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Specifications for Sheet-metal Punching Parts
Scope
This specification covers the general quality requirements and inspection rules for Huawei sheet-metal punching parts (before surface treatment).
This specification applies to Huawei’s all sheet-metal 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 Introduction
This specification provides the general quality requirements and inspection rules for sheet-metal punching parts.
Keywords
Appearance, surface status, technical rabbet, fillet radius, class A area, class B area, burr, and burr height.
Revision Declaration
Statement on the Priority of Huawei Technical Documents
Huawei products are manufactured based on the following documents which are listed in order of priority: Huawei drawings, Huawei enterprise technical standards,
telecommunications 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 & Definition
Full Spelling Class A Area Chinese Explanation Corner areas touchable by hands in the normal working position of products when delivered by sheet-metal suppliers; and areas specially required in design drawings. Areas except for Class A Area Burr on the cross section of finished products when blanking sheet metal Burr height on the cross section of finished products when blanking sheet metal Class B Area Burr Height Of Burr 2014-1-3
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2014-1-3
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Full Spelling Chinese Explanation Level 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 cabinet, subrack (involving the integrated chassis and data communications chassis), radio frequency module, box, handle bar, and the surface that you can directly see after opening the front door of the cabinet. Level 2 Surface Major outer surface is half-decorative and is commonly seen, including the front of the mount bar on the cabinet, sides outside the cabinet, rear of the cabinet, sides outside and at rear of the subrack (involving the integrated chassis and data communications chassis) and radio frequency module, and topside of the cabinet that is lower than 1.8 m. Surfaces of the ironware and accessories of the cabinet and chassis are all defined as level 2 surfaces. Level 3 Surface Minor outer surface and inner surface. These surfaces are not decoration-oriented and not demanding on the surface quality, including the inner surface and underside of the cabinet, subrack (involving the integrated chassis and data communications chassis), radio frequency module, box, and handle bar, topside of the cabinet that is higher than 1.8m, 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. 华为机密，未经许可不得扩散 Huawei Confidential 第27页, 共44页 Page 27 , Total 44
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1. Technical Requirements
1.1. General Requirements for Appearance and Surface
1.1.1. The burr surface is required to be inside the parts, as shown in 错误！未找到引用源。:
Figure 1 Burr of bends
Exceptions: the burr surface is the inner surface or non-functional 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 L-shaped parts are slideways, and opposite to the above diagram.
1.1.2. Blanked and sheared panel parts’ taper angles with outer shapes and inner edges smaller than or equal to
90° which are not noted on the drawing should be made as fillets (as shown in 0) with a radius (r) specified as Table 1.
Taper angleTaper angle
Figure 2 Taper angles of panel parts
Table 1 Radius (r) of taper angle
Thickness (t) 2014-1-3
≤0.3 >0.3~0.5 >0.5~1 >1~2 >2~3 >3 华为机密，未经许可不得扩散 Huawei Confidential 第28页, 共44页 Page 28 , Total 44
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of materials Radius (r) of 0.2 0.3 0.5 1 1.5 0.5t taper angle ≤ 1.1.3. 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.
1、 d, diameter of stop holes (as shown in 0), should be smaller than or equal to 2 t;
Figure 3 Diameter of stop holes
2、 L and b, sizes of technical rabbets (as shown in 0); When t > 0.5 mm, 1 mm < b ≤1.5 t (if 1.5 t < 1, b = 1) When t ≤ 0.5 mm, b = 1 mm. L ≥ t + r+0.5b
Figure 4 Technical rabbet
1.1.4. 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 0.2.
1.1.5. Requirements for flanging-hole with thread：
2014-1-3
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1、 Requirements for height(H) and Min removable times of flanging (as shown in 05)
Figure 5 Schematic diagram for flanging-hole with thread Table 2 The data of height(H) and Min removable times
High of Plate Inner diameter of flanging-hole(H) thickness(T) flanging-hole(D1) (Tolerance 0～+0.3) 0.8 1.0 M3 1.2 1.5 1.0 M4 1.2 1.5 1.2 M5 1.5
2、 Flanging-hole with thread for thin sheet connected
The flanging-hole is used in thin sheet connected, to achieve that standard countersunk head screw M3
could be sunk into the plate surface with thickness 0.8mm or 1.0 mm. Requirements for height(H) and Min removable times of flanging (as shown in 06).
Φ4.2 2.7 30 Φ3.3 Φ2.5 2.2 2.4 2.4 2.6 3 2.4 0.3 30 30 30 30 30 30 1.8 2 Min removable times (Time) 12 30 Thread Max. R 2014-1-3
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