3 Replies Latest reply on Mar 3, 2011 11:08 AM by David Mackie

    Thin membrane

    David Mackie

      Hi,

       

      I'm trying to build a 3d part which resembles a thin membrane with an approximate elliptical surface (xy plane) and with varying thickness in the z direction.  The membrane dimensions are approx 1.5mm x 2.5mm for the minor and major axis of the surface and the thickness varies from 1um to about 20um.  I am using an imported image of a contour map and have tried tracing around the edge with a spline, extruding this over a very small thickness and then using freeform to place control curve lines across the membrane surface, place control points and adjust each of them to the required height in the z direction.  I have encountered a few problems mainly I think because of the disparity in dimensions and very thin adjustments using the freeform tool.

       

      I suppose all I'm looking for is some advice on whether I'm going about this the right way.  I'm considering scaling up the variation in the z-direction initially (can rescale it later via separate modelling software) and using the same technique.

       

      However I'm wondering if anyone has made a similar structure before or has better ideas of how to go about this.

      Any help is most welcome.

       

       

      Thank you in advance

       

      David Mackie

       

      Ultrasound Engineering

      PhD Student

        • Re: Thin membrane
          Christopher Thompson

          If you are using surfacing, I would consider using the deform (curve-to-curve) option in place of the freeform tool. Then I would either thicken the surface or shell it out if possible.

           

          If possible and depending on the geometry, I maybe tempted to model a membrane as sheetmetal part using a forming tool for the complex geometry, or as a shelled part using the indent feature (see here). Can you post an image?

            • Re: Thin membrane
              David Mackie

              Hi,

               

              Thank you for the replies.  I've attached the contour map I'm working from.  The contour line values are in microns.  I initially allowed for the thickness changes in the membrane through a number of extrusions but this method did not produce the nice smooth membrane I'm looking for and fully believe Solidworks has the capabilities to produce a nice representation with smooth transition of thickness across the membrane, thus better mimicking the real life structure.  At the moment I will assume the bottom face of the membrane is perfectly flat and all thickness values correspond to changes in the upper surface only.

               

              I've no experience with the sheet metal tool or indents to be honest but I'll search for suitable examples and do some experimenting so thanks for the advice.

               

              Unfortunately I have no scanned cloud point or mesh data to work with.

            • Re: Thin membrane

              Hi David,

               

              Is it possible to get a scanned cloud point or mesh of the actual part? If so, ScanTo3D  (SW Premium) would be the way to go because you can automatically derive curves from the cloud or mesh data.

               

              Mark