What are the defects in deep drawing?

The main defects of deep drawn parts are wrinkling and/or necking. Wrinkling usually occurs at the flange region by excessive compressive stresses leading to local buckling of the sheet. On the other hand, necking is due to the excessive radial tensile stress.

What are the primary defects of deep drawing operation?

One of the primary defects that occurs in deep drawing operations is the wrinkling of sheet metal material, generally in the wall or flange of the part. The flange of the blank undergoes radial drawing stress and tangential compressive stress during the stamping process, which sometimes results in wrinkles.

What is cause of earing defect in deep drawing?

Earing is one of the major defects observed during deep drawing process due to anisotropic nature of sheet metal. Earing is defined as formation of waviness on uppermost portion of deep drawn cup. Mechanical parameters of mild steel are incorporated in finite element simulation of deep drawing process.

What are the defects of the deep drawing process?

The schematic drawing of the conventional deep drawing process is depicted in Figure 6.1. The stress in the flange region during the deep drawing process is a combination of radial tensile drawing stress and a tangential compressive stress (hoop stress). The main defects of deep drawn parts are wrinkling and/or necking.

What causes metal to crack during a deep draw?

Fracturing of the metal during the draw process can be caused by several issues although the most common is the clearance between the punch and the die. If this is too small, too large, or uneven, the material can be cracked during drawing. This problem is typically due to issues with the blank holder.

What causes wrinkles in the deep drawing process?

The flange of the blank undergoes radial drawing stress and tangential compressive stress during the stamping process, which sometimes results in wrinkles. Wrinkling is preventable if the deep drawing system and stamped part are designed properly. Several factors can cause wrinkles in deep drawn parts, including:

What are the stress conditions in deep drawing?

The stress conditions determine the forming process at deep drawing. The important stress condition in the cup wall is the point of transition of the punch radius to the cup wall area. This loading zone is characterized by a plane strain load, whereas the cup bottom has a biaxial stress load.