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15. Mechanical design

  • Group assignment for design a machine that includes mechanism+actuation+automation

  • Build the mechanical parts and operate it manually

  • Document the group project and your contribution

A brief introductory class from the local instructor, regarding the previous year mechanical design projects and some of the exciting examples from the previous year Fab lab courses. In Oulu fab lab, we split 2 groups with 5 members each. We are also started to discuss about our group project; the Initial idea is to develop a mechanical design of the Elevator and its automation. Further, we planned to do something exciting that is a writing machine. Design a writing machine for typing any type of text or drawing any design on a paper. The best example of writing machine is a CNC machine or laser cutting machine. Our machine is working on 3 axis (X, Y, Z). Z axis control is for lifting the pen for changing the X and Y movement for writing. Y-direction controlled by the movement of 2 vertical stepper motor setup and X movement and pen holder attached in another stepper motor and Pen lifting planned by one servo motor attached in the X-direction supporting axil The three-axis motion is given by stepper motor and servomotor, MDF board is used for the three-axis movement design. See the mechanical design group members and an initial sketch of the project is shown in the figure below.

Group members

Tools to be used

  • Laser cutter

  • Screwdriver

  • Computer/Laptop for design a 3D model

  • Glue gun

  • Sharpening knife

Material to be used

  • Stepper motor

  • Metal gear servo

  • Alignment rod

  • Boll Pen

  • Nut & bolt

  • Plastic washer

  • Screw

  • MDF board with 3 mm thickness

Yasir ( 3D design using Fusion 360) and Sahan (2D design using Inkscape) initiated the 3D and 2D design of the writing board. The designed 3D model is shown in the figure below,

I have done laser cutting and assembly of the board. Michael has done the documentation and laser cutting. Alok did video editing and planned the project strategy.

My Contribution

Laster cutting and assembly of the parts. All the parts which are collected from the Oulu Fab lab. MDF board with 3 mm thickness used for the horizontal and vertical axis package with stepper motor assembly. We follow the instruction of laser cutting in our previous week assignments. We convert the svg file to PDF format for laser cutting and follow the laser cutting instructions. We reduce the speed to 6 and increase the power to 92 % to cut the MDF board fully. See the picture of initial laser cutting and trial assembly of one unit. The main packages are assembled by pressfit, stepper motor connected by screws, the horizontal part which done by silicon glue at both on the parallel axis. writing penn attached to the slot by gueing and connected to servo motor.

Part assembly figures are shown below,