7. Textile as Scaffold#

Inspiration#

I’ve been in the MATERFAD Museum in Barcelona and found an enormous motivation for this project. They have plenty of innovative materials and composites that encouraged me to find a way to this massive poblem of single use plastics.

These are some composites that inspire me:

Research#

The benefits of plastic are undeniable. The material is cheap, lightweight and easy to make. These qualities have led to a boom in the production of plastic over the past century.

We are already unable to cope with the amount of plastic waste we generate, unless we rethink the way we manufacture, use and manage plastics. Ultimately, tackling one of the biggest environmental scourges of our time will require governments to regulate, businesses to innovate and individuals to act.

Since the 1950s, the production of plastic has outpaced that of almost every other material. Much of the plastic we produce is designed to be thrown away after being used only once. As a result, plastic packaging accounts for about half of the plastic waste in the world.

Our ability to cope with plastic waste is already overwhelmed. Only nine per cent of the plastic the world has produced has been recycled. Most ends up in landfills, dumps or in the environment.

Most plastics do not biodegrade. Instead, they slowly break down into smaller fragments known as microplastics. Studies suggest that plastic bags and containers made of expanded polystyrene foam (Styrofoam) can take up to thousands of years to decompose, contaminating soil and water.

The most common single-use plastics found in the environment are, in order of magnitude, cigarette butts, plastic drinking bottles or cups and their caps, food wrappers, plastic grocery bags, plastic lids, straws and stirrers, other types of plastic bags, and foam take-away containers. These are the waste products of a throwaway culture that treats plastic as a disposable material rather than a valuable resource to be harnessed.

Plastic waste causes a plethora of problems when it leaks into the environment. Plastic bags can block waterways and exacerbate natural disasters. High concentrations of plastic materials, particularly plastic bags, have been found blocking the airways and stomachs of hundreds of species. Plastic bags are often ingested by turtles and dolphins who mistake them for food. Moreover, the toxic chemicals added during the manufacture of plastic transfer to animal tissue, eventually entering the human food chain. Styrofoam products, which contain carcinogenic chemicals like styrene and benzene, are highly toxic if ingested, damaging the nervous systems, lungs and reproductive organs. Also, the disposing of plastic waste by burning it in open-air pits releases harmful gases like furan and dioxin.

So we need to improve waste management practices and introduce financial incentives to change the habits of consumers, retailers and manufacturers, enacting strong policies that push for a more circular model of design and production of plastics. Moreover I think we should raise public awareness, promote alternatives, provide incentives to the industry and for sure create other composites that can replace at least single use plastics, which is absurde and completely senseless as we are producing them with a long life material, intended to be used only once before they are thrown away.

Main Idea#

The main idea for this project is to do some test to replace the use of plastic in coffee cups and plant pods. Furthermore, they should be 100% biodegradable. The aim is to have a coffee cup that can also be a plant pod, and as well be able to put it into the earth with the plant and be sure it won’ t harm the environment, it will be good for it.

Composites#

Composites rely on the creativity of combining materials to merge and create a new one, with other properties. They adopt complementary qualities that can’t be found in other raw or processed materials commercially available. Therefore, they can be applied in a wide range of fields and can be designed from the starting point of the properties specifications. It’s also about fabricating the material involved, as you can manage every variable of your design.

Bio based composites are what I will to generate, and they have two or more phases combined, but use to have one element that gives it structure and another fibrous component that is the ‘fragile element’ that merges with it. The fibrous component can be derived from natural, organic fibres as well as recycled or waste products.

The purpose is to create a more sustainable material for multidisciplinary purposes, that should resist water and heat in at least short term uses, though keep it biodegrable.

In a brainstorming of possible materials I chose to work with coffee waste, pine resin, recycled cork, paper thread and burlap.

For this project I will follow the following process:

• Model 3D cup (Rhino + RhinoCam)

• Create a thick wood panel with the size of my mold 15cm x 15cm x 9cm

• Create a thick wood panel with the size of my mold ¿?cm x ¿?cm x 9cm

• CNC milling to create positive and negative molds

• Create the composites

• Cast them into the molds

• Tidy finishing

Mold making#

Rhino#

I’ve modeled a 3D cup/pod.

Cup Mold bottom by larracampos on Sketchfab

Cup mold top by larracampos on Sketchfab

New commands I used:

√ Boolean union: trims the shared areas of selected polysurfaces or surfaces and creates a single polysurface from the unshared areas.

√ Boolean difference: trims the shared areas of selected polysurfaces or surfaces with another set of polysurfaces or surfaces

√ Revolve: creates a surface by revolving a profile curve that defines the surface shape around an axis. So I gave the shape in 2d of half of the cup and then apply this command to make it 3d.

√ Points on: display curve and surface control points

√ Points off: turn off control, edit, and solid points display

√ Bounding box: creates a rectilinear box object (polyline or polysurface that encloses selected objects.

