FreeCAD: CLIL

Computer-Aided Drawing and Design

Developments in CAD applications in recent years have revolutionized the way the design, manufacturing and construction industries work. It is now used in all areas of engineering and construction.

CAD: Computer-Aided Design/Drawing/Draughting.

CAG: Computer-Aided Graphics.

CAM: Computer-Aided Manufacture.

CADAM: Computer-Aided Design and Manufacture.

Benefits of CAD in industry

Standardisation.

Speed and quality.

Ease of modification.

Storage and retrieval.

Ease of formatting and scaling.

The use of library components.

Use of layers

2D CAD

AutoCAD

2D CAD software became popular un the 1980s. It is used by architects, designers and engineers to produce fully dimensioned orthographic production drawings.

3D CAD

Solidworks

3D Modelling software allows designers and architects to create 3D computer generated models of their designs that would have previously been produced from materials such as polystyrene, clay or card. Component parts are created using various modeling techniques and assembled to form the final model.

What is FreeCAD

FreeCAD is a parametric (the 3D objects you design are controlled by parameters) 3D CAD modeler.
FreeCAD is a free, open source, multi-platform software.
It is made primarily to model real-world objects.
We use the latest stable version: 0.17-13541.
FreeCAD is hosted on GitHub.

You can learn about FreeCAD with these Videotutorials:

FreeCAD. Season I (Wiki ) Vídeos)

FreeCAD. Season II (Wiki) (Vídeos)

Installing and setting basic preferences

Download an installer (.exe) package corresponding to your version of Windows (32bit or 64 bit) from the Download page.

Start FreeCAD. Make sure you are working with FreeCAD 0.17! (Help/About Freecad)

Select Part workbench.
Go to Edit/Preferences.
Language: General/General/Language.
Auto load module: General/General/Start up (Part workbench).
Create document at start up: General/Document/Create new document at startup
Blender navigation: Display/3D view/3D Navigation = Blender.
Antialiasing: Display/3D view/Anti-aliasing (MSAA 8x).
Background: Display/Colors/Background color.
Refine: Part Design/General/Model settings: Activate 3 options.

Close FreeCAD and start it to check everything Works right.

Basic Navigation

Prusa i3

We are going to see the 3d model of the Prusa i3. Open 01-prusa-hephestos-assembly.fcstd.

Warning: the file is huge. It may take a long time to open. To see the different elements you can go to:

Source files for the Prusa Hephestos in Github.

Vitamins y Electronics: A library of Parts to be used in FreeCAD.

Notes:

Zoom in/out: Use the mouse wheel.
Pan: Hold the middle mouse button + move the pointer.
Rotate view: Hold the middle mouse button + move the pointer + shift.
Fit the content on the screen.
Fit the selected content on the screen.
Orthographic view / Perspective view (O, P keys).
View icon: Axonometric, front, top, right.
Style button (flat lines, shaded, wireframe, points, hidden line, no shades).
Create new view.
Tile windows.
Panels (combo view with the Model Tab.
Hide/make visible (Spacebar)
Tree view (to manage groups, objects and object names).
View: Freeze and save.

Exercise 1: Open the file: 02-bottle-can-euro.fcstd Make 4 different views: Bottle, can, euro and all of them.

Exercise 2: Save the views into a file. Open FreeCAD and load the views you created.

Exercise 3: Arrange 4 different Window. Place a view in each of them.

Dome

A geodesic dome is a hemispherical thin-shell structure based on a geodesic polyhedron.

The triangular elements of the dome are structurally rigid and distribute the structural stress throughout the structure, making geodesic domes able to withstand very heavy loads for their size.

Our geodesic dome is made of wood rods and printed pieces of 4m in diameter and 2m in height.

Open file: 03-domo-3D.fcstd

Here you can find some information about the dome and its construction.

Notes:

Take a look at the different folders of the dome.
Take a look at the different 3D printed pieces.
Take a look at the materials list.
Show / Hide pieces (space key).

Exercise 4: Create the following views:
* One with the blue rods and its pieces.
* One with the white rods and its pieces.
* One with the list of materials from above.
* A forth with the assembly detail of the strutcaps.

Exercise 5: Configure your FreeCAD screen to show three views: top view, the front view and the axonometric – isometric view.

