Textile Structure
how cloth is put together
Concept

Opening size — where it appears

The clear hole a woven cloth leaves between four threads, the spacing less the diameter, and the number a filter fabric is specified by. It is the number a filter fabric is bought on, and it is a hole with a length as well as an area, which is why cover is a poor proxy for it.

Named by 6 essays across 3 fields — each of them below, with the objects they name alongside it.

The hole between four threads. Three millimetres of a woven filter cloth in plan, with one clear opening dimensioned and a grain of the soil it must retain drawn at the same scale. Every hole in the repeat is this size — a woven cloth's pore distribution is a single value, which is why it is specified by an opening size while a nonwoven needs a curve.

The hole between four threads

A woven cloth's holes are all the same size. That is not an approximation — it is what a repeat means — and it is the whole reason a woven filter is specified by one number while a nonwoven needs a curve. The number is the spacing less the diameter, which this site has been computing since its first questions about setting.

applied · Cover A filter cloth has two jobs. Opening size against sett for a woven filter cloth, with the two limits that specify one: the soil is retained below the retention line, and the water passes above the open-area floor. They pull opposite ways, so the answer is an interval in the sett — and for a fine enough soil there is no interval at all.

A filter cloth has two jobs

Hold the soil back and pass the water. The first wants a close sett and the second wants an open one, so a filter cloth is not a fabric but an interval — one that is sometimes a single sett wide, and for a fine enough soil is empty. The empty case is the useful one, because it says the answer is not a woven cloth at all.

applied · Openings The stitch density that makes the strongest seam. Seam strength against stitch density, as the two limits that decide it: the sewing thread crossing the seam, which rises with the stitches, and the fabric the needle perforates, which falls. The seam is the lower of the two, so the optimum is where they cross — and whether the fabric line falls at all is decided by the clear gap between threads against the width of the needle.

The stitch that weakens the seam

More stitches per centimetre put more sewing thread across a seam and more holes through the cloth beside it, so seam strength rises, crosses and falls. Whether the fabric line falls at all is decided by the clear gap between two threads against the width of the needle — the same arithmetic a filter cloth is specified by, doing a different job.

applied · Seams Mock leno, 3 threads to a bundle. Threads that interlace identically have no weft passing between them, so nothing holds them apart and they lie touching. The reed still sets the average spacing, so the space they leave collects at the bundle's edge — a hole 0.60 by 0.60 mm, made without one thread crossing another. Drawn to scale on a fixed 9 mm square of cloth at 20 threads per centimetre and a 0.3 mm yarn.

A hole with nothing crossing

A real leno holds its holes open by crossing one thread over another, which is a topological arrangement and cannot come undone. A mock leno makes the same holes by grouping threads that nothing separates, and everything about it is friction.

weaves · Texture weaves Two pore systems in one cloth — 24 threads per centimetre. A plain weave of 20 tex cotton in section, at 24 threads per centimetre, so the yarn is 167 µm across and the clear hole between two picks is 250 µm. That hole's hydraulic radius is 124.8 µm. Inside the yarn, fibres 14 µm across packed at 0.6 leave spaces of hydraulic radius 2.33 µm — 53 times finer, and by Jurin's law 53 times higher: 6.37 m against 119 mm. The yarn's interior is magnified 6 times and the two discs at the foot are the only part drawn at one scale.

How high a cloth wicks

A woven cloth has two capillary systems and they are a factor of twenty to a hundred apart. The one every diagram draws — the hole between four threads — lifts 119 mm. The one nobody draws, inside the yarn, lifts 6.37 m.

applied · Wicking What it takes to bury a cloth's crowns. The film needed to fill a fabric's surface to a stated level, for plain, 2/2 twill, satin 8 in sheeting, at a film density of 1.2 g/cm³. Burying the crowns entirely takes 187 g/m² on the plain, 186 g/m² on the 2/2 twill, 183 g/m² on the satin 8 — and the ordering is not the ordering of roughness. A weave with plateaux presents a wide flat top that a thin film covers, and a weave with points presents crowns with valleys between them that the film has to fill before it is continuous anywhere. Every gram spent filling a valley is a gram that is not bridging a hole, which is where a coated cloth fails.

A coating fills the crowns before it bridges the holes

A film does not sit on a cloth, it fills it — and the volume it has to supply to reach a level is the integral of one minus the bearing area. Burying an ordinary sheeting's crowns takes 185 grams a square metre, which is more than the cloth weighs, and the whole of the weave's influence is spent in the first ten of them.

finishing · Coating

Named alongside it

The objects these essays reach for when they reach for this one.

SettCoverCover factorSpecificationJammingNonwovenRetentionAdd-onBearing curveCoatingContact angleCrown line

All concepts