Week 16
Wildcard week
The theme of this week was called "Wildcard Week", was to do something that we had not done in the previous weeks with digital manufacturing..
The objective of this assignment were:
- Design and produce something with a digital fabrication process (incorporating computer-aided design and manufacturing) not covered in another assignment, documenting the requirements that your assignment meets, and including everything necessary to reproduce it. Possibilities include (but are not limited to) composites, textiles, biotechnology, robotics, and cooking.
I chose to make a bowl using the composite method. Maybe I could use it for popcorn.
For this assignment I made a basic structure of the bowl that I then lined with plastic and on it I placed pieces of "Yute" fabric with resin.
For this assignment I made a basic structure of the bowl that I then lined with plastic and on it I placed pieces of "Yute" fabric with resin.
What is "Yute" or Jute?
It is the name of the textile fiber extracted from a fibrous herbaceous plant bearing the same name, from the malvaceae family, cultivated in tropical regions for its fibers.
Their fibers are usually spun in thick or medium yarns and with them are woven arpilleras for sacks, packaging, webbing and cordage.
The main destination of jute fiber is currently the manufacture of packaging sacks.
It is the name of the textile fiber extracted from a fibrous herbaceous plant bearing the same name, from the malvaceae family, cultivated in tropical regions for its fibers.
Their fibers are usually spun in thick or medium yarns and with them are woven arpilleras for sacks, packaging, webbing and cordage.
The main destination of jute fiber is currently the manufacture of packaging sacks.
My workplan was as follows:
1. Design and laser cutting of structure.
I made the bowl structure in Rhino, only hollow profiles for the laser cutter.
Then all the parts I organized in the same plane.
Then all the parts I organized in the same plane.
Using the make2d command, I created a 2d image of all the pieces and exported them as a DXF file.
File to download
File to download
I took the DXF file to the computer connected to the Laser cutter, there I loaded it with Coreldraw.
As all the lines were for cutting, I changed them to red color and sent them to cut.
As all the lines were for cutting, I changed them to red color and sent them to cut.
The parameters for the 3mm MDF cut are:
- Power: 100
- Speed: 0.50
- Frequency: 2000
In the same way, I cut the rest of the pieces.
All the work of laser cutter delayed: 25 minutes.
All the work of laser cutter delayed: 25 minutes.
These are the last two pieces of the bowl.
I separated the pieces and began to assemble the structure.
Here is an image of the armed structure of the bowl.
Then I lined up the work table to avoid messing with the resins. Once the resin dries it is hard to remove it.
Then I lined up the work table to avoid messing with the resins. Once the resin dries it is hard to remove it.
2. Preparation and application of resin material.
The materials for the composite are the following:
- Jute fabric cut into strips.
- Resin "Pox Bal" No. 1206, Part A and Part B (catalyst) Datasheet
- Cling Film Roll,
- Vaseline
- Gloves
With the Cling Film Roll I lined the structure of the bowl. Trying to take a rounded shape.
Once I finished lining the bowl structure, I applied a layer of Vaseline, to prevent the resin from adhering to the plastic and to be easier to detach it.
On a scale I placed a disposable plastic container, and added 282.6 grams of resin "Pox Bak"
The mixing ratio for the resin and its catalyst is:
- PoxBak 1206 A -> 100 parts by weight,
- Catalyst B ---> 20 parts by weight
I added 56.52 gr. of catalyst (20% of the weight of the resin) to the resin.
I cut the jute fabric in strips of 4cm approx. I gave it one last mixed to the resin, according to the Datasheet, I have 20 to 30 minutes to apply it.
I dipped the strips of jute cloth into the resin one by one, taking care not to splash. I drained it a little because this fiber is very absorbent.
I put each strip covering part of the previous one so that when the resin dries they are united.
I continued placing the strips of jute fabric with resin, being careful not to slip from the mold. It was necessary to tighten them a bit with your hands.
According to the Datasheet, it starts to become a gel in 45 minutes at 26 ° C, after 4 hours it can be demold and reaches the total hardness after 36 hours.
Recommendation.
For a better finish, I had to cut the thinner fabric strips and maybe use a finer weft fabric.
For a better finish, I had to cut the thinner fabric strips and maybe use a finer weft fabric.
3. Surface finishing.
After 6 hours it is still wet and soft, I will let it dry 24 hours.
The composite is already completely solidified, the jute fiber and the resin form a very resistant shell to impacts.
As soon as it is dry, I will unmold it, trim it and sand it.
As soon as it is dry, I will unmold it, trim it and sand it.