How to analyze and control the quality of drawing parts?


The main quality problems in the deep drawing process: […]

The main quality problems in the deep drawing process:

Wrinkles in the flange deformation zone

Fracture of dangerous section

1. Wrinkles


(1) The concept and cause of wrinkling

Wrinkle refers to the formation of heights along the tangential direction in the flange deformation zone during deep drawing deformation

The phenomenon of uneven wrinkles non metallic conduit.


(2) Factors affecting wrinkling


Mechanical properties of materials

Relative thickness of flange material

Degree of deformation

The geometry of the working part of the die: the conical die is not easy to wrinkle

In general: the larger the width of the flange, the thinner the thickness, the smaller the elastic modulus and hardening modulus of the material, the weaker the resistance to instability, and the easier it is to lose stability and wrinkle.

Whether it is wrinkled, it can be judged by Table 5-1 or formulas 5-3, 5-4 according to the relative thickness of the sheet

(3) Measures to prevent wrinkles


In actual production, the most effective measure to prevent drawing wrinkles is to use a blank holder and apply a suitable blank holder force Q

Several important conclusions about wrinkling:


(1) Wrinkle law:


Practice has proved that wrinkles are most likely to occur in the first drawing of a straight-walled cylindrical part: the initial stage of drawing


(2) Anti-crease measures: use a blank holder to apply a proper blank holder force


(3) Location of wrinkles: the main deformation zone (flange deformation zone) of deep drawing