Effect of blank holder type on deep drawing of cups

Abstract EN

The purpose of this study is to examine the change in the wall thickness of drawn cup by using fixed blank holder gap (BHG) and variable blank holder force (BHF) to hold the sheets metal during drawing operations.

The effect of BHG and BHF on drawn cups was studied by the experimental and theoretical approach.

Two blank holder gap, BHG = 0.5, and 1 mm and variable blank holder force were used in the experiments.

The study shows that a type of blank holder has a great effect on the quality change of the wall thickness of the final product, and BHG and BHF are considered important parameter to control material flow.

Punch and die with diameters 43mm, 44 mm respectively are used to draw low carbon steel sheet (1008-AISI) with a thickness of 0.5 mm to draw a (cylindrical cups) from blanks with different reductions 0.5,0.55, 0.6, 0.65, and 0.7. The punch and die have the profile radius 4mm.

Press with a maximum load capacity of 200 KN with speed 10 mm / mint was used to perform this research.

The results show that no change occurs in the thickness of cups at ρ = 0.6 R, radius of blank, whereas the maximum change (thickening) of the wall thickness occurs when ρ = R, and the minimum value (thinning) of wall thickness in the corner of the cup.

All values which estimated theoretically are slightly different for measured experimentally.

The best results were obtained from the BHG = 0.5 mm compare to BHG = 1mm and BHF.