Mesh (unit)

from Wikipedia, the free encyclopedia

The mesh (Engl. For loop ) is a unit of tissue fineness in many English-speaking countries (see Anglo-American system of measurement ) and is mainly used for screens applied. To calculate the mesh size from the mesh, knowledge of the wire thickness is necessary. At the same time, the mesh also denotes the grain size of appropriately sieved material.

A five mesh per inch (25.4 mm) screen is 5 mesh. Since the thickness of the wire mesh also has to be taken into account, 5 mesh does not correspond to a grain size of one fifth of an inch (5.1 mm), but one of 4.0 mm (i.e. 78% of 1/5 inch); a grain size of 10 mesh corresponds to a grain diameter of 2.0 mm.

With large numbers of meshes, there are considerable deviations between the grain sizes depending on the underlying standard. For example, 100 mesh (i.e. one mesh every 0.254 mm) often corresponds to a grain size of 0.149 to 0.150 mm (59%), but can also vary depending on the purpose, authority and country e.g. B. also be set with

  • 0.162 mm (64%, FEPA standard P100 for sandpaper )
  • 0.129 mm (51%, FEPA standard F100 for grinding tools ) or
  • 0.125mm (49%, J100 according to Japanese JIS R6001).

Abrasives with grain sizes around 0.013 mm are even assigned the mesh-oriented designations P1500 (77%), F600 (31%) and J1200 (61%). The number of meshes per inch varies here by a factor of almost 3. A comparison without a corresponding table or precise knowledge of the respective standards is then no longer possible.

If one accepts a maximum error of 25%, then the grain sizes between 5 and 100 mesh can be estimated well with 16.2 mm divided by the mesh value.

There are no formulas for converting mesh to millimeters, but there are corresponding tables in the respective standard.

The mesh number is also used to classify screen printing fabrics .

In reticulated tissues, e.g. B. mosquito nets , the number of openings per area is often given in mesh per square inch , not as a reciprocal length, but as a reciprocal area .

Web links