Accessible Microfluidic Mold Fabrication Using 3D...
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Aaron Heuckroth, Cassie Huang, Ryan Silva, Sonya Iverson, Traci Haddock, Alan Pacheco, Douglas Densmore Electrical and Computer Engineering Dept., Boston University Accessible Microfluidic Mold Fabrication Using 3D Printing A Fabrication Process Materials and Software 1. Design your device 3. Slice layer models into G-code 4. Print separate layers onto glass slides hello_device.py Python scripts are used to place primitive features and configure device layers. “Flipped” layers will be automatically inverted, to be printed upside-down. These scripts generate OpenSCAD files for each layer of the device, as well as an overall structural mockup. Subsequent steps require only minimal, “drag-and-drop” software interaction. 5. Assemble layers for PDMS casting 2. Compile 3D geometry Each OpenSCAD file contains a list of primitives and parameters that determine the structure and placement of features in that layer. Hello_device_control.scad hello_device_flow.scad hello_device_MOCKUP.scad An OpenSCAD library creates printable 3D models for each layer. Usage Example An FDM 3D Printer Filament Hairspray 2x3” Glass Slides Slic3r is used to slice each 3D model into G-code instructions based on nozzle size, minimum layer height, and other printer- specific factors. This process will work with nearly all G-code compatible FDM printers, since feature sizes can be optimized for the capabilities of the target printer during initial device design. Slide holders are printed in situ, ensuring proper X/Y feature positioning. Once the holders are finished, the print pauses automatically and glass slides are inserted. Hairspray is applied at 65°C, improving slide surface adhesion and mitigating imperfect z-axis calibration. The print is resumed, and mold features are printed directly onto the surface of each slide. The standardized slide shape provides X/Y alignment. “Standoff” primitives can be used to fix the Z distance between layers, such as for preserving the thickness of valve membranes. Introduction An initial prototype was designed and fabricated using our process. We then refined the design over the course of a week to dramatically reduce both individual feature size and the device’s overall footprint. To demonstrate the use of this system, we designed and fabricated molds for a theoretical microfluidic transposer element. Future Work We are currently working on… • Instructional guides and videos on our process and workflow • Easy and inexpensive procedures for casting PDMS devices from 3D printed molds • Interlocking features that aid in XYZ alignment during PDMS casting • Printable chip-to-world interfaces that can be generated in tandem with devices • Electronics, software, and hardware for automated microfluidic device control. • Improved process automation, removing manual OpenSCAD and Slic3r interaction. • Integration with Fluigi (cidarlab.org/fluigi/) for initial device design and routing This mold was fabricated in less than 15 minutes at a cost of $0.25. Flexible microfluidic devices offer biologists the ability to analyze and affect biological systems in controlled, repeatable ways. These devices are commonly fabricated by designing, ordering, and casting from photolithographic molds, a process that requires a significant investment in time, specialized equipment, and personnel training. We present an alternative fabrication process which uses inexpensive Fused Deposition Modeling (FDM) 3D printers to produce molds in minutes and at minimal cost, in which we use free, open-source software to design and produce molds with complex internal geometry from simple, parameterized components. This process removes significant barriers of cost, time, and expertise from the fabrication of microfluidic devices. This makes it easier for researchers to adopt and experiment with this technology, and facilitates the rapid prototyping, refinement, and sharing of device designs within the synthetic biology community. Size: 61 x 36 x 4 mm Volume: 1 cm 3 Footprint: 22 cm 2 Channel Width: 2mm Channel Height: .5mm Size: 19 x 12 x 1.2 mm Volume: 30 mm 3 Footprint: 2.27 cm 2 Channel Width: .2 mm Channel Height: .1 mm Size: 14 x 14 x 1.2 mm Volume: 30 mm 3 Footprint: 1.86 cm 2 Channel Width: .2 mm Channel Height: .1 mm The result is a parametric transposer module that can be easily customized and adapted for fabrication at a wide range of feature sizes. Control Flow Python is an object-oriented programming language. We use it to create designs for microfluidic device molds because it’s powerful and easy to use. Get it at python.org OpenSCAD is a procedural solid-body modeler. We use it to create the models for our device designs because it lets us turn code into 3D-printable objects. Get it at openscad.org Slic3r is a G-code generator for 3D printers. We use it to convert our 3D mold models into the instructions that run our printer because it handles tiny features well and will work with almost all FDM printers. Get it at slic3r.org All software used in our fabrication process is free, open-source, and totally awesome. Slic3r Octoprint Octoprint is a host application that provides a web interface for remotely controlling and monitoring a 3D printer. We use it to run all of CIDAR’s 3D printers because of its convenience and compatibility with almost all FDM printers. Get it at octoprint.org Source code is publicly available for this project and all examples shown on this poster. If you try it out, please let us know! Get it at github.com/CIDARLAB/3DuF This design requires that one channel “jump” over another by traversing between the flow and control layers. While difficult to fabricate using conventional photolithography techniques, our molding process allows these transverse features to be cast easily in a single step. A transposer element has the ability to selectively swap the contents of two channels, allowing the user to route fluids through the chip dynamically while maintaining continuous flow. Printrbot Simple Metal Gizmodorks White PLA Consort (Extra Hold) C&A Sci. 6101 $600* $25/kg $5/can $.10/per Price at We used… You need... *We upgraded our printer with a heated bed, an ATX power supply, and a .2mm nozzle from printrbot.com. ($200) Special thanks to Carlo Quinonez, PhD and the Bio/Nano/Programmable Matter group at Autodesk, Inc. for advice and inspiration regarding 3D-printable bioelectronic devices. Copyright ©Aaron Heuckroth, 2015
Transcript of Accessible Microfluidic Mold Fabrication Using 3D...
