This page lists DIN 6796 conical spring washers M5 / M6 / M8 / M10 / M12 / M16 (thickness 1.2–4 mm); DIN 2093 disc springs are available on request. Disc springs are short-stroke, high-load axial spring elements. The common standards are DIN 2093 (disc springs, outer diameter 8–250 mm, inner diameter 4.2–127 mm, thickness 0.2–14 mm) and DIN 6796 (conical spring washers for bolts M2–M30). They can be used singly or stacked in series or parallel to adjust load and stroke. Typical uses: mold ejector return, bolt preload, fixture clutches and mechanical valves.
A disc spring (also called a Belleville spring or Belleville washer) is a conical, dish-shaped axial spring element whose key features are short stroke, high load and small installation space — it carries a larger load in the same space. Disc springs can be used singly or stacked: stacking in series increases deflection, stacking in parallel increases load.
This series covers general mechanical disc springs (DIN 2093 / DIN 6796), in spring steel, stainless steel and heat-resistant nickel-based alloy. A JIAHON affiliated company supplies customers throughout Taiwan.
Specifications (typical range)
| Item | DIN 2093 disc springs | DIN 6796 high-load washers |
|---|---|---|
| Purpose | Machine elements, mold return, fixture clutches | Bolt preload, preventing loosening from vibration |
| Outer diameter De (mm) | 8–250 | For bolts M2–M30 |
| Inner diameter Di (mm) | 4.2–127 | Matches bolt hole |
| Thickness t (mm) | 0.2–14 | 0.4–7 |
| Free height H0 (mm) | Depends on series A/B/C (h0/t approx. 0.4–1.3) | Fixed by bolt size |
| Material | Spring steel 51CrV4, SAE 6150, SUS301, Inconel 718 | Spring steel (standard), stainless steel (optional) |
| Surface treatment | Black oxide, phosphate, oiled, zinc-nickel plating | Black oxide (standard), Geomet anti-corrosion coating (optional) |
| Stacking | Single, series (alternating, faces opposed, for more deflection), parallel (same direction, for more load), mixed |
Note: these are general size ranges under the DIN standards; actual size, material, surface treatment and load/stroke depend on your machine specifications and working environment.
Applications
Disc springs are common “short-stroke, high-load” spring elements in electronics manufacturing and machinery. Four typical applications in SMT fixture, semiconductor mold and machine maintenance MRO purchasing:
- SMT fixture and clamp return: return mechanisms for moving pressure blocks on SMT placement fixtures, IC programming fixtures and test sockets. The short stroke of disc springs gives stable clamping force in the limited space of a fixture; DIN 2093 series B in parallel stacks is common.
- Semiconductor / IC packaging mold ejection: ejector mechanisms in IC packaging molds and lead frame molds need high ejection force over a short stroke. Series/parallel stacks of disc springs allow precise adjustment of ejection force and stroke and can withstand over 1,000,000 cycles (typical experience; follow the manufacturer’s specification and operating conditions).
- Anti-loosening bolt preload on machines: anti-loosening preload for fixing bolts on SMT machines, CNC machines and robot guide rails. DIN 6796 high-load washers are fitted under the bolt head to provide axial preload against vibration loosening, with better anti-loosening performance than ordinary spring washers.
- Mechanical valve / clutch return: return elements in plant piping valves and mechanical clutches. The high load capacity of disc springs provides stable closing or release force, and they can withstand operating temperatures above 200 °C (heat-resistant specification required).
Selection guide
| Application | Recommended specification | Stacking | Material |
|---|---|---|---|
| SMT fixture return | DIN 2093 series B | Parallel, 2–4 discs | Spring steel 51CrV4 (black oxide) |
| Mold ejection | DIN 2093 series A (high load) | Mixed parallel + series | Spring steel SAE 6150 |
| Bolt preload | DIN 6796 to match bolt size | Single disc directly under the bolt head | Spring steel (standard environment) / stainless steel (humid) |
| Semiconductor vacuum chamber / chemical environment | DIN 2093 stainless steel | By load | SUS301 / 17-7PH |
| High temperature (> 200 °C) | Custom specification | By load | Inconel 718 / NIMONIC 90 |
Note: this table is a general reference; the DIN series, stacking and material depend on working load, stroke, ambient temperature and required cycles.
