Overview of Status of Analysis, Design, Fabrication, Tests, etc.
Energy Analysis with force and vector diagram for design verification
Conduct Design Proposal Presentation and basic design review from client
Work on detailed prototype design process to prepare 3D modelling
Order components to fabricate prototype and test the mechanicsm
Accomplishments from Previous Week
Successfully modeled CAD of all concepts and prototypes
Completed energy analysis including force and vector diagram
Learned/got used to using Onshape, Solidworks is still preferred
Established a meeting time that works for all team members with client
Goals for Next Week (list names after each item). Use specific and measurable objectives.
Order and receive components (hypodermic tubing and torsional spring) to build the prototype (Dohwan)
Order and receive testing components for the testing process (Dohwan)
Work on detailed prototype design process to prepare 3D modelling (Housing Case - Peter, Mandrel - Maverick)
Organize timeslot to use 3D printer (Ryan)
Fill out form to get reimbursement of our purchases: torsional springs and hypodermic needles (Peter)
Create 30 degree bevel on hypodermic needle to create a cutting edge (Ryan)
Sponsor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)
(via teleconference 4/6/17) Need to figure out how to translate 3 N of linear force into a curved needle. Need to use torque analysis with a moment arm.
(via teleconference 4/6/17) Create a drawing of all forces and their corresponding vectors by next week
(via teleconference 4/6/17) Warned to consider friction forces. We will create a 3D printed model and analyze the force needed to overcome friction forces
(via teleconference 4/6/17) Prevent needle from auto firing if dropped. We will need to implement some soft of stopper in our design
(via teleconference 4/6/17) Suggested to order hypodermic, hollow tubing wire to simulate helical shaped needle until Capillary has a model ready for us.
(4/13/17-conference call): 30 degree directional block on the bottom part of our housing device needs to machined in such a way such that the needle will not get stuck within directional block
action taken: will create fillets at the edge and a slightly larger entry point to allow the needle to enter the directional block and enter the body at a 30 degree angle
(4/13/17-conference call): Why did we choose a 30 degree bevel?
action taken: Response: based off research paper, the optimal insertion force that can cut and penetrate skin occurs at 30 degrees.
(4/13/17-conference call): Look into 3D printing and how to reserve a printer, it may get busy.
action taken: Will ask Chris for information on how do we reserve a 3D printer for our housing device and possibly mandrel
(4/13/17-conference call): Make the mandrel smaller than our planned diameter for the hypodermic needle
action taken: Adjusted CAD model to comply with sponsor suggestion
(4/13/17-conference call): Attempt to make the insertion speed up to 200 ft/sec to minimize patient pain
action taken: Get correct torsional spring that can launch at that speed when released.
Instructor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)
(via in person 4/5/17) Told to get a helicon shaped needle as soon as possible to allow us to perform some actual testing. Ordered hypodermic hollow wire.
(via in person 4/5/17) Told to get fake tissue to allow us to perform some actual testing. Ordered zip lock bags and a mason jar. Will order ballistic tissue in the future for more in depth testing.
(via in person 4/5/17) Talk to Tom about how to fabricate needle tip to find what is and what is not possible. Talked to Tom on Monday.
(4/10/17-in person) Do not use a word “cheap” as it contains negative meaning
(4/10/17-in person) Consider compression spring / piano wires to replace the hypodermic tubing
(4/10/17-in person) Are the penetration graph is done by Dohwan?
Answer: All the graph is based on X. Bao’s research paper
(4/10/17-in person) Energy Balance equation may not represent the required force
Comments from Other Students in the Class (indicate date of comments and if via email or in person)
(4/10/17-in person): How do we plan to lower the needle into the body by just rotating the top cover?
(4/10/17-in person): What are bevels and what purpose do they serve? (Multiple bevels v. just a single bevel)
Risks and Areas of Concern
Which type of spring will provide the greatest penetration force?
Answer: Torsional Spring
How much will friction forces affect the force of the helicon shaped needle
How do we prevent the needle from accidentally firing if device is dropped?
How will our testing go without the 3D printed housing?
How can we prevent needle from getting stuck in directional block at the bottom of the housing device?
Do we have machine or 3D print the Mandrel
Resources or Information Required but not Available
3D printer availability
ballistic gel from Dave
Schedule
Describe upcoming milestone
Receiving components (04/17)
CAD completion (04/21)
Prototyping & testing completion (04/28)
Update Gantt chart.
Budget (list amount spent and amount remaining)
Initial amount: $700.00
amount spent: $116.09
budget remaining: $583.91
Progress on Report and Webpage
Updated on 04/16/2017