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Centering Magnet Device
P08028
By: Aaron Burger
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Concept Level Project Plan
Project Name
– Magnet Centering Device
Project Number
– P08028
Project Family
– Artificial Organ Engineering
Start Term
– 2007-2
End Term
– 2007-3
Faculty Guide
– Dr. Steven Day (Mechanical Engineering)
Faculty Consultant
– Prof. John Wellin (Mechanical Engineering)
Faculty Consultant
– Dr. Matthew Marshall (Industrial Engineering)
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Confidential Disclosure Agreement
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The LVAD Heart Pump
The LVAD is …
• a device which assists the heart in the circulation of
blood throughout the body
• a pump that is mechanically bearing free, therefore the
longevity is significantly greater than current heart
pumps.
• has a rotor which is levitated and held axially in place by
magnets
• and needs to have the bushings and magnetic fields to
the rotor be concentric to the rotor’s radial position
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Why center the rotor’s components?
• The LVAD heart pump is levitated using magnets
• The positioning of the LVAD’s rotor is done by monitoring
the magnetic field of magnets
• Creating a concentric magnetic field is crucial in the
success of the LVAD heart pump
• Because the magnets are placed on bushings, having
bushings concentric to the diameter is also key in the
success
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Proposed Designed
1. Center the bushings using a laser and sensor which can
map the bushings concentricity and move the materials
accordingly.
2. Place a magnet on the centered bushing, then map the
magnetic field and move magnet accordingly.
3. Process of centering both the magnetic field and bushing
is completely automated.
4. Time of production is lessened.
5. First step in the mass production of the LVAD heart pump
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Current Method of Centering Magnets
Linear Stages
Sensor
Magnet pusher &
magnet
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Hall Effect Magnet & Sensor
Sensor
Hall
Magnet
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Voltage
Sensitivity of HESA on the X-axis
X-axis
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Illustration of a non-concentric magnetic field
y-axis
Magnetic Field
Magnet
x-axis
Sensor
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Pushing the magnet
A force physically
moving the magnet
Sensor
Sensor
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New position with a concentric magnetic field
After the magnet has been
physically moved the magnetic
field is concentric with the sensor
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Current Method of Centering Bushings
Dials which read the
position of the bushing
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Laser Calipers
Laser
Bushing
Sensor
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Laser Caliper cont.
Laser
Sensor
A force to physically move
the bushing
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Laser Caliper cont.
Laser
Sensor
Bushing is concentric with
the diameter
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Risks & Constraints
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Implementing a working LabVIEW program
Machining
Integration of systems (Sensors & Positioning)
Motor Control System
Linear Slides & Stages:
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Backlash
Hysteresis
Accuracy
Uni-Directional Repeatability
Bi-Directional Repeatability
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Staffing Requirements
Mechanical Engineer
1.) Team manager, responsible for organizing the meetings and setting up team with
materials and resources. Documentation of the progress of the project is an essential part
of the manager’s responsibility. In addition to these tasks, the manager will assist others in
their assignments.
2.) The mechanical engineers should be comfortable in the machine shop. Possess
the ability to machine precise parts for the test rig, because a concentricity of 10 microns
is needed. The precision of machining is essential in the success of this project. In
addition to machining, the mechanical engineers input and ideas are important in the
designing of a new centering test rig. Because a test rig already exists, persons with
ingenuity and imagination will help in the designing of a new test rig.
3.) The mechanical engineers need to be comfortable with a computer aided design
software, SolidWorks or AutoCad. As the project progresses, an organized drawing
package needs to be assembled and a bill of materials needs to documented for the
budgetary purposes. As the designing of parts becomes less frequent, the role of these
engineers will be assisting others with various operations for this project such as the
LabVIEW programming, circuitry and machining.
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Staffing Requirements cont.
Electrical Engineers
1.) Having an electrical engineer familiar with motion controls and sensory
positioning is a crucial function for this project. Because controlling the motion
and position of the bushing and magnet through a computer software and
sensors, the electrical engineer needs to control the voltage and current from
these sensors and motion devices to ensure an accurate and repeatable
process. The electrical engineer will provide the wiring necessary to power the
different devices on the test rig.
Industrial Engineer
1.) Implement test procedures to insure that the precision and specs. are met.
The documentation of the process and procedures will provide crucial
information that will help in the success of the project. Statistical analysis
performed by the industrial engineer will provide a design of an experiment
data for the finished test rig and provide a liability analysis on the purchased
parts.
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Week 1
Introduction to the LVAD Heart Pump
– how the heart pump works
– give team reports related to the LVAD project and
current magnet centering device
– have team sign confidential disclosure agreement
• Have team perform a centering test on a magnet
and get a feel for the current test rig
• Benchmark the current test rig
– identify all the parts on the current test rig
– illustrate the problems with the current test rig
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Week 2
Have team members split up into areas of their concerns:
1. Mechanical Engineers – research linear stages and
slides; come up with ways of correcting problems with
them
2. Electrical Engineer – research methods of positioning
and instituting sensors for that purpose. Get familiar with
LabVIEW
3. Industrial Engineer – research ways on organizing
material for test protocols and procedures.
Compile the research at the end of the week and start
designing a magnet centering device.
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Week 3
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Having brainstormed the team member’s reports
and initialized a design of the device, ask certain
professors for their opinions and inputs on the
team’s decisions.
Dr. Day – opinion on test rig design ideas
Dr. Marshall – Statistical Analysis of test and
liability analysis of purchased parts
Prof. Wellin – LabVIEW Programming
Machine Shop for machining advice
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Resources Needed
• Computer with programming capabilities, i.e.
LabView, SolidWorks, AutoCad, Cadence etc.
• Area for designing and building of test rig
• Machine shop equipment and supplies
• Measuring instruments
• Motor controls, linear slides, laser calipers or laser
positioning devices
• More will be added as time progresses
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