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Formats
The standard format for metal sheet is 1000x2000 mm. We have got a wide range of perforation possibilities already available on stock in this standard format. We can otherwise manufacture perforated sheets and coils in any format, from minimum sizes to a maximum width of 2000 mm.
Thicknesses
We can provide perforated sheets from a minimum thickness to 0,2 mm up to a maximum of 15 mm while those immediately available in stock range from 0,5mm a 10mm.
Holes
Holes can be ROUND, SQUARE, RHOMBOIDAL , RECTANGULAR, ROUND END SLOTS, FANTASY PATTERNS, specially customized on the basis of the client's moulding. We also supply round DRAWN holes of several diameters. Due to the perforation process, holes are always slightly conical , but taper increases with the increase in the thickness to the plate. The diameter of the hole shall be measured on the entrance side of the punch, not on the exit side.
Hole-thickness ratio
The bigger the hole diameter is, the cheaper the price is. For example, taking a 1mm thickness sheet, an 8 mm perforation is much simpler and economical if compared to the same sheet with holes of a 1mm diameter. Over the last few years, GATTI PRECORVI SPA has specialised into micro perforation (up to a diameter of 0,3mm against a thickness to 0,3mm).
Open area
Due to the perforation, a plate loses part of its weight. Through our web-site, in order to calculate the percentage of the so called OPEN AREA, please find a useful calculation software to obtain the perforation percentage. Anyway be careful when calculating this value since you need to consider that this data is referred only to the punched area on the plate and doesn't include the edges or the areas which are unperforated.
Margins and unperforated areas
The major advantage when dealing with PEFORATED SHEET PLATES when compared to metal nets and flattened plates is that you can have margins and strips inside the plate itself which are not punched at all. STANDARD punched sheet (1000x2000 mm) is mainly produced with minimum margins on the major sides of the plate (along the length), when thickness is lower than 3 mm, while plates which are more than 3 mm thick have an unperforated frame.
Beginning and end of a perforated area
Due to reasons concerning the manufacturing of dies, the distance between the centres of the punches inserted into the same hole are multiples of those between the holes to be obtained. Therefore the correct punching pitch is reached only after the second or third row of holes. As a result you might have a shift in the holes which will look alternate at the beginning and at the end of the perforated area ( false punch, o doppio colpo, or UNFINISHED PUNCHING) . We have obviously got many dies that can carry out a perfect and COMPLETE punching sequence (with no false punch or incomplete end rows).
Second machining
After having been punched/perforated, every sheet metal plate shows signs of strain and stretch, more or less marked depending on the materials employed ( CARBON STEEL, STAINLESS STEEL, ALUMINIUM etc. ) . Punched plates are flattened after being punched and this last operation is now part of the standard supply. Customers shall require special, very severe flattening processes when ordering the plates. We also carry out extra machining other than punching such as :
- High precision squaring up
- staggered shearing or special templates shearing
- moulding
-roller levelling
- folding
- moulding / shear spinning
- welding/ soldering
- assemblies
- glazing and polishing
- painting
- zinc plating/galvanizing
- anodic oxidation or anodizing |
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