Overview of Status of Analysis, Design, Fabrication, Tests, etc.
Completion prototype design - CAD (Peter)
Utilize 3D printer for fabrication
Prepared materials for testing process (Dohwan)
Experiments on stylet trajectory within the tissue material (Maverick)
Accomplishments from Previous Week
Initial design review with client
Prepare testing materials - hypodermic needle, music wire, torsional spring, ballistic gel, 3mm polyethylene sheets, and petri dishes
Finish CAD drawing for the first prototype
Analyze force and entry speed requirement for needle insertion
Goals for Next Week (list names after each item). Use specific and measurable objectives.
Energy analysis for required rotational movement for needle insertion (required velocity and acceleration point?) - (Maverick)
Develope 2nd prototype model with Solidworks (Peter)
Purchase mandrel material and create helical shape needle (Dohwan)
Prepare crock pot and melting procedure for ballistic gel testing (Ryan)
Sponsor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)
Client Meeting (04/20/2017) - Client’s Prototype
Andres has built his own prototype with using a torsional spring from McMaster Carr
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He used 180 deg torsional spring; however, he winded more than 360 deg in demonstration video
The motion was captured in slow motion, and we expect that the real time measurement of movement is very short
3D printed model is very weak
Assuming that skin has 6mm of skin tissue, 6mm polyethene layer testing was successful
Client Meeting (04/20/2017) - Our Prototype Design Review
Kennie wants to see a dial so that different force or depth can be applied and resulted in
Create a “tang” on the next design
Maverick’s concern: the spring may not store enough energy
However, the client did not respond
As soon as our testing works, we can check on this topic
Spring’s distortion while storing energy
Without the base of guiding design, the spring may not deliver the wire in a correct way
Dave thinks that guiding insertion would be a critical design solution
The guiding has been applied on CAD design model
Client Meeting (04/20/2017) - Testing
Suggestion: Fail, Forward, and Fast!
Create the prototype, try it and fail it
Move on to the next phase ASAP
Client Meeting (04/20/2017) - Cannula Availability
Estimated delivery: 05/01/2017
Straight cannula
Short cannula manufacturing is not planned yet
For the proof of concept design process, Kennie will provide one us
Client Meeting (04/20/2017) - Mandrel
Shape of mandrel can be referred based on the client’s design solution (OnShape)
The diameter of the mandrel is artificial
There is no mathematical background for mandrel diameter (“more close to art”)
Client Meeting (04/20/2017) - Upcoming Plan
One or two iterations of actual and physical devices
Operational testing equipment with robust feature
3D printed material is tend to be week
Instructor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)
Instruction Team Meeting (04/17/2017) - Wrong progress report is uploaded
if we meet at week 3, the report should be worked on week 3
Instruction Team Meeting (04/17/2017) - What is the purpose of ballistic gel?
Dave is providing us for testing material
After making a puncture, the ballistic gel can be melted to fill up the hole
Instruction Team Meeting (04/17/2017) - Try not to use the hypodermic tubing
The hollow shape and the wall can be kinked / fatigue during the rotating process
Annealing the material may prevent the fatigue, but it will change the property of material
Instead, try to use stainless steel wire (e.g. music wire, compression springs)
It might be possible to prevent the kinking fatigue from adding water inside the hypodermic tube and freezing it before rotating the tube.
Instruction Team Meeting (04/17/2017) - Mandrel
Doesn't believe Tom can construct the multi-tiered mandrel
Instruction Team Meeting (04/17/2017) - Energy Analysis
If 200 ft/s is desired at puncture, what is the required travel time, travel degree, acceleration experienced by the system?
Friction forces in 3D printed material vs Stainless Steel/Nylon/Teflon, and Plastic used for final product vs Stainless Steel/Nylon/Teflon
Instruction Team Meeting (04/17/2017) - Additional Discussion
Talk to Tom about creating the Bevel Angle, using Music wire to create the stylet
The energy relationship between force and displacement of rotational spring should be linear
Even though there may be non-linear characteristics near x=0 or F=0 points, most of the spring movement should be within the linear range
This topic contradicts with what Kennie and Dave suggested us
Reimbursement form
Go talk to Ian if it is under $250
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
3D printer availability
As many students try to use 3D printers, we are not sure the future availability
3D printed material/resolution
The first prototyped product looks weak
Resolution is not small enough to print out the guiding hole on the bottom of device
Mocking helical shaped needle
28~30G hypodermic needles are available; however, those needles should be rotated
The diameter of mandrel is not set
Different material requires different diameter of mandrel to meet the design diameter
Twisting 0.022 inch diameter music wire about a dowel to simulate stylet and cannula
How do we keep the housing device together as one piece?
Will our device (1st prototype) have enough energy to launch the needle and penetrate the skin?
how to accurately create 30 degree bevel on tip of needle?
Resources or Information Required but not Available
Soft Cannula/spring assembly (will be provided by sponsors by May 1st)
Schedule
Describe upcoming milestone
Testing of Prototype (1st) - 04/28/2017
3D CAD Drawing of Prototype (2nd) - 05/01/2017
Proof of Concept Presentations - 05/01/2017
Update Gantt chart.
Completed
Budget (list amount spent and amount remaining)
Initial: $700.00
Spent: $129.57
Remaining: $570.43
Progress on Report and Webpage
Impact on Society (04/21/2017)
Week 4 Report (04/23/2017)