Stamping is a forming process that relies on a press and mold to apply external force to sheets, strips, pipes, and profiles, causing them to undergo plastic deformation or separation, in order to obtain the desired shape and size of the workpiece (stamped part). There are a large number of stamped parts in products such as car bodies, chassis, fuel tanks, radiator fins, instruments and meters, household appliances, office machinery, and household utensils. The production and processing of metal stamping parts require many technological processes. If not careful during the operation, it is easy to cause defects such as tearing and tilting of metal stamping parts, which affects the normal use of the product. The following is an analysis and introduction of the causes and prevention methods of cracks in metal stamping parts:

1、 Reasons for cracking of metal stamping parts:

1. Excessive local tensile stress

Due to excessive local tensile stress during the processing, metal stamping parts are subjected to internal and external impacts, resulting in significant local bulging deformation and cracking.

2. Insufficient molding process parameters.

In the molding process of the parts, the process requires that the mold, the pressing core, and the two parts must be tightly matched together. When the slider of the machine tool slides downwards, the plastic deformation of the sheet is forced to achieve forming. The processing technicians did not follow the prescribed process. At this stage, it is necessary to adjust the machine tool pressure in a timely manner, as unstable operation may cause cracking of the stamped parts.

3. Design defects in the flanging molding mold

The mold is shared by the left and right parts of the mold with two cavities. In addition to flanging, there is also molding involved in this process. In addition, the parts are particularly complex, with narrow curved surfaces and forming requirements such as concave mold cores and forming surfaces, resulting in large forming stroke and small pressing area of the mold structure, leading to cracking.

4. Stamping oil cannot meet the process requirements

Stamping oil plays a role in isolating the mold and workpiece during the stamping process, but the use of non specialized oils such as rapeseed oil, engine oil, and recycled oil can cause scratches on the workpiece due to poor performance, and the oil film will instantly rupture during the stamping process, causing scratches, burrs, and edges on the workpiece. In severe cases, problems such as workpiece cracking and mold damage may occur.

2、 Methods to prevent cracking of metal stamping parts:

1. The deep drawing process of metal stamping parts: The deep drawing direction should try to maximize the contact area between the punch and the blank, and the reasonable shape and edge pressure of the pressing surface should make the resistance of each part uniform and moderate, reducing the need for deep drawing, process drilling, and process cutting.

2. Structural design of metal stamping parts: During design, the radius of each rounded corner should be larger, the actual depth of the curved surface shape in the drawing direction should be shallower, the depth of each part should be uniform, the shape should be as simple as possible, and the changes should be as gentle as possible.

3. Design of metal stamping parts molds: Measures such as reasonable design of deep drawing ribs, increasing mold corners, and reasonable clearance between convex and concave molds can be taken.

4. Use specialized stamping oil: High end specialized stamping oil is formulated with sulfurized lard and sulfurized fatty acid esters as agents, and has excellent extreme pressure and anti-wear properties. During the stamping process, the release of extreme pressure agent can effectively avoid problems such as cracking, burrs, and burrs in the stamped parts, and greatly improve the surface smoothness and production efficiency of the workpiece, thereby reducing the overall production cost of the enterprise.

Today, we will introduce the causes and prevention methods of cracks in metal stamping parts. During the processing of metal stamping parts, many defects such as cracks may occur. All of these require reasonable design and careful operation by processing plant personnel to prevent the occurrence of defective metal stamping parts and improve product quality.