Defect in deep drawing and their remedies available, for mechanical students

1. Defects In Deep Drawing And Their Remedies
Submitted to:
P.K Singh
Prof. Mechanical deptt.
S.L.I.E.T Longowal
Submitted By:
Shivam Pandey
REG. No. PGMSE1750161
Mechanical Deptt
Sub Name: Advance Metal Forming
Sub Code: MET 911

2. Table Of Content
 Introduction to Deep Drawing Process
 Common Defects And Their Remedies
 Flange Wrinkle And Wall Wrinkles
 Step Rings
 Draw Marks
 Orange peel
 Scratches
 Fractured Flange And bottom
 Corner Fracture
 Miss Strike
 Directional Earing

3. Deep Drawing
It is process of converting circular or spherical blank into cup shape
component.

4. Flange Wrinkle And Wall Wrinkles
 It occurs when compressive stresses (Hoop
Stress) in circumferential direction reaches
critical point of instability.
 It occurs where work piece is unsupported or the
blank holding force is in sufficient.
Remedies:
• Increase blank holder force
• Using a Draw Bead

5. Step Ring
 Its formed during Redrawing when the Redrawing is performed
near the LDR value, Step Rings appears on the drawn cup.
Remedies:
 Redrawing operation must be performed at lower value of draw
ratio.

6. Draw Marks
 It occurs due to the improper finish of the die surface Draw Marks
appears on the draw cup.
 Surface finish of die gets deteriorates due to improper lubrication
between blank and die.
Remedies:
 Proper lubrication
 Good surface finish

7. Orange Peel
 It occurs due to coarse grain structure of the drawn material.
Remedies:
 Grain structure should be refined before deep drawing.

8. Scratches
 Heavy scratches over the drawn cup may appear due to appearance
of yield point phenomenon in the material.
Remedies:
 Steel material must be consumed within the strain aging time of
material.

9. Fracture Flange And Bottom
 When the sheet metal is subjected to strains exceeding the safe strain
limits of the material.
 For ductile sheets this fracture usually occurs near the punch corner.
 It happens when draw ratio exceeds the LDR or holding force is
more then required.
Remedies:
 Sufficient holding force.
 Working under LDR ratio.

10. Corner Fracture
 Same as Flange and Bottom Fracture

11. Miss Strike
 Due to non symmetric placement of blank over die, this defect Miss
Strike.
Remedies:
 Proper alignment of workpiece

12. Earing
 Anisotropic sheets result in a drawn cup with uneven top edges.
(Planer anisotropy of blank material).
Remedies:
 Ironing is performed to make the thickness of drawn cup uniform.
 But excessive Ironing produces burnishing.

13. References:
 Dr. Swadesh kumar singh’s book of Production Engineering.
 R.K Jain’s book of Production Technology.
 Kalpak Jain’s book on Manufacturing Engineering and Technology
 Google.