Perforated materials have been in use for as long as, if not longer, than woven wire screencloth. Like its counterpart,
perforated materials is available in almost any type of material.

The limiting factor that determines whether or not a material can be perforated is normally at ultimate tensile strength
(U.T.S).  Materials with values up to 750 MPa can normally be perforated and above this figure the norm would be either
drill or use one of many cutting processes to produce the required aperture. It should also be recognised that some
materials with lower U.T.S. values, due to their plasticity, may also not be suitable for perforating.

For individual manufacturers of perforating materials the limiting factor could well be the capacity and size of the physical
perforating presses in use. No one manufacturer will cater for the complete spectrum of perforated materials, but he will
cater for the most commercially practical range. It is recommended that a check is made concerning all requirements
with the relevant manufacturers prior to finalising a design and / or order. Star Screens can, subject to material
thickness, aperture type and size, perforate materials from 0,2 up to 16 thick, with aperture sizes varying from
0,50 to 90,0.

Standard tool sets are generally for a specific material thickness. It may therefore be possible to have a certain aperture
specification available but not for the thickness of material required. Screen Products applies the latest relevant
International Specifications pertaining to aperture sizes on all manufactured perforated materials i.e.

	BS 1449
	BS 1669
	BS 7613
	ISO 10630

Materials for Perforation

STEEL: Plain, low carbon steel is a widely used material. However it shows a tendency to corrode. Perforated
sheets are also manufactured in bright galvanised finish.

STAINLESS STEEL: Stainless steel covers most applications. It is produced in different kinds of alloys. The most
common steel contains ca. 18% chromium and 8% nickel (AISI 304) for a higher degree of corrosion resistance a
special alloy with molybdenum is recommended (AISI 316). If perforated material made from stainless steel is
welded, they alloy should contain very low carbon or the steels should be stabilised with titanium or niob.

HEAT RESISTING STEEL: These steels are resistant to temperatures of above 600° to 1 200°C in air and in
specific gases. However, when sulphine conditions, water, vapour or ashes are added together with heat we
recommend special materials such as Incoloy DS.

COPPER AND COPPER BASED ALLOYS: Copper is a soft metal with good conducting properties for heat and
electricity. Brass is a copper-zinc alloy particularly suitable for sieving and filtration purposes. When there is
ammonia in the air,  brass is subject to corrosion. The higher the zinc content, the faster brass corrodes. Phosphor
Bronze, a copper-tin alloy is largely wear and tear resistant.

NICKEL AND NICKEL BASED ALLOYS: Nickel is resistant to a number of acid and alkaline chemical corroding
solutions. The material is suitable for welding and about as hard as steel. Nickel based alloys such as Inconel,
Incoloy, Hastelloy and others are not always weavable, so a special enquiry is advisable. MONEL-Metal consists of
2/3 of nickel,  about 1/3 of copper, and traces of iron, manganese, silicium and carbon. It is very similar to nickel,
easy to weave and resistant to atmospheric corrosion, seawater and most acids and alkalines.

Surface Characteristics

Surface Finish
Slight damage of the perforated metal plate by mechanical action during the perforation process cannot be
excluded. If this is detrimental to the proposed use, the purchaser should consult with our technical team before
ordering.

Cleanliness
Perforated metal plates are usually supplied with a light oily film. There should be no excessive seepage of oil
after stacking. Degreased perforated metal plates e.g. prepared by solvent or steam treatment, may be supplied
by agreement.  Degreasing is inappropriate for plates of low carbon steel unless subsequent protection against
corrosion is provided.

Perforated Metal Sheet Coils
Perforated metal sheet coils is limited to a sheet thickness below 3,0 mm. It shall comply with the following:

Length : The length of the coils shall be agreed before ordering.

Width : For perforated metal plate in coils without subsequent edge preparation, the tolerances on plate width
shall be the rolling mill tolerances appropriate to the unperforated material supplied. For perforated metal plate in
coils, recut along the two longitudinal edges and with a width of less than 600 mm, the tolerance on plate width a,
shall not exceed ± 5,5 mm. The tolerance on plate widths of 600 mm and above shall be agreed before ordering.

Flatness : Coils of perforated metal plate cannot be roller-levelled before delivery. Tolerances on the flatness of
uncoiled perforated metal shall be agreed before ordering, if considered an important factor.

Requirements for Ordering Perforated Materials

Perforated materials are used in various shapes and sizes. It is therefore important to ensure that a written or
verbal description is concise and leave no doubt as to what is actually required. The details below deal with the
problems of describing the various types of perforated materials that can be ordered.

Standard:
As with all products a basic description exists that identifies the variables that are common to all perforated
materials:
Perforated Material: 16 Ap(1) x 20 p(2) x 8t(3) x 2450(4) x 1225(5)

Legend:

	16 Ap: Aperture required. (Note: unless otherwise stated assumed to be round).
	20p: pitch of apertures.
	8t: thickness of material.
	2450: length of material.
	1225: width of material.

Variables:

The details shown above are common to all perforated materials. In order to manufacture the
following variables must be stated and / or supplied by means of an engineering drawing.

	Material
	Staggered / Straight pitch.
	Margins

To show the variables in the unit description they are merely added to the standard description in the
form notes:
Perforated Material 16 Ap x 20p x 8t x 2450 x 1225
1. Material: Mild Steel.
2. Staggered pitch.
3. 50 margins all round.

Note:
All dimensions in mm unless otherwise stated. When lateral and longitudinal pitches vary these would
be stated in plain language in the form of notes.

Fabrications:
All perforated materials that are required as fabricated items should be ordered referring to a
relevant sketch or engineering drawing. A drawing should be supplied to obviate any mistakes or
misunderstandings i.e. Perforated Material 16 Ap x 20 p x 8 x 2450 x 1225
Note: To be supplied as per drawing no. 12345.

FOR MORE INFORMATION PLEASE CONTACT US.

  © Copyright 2004-06. Starscreens.au.com.