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<title>Rheoprinter-Cover</title>
<h2>Table of Contents</h2>
<p><a href="#TC1"><h3>1. Background</h3> </a></p>
<p><a href="#TC1.1"><h4>1.1 Motivation & Initial Project Idea: "A Desktop Rheometer?"</h4> </a></p>
<p><a href="#TC1.2"><h4>1.2 The Science of Rheology</h4> </a></p>
<p><a href="#TC1.3"><h4>1.3 Rheometers - Operating Principles</h4> </a></p>
<p><a href="#TC1.4"><h4>1.4 Neil: "Do you actually need classical rheometry to achieve what you want?"</h4> </a></p>
<p><a href="#TC2"><h3>2. Proposed System: "The Rheoprinter"</h3></a></p>
<p><a href="#TC2.1"><h4>2.1 The Nelder-Mead Algorithm</h4> </a></p>
<p><a href="#TC4"><h3>4. Rapid Prototyping</h3></a></p>
<p><a href="#TC4.1"><h4>4.1 System Modules</h4> </a></p>
<p><a href="#TC4.2"><h4>4.2 Final System</h4> </a></p>
<p><a href="#TC5"><h3>5. Test</h3></a></p>
<p><a href="#TC5.1"><h4>5.1 Online Rheoprinter Console</h4></a></p>
<p><a href="#TC5.1"><h4>5.2 Challenges & Next Steps</h4></a></p>
<hr>
<h3 id="TC1"> 1. Background</h3>
<h4 id="TC1.1"> 1.1 Motivation & Initial Project Idea: "A Desktop Rheometer?"</h4>
<p class="lead text-justify"> In this project we aim to build a system that "learns" optimum printability conditions on the fly for materials that are primarily utilized in additive manufacturing (AM). The micro-extrusion system measures printability using computer vision and searches for optimum machine parameters using optimization algorithms. Both tasks are happening real-time allowing the system to be both a measurement and a printing device in parallel. With this strategy, we introduce "printability" as an emergent material property that can be efficiently measured and not derived through time-consuming and trial & error parametric studies following classical rheological measurements. Such systems could potentially accelerate the development of novel materials for a wide range of applications.</p>
<ul class="list-group lead text-center">
<li class="list-group-item">Material Measurements for the Masses</li>
<li class="list-group-item">Understanding the Rheology of Complex Fluids</li>
</ul>
<br>
<p class="lead text-center"> Transforming a peptide gel (99% water) into a yield-stress material for 3D pritning.</p>
<img src="images/yield-stress.jpg" class="img-thumbnail" width=50%>
<br>
<br>
<ul class="list-group lead text-justify">
<li class="list-group-item"><b>"YIELD STRESS":</b> An ever increasing viscosity as the shear rate approaches zero, i.e. does not flow/ solid-like when stationary</li>
<li class="list-group-item"><b>"ZERO-SHEAR VISCOSITY":</b> The viscosity plateau's as the shear rate approaches zero, i.e. flows/ liquid-like when stationary</li>
</ul>
<h4 id="TC1.2"> 1.2 The Science of Rheology</h4>
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<br>
<br>
<hr>
<h4 id="TC1.3"> 1.3 Rheometers - Operating Principles</h4>
<br>
<br>
<br>
<p class="lead text-center"> Transforming a peptide gel (99% water) into a yield-stress material for 3D pritning.</p>
<img src="images/TA.jpg" class="img-thumbnail" width=50%>
<br>
<p class="lead text-center"> The Instron Capillary Rheometer.</p>
<img src = 'images/capillary-rheometer.jpg' class="img-thumbnail" width=30%>
<img src="images/INSTRONnew.jpg" class="img-thumbnail" width=30% height="30%">
<br>
<p class="lead text-center">The measured qunatities (angular deformation and torque) are transferred into a material quantity (stress, strain, viscosity, etc.)</p>
<p class="lead text-center"> Instrument specific measured quantities are used to calculate material-specific parameters.</p>
<img src="images/measured-calculated.jpg" class="img-thumbnail" width=50% height="50%">
<p class="lead text-center"><b>Fluid Dynamics of Rotational Rheometry</b></p>
<p class="lead text-center"> Working Equations for rotational rheometers with <b><i>parallel plate geometry</i>.</p>
<img src="images/parallel-plate-geometry.jpg" class="img-thumbnail" width=50% height="50%">
<br>
