DOC PREVIEW
UMD ENMA 490 - Outline of the Main Device Stages

This preview shows page 1-2 out of 5 pages.

Save
View full document
View full document
Premium Document
Do you want full access? Go Premium and unlock all 5 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 5 pages.
Access to all documents
Download any document
Ad free experience
Premium Document
Do you want full access? Go Premium and unlock all 5 pages.
Access to all documents
Download any document
Ad free experience

Unformatted text preview:

Stage 2Stage 3Stage 5Outline of the Main Device StagesTo date, the ENMA490 class project has had five major stages of device design, as outlined below: Stage 1: Defining the problem and determining the Functional Requirements and Assumptions of the project.Stage 2: Initial Microchannel Test DesignStage 3: Modified Microchannel Test DesignStage 4: Pressure Actuated Valve Test DesignStage 5: Piezoelectrically Actuated Valve Test DesignStage 1The first stage of the device design was an establishment of functional requirements and assumptions that led to further development. Requirements: The design and fabrication of an actively controllable two-level micro-fluidic device using simplified packaging alternatives.Assumptions: Externally pumped fluid flow–No need to design on-chip pumping Neglect the bio-chemistry at the test sites–Only consider how the fluid is to be transportedThe final device must, at a minimum, provide the ability to transport fluid from one level of micro-fluidic channels to another, with the use of active control elements. Moreover, the device must also be designed to allow for the use of a simplified packing assembly. In order to narrow the scope of the project, it was determined that the design would assume that fluid pumping would be provided by an external pumping unit, thus not requiring on-chip pumping. Moreover, the scope of the project was further limited by neglecting the bio-chemistry that could take place at test sites. The project parameters focused solely on the input; multi-level transport and direction; and output of fluids in a micro-scale device.Stage 2Once the design requirements and assumptions were determined, the group determined that testing preliminary designs on the path to a final design was necessary to ensure constant feedback to assess the practicality of design choices. The first design stage involved the use of an SU-8 molded PDMS two micro-channel layer device using an interconnect layer to connect the north-south channels of Layer 1 to the east-west channels of Layer 2.Micro-Channel Layer 1Micro-Channel Layer2Interconnect LayerThe purpose of this device was to test the viability of multi-level micro-fluidic devices with the equipment and materials currently available. The following critical dimensions were used in design of the mask set for this device:Approximate channel and interconnect width: 150 umChannel length: 45mmReservoirs: 300um diameter Total length of channel and reservoir: 45.6mmDistance between channels: 300umMold feature height: 300umStage 3The device design from Stage 2 was modified for three primary reasons:1. The reservoir positions were changed to fit the existing packaging used by Theresa, asthis would allow for easy integration and testing.2. The current design had too many input and output sites, thus not allowing for a test ofthe devices ability to direct flow along a pre-determined path.3. The dimensions used on the device in Stage 2 were too small, and all the dimensions were increased to make fabrication and assembly of the layers easier.The result was a device with the following mask set: Micro-Channel Layer 1 Interconnect Layer Micro-Channel Layer 2The following critical dimensional changes were decided upon for Stage 3: Increased channel width from 150um to 250 um and finally to 500um for ease of manufacturing and leak prevention.Increased interconnect size from 150um to 500um and finally to 1mm to make alignment of initial devices easier.The reservoir and throughput locations were placed according to the packaging dimensions as shown below:Stage 4In Stage 4, the group focused on the creation of a device that could start to test the fabrication potential for an active control element, such as a valve. The initial design used a combination of SU-8 and PDMS layers to create an active control site. Further variation on the design led to an alternative using a full PDMS structure. Each design contained 7 levels:1. Silicon Substrate2. Bottom Fluid Layer3. Gas Layer4. Thin Flex Layer5. Top Fluid Layer6. Cover Layer7. Pyrex SubstrateSU8 and PDMS Pressure Actuated ValveAll PDMS Pressure Actuated ValveThe two diagrams above show the proposed result for the fabrication of the Pressure Actuated valve. Stage 5Given the pressure actuated valve designed in Stage 4, the group then designed an alternative valve using a similar design geometry, but piezoelectrically actuated, as opposed to pressure actuated. Below is a vertical profile of the proposed design. However, further inquiry, as to the viability of piezoelectric deposition in conjunction with SU8 and PDMS, as well as the electromechanical behavior of piezoelectrics, such as PZT, is ongoing.Piezoelectrically Actuated


View Full Document

UMD ENMA 490 - Outline of the Main Device Stages

Documents in this Course
Load more
Download Outline of the Main Device Stages
Our administrator received your request to download this document. We will send you the file to your email shortly.
Loading Unlocking...
Login

Join to view Outline of the Main Device Stages and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view Outline of the Main Device Stages 2 2 and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?