FABACADEMY 2017

Week 14 - Composites

Assignment:


read the material datasheet (MSDS) and technical datasheet (TDS) for the resin that you´re using. Design and fabricate a 3D mold (ft^2) and produce a fiber composite part in it

Theory:

An composite or composite material is a material made of two or more materials that have different material properties than its individual components. For the properties of the composites, material properties and geometry of the components are important. In my example I have use a natural composite material (yute) in combination with polyesterresin

Composite materials are generally used for buildings, bridges, and structures such as boat hulls, swimming pool panels, race car bodies, shower stalls, bathtubs, storage tanks, imitation granite and cultured marble sinks and countertops. The most advanced examples perform routinely on spacecraft and aircraft in demanding environments.

With the help of our lasercutter, I glued a three-dimensional object out of wood. The object is made of different triangles and the parts can be downloaded as an SVG file in the download area.

The object is to become an overhead of a plant and the wood mold is made with the help of jute wrap strips and polyester resin into a composite material.

1. Read the material datasheet (MSDS) and technical datasheet (TDS) for the resin that you´re using.

I read the Datasheets from the Presto Polyesterresin. You can find it here:

  • Presto Resin safety Datahseet
  • Presto Resin Datahseet

    • Possible hazards

  • Flame, flammability and fire.
  • Danger to health: May be harmful to the child in the mother's womb.
  • Can damage the hearing aids during prolonged or repeated exposure.
  • Causes skin irritation

  • Wear personal protective equipment: Wear protective gloves, eye protection.
  • Keep out of the reach of children.
  • In case of contact with the skin (or the hair): Remove all contaminated clothing immediately. Wash skin with water. In case of contact with eyes: Rinse cautiously with water for several minutes. Remove contact lenses if possible. Continue rinsing. If you feel unwell, seek medical advice

    • Disposal: Only recyclable containers should be recycled. Dispose of containers with residues to the problem disposal point.

    Shelf life / storage:
    24 months with proper storage (= 10 ° -25 ° C, relative Humidity of max. 60%) in the closed Original container. Before direct sunlight, frost and Protect the moisture

  • Dehner Jute-Wickelstrips, ca. 25 m x 15 cm

    • 2. Preparing the 2D-design into a 3D-design

    First I drew a few triangles with the software adobe illustrator, which should then be combined into a polygon-plant-pot (you can download it at the download section to make your own):

    Lasercutter-settings

    Power: 80%; speed 30%; fokus 10%; frequency 500 Hz:

    The individual triangles were glued together with the aid of wood glue. By changing from the focus I have the areas slightly bevelled. As a result, the individual surfaces could be better adhered to one another.

    With the help of wood glue and adhesive tape, the parts were now assembled:

    3. Preparing the Composite

    Here I followed the Instructions from the Datasheet and mix 2-4 % of the hardener to my resin and also made me safe against the resin:

    4. Preparing the Vacuummachine

    First try with the thermoforming press / vacuumbag method:

    Second try with the thermoforming press / vacuumbag method:

    On the following photo you can see the workflow: cover the model with the fresh film, place the yutestripes in the resin solution and put on the model (all in all 6 layers), put the whole end in the thermoforming press and cover it with a garbage bag. The garbage bag is then stretched with the vacuum and "suck" around the model. To protect the machine from the resin, I have place a wooden-board with some drilled holes on the machine bed:

    Machine Information:

    I used our 300XQ Formech vacuum thermoforming machine to press the composites together. It is a Sheet forming machine for the quick and easy creation of plastic molds by thermoforming. Simple operation, versatile tool use made of wood, gypsum, epoxy resin, 3D printer models, aluminum, etc. possible. For all thermoformable plastic plates and foils of approx. 100my to 6mm plate thickness. Plastics such as PS, ABS, PP, plexiglass, acrylic, PETG

    Thanks to the fresh film I could with the help of a screwdriver my wood mold from the hardened yute fabric without destroying it:

    Here you can see the removed wood mold and the composite of the polygon plantpot:

    Lastly I have the surface with another layer of resin coated to have a nice finish:

    After the hardening of the resin I could finally use the plantpot. The result is very hard and has a high strength:

    With some hammer hits I demonstrate the hardness of the composite material:

    It is amazing that the compounds between the polyester resin and the yute stripes have become so hard and strength. This week it was really exciting to see what you can create with this technic.