## Creating a Revolved Extrusion in SolidWorks 2008 – Part II

written by: johnsinit • edited by: Lamar Stonecypher • updated: 1/27/2009

Following the SolidWorks overview, sketch and extrude series, this article continues the tutorial on making revolved extrusions in the SW2008 and 2009 versions.

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### Introduction

So, you have mastered the sketch construction, and the extrude process in the new SolidWorks 2008. You have also studied the Revolved Boss/Base feature and used it to create parts that have a cross-section rotated about one of the parts axis. But what if the part is more complex – and the axis of rotation is not one of the sketched lines? For example – a ring:

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### Alternatives

This detail is almost impossible to construct by a simple “Extrution" feature (although it is achievable by creating a “square ring" and applying fillets to achieve the round one – but this is, of course, not a way to work with CAD program). So, using the “Revolved Boss/Base" is a must here. However, the part is not rotated about one of its sketched lines…

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### Sketch

In fact, the would be no straight lines in sketch at all… Nevertheless, as always in SolidWorks, we start by constructing a sketch:

Click on any of the principle planes, and draw a circle profile. Set the circle dimension – this is your ring “wire" diameter. Now, click on “Line" option in the sketch features. Instead of solid line – pick the “Center Line" – dashed.

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### Center Line

Next, draw the line (its length is not important), and set the dimension between the line and the circle – this would be the “Mean" diameter of your ring. Remember, it is actually a radius – so you have to divide the intended mean diameter by 2:

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### Symmetric "C"

Exit the sketch, and use the “Revolved Boss/Base" feature

e to create a ring – specifying the dashed center line as the rotation axis. Unlike the previous example of Revolved Extrusion, this time we have no need in full circle rotation. Thus, pick the mid-plane option and create a symmetric “C-profile", leaving an angle of 20 degrees.

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### Summary

Notice, that the edges of the “C" opening are not parallel but rather compliant with your specification of the revolution. It is obvious, that this “Revolved Boss/Base" feature is very useful for creating various parts that have a constant cross-section and an axis of rotation – either if it is “part" of the body or a “virtual" line and either it is a full-circle of a partial one!