On 31st October we presented our project at a Science Fair in the IO building. It was really interesting to see everyone’s projects: the range and the variety of the assignments was impressive and the level of detail they went into was great to see. It seemed that although some projects were technical, such as the ultimaker one, others (like ours) were less technical and more practical. It was interesting to speak to others and see what they had learnt over the past 5 weeks or so. Some had learned Grasshopper, others had developed their coding skills, and some had played with 3D printed textiles: a wide variety indeed.
We received quite a few questions about the feasibility of our project ‘in the real world’ as opposed to just in the lab. This was mainly due to concerns about the availability of the material that makes up the clay mixture as many of its components are not always available in areas where this project would be used. Currently, the mechanism requires four people to operate it; ideally we would want a maximum of two users to be able to operate the machine on their own as this would make the whole process a lot more efficient than current solutions.
The flow rate of the current prototype is quite slow which meant that printing the D shape took far longer than anticipated. In a further prototype this could be reduced down by automating several aspects of the machine (such as feeding the material).
If we were to make the prototype again we would have not used wooden beams as they twisted in the heat of the basement, making it slightly harder to assemble. We would have used a concrete pump to bring the soil to the extruder instead of doing it by hand – otherwise the whole thing could really be done by hand without the machine at all. It would have benefited greatly from being sturdier and lighter, perhaps by building the frame out of hollow metal tubing. Although it was fairly easy to disassemble, the parts they were awkward to move around therefore adapting the design for greater manoeuvrability would be perfect for the remote situations the printer is designed to be used in. Another improvement might be the way the fires are added in. When we took a look at the wall section after the weekend we found that it had cracked rather badly in a few places. This may be due to the layers of fibre which would have drawn a lot of the moisture out of the clay causing varied drying speeds across the structure. At the current moment it is just placed atop each layer of printed material to increase the structural integrity of the structure. This method may have led to the cracking we witnessed in the final wall model. To combat this effect we could add the fibres in before extrusion.
Unlike a normal product design project where there is a clear goal, designing for a research project is rather open ended and freer. It seems to be a lot more about ‘inventing’ rather than innovating. This lack of a predefined structure can be overwhelming at first however after a week and a half we started to find it easier, discovering new methods of making and adapting old mechanisms to fit our purpose. Compared to other projects ours was very practical with a lot of hours spent building and designing on the go. It was a completely new method of design that none of us have experienced before. This approach means that we encountered a lot of issues as we didn’t spend time considering the possible problems. Although this could be annoying, it did mean we were a lot more open to new ideas meaning we discovered different methods of doing things as we didn’t overthink anything. We spent a lot of time thinking with our hands rather than our heads.
In our future design projects we will be sure to adopt this approach more: perhaps not completely but we will be less afraid to begin prototyping. Overall this was a highly enjoyable project.
The day to test the whole mechanism had come and boy what a day it was! We met in the morning and headed down to the basement where we assembled all the pieces of the printer once more: much faster this time.
We began a test with one person hold the arms at the back to direct flow, one person to control the speed of the motor and one person to feed material into the extruder. This worked really well and we managed to print a straight section 10 layers high before the structure collapsed under its own weight. We then moved on to trying to print curved sections. To do so we had to use a fourth person to slide the extruded forwards and back. This caused the print-head to be difficult to control however with a bit of practice we started to get the hang of it.
After a few test sections we decided to attempt the final wall. This would include a curved piece (as a demonstration of the support structure inside the wall) and a straighter piece (to represent the inner wall of the house).
