Inside a 2.0 mm Wave Spring: How a Miniature Multi-Turn Wave Spring Is Made

Put a pencil on the table and look at the eraser. The component circled in the photograph sits comfortably inside that footprint: an outside diameter of 2.0 mm, several turns of flat wire, a free height you could lose in a shirt seam. It is a wave spring — and at this size it stops being something you pick off a page and becomes something you have to make.

Small does not mean forgiving. A part at this scale carries the same load specification, the same fatigue requirement and the same batch-to-batch consistency demand as a part fifty times its diameter. What changes is that every tolerance you were comfortable with gets divided by fifty as well.

This article walks through how a part like this one is specified, wound and verified: why the geometry is a wave spring at all, which structure and alloy to choose, what changes on the shop floor below about 5 mm, and where these components end up.

A note on names. The same component appears on drawings as a wave spring, a wave washer and — on older paperwork — a scrowave spring. Engineers who begin by searching for compression springs, or for a flat wire spring, generally arrive at the same shortlist. It should not be confused with a lock washer, which secures a fastener rather than storing energy, nor with a belleville washer / disc spring, which trades deflection away in exchange for height.

1. Why a wave spring instead of a coil spring

A round wire compression spring builds load by stacking wire vertically, so most of its installed height is material waiting to be compressed. A flat wire wave spring works differently. Flat wire is edge-wound into a helix, waves are formed around each turn, and the waves — not the wire stack — absorb the deflection. Run the numbers and the result is the one every designer eventually quotes: the same load in roughly half the axial space. That is also why a flat wire compression spring is often the first substitution engineers try when a housing has grown too tall.

The trade matters everywhere, but it decides the design when the envelope is 2 mm across. There is no room to lengthen a bore at that diameter. Two comparisons usually settle it. Wave spring vs coil spring is a question about height. Wave spring vs belleville washer is a question about travel: a disc washer gives force in almost no height but very little deflection, while a low profile wave spring gives a usable stroke and a flatter load curve across it.

Two jobs come up again and again at this size. The first is preload — holding a stack of parts in contact so nothing rattles. The second is take-up, where a tolerance take-up spring, or an axial play compensation spring, absorbs the accumulated slop of four or five machined parts so the assembly stays quiet for its whole service life.

2. Choosing the structure

"Wave spring" names a family, not a single geometry. Picking the wrong member is the most common reason a small part fails its first sample approval.

Single turn

A single-turn wave spring — usually catalogued as a wave spring washer — is one ring carrying two or three waves. It is thin and inexpensive, and it is limited: a single turn wave spring gives force but almost no working deflection. Wave spring washers are therefore specified for simple gap closing rather than controlled preload, and the same logic applies whether you are buying one washer or a million.

Multi turn and peak-to-peak

A multi-turn wave spring is a continuous coil of waves. In the peak‑to‑peak multi‑turn wave spring arrangement, the wave peak of one coil rests on the wave peak of the adjacent coil, so every turn contributes deflection and the spring rate drops as turns are added. This is the workhorse geometry, and a multi‑turn wave spring is what the part in the photograph is. When a drawing specifies a peak‑to‑peak multi‑turn wave spring without further qualification, this is what it means.

Nested

A nested wave spring stacks its turns peak-on-peak but in phase, multiplying force within the same installed height. Nested wave springs answer the case where the load requirement is high and the space is already fixed. Built this way, a high load wave spring — or a high force wave spring, the terms are used interchangeably — carries several times what a single-layer part of the same height manages. At the other end of the range, a low spring rate wave spring adds turns instead, trading force for a gentler curve.

Ends

Ends matter more than most drawings admit. A plain-end wave spring finishes wherever the wire finishes, so the last crest meets the housing on a point rather than a face. A shim-end wave spring adds a flat, ground lead-in at each end so load transfers evenly across the bearing surface. At a 2.0 mm outside diameter this is not cosmetic: a plain end wave spring can tilt in its bore under load, and a wave spring with shim ends will not. Shim end wave spring geometry is our default recommendation below roughly [TO CONFIRM: our recommended threshold OD] mm.

Gap and overlap

On a single ring, what happens where the two ends meet is its own decision. An overlap wave spring closes the circle with the ends riding past one another; a gap wave spring leaves a controlled opening. Overlap type wave spring designs hold a more even load around the circumference, while gap type wave spring designs drop into a groove more easily during assembly.