Once the cup is ready:

• Make and extrude a “bounding box” and locate your object inside. In order to do a boolean difference and keep the negative of the object. To do the cup mold I needed to do two bounding boxes and two molds. One for the outter part and one for the inside. Be sure your model is at least 5mm down from the top boundary of your bounding box (sets a clear boundary for your object from the tool)

• Check your scale

• Always position your object on 0,0 coordinate and position below Z plane

• Open RhinoCAM plugin

• Choose your drilling tools and techniques (developed below)

• Depending on the material you choose for your mold adjust the speed

• Keep in mind you need a clearance plane, so that the tool can lift and place itself back down onto the piece without crashing

• Step over: how much of the tool diameter is milling in each pass. Take note of your tool diameter and control how close or far apart you want your perforations.

• Step down control: set depth per layer (maximum must be the diameter of your tool)

• Milling strategies: choose the milling options and play simulation to secure there are no errors in your process

• Double check your parameters and save post in .nc format “G-code” (the language for your CNC machine to read)

RhinoCAM and CNC milling#

I sitcked layers of plywood to create a block of 150mm long x 150mm width x 82mm high for the possitive mold, and a block of 110mm long x 110mm width x 82mm high for the negative mold.

I used the CNC machine to mill the block using two end mills: 10mm width to rip and a 6mm width to mill the details.

The 3D model was made in Rhinoceros and an special plugin to simulate the milling called RhinoCAM will convert the parameters into a gcode according to our design.

To generate this molds I used diverse milling strategies:

In first place, Horizontal Roughing with a 10 mm end mill, 1mm stock offset, speed 12000 RPM (spindle) and a feed rate of 3000 mm/min (which is the recommended speed for plywood milling with this tool).

Then I applied the Radial Machining with a 6mm end mill, 25% tool diameter step over, with 12000 RPM (spindle) and a feed rate of 3000 mm/min speed.

And to finish I run another Horizontal Roughing for the four ball joints, but this time with a 6mm end mill and the same speed.

As the composite I was going to cast needs aireation to dry, I decided to reply the mold in high density foam, as it has small pores and allows some air to go through it. So I cut two blocks of the same sizes in order to mill them.

For the high density foam mold I needed the same techniques but different speed (4000mm/m suggested for high density foam) and different step downs.

In first place Horizontal Roughing with a 10 mm end mill,1 mm stock, speed 10000 RPM (spindle) and a feed rate of 5000 mm/m.

Then I applied the Radial Machining with a 6mm end mill, 25% tool diameter step down, with 10000 RPM (spindle) and a feed rate of 5000 mm/m speed.

And to finish I run another Horizontal Roughing for the four ball joints, but this time with a 6mm end mill and the same speed.

Here you can check some screenshots of the process:

Choosing the tool

Feeds & speeds for wood milling

Feeds & speeds for high density foam milling

Choosing cut parameters

You can run a simulation to check the milling looks like you want to

Some videos of the milling process:

It took for about 40min to mill the wood piece and about 25min to mil the foam. When it was ready I used sandpaper to have a smoother surface. Also I did a hole in the upper mold for the excess of the poured material to get out.

Then I applied shellac as a varnish to cover the pores. Shellac melts with heat and is not water soluble. It is a resin secreted by the female lac bug, on trees in the forests of India and Thailand. It is processed and sold as dry flakes and dissolved in alcohol to make liquid shellac, which is used as a brush-on colorant, food glaze and wood finish.

It’s very important to cover the molds with a LOT of vaseline to be able to unmold later!

Casting composites#

• Melt pine resin in a can with a gas hob (melting point 100/120 degrees)

• Add coffee waste already dried (I put it in the dehydrator for 5 hrs at 60 degress)

• Pour the mix into one mold

• Add crashed corks to the rest of the composite and mix

• Pour the mix into the other mold

• Let them dry one day

• Take them out

• Use different tools to reach a tidy finishing. In my case I used a cutter and a dremmer because the composite sticked to the walls of the mold.

Results#

As the composite sticked to the mold I wasted the pine resin + cork + coffee waste cup as well as the wood mold. It was impossible to take it out even though I tried with different ways.

While the foam mold was easy to break with different tools and although the cup was fragile and break on the top, it was possible to go over the rest of it with the dremmer to have a smooth finishing.

The composites where not what I imagened. The pine resin was hardly drying inside the mold, although I thought it dries/stiffen up when the temperature goes down. Moreover it’s super fragile, and the wall of my cup is very thin so that could be something to improve as well. If I want to reply it, then I should make it thicker.

Moreover, the vaseline was not enough even though I put excess of it. I think the pine resin is very sticky and somehow avoid the vaseline, which remains in between the resin and the shellac, that has also sticked to the resin.

I think the molding and casting can be improved to reach a smooth final piece if I add one step, generating a silicone or alginate mold, and then cast the composite in it.

I leave for future investigation to try fabricating the cups by molding recycled cardboard similar to the recycled paper method and coat it with pine resin or shellac.

Plant pods with burlap as scaffold#

While I was melting the resin I decided to do some other tests with burlap fabric and pine resin to create biodegradable plant pods.

I gave the shape I wanted with a wood or metal structure where I put the burlap fabric inside, and then poured the pine resin and coffee waste mix inside it. The idea was to create a water tight bottom to prevent the water to spout. Though they are tiny and are ment to be for plants that doesn’t need big amounts of water, as succulents or cactus.