Sinker EDM; burning thin/flat parts

[mkd]

Recently working on a project where we are burning a 316 stainless 3D printed part down to a .020" thickness. Bottom as-printed surface seemed to have gotten sucked up into the electrode. Part is a little flimsy with fixture clamping loads from the side, so some oil-canning was expected by me. But we really blew a hole through the center of the part. simple 1" dia electrode. Melting material we would have expected gravity to pull away from the 'trode.
 ideas?

[mkd]

Fixture is not ideal to say the least. I wanted 3-2-1 free state it but time cost me that battle.
crazy thing is the 3D printed surface under this pocket we burned looks to be forming something of a radius as you get closer to the blown out hole, the way the light comes off it.
 

[mkd]

Just got the part back. Absolutely crazy how the part sucked UP into the electrode. Metal went all blob-like.
 Seems like a little discoloration from heat.
 I'm the only one oddly fascinated, by EDM weirdness. Lol

[mkd]

Is it stress relieving?
From plate?
Clamped down, machined, release and it's bowed like a dogs dick (English phrase )

That's got to be part of it.
 I recently learned of the residual stresses in a 3D print. It bows the shit out of the building plates even if they are thick steel.

[crazy^millman]

That's got to be part of it.
 I recently learned of the residual stresses in a 3D print. It boes the shit out of the building plates even if they are thick steel.

Yeah I was explaining this very subject to some people print in the Datum features to finish on some parts that were $30k before we put the first tool to them. Not a single one was not on a red tag, but being launched into space. When they finally left material on the faces for the datums then every part after that didn't have any red tags.

[mkd]

Yeah I was explaining this very subject to some people print in the Datum features to finish on some parts that were $30k before we put the first tool to them. Not a single one was not on a red tag, but being launched into space. When they finally left material on the faces for the datums then every part after that didn't have any red tags.

Machinists: because even engineers need heroes.

[Brian]

Machinists: because even engineers need heroes.

Full disclosure here: I have no experience machining 3D printed parts, but lots with thin/high aspect ratio parts that need to stay flat, and I'm amazed at the general lack of knowledge on such matters by folks that *don't actually have to make stuff like this.*

If you're lucky, they get concepts like residual stress in material from processing the raw material, but have a poor/non-existent understanding of the effect of cutting forces on the finished part. Occasionally I've had good luck playing around with different finishing tools on opposing sides of a thin part to "balance" the stresses imparted during final finish ops. There's no such thing as stress-free machining!

I've wondered sometimes if this is another example of the magical thinking that can happen when we trust our computers & CAD s/w just a little too much!

Another thing: " heat fucks up everything"....I've wondered how any of the metal additive processes address this across different part geometries? (I suspect the reason most folks don't understand this sort of thing very well has to do with the relatively stable geometry of the part....the whole thing is stiff enough that the stresses imparted (or released) don't cause much movement.