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Week 15 : Machine Week 1 - Mechanical Design

Making of the Braille printer

Braille printer in action

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We have done this group project during the timeline of two weeks (May 2nd 2018 to May 17th of 2018). First week was the Mechanical Design Week and the latter week for the Machine Design.

  • Week 15 - Mechanical Design (May 2-9, 2018)

  • Week 16 - Machine Design (May 10-17)

  • Week 15 - Mechanical Design

    What I done?

  • Made a Task Chart
  • Purchasing
  • Dismantled and Procurred from the damaged printer
  • Designed the acrylic rod holders
  • Helped Amith and Vishnu in Designing the Motor Holders
  • Designed a tool cap for the first Solenoid
  • Designed the servo mount and tested with servos
  • Designed limit switch holder
  • Intro

    We as a Team needed to fix on a Project Idea, so we decided to make a list of possible machines we could build

    The below list were the last list of our ideas

    1. Tactograph - Tactile image printer by extruding fevicol
    2. Object tracking camera mount with roll, tilt and pan
    3. Braille Printer/Embosser
    4. Object Shooter
    5. Wall printer
    6. Automated drink mixer
    7. Dosa Maker

    After several thoughts and factors, we thought of making the Braille Printer. Making Braille Printer was a unique idea as of its relevence and also it is relatively simple mechanism and it would be possible to make one in the limited time available.

    The printer upon receiving the command from the computer prints the braille script by punching holes on a paper. We decided to use a solenoid with a sharp end as the printing head which will pierce holes on a paper at the specific points.

    The Braille printers available in the market are very costly and is not affordable to everyone. This further encouraged us to make a cheap Braille printer by making use of easily and locally available materials and also recycled materials.

    The size and distance between the dots are to be of the standard one and the measurement of the same are as below.


    I was assigned to make a chart of tasks to be done by the team, so I made this

    First Prototype

    After the discussions, Amith , Akhil and Rinoy made a rough idea on what all are necessary to build the X-Y axis of our printer

  • Stepper Motor - 2 nose(one for printer head movement and one for rolling the paper)
  • Rod with rubber support to roll the paper
  • 8mm smooth Rod for moving the head
  • Driven pully and driver pully suported for GT2 betl ( Head is moving using belt)
  • Linear Bearing
  • Purchasing some items

    8mm smooth Rod for moving the head
    GT2 betl(1.4mm tooth)
    Driven pully and driver pully
    couplers, bearings and screws

    The local Shop we went for purchasing, I am the one behind camera

    Our instructor Yadu gave the idea that of using solenoid push-pull mechanism for embosing the holes in paper.
    So we ordered a solenoid form online website.

    After this, along with Rinoy and Abhilash, I procured a damaged printer and opened up to get the roller with rubber bushes for the paper feed mechanisms.

    paper roller

    Me, Amith and Vishnu was assigned with designing the basic assembly of the printer.
    With a general idea, I draw a simple sketch in paper, and I designed in (Fusion360) and laser cut the side walls in an acrylic sheet and made the arrangement.


    Acrylic Rod Supports

    Download Design file

    We made a first prototype of how the machine would look. I designed the acrylic rod supports and Akila designed the first version of end effector head.


    Making an assembly with rods on the acrylic sheet we understand we need a liner bearing to hold the head and horizontal arrangement of the rod to hold head is difficult to place the solenoid push-pull me along with Amith and Vishnu.

    Vishnu made a good drawing of the printer on how it could be.


    Vishnus Sketch

    It is at this point me along with Amith and Vishnu started designing a support for the stepper motors.

    Vishnu made a small drawing in the paper, and Amith and I refer the drawing and design that in Fusion 360.
    For Designing we consider the dimension of Stepper motor, here we are using Nema 14 stepper motor which dimension is 42mmx42mmx42mm.
    We arrange the rod for carrying head is in a vertical position and center to center distance is 50mm. One side of the design we made a pocket to hold the roller motor stiff.

    By this time we divided each tasks between us. We choosed a peculiar way in designing the components i.e., while designing a part one will assist that guy in measurements and building. This would reduce the errors and if so happened we could easily rectify it.

    Sketch for Holding the Rod and Driver Motor holder

    1  2  1
    3D model of Left side along with its 3d print along with with stepper holder screwed to it

    3  4  motorholder2
    3D model of Right side along with the 3d print


    Pulley arrangement designed by akhil which was later fixed to the side


    Download Design file which is mainly designed by Amith, credit for this goes to him, I just assisted him in this.

    3D model of Braille Pinter

    After completing the design we exported the STL files and 3D printed them in Dimension. After finishing the 3D printing(around 13 hours) we arranged it assembled them with rods and stepper motors.

    After placing the motors, we connected GT2 Belt with pulley, and our assembly was now finished.


    Amith and Vishnu with the assmebly


    First Assembly of the Final Draft

    Fixing on the Tool

    We started to search for alternative methods to make the end effector work.I was assisgned along with Abhilash and Akhil for this task and each of them started to work independently.

    As I said earlier, our instructor Yadhu gives the idea that using solenoid push-pull we could embose holes in paper to make the dots of braille

    And we bought a solenoid online


    first solenoid

    I designed small tool caps to fit in the solenoid, so we could attach a sharp needle or so.

    Download Design file

    But it proved useless as the solenoid end effector power was not good enough to embose the hole for braille

    So now we have to think alternate ways, one of them was taking a servo motor for embosing and it succeeded
    This made me design a mount for the servo motor

    Download Design file

    Eventhough using a servo was a viable option, yadu had procured another bigger solenoid which was delivered the day before of presentation, and the new Solenoid was the best thing.


    The New One with tool attachment

    Other Designs

    We needed a limit switch. Limit switches serve as the mechanism that tells the computer the limits of the CNC machine. When one of the axes moves to an axis limit, the switch is activated and the machine stops.
    The limit switches are also use to inform the computer of the home position. As the axis limit was more to the right side because of the motors, I had to design a connector to keep the limit switch in position.


    limit switch holder

    Download Limit switch connector

    Later on I also designed a Solenoid press fit box which was never used actually , Download Design file

    Download All Machine Week 1 files

    Creative Commons License
    This work by Aby Michael is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.