<p class="lead text-center">Thus, by varying the shear rate and measuring the change in torque, the viscosity may be determined explicitly.</p>
<p class="lead text-center"><b> Notes on Experimental Procedures:</b></p>
<p class="lead text-justify">The most important thing is the fundamental resolution of the instrument itself since this will dictate our primary measurements. Stress and strain are not measured directly. Important assumptions are required ot convert primary measurements to material functions. You can only measure certain dynamic ranges of torque, displacement and frequencies. You have resolution limits in either of these quantities you can propagate through to the resolution o fthe viscosity that you can measure.</p>
<ul class="list-group lead text-justify">
<li class="list-group-item">Resolution/range of measured load and displacement</li>
<li class="list-group-item">Instrument inertia (if load and displacement are measured on same boundary)</li>
<li class="list-group-item">Fluid inertia and secondary flows</li>
</ul>
<h4 id="#TC1.4"> 1.4 Neil: "Do you actually need classical rheometry to achieve what you want?"</h3>
<br>
<br>
<br>
<h3 id="TC2"> 2. Proposed System: "The Rheoprinter"</h3>
<h4 id="TC2.1"> 2.1 Nelder-Mead Algorithm</h3>
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<hr>
<h3 id="TC3"> 3. Design</h3>
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<hr>
<h3 id="TC4"> 4. Rapid Prototyping</h3>
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- created a jig/fixture to mount the motors and test the asynchronous operation for easiness.
- started with BigEasy Driver where I soldered male header pins with spacing ...
- soldered jumper wires (male to female) on the nema17 motor cables
here are some interesting links for bulding cables with Dupont Headers(we have all the accessories ikjn teh inventory):
https://www.youtube.com/watch?v=c-pTsccCizA
https://www.youtube.com/watch?v=qz9Ryos1_GY
https://www.youtube.com/watch?v=N3zK9fzIPBo
and a good instructable here:
https://www.instructables.com/id/Fitting-Dupont-Connectors/
- for cable management i will order sleeves and heat shrink tubes
- downloaded Arduino and configured based on that:
https://startingelectronics.org/software/arduino/installing-arduino-software-windows-10/
- then started running examples and creating simple sketches from here:
http://www.schmalzhaus.com/EasyDriver/Examples/EasyDriverExamples.html
- Example 1:
- Example 2:
- Example 3:
INstall Accellstep library from this page:
http://www.airspayce.com/mikem/arduino/AccelStepper/
and based on this guide using the manual way of installation in libraries folder under the Documents/Arduino/
http://www.airspayce.com/mikem/arduino/AccelStepper/
Don't forget ot mention why you should the thrid party libraries there, because during Arduino Installation they might be deleted.
- Example 4
- Example 5
http://bildr.org/2012/11/big-easy-driver-arduino/
Interrupts
Now I would like ot describe something which sounds that it would real simple but it turns out
to be incredibly hard on something likme the Arduino. Lets say we wanted to blinl LED indepedently, concurrently
at different rates.
A good example is when we are working with multiple sensors like a GPS, which over time spits out serial data
and if you are over here working on something else and that GPS piles up a bunch of data you are gonna
overflow your buffer and you are going to be reading old stale corrupt incomplete data from teh serial
port. So you need to have something like an interrupt so that every little bit you can ran out and get the data off of the serial
port.
Advanced Software Interrupts for Reading Serial Data
<hr>
<h3 id="TC5"> 5. Test</h3>
<h4 id="TC5.1"> 5.1 Online Rheoprinter Console</h4>
<br>
<br>
<br>
<h4 id="TC5.2"> 5.2 Challenges & Nest Steps</h4>
<p>
<center>
<video width = "700" height = "600" controls loop autoplay>
<source src= "videos/async-motors.mp4" type="video/mp4">
</video>
</center>
</p>
<hr>