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Impossibly tangled springs. How should spring be redesigned?

Impossibly tangled springs. How should spring be redesigned?

Impossibly tangled springs. How should spring be redesigned?

(OP)
Hi,
The dual compression coil design shown works great. In assembly it is tightly surrounded by plastic molded parts and provides electrical connectivity between a battery and a circuit board.

Problem is that when received from the spring mfr, these parts are incredibly difficult to separate from each other, even with shakers. The mfr has suggested that this nickel plated high carbon steel would not be so tangled if nickel plating were eliminated. I'm not sure that I believe all the tangling occurs in the plating process. Also, for electrical connectivity it seems non-plated steel could eventually fail. Any significant changes to the spring design will require redesign of plastic molds, pcba's, etc.

My questions:
1. Should I try a different material that requires no plating? Phosphor Bronze? Stainless Steel?

2. How can I redesign the end coils so that they are easier to untangle? I'm considering fewer turns in each coil with an "open" end. Resulting spring force variations can be accommodated.

3. Is my spring mfr lacking in capabilities to properly handle and package this spring to keep it untangled?

Thank you,
Dave

RE: Impossibly tangled springs. How should spring be redesigned?

Open coils will probably make tangling worse.

Consider specifying that the parts be shipped from the springmaker stacked on wooden dowels.

... or assembled to the mating part at the springmaker's shop.


Mike Halloran
Pembroke Pines, FL, USA

RE: Impossibly tangled springs. How should spring be redesigned?

The nickel plating process is probably an electroless nickel which is done with hundreds of parts in a rotating drum so it's not possible to keep them from tangling. A stainless steel part would only solve the problem if they can ship the springs in some kind of packaging that prevents the tangling. Dumping hundreds of springs in a box would probably tangle just as much. Stainless steel will have higher resistivity than high carbon steel, might not matter if current draw is low. With a simple compression spring, tangling is avoided by having the space between the coils smaller than the wire diameter.

----------------------------------------

The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

RE: Impossibly tangled springs. How should spring be redesigned?

We deal with a lot of double leg torsion springs (not quite what you are dealing with, but similar); we specify that the spring maker pack them on tackboard to keep them from getting tangled up. It also presents the springs in a predictable orientation for the assemblers.

RE: Impossibly tangled springs. How should spring be redesigned?

(OP)
Thank you all for your guidance. The tackboard sounds interesting. Is it sticky? Can you direct me to a specific product?
Thanks again,
Dave

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