We are trying to reduce size in a handheld instrument...
One idea calls to use a slender, long travel compression spring riding over a metallic shaft. the problem being noise emitted when the spring buckles and snaps against the shaft. Secondarily, the sound emitted when the buckled spring rubs along the shaft during continued compression.
We need to see 250,000+ cycles minimum. forces are low (couple pounds compression force.) total travel is about an inch.
has anyone used coatings to mitigate audible emissions from spring assemblies? other things to look try?