156B Week 8
Overview of Status of Analysis, Design, Fabrication, Tests, etc.
CAD for the base is being redone
Gear mechanism works
Motors are too weak
A larger budget can be accounted for
Risk reduction testing videos for the gear system and motors were taken
Accomplishments from Previous Week
Build day 3
Friction locking is not working as intended
Gear locking base works
Continuing CAD for rework on base
Goals for Next Week (list names after each item). Use specific and measurable objectives.
Assemble iteration 4 where we are using pins and gears for a locking mechanism
Sponsor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)
Zoom meeting May 21, 2020:
The current assembly has give and does not lock fully, but doctors can work with some leeway displacement
Pin may not be ideal because you have to simultaneously find the right spot for the ultrasound and pin alignment
If pins can we ratchet from one hole to the next easily, so that the provider does not have to search for it
Can use budget for more expensive parts
Can go over 100-200$ over budget
What about keeping the current setup and use a gear and teeth locking over the plastic metal interface?
Instructor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)
Zoom meeting May 14, 2020:
Focus on design
Create a failure and success slide depending on results
Base is basically a vice so make it simple
Answer why did you do this
Think about machining: if you serrated those/stair step, then you will get more gripping (non rotation) which is easy to machine through multiple passes
When sending to shops: decide which corners or edges to be just an edge break instead of a true chamfer to save time and money
90 degree corner and note break all sharp edges
Report names not just week distinctions
Get to the design
Show the design
Why settle on this one
Constructive criticism goes both ways
Comments from Other Students in the Class (indicate date of comments and if via email or in person)
N/A
Risks and Areas of Concern
Too much torque for the motors with current setup
CADing and considering different locking options (gears and pins)
How to improve positioning accuracy
Some parts do not work as intended, so do we have enough time to redesign completely and machine or just keep improving on what we got?
Resources or Information Required but not Available
N/A
Schedule
Weekdays: redesign the CAD
Weekends: build days
End of Week 9: send everything out for machining
Budget (list amount spent and amount remaining)
Amount spent: $468.63
Amount remaining: $531.37
Progress on Report and Webpage
Working on Webpage and Report drafts.
Finish by Friday, May 22