How Exactly Hairsprings are Manufactured – Explained with Videos (and thanks to E2O Innovations)

How Exactly Hairsprings are Manufactured – Explained with Videos (and thanks to E2O Innovations)

Very few companies manufacture hairsprings in Switzerland (read our article, Who manufactures hairsprings? See here ) Producing this strategic component is a complex, labor concentrated cycle covered in mystery. Not very many manufacturers would make their ways for show how they work. Monochrome goes in the background, at E2O innovation, sister company of Schwarz Etienne, to give an inside and out gander at how this autonomous maker has fabricated a rather great construction and mastery in the field.

Barely one centimeter in diameter, the hairspring is the beating heart of a watch development. Christian Huygens is credited (by common agreement) with the development of the principal development with a balance haggle in 1675. From that point forward, the standards of the regulating organ of the watch have changed practically nothing. The escapement offers driving forces to the balance wheel. Consequently, it is regulated by the balance. The oscillations of the balance wheel regulate the progression of time: each swing of the balance allows the gear train to advance a set amount. Its job is similar to that of a pendulum in a clock. The amazingly slight curled hairspring guarantees that the balance swings back and forward at a constant frequency.


Conventional Hairsprings are made of iron-nickel alloys like Nivarox, whose elasticity is almost unaffected by temperature. Nivarox is an acronym for Nicht Variabel Oxydfest (Non-Variable Non-Oxidizing). This alloy is in the same category as Invar, an alloy (FeNi36%) designed by Swiss Nobel prize victor Charles Edouard Guillaume.

Combining cutting edge industrial exactness and manual work, hairsprings are manufactured through ultra-exact metal lamination methods to deliver a malleable blade. It takes days to transform a metal wire into a flimsy spring by progressive advances. Tolerances are usually under 0.1 micron (100 nanometers), as the smallest variations of the spring profile have an impact on the watch performance. The innovation is known yet the trade insider facts to meet the necessary exactness make the difference.

Let’s take a more critical glance at how this is performed at E2O Innovations – Editor’s note:  the report beneath records just the main creation steps; the manufacturing interaction including various quality techniques, quality control, cleaning, heat-treatments, and so on – E2O Innovations started to manufacture hairsprings in 2014 and it took them more than 3 years of R&D, speculation and technical improvements to be completely operational.


Everything starts with a wire of FeNi alloy. At 0.6mm in diameter, the wire is drawn to absolutely 60 microns to 70 microns (0.06mm to 0.07mm) contingent upon the ideal hairspring. It at that point experiences several diamond passes on (up to multiple times in progression), gradually decreasing its diameter dynamically to reach its final width. It takes about fourteen days to draw more than 1 kilometer of wire, specifically as the wire is getting longer and more, each time it is drawn.

Anecdote: A distinction of 0.3 microns in the diameter after drawing would bring about a rate variation of 300 seconds a day for the movement!


At this stage, the wire is still round. It then should be folded into a rectangular lace. It is flattened through accuracy rollers, the outcomes being measured with lasers. The machine is self-adjusting if any disparity is identified. This is perhaps the most delicate strides of the creation interaction. Exactness is crucial as here, a 0.1 micron contrast would bring about a rate variation of 200/300 seconds a day for the movement.


The spring is then trimmed into regular segments – probably the easiest advance in the manufacturing process – somewhat more than the ideal length of the final hairspring, to allow for adjustments.


There are then injury into their wound shaped (usually 4 at multiple times) prior to being heat-treated to make sure they will keep their shape and enhance their mechanical properties.

They are then separated in a container that is shaken. A unimaginably basic/traditional interaction in comparison to the way all different operations are performed yet this is the most productive strategy. The internal size is adjusted utilizing a trimming apparatus (inside trimming) following the specification of each hairspring, only a couple curls from the middle to allow to adjust the collet.


Springs and balance wheels are checked and their performance is measured so they can be classified (inertia for the balance, strength for the spring) so they can be paired adequately. Schwarz Etienne utilizes under 20 unique categories to pair balances and springs. In the event that necessary the balance inertia can be adjusted and totally ready thanks to laser guided tools.


Laser fastening – the hairspring is affixed to the balance wheel’s collet. The length of the spring is then checked and it is cut if necessary (outside cutting).


The way the balance wheel (along with its spring) rotates and is ready is checked.


The terminal bend allows the spring to expand and contract concentrically. Because of the trouble of shaping a particularly small bend accurately, this progression is a delicate operation. It is performed manually, here on a flat hairspring. A particular device is utilized to press the furthest point of the hairspring and shape its terminal bend following a structure calibrated for each assortment.