I plan to buy one of the two machines and would like to get some experience in my application area using folks who have such equipment and are willing to do an experiment on copper and copper alloys. Not for free, of course.
I work with Mokume Gane, a Japanese metal working technique using layers ofcopper, copper alloys and precious metals fused together by way of “diffusion bonding”.
In practice, such millets or “blocks of metal” are multilayered pieces of metal, which need to be patterned. This process was traditionally done using pinches to punch holes or lines.
One can also use drill presses for holes.
I would like to use CNC to carve pattern out of these metal blocks.
Not relevant for this discussion but just to pre-empt questions from the forum (why carve into metal): the patterned metal is then annealed and forged to create unique metal patterns not unlike Damascus blade patterns.
What alloy of copper? Some mill much better than others.
How thick are the layers?
Is the intent to mill or engrave through multiple layers to create color fringes in the designs?
What general type of designs do you envision?
Here are some metrics on what I am doing (sorry, mostly metric):
COINS
Currently and as a starting project, I work on layers of pure copper and cupronickel (75% copper, 25% nickel). Think US quarters. According to US mint infos one quarter is 1.75 mm thick.
A stack of 15 coins (2.6 cm/1") is forged down to a billet about 1cm high and 2,5 cm wide/1").
So, 45 layers (cupronickel - copper - cupronickel - cupronickel - copper cupronickel - cupronickel - copper etc) are “squeezed” to layers of about 0.7 mm average.
I typically start applying patterns at a stack height of about 1 cm and forge it down to about 5 mm final thickness.
It is recommended to carve a pattern roughly 50% of height of a billet.
So, from the CNC perspective this would mean about 3-5 mm depth, depending on how low I forge the stack.
NOT COINS
The next series of billets would be sheets of copper, white bronze and more or less pure silver (sterling or otherwise). No Nickel.
I am planning to then move to the silver alloys used by the Japanese for Mokume Gane.
Alloy details see below.
Typically, the layer thickness initially is 20-22 gauge (0.7 to 0.9 mm). 10-20 layers are fusion-bonded (heat until they sweat without melting to alloy level to maintain layering) and then forged down to about 1/3 before pattern are applied.
Shibuichi (15-25% sterling silver, the rest copper)
Shakudo (4% gold, 95% the rest copper)
Kara-kane, Sahari (>85% copper with some tin, zinc, and lead and - in case of Sahari a little silver, essentially a modern bronze)
I hope, I have answered your questions somewhat ?
looking forward to hearing from you !
BTW: this link (handverker: cnc mokume gane
) walks you through the process of CNCing (with a Tormach !) such a billet and then see the resulting engraved pattern being forged to Mokume. Pretty much what I intend to do.
I’m not sure I can personally help you here, not my area of expertise. But I thought these appropriate questions to help others with more metal experience help you. It looks like an interesting process depicted on the link.