Doug Doug R

I've been experimenting a little with deep drawing soft steel.  So far so good.  I didn't use a blank holder, only a male die and a female die.  This works fine as long as the blank diameter is not too much larger than the finished drawn part giving only a shallow draw.

Now I want to use larger blanks where some sort of blank hold down will be needed to stop the undrawn portion of the blank from wrinkling more than can be ironed out in the drawing process.

I know industrial drawing presses have an auxillary pressure device, hydraulic, springs or pneumatic, etc, to maintain flatness of the blank as it's drawn into the die.  This is beyond most of our equipment so I assume some kind of bolted blank hold down is used.  If so, I'd like to know how much clearance you allow for the blank thickness?  Or, if you aren't using a bolted hold down plate, how do you keep the blank relatively flat while it's being drawn into the die?

I'm not familiar with the terminology used with BD presses so I hope this question makes sense.

Thanks,

Doug