156B Week 4

Overview of Status of Analysis, Design, Fabrication, Tests, etc.

Accomplishments from Previous Week

• • 3D Printed the following parts for testing

    • New take-up spool

    • Guiding arm (to attach to servo)

    • Peeling mechanism (to attach to servo)

  • Tests Conducted:

    • Test with feeding mechanism using Nafion tubing as friction material.

      • Outcome:

        • Worked well, and required minimal force to peel and spool Nafion

    • Spooling Guide:

      • Using a 3D printed guide, and a servo motor, the effectiveness of guiding the Nafion on the take-up spool was conducted

      • Outcome:

        • Worked very well with 3D printed material, since PP has less friction, should work fine in final implementation

    • "Slapping Mechanism" with stepper motor

      • Using a 3D printed slapping mechanism, and a servo motor, the motor was driven +- 30 degrees to peel Nafion

      • Outcome:

        • Did not work very well:

          • Very inconsistent peeling

          • Stepper rotated, most likely as a result of not outputting enough torque

            • This maybe a current issue

    • Length Tracking

      • Using a DC geared motor with encoders attached to the second spool, 5 ft was spooled and measured with both a ruler and according to encoder counts.

      • Outcomes:

        • Able to produce 5 ft + 2 in, which included accounting for spooling of the Nafion on itself causing an increase in the effective radius of the second spool

        • Too much tension may cause additional errors in length tracking

        • 2 inches over 5 ft extrapolated to 64 in or (5 ft 4 in), which is over the required constraint.

          • However, this was preliminary and not very well setup, gave us upper bound and knowledge that second spool should be fine to track the length.

    • Iman designed the take-up spool, and looked into ordering more PP

    • Purchased DC geared motor, motor driver, shafts, couplers, and hubs for testing.

Goals for Next Week (list names after each item). Use specific and measurable objectives.

• • Preliminary Draft of Report:

    • Iman: Project Description/Description of Final Design Solution

    • Anthony: Prototype Performance/Design Recommendations and Conclusions

    • Jhon: Design of Key Components/Description of Final Design Solution

    • Patrick: Prototype Performance/Design Recommendations and Conclusions

    • Team: All other sections

  • Design and manufacture of second PP spool (Iman)

  • Test servo for guide and for peeling mechanism (slapper) (Anthony and Patrick)

  • Discussion on moving forward with feeder or slapper mechanism.

    • This includes discussion with sponsor on use of friction materials, either Nafion or possibly Nitrile??

  • Further CAD development of sub components for testing and fabrication (Jhon)

  • Finalize decision on peeling mechanism (Team)

  • Look into tensioning device if "slapper" mechanism is moved forward

Sponsor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)

• • Sponsor was okay with current progress, and will schedule meeting at workstation soon.

Instructor Comments from Last Meeting and Actions Taken to Address these Comments  (indicate date of comments and if via email or in person)

• • Instructor mentioned using Nafion as friction material in friction drive.

    • Tested this, and seemed to work very well. Will discuss with instructor further, as well as sponsor.

Comments from Other Students in the Class (indicate date of comments and if via email or in person)

• • Students mentioned in feedback that length tracking was not addressed.

    • Began preliminary tests with encoders on DC motor, and was able to produce adequate results.

      • See above of outcomes from this week.

Risks and Areas of Concern

• • Peeling mechanism is still the highest risk area

    • Since peeling needs to be decoupled, must make final design decision soon

Resources or Information Required but not Available

• • N/A

Schedule

• • Gannt chart updated and current

Budget (list amount spent and amount remaining)

• • Purchases this week:

    • DC Motor: $60.95

    • Coupler: $7.49

    • Hub: $ 13.99

    • Collar: $4.64

    • Solenoid: $19.99

    • Motor Driver: $20.44

    • Total: $127.50

  • Total Budget Remaining:

    • Budget: $1800

    • Remaining: $1596.50

Progress on Report and Webpage

• • Updated current progress report and began outline of front page in preparation for deadline next Friday at midnight.