What is the meaning of lap in metal stamping parts? How to determine a reasonable lap value?

What is the meaning of lap in metal Stamping parts? How to determine a reasonable lap value?

What is an edge? What is the role of an edge in the processing of metal stamping parts? Why should a reasonable edge value be determined? What are the main factors that affect a reasonable edge value?

When metal stamping parts are processed and laid out, there is waste between the workpiece or the side of the workpiece and the strip, which is called the overlapped edge. Although the edge is scrap, it has a great effect in the craft. The function of the edge is:

• 1) Keep the strips with a certain rigidity to facilitate feeding.
• 2) Compensate the positioning error, even if there is a certain error, it will not be wasteful. The reasonable width of the edge is a small width to ensure the quality of the cut surface of the punched part and improve the life of the mold. If the width is too small, the overlapping edge will be broken during the punching process, which will cause the metal stamping parts to produce elongated burrs and affect the feeding.

It will also make the blanking parts uneven, and even pull the overlapping edges into the gap of the blanking die, causing serious wear or damage to the cutting edge. Excessive lap edges not only reduce the utilization rate of the material, but also increase the unloading force of the mold. Experience has proved that a reasonable take-up value can increase the life of the mold by more than 50%.There are many factors that affect the size of the border value, mainly as follows:

• 1) Material properties The harder the material, the smaller the tie-up value.
• 2) Material thickness When punching thin materials, in order to maintain good rigidity, a larger lap value should be used, but for thick materials to ensure that the lap does not break, a larger lap value should also be used. Experience has proved that when the material thickness is 0.5-1 mm, the edge value is small.
• 3) The larger the working size, the more complex the shape, and the greater the value of the tie-up.
• 4) The feeding method uses a side pressure plate to make the strip close to one side for feeding, and a smaller lap value can be used.

“Major hardware stamping parts manufacturing industry” refers to the process from metal material mining and refining to the manufacture of primary metal products to the manufacture of general production equipment, and then to the manufacturing of special equipment for various industries in the national economy. The metal stamping parts industry mainly uses metal raw materials. The change of physical shape, processing and assembly then become the product.

“Small metal stamping parts” refer to various metal devices manufactured by forging, rolling, cutting, and other physical processing of metals such as iron, steel, and aluminum.