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RAL-GZ 615
DIN EN ISO 24041
Certification:
DIN EN ISO 9001:2008
Environmental Certification:
DIN EN ISO 14001:2009
Basic Terms
Basic Term 1
Perforated plates (drawing 2) are classified in four main categories: perforated plates with round, square, oblong or slotted holes.
Basic Terms 2
The hole pattern differs as follows (drawing 3 and drawings to 4.1 up to 6.3):
Round and square holes:
straight rows (Rg), diagonally staggered rows (Rd), 60° staggered rows (RV).
Oblong or slotted holes:
straight rows (Lg), staggered rows (Lv) diagonal rows, herringbone patters, checker board pattern.
The hole pattern is very important with screening plates. The best results are achieved if the holes are staggered across the feed direction (drawing 1).
Basic term 3
Width of edge e1, e2 or f1, f2 is the distance from the edge of the plate to the first holes (drawing 2). Usually a blank margin is required to manufacture perforated plates.
Plates without blank margin (throughout punched) may be cheaper than plates with blank margin provided they can be cut out of standard plates. Perforation will cause unavoidable surface tensions resulting in negative impacts with wide blank margins.
a | = width of perforated plate |
b | = length of perforated plate |
e1, e2 | = margins |
f1, f2 | = margins |
Basic term 4
Width of hole w is (drawing 3): diameter of the round hole, edge length of the square hole, the smaller dimension of the oblong or slot hole.
Basic term 5
Length of hole l is (drawing 3): the larger hole size of the oblong or slot hole.
Basic term 6
Width of bridge c ist the smallest unperforated space between round or square holes in adjacent rows (drawing 3).
Width of side bridge c1 is the smallest unperforated space between the broadsides (w) of oblong or slot holes in adjacent rows.
Width of end bridge c2 is the smallest unperforated space at the longitudinal axis between oblong or slot holes in adjacent rows (drawing 3).
Basic term 7
Pitch t is defined as the distance from the centre of two adjacent round or square holes or rows of holes (drawing 3).
Side pitch t1 is the distance on the broadside of two adjacent oblong or slot holes.
End pitch is the distance in longitudinal direction of two adjacent oblong or slot holes.
Basic term 8
The relative open surface or screening area is the percentage of the open surface (holes) in relation to the whole screening area. It is important for determination of the rate of flow and the calculation of the load-bearing capacity of the perforated sheet.
Basic term 9
Relation of hole dimension to material thickness:
In general the width of hole w (drawing 3) and the width of bridge (drawing 3) are the material thickness.
If steel sheets with higher degrees of hardness as well as corosion, acid or heat resistant sheets are to be perforated the size of hole diameter and the width of bridges should be greater than the thickness of the sheet.
If the specified figures shall fall below this level please contact us.
Technical Informations
Standards and sizes
Standards
Length and Width
Material Thickness
Squareness of cut plates
Parallelism
Flatness
Edge Bows
Wavy Edges
Blank Side and End Margins
Blank areas
Conical section of hole
Punching Burr and Shearing Burr
Missing holes / Punch Breakage
Beginning and end of perforated area
Cleanliness of the surface – Degreasing – Permissible surface
Surface finish
Hole Shapes
Round holes
DIN 24 041
RV round holes, staggered rows
RD round holes, diagonally staggered rows
RG round holes, straight rows
Square holes
DIN 24 041
QV square holes, staggered rows
QD square holes, diagonally staggered rows
QG square holes, straight rows
Hexagonal holes
DIN 24 041
HV hexagonal holes, staggered rows
Oblong holes
DIN 24 041
LV Oblong holes, staggered rows
LG Oblong holes, straight rows
LGE Oblong holes, straight rows, square