Pinching in pressing operation

[ChazzC]

Is the metal annealed?

What lubricant are you using on the metal?

As @extropic noted, this is a complex shape, with little draft and the use of progressive dies makes sense. Progressive in this case may require multiple die-sets for the full draw. Alignment of the material in subsequent sets is a function of the design of the dies.

Not an expert, but have been exposed to a number of pressing operations in the course of my career.

 

[woodchucker]

I don't understand why you are floating the die? That should push through and bottom out with exact clearance for the sheet material, in my humble opinion.

 

[whitmore]

The higher curvature of that region stretches the metal, and the adjacent edge gets indented
because of the high forces required. If your adjacent edge were farther away, it might decrease the
wrinkle. I suspect that that adjacent edge's distortion/movement during the press might be
lessened by somehow fixturing a clamp for the edge, or by using a larger blank (the extra
waste at the edge being a stiffener, like clamping).

 

[pontiac428]

I guessed from your first picture that you were making pickup covers. In that case, I would clearly take one action to improve outcome. Stop listening to Stevie Ray in the shop, and play some Dimebag Darrell instead. The metal will comply.

 

[Maplehead]

I don't understand why you are floating the die? That should push through and bottom out with exact clearance for the sheet material, in my humble opinion.

The only item “floating” is the bottom pressure plate. It’s the piece that rests on the four big springs.

 

[Maplehead]

Is the metal annealed?

What lubricant are you using on the metal?

As @extropic noted, this is a complex shape, with little draft and the use of progressive dies makes sense. Progressive in this case may require multiple die-sets for the full draw. Alignment of the material in subsequent sets is a function of the design of the dies.

Not an expert, but have been exposed to a number of pressing operations in the course of my career.

I don’t think it’s annealed. At least I didn’t anneal it. It’s just nickel-silver sheet purchased online. WD40

 

[Maplehead]

Photos are always hard to troubleshoot............
It looks to me like you're bottoming out on the shoe plate before the block though.
Are those your actual guide pins?

Yep, I had metal ones but the wood ones work a whole lot better at releasing everything after pressing. If I was bottoming out then I would think those “pinches” would get flattened.

 

[ChazzC]

I don’t think it’s annealed. At least I didn’t anneal it. It’s just nickel-silver sheet purchased online. WD40

WD40, while it works well for cutting Aluminum isn’t a true lubricant. Soap (which is saponified fat), a stick style machining compound and even Crisco work well.

 

[Parlo]

Looks like the blank is too short. If there is a pressure plate to hold the blank flat before any forming, perhaps the relief is greater than the material thickness you are using.

 

[pontiac428]

After looking at this again and knowing nothing about press work beyond forming wildcat brass, I wonder if it is possible to form the part in two operations. One to form the crest that isn't coming out right, and another to form the body. Not sure which should be first, but when forming brass you try to do a little at a time in steps to control the process.