Screen wire (woven wire screen cloth) is the screening surface made by weaving steel wires that separates material by size on vibrating screens. In crushing and screening plants the size of products such as chippings and sand is set directly by the aperture of the screen wire. If the wrong aperture and wire diameter are chosen, the product size drifts, capacity falls or the wire breaks quickly.
In this guide we explain screen wire sizes, the relationship between aperture and wire diameter, mesh calculation, an open area chart, types of screen wire and the information needed for a correct order. For a general comparison of screen media materials see our screen media selection guide.
What Are the Dimensions of Screen Wire?
| Dimension | Meaning |
|---|---|
| Aperture (a) | Clear opening between two adjacent wires (mm); determines product size |
| Wire diameter (d) | Thickness of the wire used in the weave (mm); determines strength and life |
| Pitch (p = a + d) | Distance from one wire centre to the next |
| Open area | Ratio of total opening area to screen area (%); affects capacity |
| Screen cloth size | Width × length (according to the screen deck) |
| Hook type | Angle and shape of the edge hooks on tensioned screens |
What Is Mesh and How Is It Calculated?
Mesh is the number of openings per inch (25.4 mm) and is used mainly for fine screens. The relationship between aperture and mesh is:
a (mm) = 25.4 / mesh − d
For example, at 8 mesh with 0.8 mm wire: a = 25.4 / 8 − 0.8 ≈ 2.4 mm. At the same mesh, a thicker wire gives a smaller aperture, so mesh alone is not enough; the wire diameter must always be stated as well. In crushing and screening plants, coarse screens are usually specified directly by aperture in mm.
Open Area Calculation
For square mesh screen wire, the open area is:
Open area (%) = [ a / (a + d) ]² × 100
As open area increases, screening capacity rises; but thinner wire wears and breaks faster. The table below gives examples of combinations commonly used in crushing and screening plants:
| Aperture (a) | Wire Diameter (d) | Open Area (approx.) | Typical Use |
|---|---|---|---|
| 2 mm | 1.25 mm | 38% | Fine sand screening |
| 3 mm | 1.6 mm | 43% | Sand |
| 5 mm | 2.5 mm | 44% | 0–5 crushed sand separation |
| 8 mm | 3.15 mm | 51% | Fine chippings |
| 10 mm | 3.5 mm | 55% | Chippings |
| 12 mm | 4 mm | 56% | Upper limit of No. 1 chippings |
| 16 mm | 5 mm | 58% | Chippings |
| 20 mm | 5 mm | 64% | No. 2 chippings |
| 25 mm | 6 mm | 65% | No. 3 chippings |
| 32 mm | 7 mm | 67% | Coarse fraction |
| 40 mm | 8 mm | 69% | Pre-screening |
| 50 mm | 8 mm | 74% | Coarse pre-screening |
Wire diameter is chosen according to the coarseness of the material, impact and wear conditions. Thick wire is used on upper decks for coarse, heavy material, and thinner wire on lower decks for fine material. For chippings fractions see our crushed stone chippings guide.
Relationship Between Aperture and Product Size
The aperture of the screen wire and the top size of the product obtained are not always the same. On inclined screens, material approaches the opening at an angle, so the effective cut size is smaller than the aperture. That is why, on inclined screens, the aperture is usually chosen slightly larger than the target product top size. The exact value depends on screen incline, vibration, bed depth and particle shape, and should be confirmed on site by sieve analysis. On horizontal screens the effective cut size is closer to the aperture.
Types of Screen Wire
| Type | Feature | Application |
|---|---|---|
| Square mesh weave | The most common type; precise separation | Chippings and sand fractions |
| Rectangular (slotted) mesh weave | Higher open area, less blinding | Sand, damp material; less precise product size |
| Self-cleaning (harp) screen wire | Independently vibrating wires; reduces blinding in damp and clayey material | Self-cleaning screen wire |
| Pre-crimped and flat-top weaves | Wear and flow behaviour depend on weave shape | By manufacturer |
| Stainless steel wire | Corrosion resistance | Wet and corrosive environments |
Screen wires are generally made from high-carbon, wear-resistant spring steel wire. For very abrasive or very wet applications, polyurethane and rubber panels are also considered as alternatives.
Tensioned Screen Wire and Hooks
On many vibrating screens, the screen wire is tensioned at its edge hooks by tension bars on the side plates. The hook angle, hook length and hook type must suit the screen model; otherwise the wire will not tension correctly, will break with vibration and will wear the support bars. When changing screen wire:
- Check the support bar rubbers (capping rubbers) and replace them if necessary,
- Tension the wire to the manufacturer’s recommended tension and recheck after the first run,
- Make sure the middle of the wire sits fully on the bars and the crown direction is correct.
For screen maintenance see our vibrating screen guide and screen spare parts guide.
Information Needed to Order Screen Wire
- Aperture (mm) and opening type (square, slotted, self-cleaning),
- Wire diameter (mm),
- Screen cloth width and length (deck size),
- Hook type, hook angle and hook length (on tensioned screens),
- Screen make, model and deck number,
- Material processed (sand, chippings, moisture and clay) and quantity.
Factors Affecting Screen Wire Prices
- Wire diameter and total wire weight,
- Wire material (high-carbon, stainless),
- Opening type and weaving labour (self-cleaning wires need more labour),
- Hooks and edge finishing,
- Order quantity and lead time.
Common Mistakes
- Giving only the mesh without stating the wire diameter.
- Using thin wire on upper decks and causing early breakage.
- Not checking tension after the first run.
- Fitting new wire over worn support bar rubbers.
- Persisting with square mesh on damp, clayey material without solving the blinding.
Frequently Asked Questions
How is a screen wire size expressed?
As aperture × wire diameter (e.g. 10 × 3.5 mm) and cloth size (width × length); mesh is also used for fine screens.
How do you convert between mesh and mm?
Aperture = 25.4 / mesh − wire diameter; an exact conversion is not possible without knowing the wire diameter.
Which screen wire is used for a sand screen?
For 0–5 mm sand separation, wires with apertures of about 5–6 mm are common; for damp sand, self-cleaning or slotted wires may be preferred.
Why does screen wire break?
Insufficient tension, worn support bar rubbers, unsuitable wire diameter, impact and fatigue are the main causes.
Example: Open Area Calculation
Consider the effect of choosing a 5 mm wire instead of a 3.5 mm wire for a 10 mm aperture:
| Option | Calculation | Open Area |
|---|---|---|
| 10 mm aperture, 3.5 mm wire | (10 / 13.5)² × 100 | ≈ 55% |
| 10 mm aperture, 5 mm wire | (10 / 15)² × 100 | ≈ 44% |
The thicker wire lasts longer but reduces open area by about 20%, which lowers screen capacity. Wire diameter is therefore chosen to balance wear life and screening capacity.
Field Example
At one plant, 6–8 mm particles occasionally appear in the 0–5 mm crushed sand product. Inspection shows the lower deck screen wire has torn near the edge hooks and the support bar rubbers have worn. When the rubbers are renewed and new screen wire is fitted at the correct tension, the product is back in specification. This example shows that screen wire checks should be part of the daily routine.
Glossary
- Aperture: The clear distance between two adjacent wires.
- Mesh: The number of openings per inch.
- Open area: The ratio of opening area to total screen area.
- Effective cut size: The particle size the screen actually separates at.
- Hook: The edge of tensioned screen wire that fits onto the side tension bars.
- Capping rubber: The rubber profile separating the screen wire from the support bars.
More Questions
Screen wire or polyurethane panels?
Screen wire offers higher open area and lower initial cost; polyurethane panels give longer life and lower noise. The choice depends on material, moisture and wear (screen media selection).
How often is screen wire changed?
It depends on material abrasiveness, deck position and tonnage; tonnage-based records make it possible to predict change times.
Can self-cleaning screen wire be used everywhere?
It is particularly useful with damp, fine material; square mesh is more suitable for dry applications needing precise size separation.
CSP Mühendislik Support
CSP Mühendislik supplies square mesh, slotted and self-cleaning screen wire to size and hook type, and polyurethane panels and other screen parts. For screen parts see our vibrating screen spare parts page, or use our service, maintenance and repair support for on-site changes.
