HOW TO CREATE A HOLLOW SOLID FROM 2D SURFACE

[yasna.masye]

Hello I am yet again working on my spiral design for microfluidic chip purposes. 

As I am creating the inlets and outlets I encounter an issue in which I do not know what tool or how to create a closed hollow 3D solid from a 2D drawing. 

In the first picture circled the two drawings in which I need to turn into a hollow solid continuing the hollow spiral design connected to it. I need it to be closed from all sides but hollow. When I try to just extrude, I am met with no top and bottom surface like shown in the third picture.

Please do tell me how to create the top and bottom surfaces so that the design in hollow but fully covered on all sides.

Also as a side note, have I done my sweep correctly? I had to choose NO alignment in order for all the sides of the spiral to be created, as a regular sweep would result in one side (inner) being empty/no surface covering. I created the sweep using a 2D drawing of a rectangle (0.5x0.14 mm) as the base that is sweep along a helix line. 

Is there any other way to complete the sweep and make the spiral a more cohesive 3D hollow solid?

So if possible please do confirm if my spiral sweep is already ideal 🙂 Thank you!

Here I give the file so that you can see it better

[Kent1Cooper]

Since the spiraling part is not a single object anyway, but SURFACEs along the edges and REGIONs for the base and top, do the same for those end pieces.  In plan view, use BOUNDARY to create a REGION at the base level [red], then COPY that up to the top level [yellow].  This is at the other end from where your perimeter "walls" are in your third image, just so you can see the two:

[leeminardi]

If you plan to fabricate a fluidic device I think you should be thinking of modeling the desig as a solid rather than a collection of surfaces. The fluidic walls will need to have a thickness. The shape you should be sweeping should be a region that  looks something like this.

When swept along a line or spline it will have a tubular shape with open ends and a finite wall thickness.

For the "Y" area make an offset version of the shape and edit it as shown here.  The red polyline is the outside shape while the green will be used to create the internal hollow with a Boolean subtract.  Extrude both shapes as required.  The yellow shappe is the result.  Note that it is open at the end.