Week 2

Computer Aided Design

Assignment Requirements:

Model (raster, vector, 2D, 3D, render, animate, simulate, ...) a possible final project.
Compress your images and videos.
Post it on your class page.

Learning Outcomes:

Evaluating and selecting 2D and 3D software.
Demonstrating and describing processes used in modelling with 2D and 3D software.

Introduction

I really love mechanisms and how mechanical systems work, so I decided to design a Crank-Slider Mechanism which transforms the rotating motion into reciprocating/linear motion. The assembly of a piston, cylinder, connecting-rod and crankshaft is the classic form of the slider-crank mechanism where a slider crank transmits motion generated by the linear displacement of the piston by a working fluid to rotational motion of a shaft.

The mechanism consists of 4 elements, a base which is fixed to the ground, link 1 which rotates from 0 to 360 degrees, link 2 which connects link 1 with the slider, a slider which moves along the base generating the linear movement. I will be using GIMP to make a draft for the mechanism, Inkscape for sketching the parts in 2D, XDesign for the 3d modelling and Fusion 360 for assembly, rendering, animating and simulating the mechanism.

Steps in General:

Step(1): Sketching the mechanism using GIMP
Step(2): Designing links, base and slider using XDesign
Step(3): Assembling, rendering, animating and simulating the mechanism using Fusion 360
Step(4): Sketching the final project using CorelDraw

Steps in Details:

Step(1): Sketching the mechanism on GIMP

GIMP is an acronym for GNU Image Manipulation Program. It is a freely distributed program for such tasks as photo retouching, image composition and image authoring. It has many capabilities, it can be used as a simple paint program, an expert quality photo retouching program, an online batch processing system, a mass production image renderer, an image format converter, etc.
Downloaded and installed GIMP
From the File menu, selected New to create a new image
Used the Pencil Tool with colors to draw the main parts of the mechanism
Used the Eraser Tool to erase and delete unwanted lines or curves

Step(2): Designing links, base and slider on XDesign

Opened the XDesign on a browser, created and account and then created a new component called Link 1

Drawed a slot with 160 mm length and 30 mm height and made 2 holes of 15 mm diameter as shown

Used the Extrude command to add a 10 mm thichness to the link and then pressed ok.

Used the Extrude command again to make a joint pin of 20 mm height. This pin will be used while assembling link 2 with link 1.

Now! I finished modelling of link 1 and exported it as .step file. This format is suitable when importing the link in Fusion 360 or any 3d modelling software.

Created a new component Link 2, drawed a rectangle (300 mm * 30 mm) and made 2 circles of 15 mm diameter at the end of each side with spacing of 15 mm as shown

Drawed another 2 circles of 30 mm to make rounded edges instead on sharp corners, and used the trim tool to cut the unwanted lines and curves.

Extruded the link 2 to 10 mm thickness as same as link 1 and exported it with .step format

For designing base, I drawed 2 rectangles, one with dimensions of 540 mm and 80 mm, and the other with dimensions of 420 mm and 30 mm

Extruded the shown area to 3o mm, the small rectangle will be cut from the whole part

Drawed a 15 mm circle on the base to make a pin joint which connects link 1 to base and extruded it to 10 mm

Now the base is ready and will be exported as .step file

For designing the slider part, created 2 rectangles, the small rectangle will be cut extruded to create the sliding slot, used the fillet feature to make the top edges rounded and then created a pin that will be used while assembly link 2 with the slider.

Now! Link 1, link 2, base and slider are ready for assembly.

Step(3): Assembling, rendering, animating and simulating the mechanism on Fusion 360

Started by creating a new project called Fab Academy and made a new folder called Slider Crank Mechanism and started uploading the base, slider, link 1 and link 2

Inserted the base into the current design and made it ground to restrict its movement.

Inserted link 2 to the design, made a revolute joint between base and link 1, now link 1 can be rotated w.r.t base through the base pin.

Inserted link 2 and made a revolute joint between link 2 and link 1

Inserted the slider and made a revolute joint between link 2 and slider and then made a sliding joint between the the slider and the base.

Now the mechanism is ready and rotates well

Opened the Rendering workspace and applied material for each part.

From the Sence settings, selected Ground plane and Reflections and then pressed on the In-Canvas rendering to start rendering the model locally.

After finishing rendering, I captured an image.

In the Animation workspace, I disassemblied the parts by moving each element for a distance, then used the restore home option to return each element to its place and orientation.

Here is the animation video showing the disassembly and assembly of the C-S mechanism.

For simulation, I chose to make a motion study for the mechanism when link 1 rotates from 0 to 360 degrees

Step(4): Sketching the final project using CorelDraw

Downloaded and installed CorelDraw
Created a new document of 300 mm width and 500 mm height.
Used the rectangle tool to draw a rectangle of 300 mm width and 500 mm height.
Used the rectangle tool again to draw a rectangle which represents a drawer of 100 mm width * 100 height.

Made a copy of the previous rectangle and pasted it beside and made a third one to create the first raw, did the same to create 15 identical drawers. Created a circle and trimmed it to create the following shape.

Used the text tool to write down Smart Drawer
Used the color palette to fill each drawer with a color.

Here is a basic sketch for my final project.

Finally, I have:

√ Modelled (raster, vector, 2D, 3D, render, animate, simulate, ...) a mechanism

√ Compressed images and videos

√ Posted in my class page

Downloads:

Issues & Solutions:

Issue#1: When I tried to apply a material appearance for each component, there was no change!

Solution#1: I found that it is a must to break the link between the component in the assembly environment and its original source.

Issue#2: When I uploaded the parts in .step format to be downloaded, there was an error and they could not be downloaded through the browser!

Solution#2: I compressed the files in .rar format instead of .step and it worked well.

Useful Resources & Aknowledge:

Videos showing demonstration and animation for Slider Crank Mechanisms.
OBS Studio is a free and open source software for video recording.
Thanks to Ahmed Saeed, his assignment was really helpful and easy to follow.