Toothbrush Head Stand

Topic
Tutorial
Modeling
Level
Beginner
Time to complete
Less than an hour
Authors
EmmanuelG
FreeCAD version
0.16 or greater
Example files
Thingiverse 2403310
See also
None

A daily-life problem

Electric toothbrushes rarely come with a head stand, while in a family you will often see multiple heads used with one body. Many people facing a common problem lead us to a variety of solutions, as you can see on Thingiverse (200-800 projects are related to that). Here is the first answer and how to design it.

This tutorial will take you through the steps needed to model the part shown in the image below using basic tools from the Part Design Workbench (many of the tools and capabilities are not covered).

First idea : a plate

From the start-page, select Part Design, or create a new document and select the Part Design workbench.

Create a sketch

Click on New sketch. Either from the contextual task menu at the left, or the toolbar above or from the Part Design menu at the top.

A dialog prompts you to choose the sketch orientation and provide an offset.

We will pick the XY Plane as shown in the image above (that orientation correspond to the common build plate of most 3D printers), then click OK.

You now are facing the XY plane from above, and have access to the drawing tools.

Click on Rectangle.
Place a first point.
Place the opposite corner.
Press ESC or click the right mouse button to stop using the tool.

You now have a floating rectangle of unspecified dimensions.

Click on a line of the rectangle, you now have access to the constraint tools at the right of the toolbar (depending of the size of your screen you may need to drag them to the left in order to see them all)
Click on Length
A dialog prompts you to set a dimension. Enter 80mm, click OK.
Repeat with the other side of the rectangle, also 80mm.

You now have a floating square.

Click on the lower left point of the square.
Click on the origin of the XY plane (at the intersection of the two thick lines).
Click on Coincident.

You now have a totally constrained sketch, as you are told by the solver on the left and the change of color. It is a good practice to always have a totally constrained sketch.

An under-constrained sketch can leave room for unwanted change, if you modify something later on. On the opposite, an over-constrained sketch is also not good. In that case the solver warn you of redundant constraints and you should remove some of them.

To leave the sketch, click either on the "Close" button on the left, or the icon in the toolbar, or press ESC.

You now only see the square, and the contextual task menu on the left show you more options than before.

Create a pad

Click on Axonometric among the standard views, to better see what will happen.
Click on Pad.
Enter 4mm and click OK.

Your sketch is now in volume !

Create a sketch on it

Select the upper face

The color of the face change and you have more options in the contextual task menu.

Click on New sketch. As a face was selected it will not ask you to choose a plane.

Click on Circle, place the center, then the radius.
Draw 4 circles
Press ESC or click the right mouse button to stop using the tool.

Select the circles
Click on Equal Length

Now the circles share the same radius.

Click on External geometry.
Click on the four sides of the square, it add lines, color magenta.

Theses lines will serve as reference to position the circles.

Use the to position them at 20mm from the edges.

Leave the sketch.

Create a pad

Cylinders !

Final touches

Rounding the edges.

Second idea

Main part with pad

Now in the Combo View, click on the OK button to leave the sketch edit mode and select Pad from the toolbar or from the Part Design menu. This will give you a Pad dialog in the Combo View. Using that dialog, first using the Type pulldown menu, select Two dimensions. Drawing presented at the beginning of this tutorial says the part is 53 mm long. We do it by Padding our sketch both ways from the center plane to make up that distance i.e. make the pad symmetric in relation of sketch-plane. The reason for is seen later when creating features. For now, given we want it to be 53 mm long in total we will input 26.5 for Length, and 26.5 again for the Second length. Alternatively, you can provide a single length of 53 mm and click the Symmetric to plane check box. Once that is done we now have our base solid upon which we will add additional features to construct our part.

Your model will have some extra lines on it compared to the images in this tutorial. To remove these extra lines, change to the OpenSCAD workbench, select Pocket001 from the hierarchy tree, and click the Refine Shape tool: . This creates a refined version of the model that is parametrically linked to Pocket001 and so is also linked to the entire history of the model. If we change, for example, the numerical value of a distance constraint the Refined Shape will update. In contrast, the Part WorkBench also has a Refine Shape tool in the pulldown menu, and it creates a Refined Shape that is more like a snapshot of the model as it existed when the Refine Shape tool was used. If we change (for example again) the numerical value of a distance constraint, Refine Shape created from the Part Workbench remains the same and does not update.

This tutorial and your model are complete.

Additional Resources

Links to accompanying video have been included.
FreeCAD file for comparison (made with 0.16.6706) Download

Other languages: