Stamping Knowledge

What is metal stamping?

Metal stamping refers to the process of shaping sheet metal materials through specific tools. The manufacturing process involves various complicated steps by external forces such as blanking, stamping, bending, and perforation, etc. to bring sheet metal to the desired shape. The finished products are called stamping parts. Three major goals of metal stamping:

1. Mass production
2. Quality stability, durability, consistency
3. Low cost

The basis of stamping:

Stamping starts with feeding the material into the punching machine where the die tool is positioned. The die tool is designed in accordance with the requirements to punch, blank, bend, emboss, flange, emboss and cut the sheet metal into the finished products. At the beginning of die set design, professional engineering designers use CAD/CAM as development platforms. The designers must possess a certain degree of knowledge of the material characteristics before proceeding to design based on the desired shape of the finished product. The design must be precise to maintain a viable gap between each punch or guide pin with the die set to ensure normal and smooth operation. Each die set comprises dozens or hundreds of parts that require a high level of experience and professional technology, which is a time-consuming and complicated process. Once the design is done, the most suitable metal will be chosen for further processing including cutting, grounding, drilling, and punch embedding to finish the die set production. The completed die set will then be put to numerous tests in the workstation for further modifications to ensure operation accuracy before it is utilized in mass production.

Types of metal stamping:

Stamping manufacture primarily involves progressive dies and single-stage dies. Progressive stamping refers to the machine that can perform multiple processes with each workstation functioning independently. When the material is fed to the machine for automatic stamping, the workstation operates up-down stroke in a vertical motion with upward movement of the die set corresponding with the onward movement of the metal strip on the feeding conveyor belt. Each workpiece moves forward with continuous downward strokes of the die set while various steps such as punching, bending, cutting, etc. are performed step by step to gradually complete the products. The size of the stamping machine is directly proportional to the tonnage, which means the higher the tonnage, the thicker the sheet metal the machine can handle. The shape of the finished products, however, correlates with the die set design and development capability. The progressive stamp die sets are more efficient with faster operation speed and a higher level of intricacy, hence leading to higher developing costs. Nevertheless, when there is a demand for mass production, the actual production costs may decrease due to the operation efficiency of progressive stamping. Generally speaking, most precision metal stamping components in high demand are manufactured by progressive stamping. Single-stage dies are used for a single motion of the stamping machine, such as bending, embossing, or punching. When there is a small-quantity order for finished products that have a simple shape and are required to be made of thicker material, it is more likely single-stage dies will be used for production. A single-stage die is easier to make with simpler structures and lower costs, while its biggest disadvantage is the low production efficiency. In general, the decision on the production method should be made based on the following factors:

1. Product shape complexity
2. Material thickness
3. Material characteristics
4. Annual demand
5. Tolerance requirements

After all the above factors are taken into consideration, the production method can be determined to accomplish the ultimate goal of the highest economic benefits. Stamping parts, with a wide range of applications, are commonly used in industries such as automobiles, household appliances, electronics, instrumentation, machinery, railways, communications, chemicals, light industry, textiles, and aerospace, etc.