Bench power supply enclosure (PartDesign, SheetMetal "Fold a Wall" function, TechDraw & Inkscape)

This tutorial explain how to make a sheet metal enclosure on FreeCAD 0.19 using a Bench Power Supply as an example. Step 1 to 5 show how to model the enclosure starting with flatten sheet metal. Step 7 to 8 provide some tips to make drawing with all required information to manufacture the enclosure.

  1. Step 1: Modelling of the sheet metal shape

    1.1) Go to Part Desing WB ;

    1.2) Creates‎ a new sketch on XY Plane ;

    1.3) Sketch the geometry as below ;

    1.4) Constrain geometry as below ;

    1.5) Leave the Sketch editing mode ;

    1.6) Extrude a solid of 1.5 mm from sketch (with Pad function) ;

    1.7) Make a symetrical extrusion with Mirrored function in the plane corresponding to the vertical sketch axis (here YZ) ;

    1.8) Set Refine parameter to "true" to remove the centre edge.

  2. Step 2: Sketch of components mounting holes

    2.1) Create a new sketch on face to be drilled ;

    2.2) Sketch vertical construction lines at the bends to add visual cues to the sketch;

    2.3) Sketch circles as below, positioning them approximately at their final location. There are 5 circles in the first section, 7 in the second and 1 in the third ;

    2.4) Apply vertical and horizontal alignment constraints as below, by selecting the centres of the circles to be aligned and then using the Vertical and Horizontal functions (shortcuts "V" and "H");

    2.5) Add diameter constraints as follows: 12.00 mm, 11.12 mm, 6.30 mm (2 slots), 9.52 mm (2 slots), 3.17 mm (7 slots) ;

    2.6) Add the distance constraints starting with vertical constraints as follows;

    2.7) Add horizontal distance constraints as follows ;

    2.8) Finally, add a symmetry constraint.

  3. Step 3: Sketch of ventilation holes

    3.1) In same sketch, add a circle of diameter 6.35 mm with distance constraints as below (76 mm and 13 mm);

    3.2) Select the circle and click on Rectangular Array function;

    3.3) Set rectangular array with 4 columns and 3 rows, equal vertical/horizontal spacing and constrain of separation between elements ;

    3.4) Click on OK and then in any direction to place the array ;

    3.5) Constrain the elements with a spacing of 13 mm and a horizontal direction;

    3.6) Make a Symmetry of the rectangular array ;

    3.7) Constrain the symmetry with a horizontal alignment and a distance of 25 mm.

  4. Step 4: Creates the holes from sketch

    4.1) Use Pocket function to create holes from the sketch ;

  5. Step 5: Create bending edges

    5.1) Create a new sketch on sheet metal face ;

    5.2) Create a Line at the first bend with Coincidence constraint as below ;

    5.3) Leave the sketch editing mode ;

    5.4) Repeat the same operation for the second bend : create a new sketch -> create a line -> leave the sketch ;

    5.5) Same for third bend ;

    5.6) And so on...

  6. Step 6: Fold the enclosure

    6.1) Go to Sheet Metal WB ;

    6.2) Select the designed part and first edge ;

    6.3) Apply Fold a Wall function to fold a wall at a chosen line ;

    NB : invertbend parameter allow to fold in other direction, so that the right side is folded ;

    6.4) Repeat the same operation for the second fold : select face -> select edge -> Fold a Wall ;

    6.5) Same for third fold ;

    6.6) And so on... Enclosure is now complete !

  7. Step 7: Place view and quotations

    7.1) Go to TechDraw WB ;

    7.2) Add a new page using a selected template or using the default template ;

    7.3) Add a 2D projection view of unfold sheet metal ;

    7.4) Add a horizontal length dimension, vertacal lenght dimmension and diameters as below ;

    NB : Each diameter is placed on only one circle so as not to overload the drawing ;

    7.5) Save the current page as SVG file.

  8. Step 8: Place lines and annotations

    8.1) Open the drawing with Inkscape software ;

    8.2) Use the Bézier curve and line segments function to place all the lines, starting by folding lines represented by interrupted line ;

    8.3) Placing mixed one-point lines for axes of revolution and symmetry ;

    8.4) Placing text for annotation and product information to finish the drawing ;

    8.5) Remaining space can be fill with an isometric view of the folded part, as below.