16. Wildcard Week

This week was interesting. I took a look at Composites and Wet laying, along with the Metal Etching machine at our sister lab!

Wetlaying / Composites

To start off, I looked at Jesal Sir’s documentation and then at Adrian’s documentation.

I understood that a composite is essentially fibers of one material suspended in a substrate of another material. For example, reinforced concrete, carbon fiber in epoxy, glass fiber reinforced polymers and so on. Their main purpose is to provide structural strength and stability.

After this, I began making my own composite!

The process I embarked on was Wet-laying, which is basically using a piece of cloth or so and dipping it in resin and clamping it in a mold.

I began by making the mold on fusion 360. I wanted to start off simple so I took a cube and gave it various curves on one surface.

3D modeling for the mold

I started by making a sketch with many joint curves.

Then I used the extrude option under “Surfaces” to get a plane that matches these curves.

Next, I created a projected this curved surface onto a new sketch by pressing the “P” key. This gave me a rectangular projection of this which was then lofted with the curved surface to get a solid body as such:

And then I created a separate cuboid of the same dimensions and used the boolean tool to Cut the curved body out of the cuboid. This gave me the other part of the mold.

Final:

Video of Fusion process:

Actual Wet laying

Next I 3D printed these two parts of the mold.

My first print failed:

My second print iterations were successful.

I cut off a small piece of cotton fabric from an old piece of clothing for the wet laying.

Then I made my epoxy resin mixture by mixing resin and hardener in a 2:1 ratio.

I layed out a sheet of plastic (cling film) around my 3d printed mold so as to prevent the resin from bonding with the PLA.

I dipped the piece of cloth in the resin and laid it out on the wrapped mold, clamping the cloth between the 2 parts of the mold with rubber bands.

Once the resin had cured, I took off the mold and the plastic. Unfortunately, some resin leaked away and did bind with the PLA.

But the piece of cloth was solidified!

I hadn’t cut the cloth to the actual size of the mold which resulted in a bit of extra cloth hanging out from the side and leading to an uneven curved surface.

Metal Etching

This is the machine that we used for Metal Etching. it is called the Silaser F-20 Accuwrite.

Beside the machine is Sangram sir, the lab manager who helped us learn about the machine.

The machine comes with a CPU of its own as shown above.

About the machine:

Safety guidelines for the lab:

Parts of the machine:

Object detecting sensor:

The control panel:

Insert the key before switching the laser on. Green light indicates whether it is ready or now. You can also control the Z-axis from here.

The laser and lens:

The machine emits a assistive laser to help set origin. This can be seen in the red dot below. This red origin then expands into the border/outline of your 2D contour helping you position you work piece accurately.

Tool path creation:

Start by opening SAMLight software that comes along with the machine.

Import your file onto the software:

You can import a variety of file-types as shown here:

Once opened, you can move/alighn/rotate your vector and position it within the red outline.

On the right-hand panel, you will find a variety of options. Start with “Hatch”. Enable the “Original Values” option. On the left-hand panel, you can right-click and ungroup your vector to edit it individually.

Next, under the Mark option, you can select the color presets. each preset has a unique value of Power-Speed-Frequency.

You can also click on “Edit” and manually enter the values.

Next, hit apply, and this dialogue box opens up. Here, you can click on Total Outline and then Start Pointer so that the red laser outline shows up on the bed where you can align your workpiece.

We used the following values:

Power: 20 Watt
Speed: 31 mm/s
Frequency: 108 kHz

And we Etch!

The workpiece I used was a small rectangle cut out with rounded edges and two holes for mounting. It was made from Mild Steel with dimensions of 104 x 65 mm.

I chose to etch out the Title logo I had made in week 2 (CAD week) using Illustrator:

I used the Pathfinder tool on Illustrator to merge all the vectors into.

This is the rectangle outline that the machine projects.

Etching in progress:

Hero Shots:

Design Files:

Wet Laying Mold Fusion file
Wet Laying Mold part 1 STL
Wet Laying Mold part 2 STL
Metal Etching SAMlight file
Metal Etching DXF