Fab Lab CEPT

Week 9/10

Mechanical design and Machine design


Candle Decorating Machine

The Candles and Diyas are very important part of Indian culture. Many festivals are celebrated in India are focused on the light and the tradition of lighting. The Diwali is a festival in which the illuminations with lighted diyas bring the supernatural brightness and joy with the hope of finding light in darkness, achieving knowledge where there is ignorance, and spreading love amidst hatred. Diwali is also known as the Festival of Lights. Light is significant in Hinduism because it signifies goodness. So, during the Festival of Lights, diyas, candles or oil lamps, are burned throughout the day and into the night to ward off darkness and evil.

"Machine that Make", Term says a lot.


Initially all of us started to think upon what all we will be making for the machine. Initial ideas were collaborated  together for the major decisioned or idea brainstorming and machine building.


The elements that we planned to keep in the machine were derived from the various techniques that we were already known.


It had the ideas of multi-tool router, gripper, drawing maker on the basis of vinyl cutter, automated 3d scanner compatible our mobile phones, etc. With all these ideas nobody of us was satisfied, because we thought to make something for different usability than already available, and we again started thinking and came up with an idea of decorating candles with melting wax using MTM module and then we started working on it.


We were working on a single axis rotatory module. But due to customs and other transportation reasons we were not able to get the MTM kit.












We all re designed all the components and parts and had a clear understanding of what we are making and how we will do it.


Later we decided to start working as a system and the flow of work is as following:


  • Making a basic design and structure of machine
  • Figuring out the material and components needed
  • making a 3D model
  • making a working model of machine
  • making it automated
  • final testing and video making






Rudrapal :

Once all the ideation is done, I took upon the task to make the 3D of the machine and also detail out what the machine have and how each components are connected to each other. I started working on the 3D model files while tapan started working on the materials required and their assembly and vipul started work for the extruder/holder. Once the model was ready I made files for the laser cutting and side be side tapan started assembly of the unit. Then the task was transfered to tapan as the assembly was done by him. Then I started working on the website and the documentation part of the machine. The best part of the MTM weeks were that i learned soo many new ways to work on electronics, as we have very different skill set as individuals and so the week came up with all the new and exiting decisions and discussions among ourselves and the other people working in the lab.



When the laser cutting files were made I started working on cutting and assembling the parts of the machine. Then I started working on the fixing of the pulley and belt and other components in the machine. Once the machine is assembled then the electronics in added into the system. I started working with vipul and mohit (one of the helping hand for electronics as he taught us how to make a system work and do coding). I started working on the coding part of the system and developed the code for moving the extruder.

Vipul :


I helped at very initial stage where the system was not there. We decided upon the final machine that we were making. Once that is formed rudra started working on file and I developed the extruder that has the complex geometry that can lock the belt and also it holds the extruder or the head that will work.

I am the youngest member of the team and I kept on jumping on each individual work and discuss and help them at any point of time with anything that they wanted. I helped with the joining of the circuit and fixing of the motor to the system.


Here are some sketches that can explain the structure and design of the machine:

Above images are the basics from which we started building this machine in our minds, on paper, CAD modeling and then physically.

We figured out the materials, geometry, axial and rotational movements, place of component, etc

This can be made with horizontal and vertical both the axis; but with small experiments with wax we choose horizontal one. Horizontal movement of nozzle help material stick properly on the workpiece and give enough time for cooling down the melted wax.


After this we worked on the timing of melting of wax, cooling of wax, rate of extrusion, controlling the speed of motors, etc.


