If this condition exists, a greater tolerance should be applied to certain areas surrounding this characteristic. If the part has a closely spaced perforated pattern or formed features such as dimples or counter sinks the result can cause the sheet to warp and distort - this can cause unwanted variation between holes or features. However, all holes and features punched through the sheet can introduce stress into the sheet metal. Generally speaking, +/-.003" is a reasonable and functional tolerance.Īccuracy of the distance from one hole to another is dependent primarily upon the machinery used to process the sheet. When that is not possible, a capital investment in new tooling is required. This is why we look to the designers, engineers and draftsmen to give us a tolerance range that allows us some flexibility in using tooling that we have in house. Vista Industrial Products has an extensive library of tooling, but we do not stock all possible tool sizes. Except for tooling wear, there is very little variation from one hole to the next. The size of the hole on the die side will be the same size as the die tool. The size of the hole on the punch side will be the same size as the punch tool. 100 % aluminum and the punch diameter is 1.000", the die diameter would be 1.010". Generally speaking 10% of the material thickness is used for most applications. The die tool is slightly larger than the punch to minimize tooling wear and to reduce the pressure required to punch the hole. A minimum hole or relief size is determined by the thickness of stock to be used, for best results the punched feature can be no less than the material being punched. The size and shape of the punch and die tooling determine the size and shape of the hole. When the punch retracts the slug remains stuck in the die tool and a hole is left in the sheet metal. Hole SizesHoles are produced by forcing a punch tool through the sheet metal in order to rip out a slug. Correctly toleranced parts still have excellent fit and function, with the added benefit of manufacturing efficiency. The result of tolerances that are too tight is simply higher cost and lower productivity. Such over kill forces additional labor in sorting and inspection. 004", it is a mistake to simply engineer all mating parts expecting +/-.005" accuracy.
Tolerancesīest Practices in Tolerance SpecificationĪlthough the machinery and tooling will repeat within. Wilson Tool International: Manufacturers of standard and special application tooling for turret presses. This site contains electronic CAD files that can be downloaded for use in designing your assemblies. Southco: Manufacturers of access hardware, latches, hinges and rivets. Pem Engineering& Manufacturing: Manufacturers of PEM® brand threaded inserts, standoffs, studs and more. LINKS TO COMMONLY USED SHEET METAL PRODUCTS For two decades Tedco has been producing precision parts at competitive prices Capabilities Programming:
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