Mechanical springs are always being a subject of my interest. I have created a calculator for designing helical compression spring, in fact i have created and published even an mobile app for helical spring design. Although, i must agree , as reported by many of my readers, it was not very user friendly to follow the instructions there and thus confusing to purchase the right spring for your project needs. So i decided to give it another try, this time i will write about the subject by breaking it in small chunks.
So, here, today i want to discuss how you can calculate the free length of the spring.
Free Length (FL) = Solid Length/height (SL) + Travel (T) —————- Eq.1
Also, the Travel (T) depends on the Spring Rate (K),
Travel (T) = Load (L) / Spring Rate (K) ——————- Eq.2
So, by now , it probably is clear to you that to calculate the free length (FL) , you either need to know directly the travel or the max. load on which the spring should operate and the spring rate.
Let’s take an example, say, you want to find out the free length of the printer bed leveling spring for your custom designed FDM 3D printer. for this, say:
Max. load exerted by the extruder head, L = 1.2 N
Spring rate = 0.2 N/mm
So, max. travel (T) =1.2/0.2 = 6 MM
Also, let’s assume that we have 1.2mm wire diameter and the number of turn = 8. So, SL = 8*1.2 = 9.6 MM.
Hence, the free length of the compression spring here = 9.6 + 6 = 15.6 MM
Hi, I am Shibashis, a blogger by passion and an engineer by profession. I have written most of the articles for mechGuru.com. For more than a decades i am closely associated with the engineering design/manufacturing simulation technologies. I am a self taught code hobbyist, presently in love with Python (Open CV / ML / Data Science /AWS -3000+ lines, 400+ hrs. )