Generic Objects

There is a FreeCAD Library, maintained by the community of users of FreeCAD: FreeCAD Library.

In the Generic objects folder you can find familiar objects such an euro coin, a beer bottle, a soft drink can,… We are going to work with them.

Open the file 03-bottle-can-euro.fcstd, that contains the bottle, coin and can.

Those objects are in a full-size scale and will be used as a reference to know the size of our designs.

Constructive and solid geometry (CSG)

CGS stands for Constructive Solid Geometry and describes the most basic way to work with solid 3D geometry, which is creating complex objects by adding and removing pieces to/from solids by using Boolean operations such as union, subtraction or intersection. The simplest solid objects used for the representation are called primitives. Typically they are the objects of simple shape: cuboids, cylinders, prisms, pyramids, spheres, cones.

CSG: Placement

Open the file with the reference objects: 03-bottle-can-euro.fcstd.
Select Part Workbench. A workbench is a collection of tools that make it easy to perform a task. The Part Workbench provides basic tools for working with solid parts: primitives, such as cube and sphere, and simple geometric operations and Boolean operations.
Placement specifies the orientation and location in the 3D Space.
Example: Change the position of Euro Coin.

Notes:

To move objects it is better to use the Move tool of the Draft Workbench. With this tool you can snap a point in a object to an endpoint, midpoint, center of a circumference, etc.

Exercise 6: Move the objects as in the picture.

CSG: Primitive object ‘Cube’

Toggle axis cross.
Create a cube solid.

Take note the default cube is very small (10x10x10 mm), positioned at the origin with the label ‘cube’.

View the Properties of the cube.
Change its dimensions (Length, Width, Height).
Change the shape color.
Appearance: Change material to gold.
Example: Set the dimensions to 10x10x3mm.
Draw style: Shaded.
Point as a decimal separator.

Exercise 7: Make the Space Odyssey Monolith with the ratio 1 : 4 : 9 dimension.

CSG: Primitive Object ‘Cylinder’

Click the Create Cylinder button.
Select it and fit it on the screen (V, S).
Take note of the generatrix.
The generatrix of the cylinder is not shown if we select the shaded mode!
Test different modes: Flat lines, Wireframe, Points, Shaded …
In the Data tab you can edit the properties that define a cylinder: Radius, Height and Angle.
Set the radius to 1.6 mm.

Example: Place it in the center of a box (10x10x2), in the position x=5, y=5, z=0.

Exercise 8: Create a casino chip. It is a cylinder with the following dimensions:
* Diameter: 39 mm. Height: 3.3 mm.
* Export the casino chip as a .STL Mesh, to 3D print it.

CSG: Boolean substraction

We will make a drill in the box. We will use the cylinder as a drill bit and the subtraction (cut two shapes).

Move the cylinder in the z axis so it crosses the box.

To make the subtraction, select first the box and then, holding the Ctrl key, the cylinder so that both shapes are selected at one. Click the Make the cut of two shapes.
This will create a new object called Cut, in the model tab. Rename it to ‘Drill’. It’s important to name the objects (document) to find them later when the design gets complicated.
The underlying objects are still available and can still be accessed. They appear grayed in the Model tab as they are not currently displayed on screen.
Change the radius of the cylinder to 2mm. The Drill gets automatically updated. Change the dimensions of the box.
To delete the subtraction simply delete the Drill. The original objects won’t get deleted.

CSG: Boolean union

Union unites (fuses) selected Part objects into one. This operation is fully parametric and the components can be modified and the result recomputed.

Items can be added and removed from the fusion, by dragging them in or out of the fusion feature in the tree view with the mouse. A manual recompute (press F5 key or click on the recompute icon) is required to see the results.

After this operation it may be necessary to clean the shape with RefineShape.

Refine Shape cleans unnecessary lines. To use it, select the shape to be reshaped and click the Part → Refine shape menu.

Example: Unite (fuse) two hexahedra. Check the properties (Edit > Preferences>Part Design). All Model Settings must be “on”. Change the size of the cube within the union.

Exercise 9: Make the Tetris Tetromino (Polyomino made of four square blocks). I, O, T, S, Z, J, L.

Exercise 10: Design a standard Mecanno perforated with five 3 mm holes separated by 6mm in distance. Use copy&paste to duplicate the cylinders.

Tecnología E Ingeniería

FreeCAD: CLIL