SATPC0030903 Tab 04 SOW revised.pdf

STATEMENT OF WORK FOR LASER SINTERING RESEARCH SUPPORT

1. Objective/Requirements The On Demand Manufacturing of Electronics (ODME) project needs support work on laser sintering research for integration into a nScrypt multi-material printer (FabLab) on board the International Space Station (ISS) to demonstrate 3D printing capability. 3D direct ink write (DIW) printing is one of the main methods for FHE fabrication, and materials are deposited in the form of inks or colloidal suspensions.

Unfortunately, many printing technologies suffer from a major problem, in that the “printing” does not provide a consolidated thin film of the desired material on the flexible substrate; all it does is simply deliver the ink to the substrate, leaving the material on the substrate in the form of wet nanoparticle (NP) agglomerates or clusters. Thus, a post-sintering or a post-annealing (thermal) step is mandatory to consolidate these NPs into a film for providing connectivity and realizing the desired film properties. This thermal step requires a significant power budget aboard the space station, and a search for a low-power alternative has become increasingly important. Laser sintering is an attractive technology for creating the desired film due to its low power requirements and ability to selectively sinter parts of printed films in a multilayer device. This is in line with the current ODME plan to include a laser on board with the FabLab system on the ISS. Various parameters of the laser, in addition to the substrate, play a role in sintering, such as wavelength, pulse duration, intensity, and power. I

In this project, we seek to expand the capability to determine the laser parameters for (a) other substrates, specifically acrylonitrile butadiene styrene (ABS) and polyimide, and (b) other inks, specifically silver, palladium, and zinc oxide. We further seek to expand the knowledge of laser sintering by modeling the heat penetration from laser sintering into the printed film. We will be utilizing this knowledge to create prototype devices.

2. Objective Characteristics, Scope, and Specs

Objective 1.1: Investigate laser sintering parameters for silver ink for substrates, such as ABS and polyimide.

Task 2.1.1: Investigate and optimize the laser parameters required to sinter silver using 445nm, 808nm, and 1064nm for ABS and polyamide substrates.

Task 2.1.2: Investigate the effect of the femtosecond laser system and its effect on speed and surface morphology at 1040nm and 520 nm.

Task 2.1.3: Investigate the laser power threshold to create laser-induced graphene, with and without the silver ink.

Objective 1.2: Determine laser sintering parameters for new inks – Silver palladium and zinc oxide

In this objective, we will determine laser parameters for new inks such as silver palladium, and zinc oxide. We will also further optimize the parameters for barium titanate. We will study the surface morphology along with adhesion when sintered with four different types of lasers with the capability to utilize three different wavelengths at 808nm, 1064nm, and 455nm, at two different pulse duration (continuous wave and femtosecond) and at different speeds. We identify the following tasks for this objective:

Task 2.2.1: Identify the threshold for sintering and the best laser parameters for silver palladium, zinc oxide, and barium titanate.

Task 2.2.2: Verify that the parameters are applicable across different substrates identified in objective 1.

Objective 1.3: Determine laser sintering parameters for multilayer structures

We plan to study the laser sintering and ink parameters for creating multi-layer structures. The assembly of complex multilayered devices is challenging as it requires carefully controlled deposition of precise layers of different inks on top of each other. Multiple challenges arise due to the compatibility of inks and due to thermal coefficient mismatch between the inks, resulting in poorly adhering layers. We seek to utilize the knowledge gained from the first two objectives to study the creation of multi-layer structures. We have identified the following tasks for this objective:

Task 2.3.1: Determine laser sintering parameters for layer-by-layer sintering. In this task, we will seek to dry and sinter the first layer before printing the second layer and sintering it.

Task 2.3.2: Determine laser sintering parameters for bulk materials. In this task, we will seek to dry the first layer, and then print and dry the second layer. We will then sinter the film through a z-scan approach.

Objective 1.4: Create a thermal model for laser sintering of multiple inks.

The thermal dynamic effect of single-layer and multi-layer laser sintering is complex and dependent on various parameters from ink composition to substrate. To gain a better understanding of this process a detailed heat transfer process is needed for nScrypt-printed ink. A finite element model simulation of laser-matter interaction with COMSOL will provide crucial insight into the heat transfer process governing the laser sintering of printed inks. This objective will also help in creating an understanding of the laser parameters needed to create larger structures applicable to the On Demand Manufacturing of Metals (ODMM) project. We have identified the following tasks for this objective.

Task 2.4.1: Create a thermal model for laser sintering using COMSOL.

Task 2.4.2: Understand the thermal variations for different substrates, ink thicknesses and compositions

Task 2.4.3: Apply heat transfer models to thicker inks for ODMM structures

Objective 1.5: Create a device based on the parameters.

In this objective, we will create a simple device such as a blinking LED or a strain sensor, utilizing the parameters determined by Objectives 2.1-2.4. We identify the following tasks.

Task 2.5.1: Create a blinking LED device or a humidity sensor.

Task 2.5.2: Create a strain sensor.

Task 2.5.3: Create a diode utilizing zinc oxide.

Deliverables

Project Deliverables D1 Laser parameters for sintering different inks on ABS, paper, and Kapton D2 Three different multilayer devices using laser sintering of printed inks D3 Thermal model for laser sintering

3. Place of Performance Oregon State University in Corvallis, OR. Documents and test prints will be delivered to the On Demand Manufacturing of Electronics (ODME) project at NASA MSFC in Huntsville, AL.

4. Period of Performance and Timeline

Objectives ATP +3 months

ATP +6

months

ATP + 9

months

ATP + 12

months

Investigate laser sintering parameters for silver ink for other substrates such as ABS, paper, and polyimide.

Determine laser sintering parameters for new inks – Silver palladium & zinc oxide

Determine laser sintering parameters for multilayered structures

Create a thermal model for laser sintering of multiple inks.

Create a device based on the laser sintering parameters determined.

This research is needed ASAP once there is Authority to Proceed (ATP) and will take 12 months to complete.