I am new to blender and trying to create a cookie cutter, which I can then print using my Tevo Michelangelo printer.
What I have tried so far -
I created 2 svgs using Sketch as follows

Then I imported these in Blender.
Fill - applied solidify, and set thickness as 3mm, and offset as 0. Then converted this to mesh. This will be the roof of my cutter (top part, where I can press using my hand pressure)
Stroke - Converted to mesh, selected all edges, extruded 20mm to form the wall of my cutter. Then applied solidify and set thickness as 2mm. This is how both objects look like
Method 1 - I aligned them (using top view) and joined both objected using Command+J. This is how it looks after joining
I exported this to stl file and when I import it in CURA, it looks fine, but upon slicing, it does not print the walls.
Before Slicing -
After Slicing(Preview mode) -

Method 2 - Instead of joining them using Cmd + J, I perform the boolean union operation with an overlap threshold of 0mm.
After importing in Cura, the same thing happens as above. (Same settings)
Have been struggling really hard to figure out where it went wrong. Any help would be greatly appreciated. Thanks in advance