Aaron Heuckroth, Cassie Huang, Ryan Silva, Sonya Iverson, Traci Haddock, Alan Pacheco, Douglas DensmoreElectrical and Computer Engineering Dept., Boston University
Accessible Microfluidic Mold Fabrication Using 3D Printing
A
Fabrication Process
Materials and Software
1. Design your device
3. Slice layer models into G-code
4. Print separate layers onto glass slides
hello_device.pyPython scripts are used to place primitive features and configure
device layers. “Flipped” layers will be automatically inverted, to
be printed upside-down.
These scripts generate OpenSCAD files for each layer of the device, as well as
an overall structural mockup. Subsequent steps require only minimal, “drag-and-drop” software interaction.
5. Assemble layers for PDMS casting
2. Compile 3D geometry
Each OpenSCAD file contains a list of primitives and parameters that determine the structure
and placement of features in that layer.
Hello_device_control.scadhello_device_flow.scadhello_device_MOCKUP.scad
An OpenSCAD library creates printable 3D models for each layer.
Usage Example
An FDM 3D PrinterFilament Hairspray
2x3” Glass Slides
Slic3r is used to slice each 3D model into G-code instructions based on nozzle size, minimum layer height, and other printer-
specific factors.
This process will work with nearly all G-code compatible FDM
printers, since feature sizes can be optimized for the capabilities of the target printer during initial
device design.
Slide holders are printed in situ, ensuring proper X/Y
feature positioning.
Once the holders are finished, the print pauses automatically and glass
slides are inserted.
Hairspray is applied at 65°C, improving slide surface adhesion and mitigating
imperfect z-axis calibration.
The print is resumed, and mold features are printed
directly onto the surface of each slide.
The standardized slide shape provides X/Y alignment. “Standoff” primitives can be used to
fix the Z distance between layers, such as for preserving the thickness of valve membranes.
Introduction
An initial prototype was designed and fabricated using our process. We then refined the design over the course of a week to dramatically reduce both
individual feature size and the device’s overall footprint.
To demonstrate the use of this system, we designed and fabricated molds for a theoretical
microfluidic transposer element.
Future WorkWe are currently working on…
• Instructional guides and videos on our process and workflow
• Easy and inexpensive procedures for casting PDMS devices from 3D printed molds
• Interlocking features that aid in XYZ alignment during PDMS casting
• Printable chip-to-world interfaces that can be generated in tandem with devices
• Electronics, software, and hardware for automated microfluidic device control.
• Improved process automation, removing manual OpenSCAD and Slic3r interaction.
• Integration with Fluigi (cidarlab.org/fluigi/) for initial device design and routing
This mold was fabricated in less than 15 minutes at a cost of $0.25.
Flexible microfluidic devices offer biologists the ability to analyze and affect biological systems in controlled,
repeatable ways.
These devices are commonly fabricated by designing, ordering, and casting from photolithographic molds, a process that requires a significant investment in time,
specialized equipment, and personnel training.
We present an alternative fabrication process which uses inexpensive Fused Deposition Modeling (FDM) 3D printers to produce molds in minutes and at minimal cost, in which we use free, open-source software to design and produce
molds with complex internal geometry from simple, parameterized components.
This process removes significant barriers of cost, time, and expertise from the fabrication of microfluidic devices. This makes it easier for researchers to adopt and experiment
with this technology, and facilitates the rapid prototyping, refinement, and sharing of device designs within the
synthetic biology community.
Size: 61 x 36 x 4 mmVolume: 1 cm3
Footprint: 22 cm2
Channel Width: 2mmChannel Height: .5mm
Size: 19 x 12 x 1.2 mmVolume: 30 mm3
Footprint: 2.27 cm2
Channel Width: .2 mmChannel Height: .1 mm
Size: 14 x 14 x 1.2 mmVolume: 30 mm3
Footprint: 1.86 cm2
Channel Width: .2 mmChannel Height: .1 mm
The result is a parametric transposer module that can
be easily customized and adapted for fabrication at a wide range of feature sizes.
Control
Flow
Python is an object-oriented programming language. We use it to create designs for microfluidic device
molds because it’s powerful and easy to use. Get it at python.org
OpenSCAD is a procedural solid-body modeler. We use it to create the models for our device designs
because it lets us turn code into 3D-printable objects.Get it at openscad.org
Slic3r is a G-code generator for 3D printers. We use it to convert our 3D mold models into the instructions that run our printer because it handles tiny features
well and will work with almost all FDM printers. Get it at slic3r.org
All software used in our fabrication process is free, open-source, and totally awesome.
Slic3r
Octoprint
Octoprint is a host application that provides a web interface for remotely controlling and monitoring a
3D printer. We use it to run all of CIDAR’s 3D printers because of its convenience and compatibility with
almost all FDM printers.Get it at octoprint.org
Source code is publicly available for this project and all examples shown on this
poster. If you try it out, please let us know!Get it at github.com/CIDARLAB/3DuF
This design requires that one channel “jump” over another by traversing between the flow and control layers. While difficult to fabricate using
conventional photolithography techniques, our molding process allows these transverse features to be cast easily in a single step.
A transposer element has the ability to selectively
swap the contents of two channels, allowing the user to route fluids through the
chip dynamically while maintaining continuous
flow.
Printrbot Simple MetalGizmodorks White PLA
Consort (Extra Hold)C&A Sci. 6101
$600*$25/kg$5/can
$.10/per
Price atWe used…You need...
*We upgraded our printer with a heated bed, an ATX power supply, and a .2mm nozzle from printrbot.com. ($200)
Special thanks to Carlo Quinonez, PhD and the Bio/Nano/Programmable Matter group at Autodesk, Inc. for advice and
inspiration regarding 3D-printable bioelectronic devices.
Copyright ©Aaron Heuckroth, 2015
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