Brief Overview

In the year, 2017 I decided to delve into the aspect of sustainable construction technology i.e. 3D printing. I received a small funding from fab Lab, CEPT, Ahmedabad, India to develop a binder jet 3D printer. After analyzing and comparing various kinds of 3D printer, I decided to make a binder jet 3D printer for its versatility with various forms it can print using different materials. For me the process of creating and developing a 3D printer is much more important than just the final product. The photograph displayed above is the very first version and I have altered few things to make it more efficient. Various components used were either scavenged or taken from older machines. This brought down the cost of the 3D printer to 200 USD approx. The ultimate goal was to create a machine in assisting construction while reducing energy consumption. This is the first prototype machine.

Snapshot of various components

Three major electronic components that will drive our 3D printer, Arduino Uno, CNC Shield and motor driver

CNC Shield mounted on the Arduino Uno. Furthermore, motor driver is mounted on CNC Shield

Details of the components and assembly

To keep the costs down, most of the components for building the 3D printer were either salvaged, for example, the stepper motors were salavaged from an old 3D printer or were milled and 3D printed using Laser Cutter and 3D printer, for example, the chasis was laset cut and the small components like L's for joining the base were 3D printed. The components that had to be bought included hexnuts, bolts, washers, Makerslide rails, Arduino and Power Supply. The video below shows the timelapse of arranging various components to build the first prototype of a 3D printer.

The detail GT20 belt to drive the Y axis.

The detail of connecting various components using L plate.

3D printing L plate using ABS material

Geometry to be 3D printed and why?

As compared to many geometries our there minimal surfaces are the most complex geometries. In order to build thes geometries in concrete one needs to really spend large amount of money to build a framework to cast concrete. Hence it is very unfeasible to create framework to build such geomtries. 3D printing only seems to be a viable option here, but amoong many other 3D printing technology, binder jet allows complex geomtries to be printed without required external support.
Scherk's first surface is a doubly periodic surface and complex enough to be printed thorough 3d printing, but the challenge is on. There is a tradeoff between using conventional 3d printing approaches and binder 3d printing. The latter has to tradeoff precision in lieu for being fast. The images below are in sequence of the 3d printed geometries displayed above and on the page before.

I used a plugin called grasshopper for a 3D software called Rhino 3D to subdivide the geometry into lines and points for G-Code generation

I used a plugin called grasshopper for a 3D software called Rhino 3D to subdivide the geometry into lines and points for G-Code generation

Code and Execution

Step 1: The custom made grasshopper code to generate G-code. In this particular case I wanted to test out complex geometries hence various minimal surface geometries were generated. The series of illustration show varous layers that are abstracted as lines and then as points. G-code is nothing but a series of points that any external software like GRBL can read and execute.

Step 2: The first image on the left: After generating the G-Code file, it needs to be saved in .nc format so that it could be opened in GRBL software that acts as a communicator to read the G-Code and translate that G-Code to machine language which machine understands. A major step is always to calibrate the machine, the one step of the machine might not be equal to 1mm/cm/inch as per your digital model.

Step 3. The second image on the left: It shows that G-code is being executed. The G-code executes at a very fast rate, which can also be defined by the user. I plan on to create a complete pipeline from Grasshopper to machine end, so that one doesn't need to shift to any other software.

The code is flexible enough to change the number of points per layer for getting a smooth G-Code

The workflow

The code written in visual programming language called Grasshopper

The geometry displaying various lines that are derived from the code

>Once the G-Code is generated it is sent to GRBL which in-turn sends it to the 3D printer. We start with calibrating the GRBL software

Once the G-Code is sent to the machine, the lines of executed are displayed one by one.

Final results

The geometry that I printed using the 3D printer as discussed above is Scherk surface and there is always a trade off that is involved while 3D printing using binder jetting. SInce the process involves the water slowly dripping on the concrete powder bed, the tradeoff is between accuracy and complex geometries. At this point I was fine with the trade off of giving upon the accuracy since the aim was to print complex geometries. The following are the results of the print. The print was cured for about 7 hours before remove the powder around it.

Front view of 3D printed Scherk surface

Left view of 3D printed Scherk surface

Right view of 3D printed Scherk surface

Right view of 3D printed Scherk surface

Workshop

During October,2018 I was invited to give a workshop to 30 students from various parts of South India on binder jet 3D printing. The three day workshop was in and around various types of 3D printing as well as displaying how machines could be made using digital fabrication processes. On the final day, we assembled the 3D printer and printed couple of geometries including a dome. The following videos provide a very brief overview of the workshop.

Message

If you like my work and this website or would like to further discuss about any project, feel free to connect with me. Thank you so much for your time.