Week: 9-
Mechanical Design & Mechine Design
Scrapbot- Automated Dust Collector(Made using scrap materials)
This week we have a group assignment.The assignment is to make a machine, including the end effector, build the passive parts and operate it manually, document the group project and your individual contribution.
Link to Machine project, Click here
Our Team
For our machine building group project we shuttled across a few ideas during the branstorming session. First idea was to build mini an electric wheelchair which could be used by handicapped children, specifically for children with no legs.The sitting platform will be only be slightly above ground, thus making it easy for handicapped people to get on it.
Halfway through the project, since we couldnt get access to the required motor, we decided to change the project to Automatic cleaning machine.The entire machine would be built using scrap materials so as to minimize the cost.
we decided to make the machine from scrap and hence named it as "Scrap Bot".The project tasks were divided and given to each members.For documentation of the project, we created a seperate group page as per the requirement.
My Contribution
First Me and riyas discussed how to design this mechanical part,Our first idea was for handicapped childrens so we designed a body which is capable to carry the weight a person,we designed a heavy thing and that should drive the person.
Design aspects
Wheel must be able to carry load,and shaft must be capable to carry load along with entire body,that is entire body weight should be concentrated on rare wheel.stearing should be smooth.
We did Sketch external features,I suggested the product must be in wood,base should be strong ,so that person can sit somfortable.
This plan is to fit wheel and axile. Axile should have 2 supports to avoid bending when it takes the laod.i am planning to drive each wheel seperately.so each wheel need seperate axile.
First we decide to use stepper motor combination,for that we need a gear box,we did splan to set up a 6 gear train ,i did that calculation.,
Vaccum cleaner setup,this was the most risky part of this project.we decided to do vaccum from scrap.
Design
Using Autocad software i designed 2D design,used side playwood 12 mm thickness and base load carry plywood is 20mm ,and also decided to make the wheel using wood.Now 2D drawing is complete.
I did check is press fit and alignment are correct after 2D design extrude to 3D design by using the commands Extrude ,substract ,union ,3D rotate,Champher,fillet
To get a demo view i did select some colors,it looks fine.
3D view of my fianl design
It was then machined using shopbot ,it was quite simple to assemble the machine parts.We had a thought to properly utilize fab inventory items we have in our lab. The idea to make wheels using plywood and rubber sheet, we used it as rear wheels of the machine.For front wheel we had to buy freely movable wheels.
The axle is also made up of plywood and is stationary.At the center of axle there is hole to place the ball bearing which helps to fix the shaft at a time,and also allow it to rotate.
The motor we used to drive the machine is a wiper motor which we bought from a scrap shop.We used two of it, each for two rear wheels.
Since the shaft of the motor was small, we increased it's length by welding a similar sized rod to it at a local workshop.
After assembling the body, motors and wheels our part of the project (mechanical) was ready.
