looking for polymer as a compression spring
looking for polymer as a compression spring
(OP)
Greetings,
I am looking to use a polymer/rubber as a replacement for a spring in a device redesign.
Can someone give me some guidance on how to find a suitable compressible material?
It needs to be able to produce around 55 N over .40cm and occupy no more than 1.5 cm^3.
thank you
-bhays
I am looking to use a polymer/rubber as a replacement for a spring in a device redesign.
Can someone give me some guidance on how to find a suitable compressible material?
It needs to be able to produce around 55 N over .40cm and occupy no more than 1.5 cm^3.
thank you
-bhays





RE: looking for polymer as a compression spring
RE: looking for polymer as a compression spring
How many cycles must it withstand and how much tension can it lose over time.
Regards
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RE: looking for polymer as a compression spring
RE: looking for polymer as a compression spring
Regards
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RE: looking for polymer as a compression spring
The amount of space available it pretty restricted and as a result, There is a lot of force in a small area where the spring is held.
I was thinking that employing the right polymer would present a better way to distribute the load.
RE: looking for polymer as a compression spring
Regards
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RE: looking for polymer as a compression spring
"Polymers will take a permanent set with time and lose tension."
And pretty darn quick too. There is only one choice of polymer for springs and it's Acetal.
Read this manufacturer's overview with a large pinch of salt and a good dose of sceptism!
http://tinyurl.com/5lpwsp
Lot of force in small area/volume = steel.
Cheers
Harry
RE: looking for polymer as a compression spring
A bit of advice: If you're going to redesign the device, then redesign the device in its entirety, not one piece at a time. The real opportunity comes from eliminating parts by combining functions; nothing is cheaper than a part that isn't there.
Mike Halloran
Pembroke Pines, FL, USA
RE: looking for polymer as a compression spring
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RE: looking for polymer as a compression spring
To use an elastomer as you suggest, would it be best to constrain it so as to control the amount and direction in which the silicone part can deform? i'm imagining a silicone rubber plug in a cavity or guide and a plunger pressing against the plug. Is this on track with the usage you had in mind?
-Bryan
RE: looking for polymer as a compression spring
If you push on the end with a plunger, you have to leave room for the plug to expand in other directions, e.g. back up around a very loose fitting plunger, or radially through holes in the cavity, or radially in a loose fitting cavity, or just restrain part of its axial length and let the rest expand freely.
You need to get hold of a Pink Pearl and push on it for a while until you understand Poisson's Ratio a little better.
Mike Halloran
Pembroke Pines, FL, USA
RE: looking for polymer as a compression spring
Of course one must allow an elastomer to expand in one direction if it is compressed in another. However, one cannot exert a meaningful force on the elastomer without constraining it in at least one direction.
Controlling the direction of that expansion by design is what I would call constraining it so as to control its deformation.
RE: looking for polymer as a compression spring
Most elastomers will actually compress a little even if restrained as their molecular structure is flexible and they can be compressed to very slightly reduced volume.
Regards
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RE: looking for polymer as a compression spring