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Week 14

Mechanical Design

Assignment


Individual

• plan and make a machine.

• document the group project and your individual contribution.


Desktop laser engraver


The machine is meant to be a desktop laser engraver that uses an 8W laser . We began the planning process by examining different mechanisms and finally chose timing belts as the most favourable. Below is a breakdown of the pros and cons list used. We also wanted the parts to be as Fabbable as possible and to buy as few components as possible so most parts are 3D printable and laser cut.

Rack and pinion

Pros Cons
Easy to design and make Has backlash during motion
Easy to implement Motion is not too smooth
cheap(can be laser cut) Calibration is hard


Threaded rods

Pros Cons
Easily available in shops expensive
strong Makes the motion slower hence slow response
Can handle heavy weight Require coupling


Timing belts

Pros Cons
Easy to implement No protection against overloading
Fast response during motion costly
Minimal vibration Need pulleys to accompany
No lubrication needed


After examining the different pros and cons of the different mechanisms we chose timing belts since our machine needs to be fast and does not need to handle heavy weight. We also wanted a machine that is easily implementable.

The Sketches

We began the design process by sketching on paper as shown.



CAD

2D design



3D design



BOM

Part Quantity
Steel rods 8mm 6
3D printed parts(for holding bearings) 10
Acrylic cut parts 14
Nuts and bolts packet
Motors 3
Timing belt 2

prototyping



Assembly process


We used a vinyl material to cut out the body parts for the cnc machine using a lasercutter. Once the body parts where cut we joined them together as shown. The upper part was using an 8mm rod for holding the moving part of the cnc machine which we cut to sizes. I 3d printed the holding motors







Manually controlling the machine


Downloads