Tuesday, July 8, 2014

Inventor Surfacing Triangular and Star Springs

This tutorial shows how to make a springs of non-circular section like Triangular, Star, Square, etc. using the Intersection Curve tool.


Spring_Triangle_320.ipt           Spring_Star_320

A similar tutorial that shows how to model an Hourglass spring is here.

Index of all Inventor tutorials is here.

• This tutorial and the steps illustrated herein are by no means claimed to be the best or the only way to create the given object(s).
• This tutorial is an attempt to introduce and demonstrate the awesome set of tools that Inventor has for curve creation and surface manipulation.

Start with Sketching image in the XZ plane.

Create a Triangle using Polygon 
image and Fillet image its corners.

Apply a Horizontal constraint
image to one of the sides.
Finish image the sketch and start Extrusion image

Set the output to Surface image and create a surface as shown
Again start Sketching image in the XY plane and create a horizontal line and a vertical construction line as shown.

These will be used to create a coil.
image the sketch.
Start Coil image

The line would already be picked as the profile and the Axis button active.

Set the output to Surface

Take the Coil Size tab and enter values as shown.

(Pitch) x (Revolutions) match the extrude distance of the triangle in earlier step.

Pick the construction line as axis and click OK in the Coil dialog.

This forms a helical surface as shown.

From the 3D Model - Sketch panel, start 3D Sketch
Start Intersection Curve image

Pick the triangular surface and the coil surface one after other.

Click OK in the Intersection curve dialog.

Hide all surfaces and sketches from the Browser bar.

This reveals the intersection curve formed.

image the sketch.

Create a new work plane using Normal to Curve at Point image

Pick the intersection curve and pick a point as shown when a new work plane starts appearing.

Right click the newly created work plane and select New Sketch.


Create a circle at the center.
Start Sweep image and use the circle to sweep along the intersection curve.

This creates the triangular spring.

Next from the Tools - Materials panel, select Appearance
Select the spring and apply any suitable material by first selecting the spring and then right-clicking on the material swatch followed by selecting Assign to Selection from the context menu.

Similarly a star shaped spring can be created by making the first sketch in a Star shape instead of a filleted triangle.
Finally, from the Environments panel, Start Studio image_thumb53[6]

then click Render image_thumb54[6] and select the Pleasant Lighting Style. Click the Render button on the dialog to render the image.
Equally simple and interesting is creating your own, brand new, fully functional CAD system with 3D sketching and surfacing capabilities using a geometric modeling kernel.

cMayoCAD from CADVertex is one such program.

Download the detailed course contents for cMayoCAD here.