EDM, be it plunge or wire cut, produces a recast edge (15-20thou thick) which needs to be removed from a highly stressed part.

Power&Passion
The suggestion that the existence recast edge produced by laser or EDM is “anecdotal” is stupid considering even a very elementary understanding of the process. Just try googling the subject and you find a good number of technical description of it and its detrimental performance on the material properties.

Not wanting to look like a fool myself I will not argue with one.

VegaECM, I respect your knowledge. You have provided the most detailed, logical and considered flight over a topography I want to learn about, I appreciate it.
But play the ball, not the man, otherwise I will find you, marry your daughter, then you and I will sit and glare at each other over the Christmas turkey for the next 28 years while I, mouth full, cutlery waving, hand on daughter’s leg, make bold announcements over things I know nuthin’ about !

Anecdotal refers to conversations, posts, experiences I have come across. I would love to have some links to scientific papers which may provide more detail as part of a discourse. Until I get this wrapped in a rock and thrown through the window even Vega ECM is anecdotal !

Last week I was quoted $3,000 Australian dollars, enough to buy a dinner with Bill Clinton, to make up a press tool for a short run antique aircraft part. I have been sufficiently impressed with my public picking of fluff out of my belly button on this laser cutting topic to consider making up the same press tool out of 1mm high tensile steel in the ‘sliced crim’ method previously described. Sliced crim was the guy in America who volunteered after execution to be cryogenically frozen then sliced on a ham slicer, each slice being photograped to allow some interesting time lapse video to be made 15 odd years ago. I have not eaten ham in the US after this. I will find out his name and call this proposed tool making process after him. I really hadn’t thought about ham dude for 15 years until this stream of conciousness about laser cutting, and I appreciate folk have been very indulgent of me as I work the potter’s wheel, thank you.

Understanding, anecdotally, that laser will recast an edge from 5 thou to 15-20 thou on high tensile steel, starting from a CAD model, I will make up a press tool 150mm wide out of 150 slices of 1mm sheet bolted together through laser cut bolt holes. If the slices make an impression on the work, I will experiment with rubbing two pack car body filler over the working face, but I do not think I will need to do so. My hypothesis is that I will do this in one day, not the 4 weeks proposed by the toolmaker and at less cost than $3,000 quoted, using a cheapo laser located at the back of a take away food shop. I will let you know how much it costs, and I will run myself at parliamentary rates. Good people may be shaking their heads at me, but if I can make a short run stamping tool at a fraction of the cost then a lot of possibilities will open up.

I have also been struggling with the idea of turning up a sequence of strip forming wheels in a roll former to develop the flower of a profile, where material springback is an unknown factor. Now I think I might laser cut a 25mm wide wheel out of 1mm thick laser cut discs, and bolt them together. If I need more or less bias on a particular wheel then I can just change some discs rather than throw a whole turned piece away. It will be like Lego. At least I hope I will resolve a working set that can then inform a conventional turned up set at a fraction of the cost.

In respect of EDM I have been sufficiently excited to go and look at a second hand one left in the corner of a shed, just to play around with. I will see what it can and isn’t supposed to do. EDM is all new to me, I feel like I am about to go on a date with a really hot sparkin’ babe. Love it !

In the end, for the beer, I will lay identical test pieces together, calculate cutting cost per cubic mm, spread some anecdotal jam over the top, and move off to perplex on other issues. No one has yet complained over the choice of Coopers Stout for the beer competition, which means no one has tasted this elixir of youth that can double as boot polish. If we had a forum where people could feel safe to say ‘I do not know’ then I would twist the tops of more beer and say ‘try this’, as I too might be given a lesson in hoppy American cheerleader beer or something British strained through a grandmother’s overcoat.