We all tried out hands at the different stations around the machine: controlling the motor speed; feeding the extruder; sliding the extruder forward and back; controlling the height of the arms. But we soon realised that switching positions each layer was causing some inconsistency in the quality of the print. In order to create a high quality structure we needed to all pick a station and stick to it. By doing so we managed to print a wall section 7 layers high! In order to increase the strength of the structure we placed a small amount of fibres between each layer. We then left it to dry. On Monday we shall see how well the print dries…
We intended on printing on Thursday but fully expected there to be some problems, so we were not surprised when we found that the extruder had a tendency to pop out of its pivot fixtures on the frame. This would not do when printing and the cause was found to be the axels which attached the extruder to the arms. Their short lengths meant the extruder would easily detach from the top two arms. New axels were made with an extra 1.5cm in length however then another issue occurred: the new axels made it rather tricky to attach the extruder because they required the frame to be loosened in order to be slotted into the pivot holes. Seeing as the whole assembly is intended to be used by ideally 2-3 people this issue would not be acceptable as it would make the whole thing too fiddly to put together. A solution was found by changing the holes in which the axels rotate into slots. This meant that the frame could be fully assembled and tightened before slotting in the extruder.
Whilst these adjustments were being made, the extruder was tested and found to be faulty: it was not extruding enough material and the flow was inconsistent. The cause of this was the placement of the hopper in comparison to the screw of the extruder. The screw began half way down the feeding hole of the hopper meaning that most of the material was not being grabbed and dragged down at all and was instead just sitting at the top. To fix this the hopper was moved further down the screw. When tested the extruder worked better with a more consistent flow. To improve the flow even further we fitted an adapter to the top of the hopper that increased its diameter allowing more material to be fed into the extrusion pipe.
Due to the issues faced today we were not able to move on to the final print, however we are not disheartened by this. We expected to run into issues and are glad that all problems that were encountered were easy to fix. Tomorrow is set to be an exciting day as we plan on printing a wall section.
The last weeks of the project we focused on designing and making the frame of the ‘3D printer’. After a few trips to the Gamma we had all the material we needed for the frame. We had a clear vision of how the frame had to look: we will use the standard of the old extruder Tomassow already made. In the middle of this standard there comes a plastic pipe that will be able to turn 360 degrees because we will let it stand on a turning metal plate. On each side of the pipe there will come two arms, which will be connected to eachother through screwthread and in the middle, through the plastic pipe, there would come a wooden stick. At the end of each arm (on the front), there will come a slider. The extruder will be connected to these sliders and on the other side it will be connected t some wooden pieces that will make it able to go back- and forward on the sliders.
So now it was time to build the whole frame! We started with making the arms. We marked out were the holes for the screwthread and the wooden stick had to come and were the sliders were going to be. After that, we drilled the holes and screwed the sliders on. This took a little more time than hoped because we first had put them upside down on the arms. We saw the screw threads but when we were finished, we came to the conclusion that they were to short…. So we had to go back to the Gamma and got some more. We already made a start on the connection block between the extruder and the frame. After some puzzeling we decided how we would connected it to the frame: We would attach some wooden pieces to the sliders and in these pieces we would put a metal stick which on the other side is connected to the extruder. After we had all the pieces of the frame done, we moved everything to the basement to connect them there. We screw the pipe to the metal turning plate, and connected the arms with the pipe. During this, we sam that the wooden sticks through the pipe could slide, because there was some space over on the side of the pipe. We made some wooden blocks which we shove on the stick so that the sticks would stay in place.
After all the pieces were connected, we came to the conclusion that the extruder was not good connected to the sliders: the metal stick slid out of the holes in the wooden pieces on the sliders. We came up with another way to connect the extruder to the wooden pieces on the sliders: we made a ‘U’ shape hole in the wooden pieces, where the metal piece exactly fits in. This idea worked: the metal stick stayed in place and it was even easier to get the extruder in and out the frame.
After finishing the frame, we tested if it could turn and if it was possible to ‘flip/turn’ the extruder by the wooden circkle construction. And it worked! Well, we did had to make a new circkle construction because the first one was to big, but after we made a smaller one it worked.
- Sketches well all did then picked solution.
- Refined ideas down to 4 best
- Split and developed these ideas
- We used manual extruder to make circle
- We searched on the web for a good motor that went in both directions and variable speed
- We tried searching for a thinner drill that went in the opposite direction.
At the start of week 2 we decided what some of the main problems with the project currently were. We then separately came up with various ideas on how might approach these challenges all while keeping quite an open a mind.
