Composites

As the layers stick together

The tasks asked are:

- Read the material safety data sheet (MSDS) and technical data sheet (TDS) for the resins that you're using.
- Design and make a 3D mould (~ft2 /30x30cm), and produce a fibre composite part in it.

Class material: Composites

Equipment listed below:

Insper FabLab's operational manual here.

Epilog Mini - laser machine - tutorial01; tutorial02 and turorial03.
DuploTech - laser machine - software tutorial; user operation tutorial and machine download manual.
Clamps, scissors, stiletto, hammer (hand tools).

Materials:

- MDF 3.00 mm thickness
- Imperveg resine AGT 1315.
- fabric
- Gloves

Softwares:

- Inkscape
- GIMP2.0
- Fusion360

Assignment report

Fusion360 design file tray.

Again thinking about the coffee machine and how to enjoy it when ready, I thought building a tray to serve two cups of coffee would be nice. As basic material we had Imperveg resine and a cut of plaid fabric.

Laser cut a piece of mdf to make the mold and then press it with clamps was the technique applied to this assignment. The result will be shown below (as other images of this process).

Imperveg resine AGT 1315 was the material. It comes in two bottles (A and B). The mixture has a proportion of: 1 A + 1,5 B = good mixture. More information about it (in Portuguese) will be found here or here. It includes MSDS and TDS information.

At first, InkScape was the tool I choose. But I changed to Fusion 360 in orther to make the round corners I wanted. InkScape is not the software I had understanded yet. But, in the end, I moved back to InkScape and did some boolean operations to cut the parts I intended to have. From InkScape, I saved a pdf file and cut the mdf - 3.0 [mm] - with Epilog laser cut mini.

machine setup:

- Speed = 10;
- Power = 100%;
- Hz = 5.000.

- Tray design .DXF
- Tray design .SVG
- Tray design .PDF

We have EpilogMini as a printer installed in the computer, so I used the pdf file for production.

Later notes on this assignment

The seven layers of fabric iquals the thickness I would like to achieve. This is the tray hanger side thickness. Having only finer fabric brings the issues of mechanical resistance. After readdy, I used the tray with different objects, nocnoc it in order to check how it sounds, and after several experiments, I concluded that it is very resistent.

Puring the resin over the fabric inside the mold may not be the first and ideal way to work with this finer fabric, but I build the mold in order to make it work like that. The strategy - or process workflow - was:

- design the mold.
- build the mold and place it where I could easely clamp it (hold it tight).
- measure how many layers of fabric would be necessary for the tray side wall thickness (5.00 mm).
- cut and place the fabric inside the mold.
- work with the resin to make it readdy, pour it over the fabric.
- close the mold and add pressure.
- wait enought time for the resin to spread thrugh the fabric and dry.

The tray is part of my desk objects now. It helped me out with picking lists (eletronic components) and tools (selecting and keeping safe mills and drills during different production operations).

Developing tray model design - 1 - Fusion360.

Developing tray model design - 2 - Fusion360.

Developing tray model design - 3 - InkScape.

Developing tray model design - 4 - InkScape.

Finishing laser cut parts.

Assembling the mold.
- As I mentioned before, this assembly was intended to have pressure over it. This is the mechanism to spread resin over the fabric evenly.

Cuting plaid fabric parts.

Measurement of area and number of layers (7 layers was the choice).

Mold top part assembled as a test.
- The closing with fabric tight before adding resin was a practical evaluation about the number of layers needed.

Preparing the composit resine mix.
- The first mixing experience was mold and casting.
- I was more carefull now, because I had that (short) experience.

Clamp press after packing mold + fabric + resine.
- This setup helped me keeping and checking pressure clamps were applying over the mold.
- In time, with pressure, the resin would spread along the fabric fibers.

The result tray, I know there is room to better finish this piece, maybe later.
- The edges could look better, but the tray center became bright and I liked it.
- Strength: it holds whatever tool or material from the lab that fits in it.

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