Less common variants

A linear wave spring ships as a straight length and is formed to circumference at assembly, which is how very large diameters are handled economically. A spiral wave spring winds inward rather than stacking upward. An interlaced wave spring interleaves two coils to hit a specific rate. A round wire wave spring exists, but it surrenders most of the flat-wire height advantage and is rarely the right answer.

Whatever the structure, the winding method is constant. The wave spring is coiled along the narrow edge of flat wire — a manufacturing technique referenced on older engineering drawings. This production method maintains stable outside‑diameter tolerance. A wave spring manufactured in this fashion holds its OD within the bore far better than a stamped ring, and this is how axial wave springs as small as 2 mm OD can be produced. The physics does not change between a small diameter wave spring and a large diameter wave spring; what changes is that every choice above has to be settled before the first metre of wire is wound, because none of it can be adjusted afterwards.

3. The material shortlist

Most work starts as a stainless steel wave spring and moves outward only when the environment forces it.

1. 302 stainless steel wave spring — the default. Good strength, easy to wind, and correct for the large majority of room-temperature assemblies.
2. 316 stainless steel wave spring — chosen when chloride or chemical attack is in play. The standard corrosion resistant wave spring specification for marine, food and process equipment.
3. 17-7 PH wave spring — precipitation hardened, noticeably higher strength than 302, and it holds load to around 315 °C. This is the usual step up when a 302 part relaxes in service.
4. Carbon steel wave spring and spring steel wave spring — cost-driven choices for dry, protected environments where plating handles the rest.
5. Beryllium copper wave spring — specified for electrical conductivity and non-magnetic behaviour, which is why it dominates connector work.
6. Titanium wave spring — mass reduction plus non-magnetic behaviour, at a price that has to be justified.
7. Inconel wave spring alloys — an Inconel X-750 wave spring holds load through sustained heat, while an Inconel 718 wave spring is chosen when strength matters more than creep. Both sit inside the wider nickel alloy wave spring group.
8. Hastelloy wave spring — reserved for aggressive chemistry where even 316 gives up.

A high temperature wave spring is really a material decision rather than a geometry one. Set the continuous service temperature first, then the corrosion condition, and the alloy list narrows to one or two candidates before anyone opens a design calculator.

4. What 2.0 mm actually changes on the shop floor

The design principles above apply at any diameter. Manufacturing does not scale so politely.

1. Wire cross-section falls to a fraction of a millimetre. Forming tools are reground for the specific part, and tool wear that would be invisible on a 60 mm spring shows up as a load shift within a single shift.
2. Free height has to be measured on a part weighing a few milligrams, where the measuring force itself is a meaningful fraction of the working load. Non-contact measurement stops being a luxury.
3. Load at working height is the number the customer actually buys, and on a miniature wave spring the acceptance window is narrow enough that sampling is not good enough — small parts are inspected at 100 %.
4. Burrs and cleanliness matter disproportionately. A burr that is a rounding error on a large part is a functional defect on a 2 mm one, particularly in medical and semiconductor assemblies.
5. Wave spring installation changes too. A 2 mm part goes into its bore with tweezers or a placement tool, not fingers, and it is worth designing the installation method at the same time as the spring.

5. Getting from a requirement to a part number

Good wave spring design starts from four numbers: bore diameter, available axial space, required load, and working height. Everything else follows. From those inputs a wave spring calculation returns the turn count, wave count and wire section that satisfy the load without exceeding the allowable stress at solid height — and it will also tell you honestly when the envelope cannot be met and the assembly has to change instead. If you prefer to run the first pass yourself, any wave spring calculator works from the same four inputs.

For standard requirements, wave spring selection is a table lookup. Our published wave spring specifications, wave spring dimensions and wave spring sizes cover more than ten thousand stocked items, and the wave spring catalog (spelled wave spring catalogue in most of our export markets) is the fastest route to a part number and a price. Where a listed item fits, the wave spring price and lead time are both known before you ask.

Where nothing fits, a custom wave spring is not the expensive exception it is often assumed to be. Because we form on wound tooling rather than dedicated dies, custom wave springs at this scale usually need no new tooling at all, which is why the wave spring cost of a bespoke geometry stays close to a catalogue equivalent. Send a groove drawing and a target load, and we will return a proposal with a wave spring CAD file and a wave spring 3D model for your assembly check.