List of components and material needed to build the machine

1) D.C. motor

2) D. C. motor supply

3) Stepper motor

4) Stepper motor driver

5) Counter weight for stepper motor

6) 2 Pulley

7) Belt

8) Extruder

9) Extruder mounting

10) Shaft for Extruder mounting

11) Shaft for mounting pulley

12) Rollers

13) Roller nut, bolt and washer

14) Candle holder

15) Cooling fan

16) Extruder temperature controller

17) Lever(for manual operation)

18) Joy stick(for manual operation)

19) Jumper wires

20) Push buttons (to control material flow)

21) D.C. motor for feeding the material

22) Bread-board to make the circuit

23) MDF/plywood for frame and structure

24) Screws

25) Drill machine

26) Electronic components

27) On/off switches



Basic dimensions of the Machine:


Front view

Side View:

3D virtual View of the machine

Construction of the machine

The first part was to develop all the laser cutting files according to the machine. Once the model is ready in the computer we designed the individual components of the box and did the laser cutting of the files.

Nozzle and it's Mounting

After making a 3d model we came to physical model and one of the challenge that we faced was of mounting for nozzle, we had to design something which can hold up to a certain temperature.


We used a 3D printed part with MDF, 3D printed part is going to be mounted on shaft and belt-pulley drive and with mdf we are holding nozzle of the machine.


Assembly of the Machine

Once all the components are ready and now the main task will start to assemble the whole kit and start coding it.


All the base and other MDF components are designed to be press fit in nature, so it is easy to assemble the base plane and other planes adjoining and to make the D.C motor box.

All the M.D.F cutted members are joined to each other.


All the elements are joined to one anther through the given connectors.


Then the guides are connected to the box.


The guides are now aligned and pulleys are joined to the box and the alignment of the wheels is checked.


Then the belt is connected to the pulley through  a 3D printed gripper that locks the belt and it can also adjust the length.

Once all the components are ready and now the main task will start to assemble the whole kit and start coding it.


All the base and other MDF components are designed to be press fit in nature, so it is easy to assemble the base plane and other planes adjoining and to make the D.C motor box.


The rollers are fixed to the base plate for the rotation of the candle.



The candle is placed in the machine and the axis of the candle is checked and placed carefully.


Once all the basic elements in the machine is placed it is ready for the electric circuit.




The Circuit is made according to the step by step process.


Stepper motor driver id fixed to the Arduino board with the help of codes that has a moment on  xy plane.


Then the stepper motor is connected to the circuit to take the movement of the header and controlling its speed through the belt and pulley.


Then all the other connections are checked through the bread board and than its ready to work.

End stoppers

The codes of the machine is as follows

#include <Stepper.h>


// change this to the number of steps on your motor

#define STEPS 200


int val[] = {35, -35, 23, -23, 34, -34, 12, -12, 50, -10, 23, -73, 10 };

int i = 0;

Stepper stepper(STEPS, 8, 9, 10, 11);


void setup() {



  pinMode(7, INPUT);




void loop()

{ while (i < 10)

  { if (val[i] > 0)

      for (int j = 0; j < val[i]; ++j)





    if (val[i] < 0)

      for (int k = val[i]; k < 0; ++k)







  if (i == 10);

  i = 0;



The working trial video with the stepper motor code:

Logic Behind the Code:


As shown in figure, following components are needed to be controlled with the controller.


  • stepper motor
  • end stoppers
  • DC motor
  • Hot nozzle temperature (if we use material additive process)


End Stoppers, as shown in the figure end-stoppers are fixed on the both ends from where motion of the nozzle should get stopped and for returning of the nozzle.


Initially i thought to start with end-stoppers but while experimenting with various types of tools, i figured out a way to make this without end-stoppers and without making it complex.


We took a mean point of the nozzle about which the nozzle was moving exact equal distance in both the direction.


Code without end-stoppers,  Look at the code,

you can see the line which states

"// change this to the number of steps on your motor

#define STEPS 200"


So here as you can see we have defined the maximum number of steps before defining the motion and after defining the distance it can travel i gave it the code of randomization.


Anyone can define the reciprocatory motion in terms of the steps on the stepper motor if you are making this machine in different size.


Also, you can try code if rendomization from internet for checking the working and to make new designs.

The Final machine Video: