【正文】 panel hardware for Class A and B .......................36Figure 13 Identification of Class A and Class B Areas of Boxes .....................36Figure 14 Height of chamfer.................................................373. TablesTable 1 Radius (r) of taper angle..............................................28Table 2 The data of height(H) and Min removable times .........................30Table 3 The data of height(H) and Min removable times for flanginghole with thread for thin sheet connected .....................................................31Table 4 Riveting parameters................................................31Table 5 Minimum pulling force borne by riveted points............................32Table 6 Ultimate value of burr height (Unit: mm) ................................37Table 7 Tolerance levels and values ............................................3826 / 43Specifications for Sheetmetal Punching PartsScopeThis specification covers the general quality requirements and inspection rules for Huawei sheetmetal punching parts (before surface treatment).This specification applies to Huawei’s all sheetmetal punching parts (before surface treatment). Reference is given to the design drawings with noted requirement and to this specification if not noted in the design drawing.Brief IntroductionThis specification provides the general quality requirements and inspection rules for sheetmetal punching parts.KeywordsAppearance, surface status, technical rabbet, fillet radius, class A area, class B area, burr, and burr height.Revision DeclarationStatement on the Priority of Huawei Technical DocumentsHuawei products are manufactured based on the following documents which are listed in order of priority: Huawei drawings, Huawei enterprise technical standards, telemunications industry standards, China national standards, and international standards. Shall there be discrepancy between these documents, the document of the highest priority takes precedence.Among Huawei enterprise technical standards, specific product standards have higher priorities than general standards.Term amp。 DefinitionFull Spelling Chinese ExplanationClass A Area Corner areas touchable by hands in the normal working position of products when delivered by sheetmetal suppliers。 and areas specially required in design drawings.Class B Area Areas except for Class A AreaBurr Burr on the cross section of finished products when blanking sheet metalHeight Of Burr Burr height on the cross section of finished products when blanking sheet metal27 / 43Full Spelling Chinese ExplanationLevel 1 Surface Critical surface represents the product appearance. Through this kind of decorative surface, you can directly see the major product appearance, including the outer surface of the front and of the main parts installed on the front of the cabi, subrack (involving the integrated chassis and data munications chassis), radio frequency module, box, handle bar, and the surface that you can directly see after opening the front door of the cabi.Level 2 Surface Major outer surface is halfdecorative and is monly seen, including the front of the mount bar on the cabi, sides outside the cabi, rear of the cabi, sides outside and at rear of the subrack (involving the integrated chassis and data munications chassis) and radio frequency module, and topside of the cabi that is lower than m. Surfaces of the ironware and accessories of the cabi and chassis are all defined as level 2 surfaces.Level 3 Surface Minor outer surface and inner surface. These surfaces are not decorationoriented and not demanding on the surface quality, including the inner surface and underside of the cabi, subrack (involving the integrated chassis and data munications chassis), radio frequency module, box, and handle bar, topside of the cabi that is higher than , and all surfaces of the installing support, bundling rack, inner frame, and inner solder. Surfaces that not belong to level 1 and level 2 surfaces are level 3 surfaces.28 / 431. Technical Requirements. General Requirements for Appearance and Surface. The burr surface is required to be inside the parts, as shown in Error! Reference source not found.:Figure 1 Burr of bendsExceptions: the burr surface is the inner surface or nonfunctional surface of parts if the assembling relationship between parts is analyzed based on the coding level。 the burr surface is the outer surface of parts if Lshaped parts are slideways, and opposite to the above diagram.. Blanked and sheared panel parts’ taper angles with outer shapes and inner edges smaller than or equal to 90176。 which are not noted on the drawing should be made as fillets (as shown in 0) with a radius (r) specified as Table 1.T a p e r a n g l eT a p e r a n g l eFigure 2 Taper angles of panel partsTable 1 Radius (r) of taper angleThickness (t) of materials ≤ ~ ~1 1~2 2~3 329 / 43Radius (r) of taper angle ≤ 1 . If allowable as marked in design documents or drawings, stop holes or technical rabbets can be open according to the following hole diameter and rabbet size. d, diameter of stop holes (as shown in 0), should be smaller than or equal to 2 t。Figure 3 Diameter of stop holes L and b, sizes of technical rabbets (as shown in 0)。When t mm, 1 mm b ≤ t (if t 1, b = 1)When t ≤ mm, b = 1 mm.L ≥ t + r+Figure 4 Technical rabbet. Parts formed by curving without a curving radius noted on the drawing can be made with an internally curving radius R no larger than t (thickness of materials) and no smaller than .. Requirements for flanginghole with thread： Requirements for height(H) and Min removable times of flanging (as shown in 05) 30 / 43Figure 5 Schematic diagram for flanginghole with threadTable 2 The data of height(H) and Min removable timesThread Plate thickness(T) Inner diameter of flanginghole(D1)High of flangingho