Fusion Tutorial 1b: Design of an Electronic Box, Continued

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Link to: Tutorial 1a (prev)

Link to: Tutorial 1c (next)

Introduction

This tutorial is the second in a series teaching basic Fusion CAD sketching and modeling tools.

In the previous tutorial, we designed a simple hollow box. In this tutorial we will start to add the features that will give it its function: A sample electronics enclosure that could be made on a 3D printer.

In this page we will explore more aspects of sketching, especially those that add features to the surfaces of an simpler model, and adding geometric constraints between features so that changes to the model's dimensions will carry through more smoothly. This is an example of parametric modeling. The goal is to tie together the features so only the minimum necessary set of dimensions needs to be displayed.

The pace of this tutorial will be somewhat faster than the previous one because knowledge of tools already presented will be assumed.

Add Mounting Lugs

Lugs to mount the E-box to a surface are the first features we will add to the design. We will repeat the sequence of opening a sketch on a plane, followed by extrusion into the third dimension.

Create a Sketch

Using the () "Rotate" tool, turn the box over in the window so the box bottom is exposed. Click the cusor on the plane of the bottom to select it. Next, use the () "Sketch" tool to open a sketch on that plane.

Use the () "Rectangle" tool to sketch two () "Center" rectangles off the sides of the box bottom. They need not be the same size at this point: We will apply geometric constraints that will help fix the dimensions.

Apply Constraints

• First we constrain the centers of the two rectangles to sit on the X-axis. In the "Constraints" group in the tool-bar, select the () "Horizontal/Vertical" constraint tool. This tool works by getting the user to pick points in pairs. Click on the ORIGIN as one of the points, followed by one of the center points of the rectangles you just drew.

As you make these selections you should see the rectangle centers snap to the X-axis in the sketch.

• Next we set the edges of the rectangles to sit on the edges of the box bottom. From the "Constraints" menu, select the () "Collinear" tool. Click on adjacent vertical edges to link the sides of the box bottom with the corresponding edges of the two rectangles.

You should see the edges of the rectangles snap to the sides of the box bottom.

• Next we tie the heights of the rectangles together. With the () "Collinear" tool still selected, click on the upper horizontal sides of the two new rectangles.

• Now we dimension the heights of the rectangles. In the "Create" group in the tool-bar, select the () "Sketch dimension" tool. Click on the outer vertical side of one of the new rectangles. A set of dimension bars should appear with an edit box associated with them. Drag the displayed dimension to a convenient location and type "5/8" into the edit field. When you hit the -ENTER- key the application should replace the fraction with its decimal equivalent: 0.625 in.

Both rectangles should move together to the revised height.

• Set the width of one of the rectangles also to 5/8". We will use the () "Equal" constraint tool later to fix the width of the other rectangle.