cordless drill. Moreover, part numbers are referenced throughout the paper to make it more clear what we are discussing.

We elaborated on the information concerning special use situations in water/inclement and an explanation about the need for decent hand strength can be found under the subheading Different Users / Use Scenarios in section 4.4. The rhetoric concerning torque and power in section 4.2 has been adjusted for accuracy. We expanded our summary of our DFMA analysis in section 6 and we clarified the purpose of our results from our FMEA analysis in section 7. We discussed opportunities for battery use improvement in terms of DFE in section 8. Finally we have included a Free Body Diagram and analysis in our product description part of our report (Section 4.2).

We hope you find our analysis and suggestions useful in uncovering different avenues for improving your product. Moreover, we hope our addendums clear up any vagueness or discontinuities in our original report. If you have any more questions feel free to contact us.

The Cordless Drill Think Tank
Ming Huo Mark Rockwell
Scott Miller Vishesh Nandedkar


We received your response to our comments on the first report, and you have generally addressed our concerns. We would have liked to have seen some estimates of forces in order to study the degree and type of forces on the user as well as the effect of the battery pack on balance. See if such an analysis would be relevant to your redesign concept, depending on which direction you go.

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