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Brown-Campbell Company 1-800-GRATING (800-472-8464) |
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Perforated Design Details
•Minimum
Hole Size
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| Minimum Hole Size |
| The rule of thumb for perforating carbon steel and aluminum is that the hole diameter should not be less thant the thickness of the material. The closer this 1-to-1 relationship is approached, the higher the probability for tool failure, and the greater the precautions necessary to avoid it. For stainless steel and other higher strength materials, it is best to drop at least one thickness gauge thinner than hole diameter. In some cases, variations to these recommendations can be accommodated but with additional production costs. |
| Minimum Bar Width |
| The material left between perforations is called bar width. The same rule of thumb of the 1-to-1 relationship to thickness is the limit for bar width as in hole diameter. Keep the bar width greater than the thickness of the material to avoid problems. As the 1-to-1 relationship is approached, the increasing number of punches required sharply escalates the process tonnage needed to perforate the pattern, thus creating potential for problems. In some cases, variations to these recommendations can be accommodated but with additional production costs. |
| Flow of Material |
| If the sieving process requires a specified arrangement of holes, the direction of flow must be clearly specified. |
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| H.P.S.I. = Holes per square inch D = Diameter of hole or size of square hole C = Centers (distance between centers) |
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60° Staggered Round Hole Pattern % Open Area = (90.69 (D)(D)) / (C x C) H.P.S.I. = % Open Area / (78.54 (D)(D)) |
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Straight Line Round Hole Pattern (not shown) % Open Area = (78.54 (D)(D)) / (C x C) H.P.S.I. = % Open Area / (78.54 (D)(D)) |
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45° Staggered Round Hole Pattern % Open Area = (78.54 (D)(D)) / (C x C) H.P.S.I. = % Open Area / (78.54 (D)(D)) |
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Square Hole Patterns - Straight and Staggered % Open Area = (100 (D)(D)) / (C x C) H.P.S.I. = % Open Area / (100 (D)(D)) |
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