Why “dish-shaped”? Disc springs vs coil springs
A disc spring is a conical, dish-shaped metal washer. Under axial load the dish is pressed flat, producing elastic deflection through its thickness. Energy is stored as bending strain as the dish flattens, not by torsion of the wire as in a coil spring. This structural difference gives several key properties:
| Property | Disc spring | Coil spring |
|---|---|---|
| Load density | High (clearly higher in the same space) | Low |
| Stroke | Short (small deflection per disc) | Long |
| Space | Small (thickness 0.2–14 mm) | Large (needs enough coils) |
| Stacking | Flexible (series / parallel / mixed) | Hard to stack |
| Typical use | Bolt preload, mold ejection, fixture return, clutches | Valve return, shock absorbers, keys |
Decision logic: choose a disc spring when installation space is limited and high load is needed; choose a coil spring when the stroke must be long and the load is relatively small. SMT fixture pressure blocks, IC mold ejection and CNC bolt locking are all “short stroke, high load” — the home ground of disc springs.
DIN 2093 vs DIN 6796: what each standard covers
| Standard | Purpose | Series |
|---|---|---|
| DIN 2093 | Disc springs (general machine elements) | A (high load, low deflection), B (medium), C (low load, high deflection) |
| DIN 6796 | High-load anti-loosening bolt washers | For bolts M2–M30 |
A common misconception: “if a bolt loosens, just switch to a DIN 2093 high-load series A spring” — not correct. DIN 2093 is a general disc spring and you must calculate the load yourself; DIN 6796 is designed specifically for bolt preload, with size and load already matched to the bolt size, so just fit the DIN 6796 washer that matches the bolt’s M size — no calculation needed.
Note: the sizes listed in the options above apply to this page; other DIN 2093 / DIN 6796 sizes are available on request.
Stacking calculation: series, parallel, mixed
The design flexibility of disc springs comes from stacking. Assume a single disc has load F and deflection s. Three stacking methods:
| Stacking | Arrangement | Total load | Total deflection | Use |
|---|---|---|---|---|
| Single | 1 disc | F | s | Baseline |
| Series (n discs, alternating) | ○⊃⊂○⊃⊂ | F (unchanged) | n × s (increased) | More stroke needed |
| Parallel (n discs, same direction) | ○○○○ → | n × F (increased) | s (unchanged) | More load needed |
| Mixed | m in parallel × n groups in series | m × F | n × s | Adjust both load and stroke |
Example: a mold ejector needs 1000 N load + 5 mm stroke. Choose a single disc spring rated 250 N at 2.5 mm deflection, stack 4 in parallel (1000 N), then 2 groups in series (5 mm) — 8 discs in total.
Note: the more discs stacked in parallel, the more friction between them — the measured load during compression is higher than calculated, and lower during return. Parallel stacks should generally not exceed 2–4 discs; the total length of a series stack should not exceed 3 times the outer diameter — split longer stacks into sections and use a guide to prevent radial shifting.
Selection steps and practical tips
Practical selection does not start from “which DIN series” but works back from the required load, stroke and space: required load F (N or kN) → required stroke s (mm) → available space (outer diameter / height) → working environment (dry / humid / high temperature) → stacking (series/parallel) and material.
Keep working deflection below 75% (typical): in dynamic applications, working deflection s should not exceed 75% of the free deflection h0, which allows a cycle life of 10^6 or more (typical experience; follow the manufacturer’s specification and operating conditions). Beyond 100% the disc flattens and deforms permanently. Static preload (bolt anti-loosening) can approach 100%.
Series stacks need a guide, or they shift radially: with 4 or more discs in series, the discs slide radially and become eccentric over time. Use a guide pin (dowel pin) or housing guide, leaving clearance between the guide and the disc’s inner (or outer) diameter — about 0.2 mm (16 mm and below), increasing step by step to 1.0 mm (80–140 mm) (typical).
Check free height regularly: after long use, disc springs lose a little free height (spring fatigue). Measure regularly and replace when the drop exceeds 5%; in vibrating environments, replace DIN 6796 preload washers with new ones every time the bolt is removed (they are low-cost, and this avoids the risk of failure).
Trademarks: Inconel, NIMONIC, Geomet and the material and model names on this page are trademarks or names of their owners, used here only to identify the products.
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