6. Where parts this small go

A 2.0 mm outside diameter narrows the field, but not as much as you might expect.

1. Electronics and instrumentation — a connector wave spring maintaining contact force through thousands of mating cycles; a precision instrument wave spring holding an optical element against its seat.
2. Medical — a medical device wave spring inside a handheld surgical instrument, where consistency between batches is what the surgeon actually feels.
3. Motion and automation — a robotics wave spring in a compact joint, and a motor wave spring taking up axial play in a small brushless rotor.
4. Bearings — the classic case. A bearing preload spring, sold at ring sizes as a bearing preload washer and at coil sizes as a bearing preload wave spring, removes internal clearance and stops the raceway from skidding. A bearing wave spring is often the cheapest way to buy quiet running.
5. Fluid power and sealing — a valve wave spring returning a poppet, a hydraulic valve wave spring in a compact manifold, a mechanical seal wave spring keeping faces loaded, a pump wave spring, and a rotary union wave spring where a shaft has to turn and stay sealed.
6. Drivetrain — an automotive wave spring in almost any modern assembly, a gearbox wave spring and a transmission wave spring managing axial stack-up, a clutch wave spring softening engagement, a brake wave spring returning a piston.
7. Electrification — an EV wave spring and, written out in full on most enquiries, an electric vehicle wave spring, compensating thermal growth in an e-axle where a coil spring simply would not fit.
8. High-duty sectors — an aerospace wave spring under AS9100D control, an oil and gas wave spring downhole, an electro hydraulic actuator wave spring in flight control, and a high temperature equipment wave spring wherever a nickel alloy is the only option left.

7. How Lispring makes and proves these parts

Lispring has manufactured wave springs and retaining rings since 2009 from a 21,400 m² plant in Wenzhou, China. We are a single-family manufacturer by choice: wave springs, spiral retaining rings, constant section rings and laminar seal rings, and nothing else.

1. Winding on imported Japanese coiling equipment, with geometry developed in German FERD design software — the combination that lets a custom part reach first article without dedicated tooling.
2. An in-house testing centre accredited to ISO/IEC 17025 by CNAS, running spectrometry on incoming material, metallographic analysis after heat treatment, fatigue testing to the specified cycle count, and compression testing for the load curve on the datasheet.
3. Quality systems for the industries above: IATF 16949 for automotive, AS9100D for aerospace, ISO 13485 for medical devices, alongside ISO 9001, ISO 14001, ISO 45001, ISO 50001 and ISO/IEC 27001 for customer drawing confidentiality.
4. 43 authorized patents as of 2025, with about 7 % of annual revenue returned to R&D — and, for the record on what small and reliable can mean, a high-temperature wave spring built here flew on China’s Tianwen-1 Mars lander.
5. More than 10,000 standard items held in stock and over 20,000 variants in the catalogue, supported by a US subsidiary for North American lead times.

As a wave spring manufacturer we are asked the same question by every serious buyer: can you hold this, batch after batch, and prove it. The lab above is the answer, and it is the reason customers who first contacted us as one of several wave spring manufacturers on a shortlist stay with us as a single wave spring supplier. If you are currently qualifying wave spring suppliers, a sample with its full test report is the fastest way to compare.

8. Common questions

How small can a wave spring actually go?

The part in the photograph is 2.0 mm OD. Below that the limit is set by wire section and by whether the load can still be measured repeatably, not by the winding process. Send the envelope and we will tell you plainly whether it is makeable.

How long will it last?

Fatigue life is governed by the stress at working height, not by size. Specify the required cycles with the load and we will design to them and test to them.

Is there a standard to reference?

For single-turn wave washers, DIN 137 is the usual reference. Multi-turn geometries are specified by dimension and load rather than by a standard number, which is why the drawing matters more than the part name.

I already have a part number from another catalogue.

Send it. Cross-referencing an existing wave spring part number to an equivalent geometry is routine work, and it is usually faster than starting from the application. [Optional: name the competitor catalogue here if you want to target that cross-reference search term. Left neutral for now.]

Ask for a quotation

Send a groove drawing, or simply the bore diameter, available height and required load. You will get a recommended geometry, a material, a CAD file and a price — and for stocked sizes, samples on the shelf. Contact: +86-577-62606161 · [email protected]· www.lispring.com