Next, we discussed all our design ideas in turn and their potential. As a group we then developed these ideas into four distinct and reasonably feasible ideas.
We split up again to develop and research these ideas further.
While this design process was happening, we used some of the other sessions to go down into the basement of architecture school to test the physical prototype Tommi had already constructed. We continued to run tests with the manual extruder to find problems with the set up. A circle wall was printed with the extruder, one person turning, one person directing the flow and two people filling up the extruder by hand.
As the manual extruder had proven a success it seemed logical that with the addition of a motor to replace the person turning the hand handle of the extruder we could make the process slightly more automated. It occurs to us as we test that the perfect speed is not that fast as the soil is quite viscous.
We purchased a motor with variable speeds so that the screw could be rotated at a suitable speed where it functions best. When we attached the motor to the screw and began testing we quickly realised that it is turning the wrong way and not pushing the soil down. We tried in vain to find a motor that was omnidirectional or even a screw thread with a coil going the opposite way around. Eventually we decided to take the motor apart and switch the brushes round. Luckily we were successful and could now attach the motor to the screw.
Ok, we have a working motor that’s turning in the right direction, a design for the extruder and a rough design of the rig. Today we started forming ideas into working prototypes, joining the motor with the drill, making the basic forms of the extruder and ordering materials for the rig.
The drill is not made for this type of motor so we started making a connection between the motor and the spiral drill witch is able to whir stand the torque. For the extruder we went to the hardware store to get some piping. The pipes will fit snugly around the spiral drill, making the central part of the extruder. The nozzle of the extruder is designed and will be printed Thursday. We figured out the dimensions of the rig needed to make a small-scale model that still is able to hold our extruder and the weight of the clay. The next couple we’ll spending a lot of time in the workshop.
After we got the concrete mixer (motor of the extruder) we noticed it was spinning in the wrong direction. It will pull the clay up instead of pushing it down. To fix this problem we had two options: make the motor turn the other way or try finding drill with a inverted spiral. We noticed that al the spiral drills on the market are roughly the same. The only option left was inverting the motor. To do this we disassembled the motor, get to the carbon brushes and switch the wire of those brushes. Easier said than done.
After half a day of struggling cutting and soldering we managed to do it, the motor spins in the opposite (good) direction now!
In the first week, Tommaso showed us his work space and his tools. He explained what the problems were at the moment and where we had to work on. We experimented a bit with the mixture (sand, clay, water, fiber) in the extruder. We founded out that the extruder does not flows continiously, but with ‘shocks’.
After we spend some time getting familiar with the material (playing with dirt) we got together to talk over all the possibilities and make a plan for the following weeks. During this meeting we found a few problems we need to solve, we have to make a motorized extruder that will create a continues flow of clay. This contraption should be able to handle fibres in the mixture giving the shelter more strength. Apart of the extruder we’ll need a rig that’s able to hold and move the extruder. To speed things up we divided the project in the following tasks:
Designing the extruder
Motorize the extruder
Designing the rig holding the extruder
We are the team that works on the TERRA-ink project. Because this is our first post, we’ll first introduce our team and explain the project:
We are Tim Boxall, Mees de Smet, Doug Marriott and Lotte Pool. We are doing the minor Advanced prototyping at the TU Delft. For this minor we have to do a four week project. We are doing the TERRA-ink project.
‘Aim of the project is to successfully address the housing emergencies in terms of time and cost while simultaneously creating satisfactory living conditions, by implementing 3D-printing and local soil for creating durable structures that can be easily de-constructed once they served their purpose. The use of locally sourced materials in combination with additive manufacturing can lead to significant reductions in financial investments, shipping materials and resources and human labor needed.’ (source: https://www.4tu.nl/bouw/en/lighthouse2017/TERRA-ink/)
Our mentor for this project is Tommaso. During this project we’ll have to experiment with the materials and make a good mixture that is usable for our goal. Furthermore we have to think about the tool were we want to make the houses with: the 3D printer. Also we have to think about the design of the emergency houses.
In this blog we’ll keep you updated about our progress and problems that we find during the experiments.