Process analysis of electronic sheet metal structure design

introduction


Sheet metal manufacturing is a comprehensive cold working process for metal sheets (within 6mm), including shearing, punching, cutting, folding, welding, riveting, etc. Its obvious feature is the same thickness of the same part. Especially in recent years, the rapid development of domestic electronic technology and the emergence of various electronic high-tech enterprises have made Fanjin components occupy a considerable proportion in the mechanical field. It is very important for professional talents involved in electronic structure design. The need is even more urgent. Quite a large number of college students directly enter the design agency of the company, and almost never practice internship on the front line of production, which makes the design of the finished product fail to meet the standards, which brings great difficulty to the manufacturing, which not only increases it. The investment in the product and the appearance of the product are not satisfactory, and it delays the production time of the product, and finally leads to the lack of competitiveness of the product in the market.


1 Sheet metal structure design process

Sheet metal is also called pull metal. Generally speaking, some thin metal plates are passed through. The tool or mold is impacted and pressed to plastically deform and become the required shape and size, and it can be further welded or a little mechanically processed into more complex parts, such as chimneys and iron rings used in daily life. , Fuel tanks, oil cans, air flow channels, etc., as well as the enclosures of various special facilities such as electrical cabinets, computer cases, vehicle enclosures, etc., are all sheet metal parts. In short, the design of sheet metal structure has not yet been simulated by standard modules. In actual production, it must be changed according to the needs of the product. This is also the difficulty of sheet metal design.


2 Sheet metal structure design standards and issues

2.1 Board selection criteria

Sheet metal is commonly used in the housing of facilities and the assembly of electrical circuits. Therefore, the selection of sheet metal materials is quite critical. Proper selection will not only benefit processing, but also reduce capital investment on the basis of ensuring strength.

2.2 Hole and gap structure design standards

For the manufacture of holes, not only should be adapted to the needs of the product, it should also be adapted to the principle of convenient processing. In addition, after the processing is completed, the subsequent procedures and appearance requirements will not be damaged.

(1) Try to avoid punching the square hole to the bottom of the bend. Stretching and pulling of the sheet metal material after bending will cause the hole to be deformed. If the hole is to be made manually, it will increase the processing difficulty.

(2) The processing method of the screw hole should be completed with different measures. For sheet metal materials such as tapping, flanging tapping, riveting nuts, spot welding nuts, etc., different sheet thicknesses and screw hole sizes should correspond to different methods.


2.3 Design standards for curved structures

(1) There is a standard for the lowest side of the inner diameter for bending, and the common bending die is shown in Figure 1.


Figure 1 The relationship between the width of the lower die and the height of the bending edge (mm) Enlarge image


Figure 1 The relationship between the width of the lower die and the height of the bending edge (mm)


(2) The gap between the edges of the holes on the bending member. One punch and two bends, the orientation of the hole should be outside the zigzag deformation zone, avoiding the zigzag deformation of the hole.

(3) The standard for bending dead edges. The length of the dead side is related to the width of the material. Generally, the minimum length of the dead edge is ≥3.5t+R, t represents the width of the material, and R represents the lowest inner bending radius of the process in the early stage of the dead edge.

(4) In order to avoid the bending, tearing and bulging of parts, for parts with a material thickness of ≥2.5mm, when the design width is (1～1.5)t process gap; or set the twists to be perpendicular to the line of the sheet metal material.


2.4 Design standards for welded structures


(1) In order to ensure the excellent processing technology and excellent shape effect of the product structure, the welding spot and the weld seam should be strengthened on the relatively minor surface layer.

(2) Use fillet welds as much as possible, and do not choose butt welds as much as possible.

(3) When designing the welding structure, it is necessary to install the welding seam appropriately according to the requirement of "place the welding seam symmetrically", and should not produce intersection, so that the secondary welding seam is stopped, the primary welding seam is uninterrupted, and the welding seam is as good as possible The ground is close to the neutral axis, far away from high stress areas, stress concentration areas, processed layers, heat-treated surface layers, etc.


2.5 Design standards for structural gaps

(1) The connection between the gap between the rotating door panel and the frame and the height of the door.

If the height of the door is H≤1m, then the unilateral spacing a=1.5mm; if 1m1.8m, then the unilateral spacing a=2.5mm.

(2) Stabilize the relationship between the door panel, frame spacing and door height. If the door height is H≤1m, then the unilateral distance a=0.75 mm, and the door height is 1m1.8m, then the unilateral distance a=1.5mm.


3 Conclusion

There is an inseparable connection between sheet metal structure manufacturing and production technology. Accompanied by the improvement of the degree of intelligence of sheet metal facilities, relevant designers are required to continuously understand and pay attention to advanced sheet metal knowledge. Designed parts have excellent processing technology to ensure that, in an environment that adapts to product functions, the designed parts are made to become more complete processing techniques as much as possible, reducing processing capital investment, and improving product quality.