Wednesday 28 September 2011

Flexible Coils

Every now and again someone asks me a question that gets the grey cells jumping.  How can I ....?
This time my colleague Mike was asking about bent coils for a PVC tube.  A lot of users out there know about the helix command that allows us to create straight coils e.g. for heat exchangers, but what about something more complex?  A coil following a complex path.  How can I create this?
Well you need to use some of the flexibility with the sweep feature.  This is a really powerful tool that can create truly complex parts with a single feature.  So where to start with the bent coil?
STEP 1:  Draw the spline for the hose

STEP 2:  Draw a line.  This will be the radius of the coil

STEP 3: Use a swept surface.  One of the options for sweeps is how the sketch will follow the path.  The advanced parts course goes into this in great detail and shows just how powerful the command is, but for this example I selected twist along path and chose 10 turns.

STEP 4: I selected the edge of the new surface and the end point and created a new reference plane.  Preselecting ensured that all the default options would be used.  I also ticked to set the origin on the curve

STEP 5: Create a sketch.  Here I used just one circle that matched the OD of the tube I was after

STEP 6: Sweep.  I selected the Thin Feature option to specify a wall thickness.  Thin features are a great way to create tubes and thin plates with the minimum of sketching.

STEP 7: Delete surface.  Use the delete body command to delete the 'construction' surface.

That's it.  A little more work than a straight coil, but you can create some really intricate designs with this one.

Gordon

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