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SS SHEET DESIGN NOTES
1. Introduction
Thin plate refers to a steel plate whose thickness is much smaller than its length and width. Its poor transverse bending resistance is not suitable for occasions subjected to transverse bending loads. The thin plate is metal in terms of its material, but because of its special geometric shape and small thickness, the processing technology of the thin plate member has its particularity.
1.1 There are three types of processing technology related to thin plate components:
(1) Blanking: It includes cutting and punching.
(2) Forming: it includes bending, folding, curling and deep drawing.
(3) Connection: It includes welding, bonding, etc. The structural design of thin plate components should mainly consider the requirements and characteristics of the processing technology. In addition, pay attention to the batch size of components.
1.2 The reason why thin plate components are widely used is because thin plates have the following advantages:
(1) It is easy to deform, so that a variety of components can be manufactured with simple processing techniques.
(2) The thin plate member is light in weight.
(3) The processing volume is small, because the surface quality of the thin plate is high, and the dimensional tolerance in the thickness direction is small, and the plate surface does not need to be processed.
(4) It is easy to cut and weld, and it can manufacture large and complex components.
(5) The shape is standardized, which is convenient for automatic processing.
2. Structural design criteria for ss sheet design
When designing product parts, the problem of easy manufacturing must be considered. Try to think of some methods that can not only make the processing easier, but also save materials, but also increase the strength, and not produce waste products. To this end, designers should pay attention to the following manufacturing matters.
The manufacturability of sheet metal parts refers to the difficulty of parts in punching, bending and drawing. A good process should ensure that the material consumption is small, the number of processes is small, the mold structure is simple, the service life is high, and the product quality is stable. Under normal circumstances, the greatest impact on the manufacturability of sheet metal parts is the performance of the material, the geometry, dimensions and accuracy of the parts.
How to fully consider the requirements and characteristics of processing technology in the structural design of thin plate components(SS SHEET DESIGN), here are a few design guidelines recommended.
2.1 Simple shape criterion
The simpler the cutting surface geometry, the more convenient and simple the cutting is, the shorter the cutting path, and the smaller the cutting amount. For example, a straight line is simpler than a curve, a circle is simpler than an ellipse and other higher-order curves, and a regular figure is simpler than an irregular figure (see Figure 1).
The structure of Fig. 2a is meaningful only when the batch size is large, otherwise cutting is troublesome during punching. Therefore, the structure shown in Fig. B is suitable for small batch production.
2.2銆€Raw material saving criteria (configuration criteria for die-cut parts) during ss sheet design
Saving raw materials means reducing manufacturing costs. Fragmentary scraps are often treated as waste, so in the design of thin plate components, scraps should be minimized. Punching and discarding the material at least to reduce the waste of the material. Especially when the large batch of components are cut, the effect is significant, and the ways to reduce the scrap are:
(1) Reduce the distance between two adjacent members (see Figure 3).
(2) Ingenious arrangement (see Figure 4).
(3) Take out the material at the large plane for smaller components (see Figure 5).
2.3 Sufficient strength stiffness criterion
(1)Bending edges with beveled edges should avoid deformation zones
(2)If the distance between the two holes is too small, there is a possibility of cracks during cutting.
The punching design on the parts should consider keeping proper hole margin and hole spacing to avoid punching. The minimum distance of the punching edge of the part from the shape has a certain limit depending on the shape of the part and the hole. When the punching edge is not parallel to the shape edge of the part, the minimum distance should not be less than the material thickness t; when parallel, it should not be less than 1.5t. See the table for minimum hole margin and hole spacing.
Round holes are the most solid and easy to manufacture and maintain in the mold making, but the hole opening rate is low.
The opening rate of square holes is the highest, but because of the 90-degree angle, the corner edges are easy to wear and collapse, causing the mold to be repaired and the line is stopped. The 120-degree angle of the hexagonal openings greater than 90 degrees is stronger than the square hole openings But the porosity is a little worse than the square hole at the edge.
(3)The slender slat has low rigidity, and it is also easy to produce cracks during cutting, especially the serious wear of the cutter.
The depth and width of the protruding or recessed parts of the punched parts should generally not be less than 1.5t (t is the material thickness), and narrow and long cuts and excessively narrow cuts should be avoided in order to increase the die The edge strength of the corresponding part. See Figure 3.3.1.
For general steel A鈮?.5t; for alloy steel A鈮?t; for brass and aluminum A鈮?.2t; t鈥攎aterial thickness.
3.Need to consider processing difficulty when working on ss sheet design
The semicircular tangent structure shown in Fig. 9a is difficult to punch. Because this requires accurate determination of the relative position between the tool and the workpiece. Accurate measurement and positioning is not only time-consuming, but more importantly, the tool can be worn and installed errors, the accuracy usually does not meet such high requirements. Once this structure is processed with a slight deviation, the quality is difficult to guarantee and the cutting appearance is poor. Therefore, the structure shown in Figure b should be adopted, which can ensure reliable punching processing quality.
4. Avoid sticking the mould
During the punching and cutting in the middle of the component, there will be the problem that the cutter and the component adhere to each other tightly. Solutions: (1) leave a certain slope; (2) the cutting plane is connected (see Figure 10 and Figure 11).
When overlapping 90掳 flanges by punching in one process, the material should be selected not to be too hard, otherwise it will easily break at right angles. Technological incisions should be designed at the bends to prevent cracking at the corners.China Stainless Steel Engineering
website:http://www.iwonprecisefabrication.com/stainless-steel-engineering/