Sheet metal fabrication makes some metal sheets plastically deformed by manual or die stamping to form the desired shape and size. The metal can be further welded or mechanical processed to form more complex parts, such as chimneys, tin stoves, and car shells. Those are all sheet metal parts.

The main processes are cutting, bending, forming, welding, riveting. You need some certain geometric knowledge. Sheet metal parts are thin-plate hardware parts. A general definition is - parts with constant thickness during processing correspond to castings, forgings, machined parts, etc. For example, the outer iron shell of a car is a sheet metal part. Some kitchen utensils made of stainless steel are also sheet metal parts.

Common issues & reasons

1. Burrs

There are not enough remaining materials in the process of punching or cutting corners. Burrs are generated on the lower part of the cut-off surface of the steel plate. Based on the cut-off surface, when the height of the burrs is more than 0.2mm, the iron powder generated will damage the mold and produce unevenness.

2. Convexity

The surface of the material is abnormally convex or concave, which is caused by the mixing of foreign matter (iron filings, dust) in the uncoiler.

3. Roller print

It is caused by foreign matter attached to the cleaning roller or the feeding roller (occurs at a fixed pitch). Generally, the foreign matter on the roller print on the sheet can be removed.

4. Slip marks

They are caused by roller slippage, occurs when suddenly stopping or accelerating.

5. Wrinkling on the edge of mold

When the gap between the guide roller of the uncoiling line and the mold is small, it causes wrinkling. The reason is the unbalanced feeding of the coil material.

6. Scratches

If there are spikes on the mold, or metal dust falls into the mold, the part is scratched. The preventive measures are grinding the scars on the mold and removing metal dust.

7. Cracking at the bottom

The main reason for cracking at the bottom is that the plasticity of the material is poor, or the blank holder is pressed too tightly. The preventive measures are to replace the material with better plasticity, or loosen the blank holder.

8. Wrinkles on the side wall

The main reason is that the thickness of the material is not enough (the allowable thickness is relatively small), or the upper and lower molds are installed eccentrically, resulting in a large gap on one side and a small gap on the other side. The preventive measures are immediate replacement of materials and readjustment of the mold.

Sheet metal parts have the characteristics of light weight, high strength, electrical conductivity (It can be used for electromagnetic shielding), low cost, and good mass production performance. They have been widely used in electronic appliances, communications, automobile industry, medical equipment and other fields. The remarkable feature is that the thickness of the same part is consistent.

With the popularity of sheet metal, the design as become a very important part of the product development process. Mechanical engineers must master the design skills of sheet metal parts proficiently, so that the designed sheet metal can not only meet the requirements of product function and appearance, but also make the stamping die manufacturing simple and low cost.