micro-clamps for biomechanical testing.

spring. 2018

Swanson School of Engineering Mechanical Engineering Senior Design Project

problem statement

2.7 million people in the US & 60.5 million people globally are affected by glaucoma. glaucoma is a condition of increased pressure in the eyeball due to insufficient fluid drainage, causing gradual loss of eyesight.

studies of glaucomatous eyes have identified lamina cribrosa abnormalities, but the exact relationship between between lamina cribrosa defects and glaucomatous neural damage are not fully understood. no studies had previously been conducted on the mechanical properties of the collagen fibers within the eye that are most affected by this increase in pressure.

design goals

in response to seeing that no previous studies had been conducted, the UPMC laboratory of ocular biomechanics at the UPMC eye and ear institute focused their efforts on thus groundbreaking research.

the lab tasked our team with updating the design of a micro-clamp used for within a tensile testing device for testing of lamina cribrosa samples

design requirements

the original design allowed the samples to slip too much, caused glare in the final image, took 30 minutes to load, and could not hold 16µm samples

design process

design 1

sufficient clamping

force

decrease loading time

reduce glare

hold a 16µm

sample

singular screws caused a moment on the opposite end of the clamp preventing sufficient clamping force and causing slippage

slippage on right side of image

design 2

sufficient clamping

force

decrease loading time

reduce glare

hold a 16µm

sample

design 3

focused force on end of clamp

sufficient clamping

force

decrease loading time

reduce glare

hold a 16µm

sample

updated loading process

cut sample

place the top plates on sample

evenly screw down t-bar

wet with PBX

unfold l.c. and position b/w plates

place in a PBX bath under microscope

-5 min

-10 min

scrape sample

off slide

place sample on bottom plates

perform tensile test

deliverables

more effective design

50% more efficient loading process

higher quality final images

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Benji

micro-clamps for biomechanical testing.

problem statement

2.7 million people in the US & 60.5 million people globally are affected by glaucoma. glaucoma is a condition of increased pressure in the eyeball due to insufficient fluid drainage, causing gradual loss of eyesight.

design goals

in response to seeing that no previous studies had been conducted, the UPMC laboratory of ocular biomechanics at the UPMC eye and ear institute focused their efforts on thus groundbreaking research.

​

the lab tasked our team with updating the design of a micro-clamp used for within a tensile testing device for testing of lamina cribrosa samples

design requirements

the original design allowed the samples to slip too much, caused glare in the final image, took 30 minutes to load, and could not hold 16µm samples

design process

design 1

sufficient clamping

force

decrease loading time

reduce glare

hold a 16µm

sample

singular screws caused a moment on the opposite end of the clamp preventing sufficient clamping force and causing slippage

slippage on right side of image

design 2

sufficient clamping

force

decrease loading time

reduce glare

hold a 16µm

sample

design 3

focused force on end of clamp

sufficient clamping

force

decrease loading time

reduce glare

hold a 16µm

sample

updated loading process

cut sample

place the top plates on sample

evenly screw down t-bar

wet with PBX

unfold l.c. and position b/w plates

place in a PBX bath under microscope

-5 min

-10 min

scrape sample

off slide

place sample on bottom plates

perform tensile test

deliverables

more effective design

50% more efficient loading process

higher quality final images