Technical Info - 02.


Expanded metal meshes are made with thickness range of 0,5 to 4mm*, width of sheet up to 1500mm, and "bridge" (c) parameter up to 24mm (depends on meshes size and thickness of raw material). "C" parameter over 5 mm value is available after consultation with sales department.

*products with thickness 4mm, max width 1000 mm - after consultation as well.

t - width of pitch
t1 - length of pitch
a - length of mesh
b - width of mesh
c - bridge
g - thickness of raw material
g1 - thickness of expanded metal mesh
L - lenght of expanded metal sheet
W - width of expanded metal sheet
K - direction of production process

It is assumed that values of "t" and "t1" are constant, indicated in the purchase order. Values "a" and "b" are adjustable and depends on "c" and "g" parameters.
Wymiary oczka, mostek, grubość blachy

Sketch 1. Mesh dimensions, bridge, raw material thickness

02. Dimensions of sheets or rolls of expanded metal mesh

Nets are prodeced in standard widths it is . 1000, 1250, 1500mm. Upon client's request it can be cut to various dimensions (an option).

For the dimensions of nets produced with standard metal sheets width's (1000, 1250 or 1500mm) tolerance W amounts +/-8mm. For the nets without final cutting length tolerance L amounts ca. +100mm.

For nets made with thickness of material up to g=2mm - it can ve offerd in rolled version as well..
Siatka w arkuszu

Sketch 2. Expanded metal sheet
Siatka w rolce

Sketch 3. Expanded metal in roll

03. Arrangement of meshes relative to the size of expanded metal sheet

It is assumed that width of pitch "t" is taken as parallel value to the size "W" (w max= 1500mm). Although for parameter "L" up to 1500mm reverse option is available (to be agreed before implementation).
Siatka w rolce

Sketch 4. t II W

04. Edges of expanded metal mesh (possible ends)

Depends on raw material there ar various variants of expanded metal meshes ends. On special client's request (an option) there is a possibility to cut the sheets according to sketches shown below. However it must be taken under consideration that the plates with the "full meshes ends" final size of plate depends on numeber and size of meshes and may not meet theoretical assumption.

* full meshes ends on the length L depends on the width W and pitch "t".
Siatka w rolce

05. Additional processes

Upon clint's request expanded metal sheets may be straigten (an option) or flattened (an option).
g1 - thickness of expanded metal*
* g1 thickness for the meshes without flattened option, g1 tis a parameter resultant depends on bridge "c"
br /> * it is assumed that g1 after flattening process amounts ca g (thickness of raw material)br /> Nets can be flattened to the thickness of raw material (max thk. 3mm, width W up to 1500mm.
Siatka cięto-ciągniona bez dodatkowych operacji

Sketch 7a. Expanded metal without any additional processes
Siatka cięto-ciągniona zgniatana

Sketch 7b. Expanded metal mesh (flattened version)

06. Possible effects of cutting and expanding process

Expanded metal mesh has got two sides: the front one (decorative) and technological. On technological side some scratches may occur as an effect of production process.

ATTENTION: For decorative applications (elevation/panels) it is suggested to mount nets on whole wall according (along) to the cutting process of sheet and strictly using as an external surface correct side of nets (front side). Correct method of mounting is especially important for nets with thick bridges (c).

Sketch 8 Decorative expanded metal

Siatka dekoracyjna
For the parameters listed below we apply tolerance according to the norm PN-EN 10051:2011.

Distortion of rectangular shape is permitted for the nets without final cutting. It can be up to 2% of the sheet edge length.


Sketch 9. Distortion

Flatness of expanded metal

Expanded metal mesh is deemed as flat, if arranged on smooth surface does not show curve higher than 30mm, on width 1000mm (3% of the width). For stainless sheets "f" values amounts 50mm (5%). For heat- resistant sheets "f" value can not be determine. Other requirements must be predetermine before ordering.

Wybrzuszenie siatki f wzdłuż jej szerokości W

Sketch 10. Bulge "f" of the nets along to the width W

Wybrzuszenie siatki f wzdłuż jej długości L

Sketch 11. Bulge "f" of the nets along to the length L


In some cases during cutting process on the areas without any material's support cross section of metal changes and becomes flattening what has an impact on final thickness of expanded metal. On the supported areas final thickness becomes thinner only for 0,1 mm. This occurrences are caused and imposed by technology of production.

Spłaszczenie grubości materiału wsadowego

Sketch 12. Flattening of initial material (example : g=2mm)


Z uwagi na rozciągniętą strukturę stali siatki cięto-ciągnionej, podczas procesu gięcia istnieje ryzyko wystapienia pęknięć mostków siatki w miejscu zagięcia.
Pęknięte mostki w miejscu gięcia siatki

Rys. 13 Pęknięte mostki w miejscu gięcia siatki

07. Way of ordering

In general width of pitch "t" is taken as parallel value to the size W (W max = 1500mm). Although for parameter L up to 1500mm reverse option is available (to be agreed before implementation).
Przykładowy sposób ułożenia oczka względem wymiarów siatki

Przykładowy sposób ułożenia oczka względem wymiarów siatki

* t II W (width of pitch "t" parallel to the width of sheet W)

Additionally while ordering it is im portant to explain final application of product (ex. casings, panels, piece of steel construction).

Secondly it is also important to know if nets in further process (by cutomer) will be welded to any frames. This knowledge is helpfull in adjusting correct technical parameters during production and finally meeting client's demand.

ATTENTION: Regarding galvanized steel: we use pre-galvanized raw material so after cutting process there is no zink layer on the edges of meshes.

© Perfopol Sp. z o.o. 2021
76 Radomska St, 27-200 Starachowice, Poland
NIP: 664 000 08 22

phone +48 41 274 58 08

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