17. Machine design¶
This week was based on doing a group project and documenting the contribution of each team member.
Through the week¶
Basically the idea was to automate anything traditional or enable a numerical controlled mechanism
After a couple of brainstorming sessions among the team members we were brought up to make a plotter based on parallel movement mechanism
The very first thing we did was to study in detail about the mechanism
The system has 3 connected linked arms that are free to rotate at joints. The linkages no 4 and 5 are rigidly connected as one piece. These two together form the elbow.These linkages are made of weightless material that it operates in cantilever position from the central shaft during operation. The pen holder is placed at the tip of the link 5 (Seen in the picture below). Linkages no 3 is connected directly to the pulley erected in the central shaft. The main rotation of the arm is controlled by linkage 3. Linkage no 1 is connected at an offset to the pulley using a small linkage no.2(Later this was directly incorporated with the pulley itself).Linkage no 1 controls the rotation of the elbow linkages 4 and 5 indirectly. These connected linkages behave in such a way that at any point a parallelogram in closed connection is formed by them. The desired position of the pentip can be achieved by calculated rotations of the connected linkages no 3 and 1. Mechanism testing1 For testing the mechanism we cut the scaled sizes of the plotting arm in pvc and fixed it to the plywood base to simulate the plotter arms motions. The pvc panels are screwed at the joints to simulate hinges at the joints. testing2 The arms are pivoted at the base and checked for free motion of the arms to understand the behaviour of the lnkages.
The very next thing we have planned is to divide the work among team members.
obviously we were a group of three members came from different background.Since the designing Jaisu Joseph came from an architectural background he was in charge of designing works.The assembling works were assigned to me and the programming works were assigned to Manu Mohan from the group.
Even though the works were distributed everybody contributed in every level of work.
My contribution¶
The idea of making pargolas in the arm plotter end in order to reduce the weight was contributed.
Click Here to download the testing of motor video
The Assembling works was assigned to me .
So primary designs was 3d printed using ULTIMAKER
It was a difficult part to assemble a new mechanism which we are seeing it for the first time.
The very first thing I did was checked all the electronic parts that whether it was working.
For that I connected it to the rams and stepper motor driver and connected to the arduino uno and uploaded a sample program to check the connections.
I made sure that all the electrical components were working properly.
After deciding the board dimension the 2d profile was cut in shopboat
Then the lead screw was fixed using two nuts firmy.
Then two stepper motors were fixed in the board
e to fix the stepper motor in the board because of the following reasons.
It requires a tight profile between the motor and the lingages so the conveyor belt used should be of as much as tight in order to define the precision.
The problem was fixed by making a length groove at each surface of screwing parts.
positioning video¶
There came another challenge .Since the wood is having a spongy behaviour the motors wre not able to fix properly.
Then I came to a conclusion to make bush with acrylic and later it was decided to make a complete housing using acrylic and it will provide a good attractive feature too for the machine.
Then the Extender were difficult to connect with the conveyor belt because of its spring action.So I plan to make a jacket with PLA to uphold the Extender prevented from the deflection.
After that the motor was well arranged in the casing and the next challenge was to connect the motors from motors to pulley and it was done successfully.
Then it came with the clamping of linkages and was effectively done by using screws.
CLICK HERE TO DOWNLOAD THE WORKING VIDEO¶
This was the basic part i have done in the machining week.