The finish line

After 5 intense and instructive weeks we finished the project Augmented Prototyping with a satisfied feeling. We created the oscillation Belousov-Zhabotinsky reaction and tried to manipulate it in many different and new ways. We broadened our knowledge about 3D printing and the software needed to create a model. We had a taste of using reaction diffusion in 3D printing and saw it change from an untouchable concept to a physical bicycle saddle. The possibilities are even broader than we expected and we are thrilled to see how 3D-printing and the concept of printing chemical/natural processes will evolve in the future.

We are from different faculties and our specific skills could not always be used to the fullest in this project. We all had to experiment and learn as we went along. This was intense but also created a sense of equality. Most of us were not really familiar with groupwork but we functioned quite well as a group; We learned to exchange information and opinions in an efficient way (even when talking about really intangible concepts), we had a clear division of responsibilities and even if someone was late or could not finish something in time, the other group members were understanding and forgiving. It created a pleasant work environment. The mix of different fields of expertise helped to come up with some unexpected new ideas. Our different personalities complemented eachother in such a way that we had a good mix of time management and proper/deepened research.

We had some struggles too. The theme of the project was quite global and at the start it was hard to choose the path we wanted to take. Because of this it took a while before we were able to make a kickstart. Whenever we did narrow down our focus, we had to simultaneously keep in mind the bigger picture to assure that we were not forgetting important aspects. This was challenging. Also, the software was harder to work with than we thought. We spent quite some lost time on Monolith and during the last days we made lots of extra hours to get a valid and printable STL file.

All in all this was a great learning experience and we are thankful for this opportunity.

– Max, Heleen, Isabelle and Lemin

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Avizo and the Connex3

Afbeelding van Lemin ChenThis week we tried to use different software to build a 3D model from 2D images. The program is called Avizo and it is mainly used in hospitals and medical research facilities. It is easy to handle and gives us all the needed parameters to create a smooth 3D surface. The interface of monolith was way harder to work with so not a tear was shed when we said our goodbyes today.

 

When we filmed the reaction we wanted to amplify the contrast between the two colours of the oscillating reaction. We tried using red and blue paper as background, but this did not give good results. White paper gives a good contrast but the footage has some light pollution because of the environment. In Avizo we found a filter called channel 3 that eliminates most of the light pollution and that gives great contrast between red and blue. By using this filter we have more tolerance during filming and we have one less problem to worry about. In Avizo we start with uploading the set of images and choose a scaling for all the axes. Knowing that a bigger z-direction scaling makes the conical structures narrower, we create the wanted 3D model.We then choose a greyscale value that separates the model into two parts (above and below the given value). Avizo creates two STL files that we send to Rhino. Here we scale it correctly and cut out the wanted saddle shape. We assign different colour and material properties to the different STL files and from that point on, the Connex3 printer does the rest.

 

Belousov-Zhabotinsky reaction

The Belousov-Zhabotinsky reaction is a so called oscillating diffusing reaction. Summarized there are three processes: A, B and C. In process A bromate turns into bromide, in process B bromide turns back into bromate and in process C the products from the reaction will react with each other. The critical concentration of bromide causes the oscillating pattern as it fluctuates from process A to process B. This reaction is made visible by using the ferroin indicator, which turns red when it is in its reduced form in process A and turns blue when it is oxidised in process B as shown in the left picture.

Processes

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We use 5 solutions to create the reaction:

Solution A: 2 ml sulphuric acid and 5g sodium bromate (NaBr03) in 67 ml water                   Solution B: 1g sodium bromide (NaBr) in 10 ml water                                                             Solution C: 1g malonic acid in 10 ml water                                                                             Solution D: 1 ml ferroin (25 mM phenanthroline ferrous sulphate)                                         Solution E: 1g Triton X-100 (a kind of detergent) in 1 litre of water

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We put 6 ml of solution A into a petri dish, add 1-2 ml of solution B and 1 ml of solution C. The solution turns a brownish colour. After a minute or so the brown colour will disappear. Once this has happened, we add 1 ml of solution D and a drop of solution E and the liquid tIMG_7880urns red. We swirl the petri dish gently to mix the solutions. It will turn blue and then quickly reverts to red again. Gradually, blue spots will appear randomly and the reaction will start. Below there is a video of our first experiment. In real time the reaction lasts about 45 minutes as it evolves chaotically, in the video it has been speed up 8 times.

