Basic Beginners FreeCAD v1 / 0.22 | Lesson 10 | Part Design Basic Exercise 3 | Coupler

Introduction

In this tutorial, we will learn how to model a coupler in FreeCAD's Part Design workbench. This exercise is based on a technical drawing and will help you understand how to simplify complex objects into manageable components. We will explore essential tools such as revolving, grooving, and using the polyline and symmetry features in sketches. By the end of this tutorial, you will have a solid understanding of basic modeling techniques in FreeCAD.

Step 1: Setting Up Your Workspace

• Open FreeCAD and create a new project.
• Switch to the Part Design workbench by selecting it from the drop-down menu.
• Save your project with an appropriate name to avoid losing progress.

Step 2: Creating the Sketch

• Click on the "Create a new sketch" button.
• Select the appropriate plane (XY, YZ, or XZ) for your sketch based on the technical drawing.
• Use the polyline tool to draw the outline of the coupler shape.
• Ensure that your lines are connected and that the shape is closed for successful revolutions.

Step 3: Applying Constraints

• Use the constraint tools to define the dimensions and relationships between the lines in your sketch.
• Apply symmetry to your sketch to make adjustments easier. This can be done by selecting the symmetry tool and defining the mirror axis.
• Double-check your constraints to ensure the sketch is fully constrained.

Step 4: Revolving the Sketch

• Once your sketch is complete and constrained, close the sketch.
• Select the sketch from the model tree.
• Click on the "Revolve" button in the Part Design toolbar.
• Define the axis of revolution and the angle (typically 360 degrees for a full revolution).
• Confirm the operation to create the 3D shape of the coupler.

Step 5: Adding Grooves

• Create a new sketch on one of the faces of the revolved coupler.
• Use the polyline tool again to draw the profile of the groove.
• Apply constraints to define the groove's dimensions accurately.
• Close the sketch and select it from the model tree.
• Click on the "Pocket" or "Groove" feature to remove material from the coupler, creating the desired groove effect.

Step 6: Final Adjustments

• Inspect your model and make any necessary adjustments by editing the sketches or features.
• Use the "Measure" tool to verify dimensions and ensure accuracy.
• Save your work frequently to prevent data loss.

Conclusion

You have successfully modeled a coupler using FreeCAD's Part Design workbench. You learned essential techniques like sketching, applying constraints, revolving, and grooving. To further your skills, consider exploring more advanced features or additional tutorials on FreeCAD. Keep practicing, and you'll become proficient in CAD modeling in no time!