December 13, 2023

Week 13

Wildcard Week

- Laser-Induced Graphene (LIG) Fabrication -

Bissa

Design and produce something with a digital fabrication process (incorporating computer-aided design and manufacturing)

These are the steps for creating Laser-Induced Graphene (LIG) Fabrication. We want to use LIG to create a sensor that measures the difference in pressure, thus the force applied to the LIG. Unscrew the two screws at the front to remove the checkered part (the bed)

Bring the bed back up with the arrows on the right Paste the Polyamide on the aluminum with black tape.

Clean it with IPA

Place the aluminium with the Polyamide on the laser bed.

Use the tool to set the arm at the right height (FOCUS TOOL)

Open the program, CORELDRAW, Open my PDF file. Use these settings for the machine:

Parameters for LIG


				DPI: 1500
				PPI: 1500
				Power: 8%
				Speed: 10%
				Focused

First, I need to see what the laser's workspace is. So, I select the black perimeter around the black box, choose print selection, and press Start on the machine. Then hit OK, then SELECTION, because we only need the black square selected:

What we obtain:

• Used as a functional material for sensing. • Digitated type of electrodes for super capacitors that can store charges. Silver epoxy (conductive glue). It can be used to make the material for PCB (FOR SOLDERING) If I increase the POWER, I make it more foamy, so it will be a better sensor for pressure. I can try to add more power. Now the power is at 8%. I will try with one at 15% and one at 20%. (Substrate of Polyamide 150 micrometers)

Now we try with 25% of power and speed 10 with the thicker layer (substrate of Polyamide 250 micrometers). They all flaked off. So, we now try a last one with power 10% but speed 5.

We tested the resistance of this piece, and the difference in resistance was impressive! 500 OHMS difference. P13 S3 = power 13 and Speed 3 PDMS: poly dimethyl siloxane

It's thick enough for us to measure the difference in resistance. So now we transfer our last laser print on the PDMS. Casting of the first layer: We use a plastic box as a mold. Then we cast over the PDMS, then we put the mold with PDMS in the oven. We cast the already made PDMS inside the mold. How to make PDMS: Mix together a ratio of 10:1 of: • Sylgard 184 silicone elastomer base (10) • Sylgard 184 silicone elastomer curing agent (1)

Then we measure the quantity of the two components: 20 of one and 2 of the second, totaling 22.

Next, we place it in the degassing chamber for 20 minutes. (I adjust its size - screw it in - start the machine with the black button on the right - and then turn the red screw until I hear a different sound.)

We pour PDMS also in the mold with the other sheet we made:

Now we need to vacuum it for 20 minutes. We want to get all the air out so the PDMS can go in between all the particles. So, when we cure it, it will be easier to do it nicely:

Once it's out from the vacuum, we put it in the oven at 90°C for 1 hour. In order to recreate a sample with this much difference in resistance, we make many different trials changing power, speed, focus, air, PPI, and Polyamide thickness (125 and 250):

And many others...... Until we find the right settings: It's finally working 💫💫💫💫💫💫 40 power - 20 speed - 1500 PPI - normally focused

I can now design my fingerprints first on Photoshop connected to a WACOM board and then on Illustrator:

FINGERPRINTS: 1 cm × 1.5 cm

Parameters for Fingerprints LIG


				DPI: 1500
				PPI: 1500
				Power: 30%
				Speed: 20%
				Focused 
				AIR

I then added silver apoxy and connect with conductive wires to measure the difference in resistance.
My fingerprints work!!!

Here's the overview on the group projects: Laser Induced Graphene Overview

Design: HTML5 UP

Welcome to Rocky96's HTMAA world

Parameters for LIG

Parameters for Fingerprints LIG

Welcome to Rocky96's
HTMAA world