Compression Springs

chrisjh777

Hi,

I've spend considerable time designing a generic compression spring with closed and ground ends.  

The design intent being, I want to build a document containing various springs sizes that I use by:

1.    duplicating the original compression spring in a new tab (Named with Spring Size Detail),

2.    then alter the parameters Spring Diameter, Wire Diameter, Closed End Lengths, Mid Section Length to end up with a new size spring.

I ended up with a successful original, but when I try to edit the it or the duplicates, I end up with a Sweep Error indicating the problem is with the wire diameter.

This is driving me nuts.  Obviously I am overlooking something.  Help appreciated.

Check it out here:  https://cad.onshape.com/documents/9da6fc064823190c070745f0/w/86325936fb2eb30a1c6b1ad9/e/2b51ab92c27568933572cacf

jakeramsley

By using multiple helices, there is a possibility of a discontinuity at the connections.  What I think is happening is when you change the diameter, the face is twisting (which you can't see because it is circular) and at the point where the helices line up the edges of the twist isn't aligned and creates a discontinuity.  I would suggest doing each segment as a new sweep using the ending face of the previous sweep as the profile to sweep.  This will create an edge at this point, but should work.

jakeramsley

By using multiple helices, there is a possibility of a discontinuity at the connections.  What I think is happening is when you change the diameter, the face is twisting (which you can't see because it is circular) and at the point where the helices line up the edges of the twist isn't aligned and creates a discontinuity.  I would suggest doing each segment as a new sweep using the ending face of the previous sweep as the profile to sweep.  This will create an edge at this point, but should work.

chrisjh777

jakeramsley said:

By using multiple helices, there is a possibility of a discontinuity at the connections.  What I think is happening is when you change the diameter, the face is twisting (which you can't see because it is circular) and at the point where the helices line up the edges of the twist isn't aligned and creates a discontinuity.  I would suggest doing each segment as a new sweep using the ending face of the previous sweep as the profile to sweep.  This will create an edge at this point, but should work.

Thanks for the heads up Jake.

Your suggestion does work.  I had used this method in a previous spring, but had forgotten about it.

I tried again with 3 helices to generate 3 "Parts", (Top Closed, Mid, and Bottom Closed Segments of the spring), then used a Boolean function to blend them together.  This approach works with caveat that the number of turns in each segment must be a whole number.  In other words, you cannot use 1.5 turns.

I can now successfully duplicate a compression spring, then change the parameters to quickly form a new spring, and add it to my library.

Parameters like:

Wire diameter,
length of each segment,
number of turns in each segment,
whether it has ground ends or not (achieved by suppressing or not suppressing the ground ends).

Here is my latest:  https://cad.onshape.com/documents/709d86590c01607e42a93ad9/w/20df6d0e3d11bbb9121b718a/e/8fa62e852500412ac253824c