Week 3: Hands-on in the laboratory

A lot of progress has been made this week. During the first meeting we put together our findings about pattern properties. We concluded that patterns can have a big influence when it comes to pressure and shock resistance and this is also something we can investigate and apply easily. Our global idea is to let the Belousov-Zhabotinsky reaction create a pattern that follows a pressure distribution. We can apply this in a product like a bicycle saddle, a chair, barstool, a shoe sole or a pillow.

pressure1small SIT-CATscience1A basic visualization of a pressure distribution in 2D and 3D

Tuesday Zjenja informed us that the chemicals would be delivered shortly. As preparation we built a holder for our petri dishes that allows us to make clear pictures. This is important because unwanted shadows and disturbances interact with the grayscale intensity and this gives an unwanted pattern in monolith. The holder also gives us room to interact with the reactions.

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It took a while before the chemicals for the Belousov-Zhabotinsky reaction were delivered but this Thursday we received the essentials and we were able to start our work in the lab. We walked through the process with Zjenja and executed the reaction for the first time. We are still missing some materials so next week we will be doing more accurate experiments. This week we had time to figure out the best way of getting a homogeneous pattern. We posted our findings in the research folder.

Next week we will start interacting with the reaction. How can we transfer the information about the pressure distribution to the reaction? Some ideas we want to try out:

  • Letting the pattern start at a certain position
  • Using heat
  • Using light
  • Touching the reaction
  • Changing the concentrations
  • Adding indicator
  • Starting the reaction on a surface with relief

Besides executing the reaction we will also be focussing on printing new models. We need to get a better grip on monolith and the connex3 printer to get a model in which the pattern is as clear in 3D as it is in 2D. One of our ambitions is to print with multiple materials at the end of next week.

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Week 2: Getting familiar with printing structures

32Oscillating circle pattern in Netfabb and 3D printed.

This week we received the first two printed models, one is an oscillating circle reaction over time. We were expecting a pattern of many stacked hollow cones but this is not really visible in the print. When we worked on the model in Rhino we scaled it in the z direction to make the cones bigger but it actually made the pattern messy and ruined the details. Next time we’ll skip this step and get more detail by letting the reaction run for a longer time. Furthermore this model is not good enough for testing but it showed us the do’s and don’ts when using the Connex3 printer.

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Reaction diffusion pattern in Rhino and 3D printed.

The second model is the diffusion of a single substance over time. This pattern is really promising because the 3D structure consists of a single surface with shapes like tubes, holes and funnels.

Last week we did some individual research and today we put all the information together during a brainstorm session. Some of the questions we asked ourselves:

  • What properties can patterns have?
  • Which shapes can be created by the Belousov-Zhabotinsky reaction besides spirals, circles, trees and waves?
  • How can we use the regularity of certain patterns?
  • How can we use the self organizing nature of reactions?
  • Can patterns maximize the contact surface?
  • Can a pattern hold information?
  • Can we interact with the pattern formation during printing?
  • Can patterns minimize material use but give maximum strength?
  • What is the advantage of visualizing the passage of time as a dimension?

We want to create something valuable and tangible with this project so we decided to apply the Belousov-Zhabotinksy pattern in a product.To get a better grip on how we can do this, we are going research the relationship between patterns, pressure and shock resistance.

Monolith

The 3D-modelling program monolith allows us to translate a stack of 2D images into a 3D model. Through multiple parameters we can change the way in which the images are read and we can come up with many different models for one reaction.

We created a stack of 2D images of the Belousov-Zhabotinsky reaction and we optimilized the model. We did the same for other micro- mono1and macroscope processes like single diffusion displacement, oscillation diffusion, growth of amoeba and the long-term change of temperatures on earth. By doing this we get a feeling for the different 3D structures that can be created. Some of the structures are really complex and inspiring. The image on the right is such an example, it shows the growth of amoeba over time (where time is the z-axis).

For the final printing we are able to use the Formlabs and Connex3 printers at the Applied Labs of Industrial Design. Formlabs is a desktop stereolithography printer that builds a model layer by layer using photopolymerization. There are currently two of these printers in the Applied Labs, one of which is broken. A possibility for this project is hacking the broken Formlabs printer so that we could feed it information during printing. This is a really promising idea but nobody in our group is that good with hardware so we decided to head in a different direction. The other printer is the Connex3. It uses extrusion and has some really nice features: it can print in a wide range of colours, it can print with two materials at a time and it can print with material with properties like flexibility and transparency.

We are currently experimenting with both printers but later on in the project we will turn to one printer in particular.

Week 1: The first steps

We had our first meeting with Zjenja on the 29th of September to get a global idea of the project. Not much has been done yet with reaction diffusion in 3D printing so our focus is reactionProductsmainly on research and experimenting. To give this some direction, we looked at the work of pioneers in this field. Some inspiring examples:

Housewares inspired by the nervous system by Nervous

img_32863D print of reaction diffusion by Christev Creative

 Pattern formation under given conditions generates a perfectly fitting shoe sole

 Neri Oxman experiments with natural growth

This first week we will continu to do research and we will get started with the hard- and software that allows us to print the reaction diffusion patterns.