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One Step Blanking and Embossing


#1

The new trick below was posted to the Bonny Doon Discussion Group
recently. A tiny bit of background though, for those unfamiliar with
the concept. That being attaching wire (or other) designs to the face
of a Pancake/RT blanking to make a die which cuts out a part (in sheet
metal) and embosses it in the same pressing stage. In it’s simplest
incarnation it is as simple as a die thusly modified, and a pad of
urethane (usually). The RT die functions normally, but it is set onto
the pad in the press and after the part gets blanked, more pressure
is added and the part gets embossed, sandwiched between the die and
the urethane pad.

In less simple varieties, forms are deeper and more 3-D instead of
just wire designs. In extreme cases, where the depth and/or detail is
too much for pads alone to handle, a female mold of some sort is
used; this has the negative impression of the desired form in it, and
the blanking die is set (also precisely located and registered) on
this base in the press. Here, after the part is cut it is pressed into
the conforming mold, and the forming can be done to a greater degree
; more depth and definition, and at a lower pressure for each degree
of forming achieved. One may still need very high pressure but more
is being achieved. The above will hopefully help the below be
digested more smoothly, and assimilated properly. I’ve had to push
these techniques to their limits over the last several years, in the
course of doing work for all the nice jewelers and artists out there
who require my services . Photos of most of this can be found on my
site and the BD Forum. I really haven’t had a lot of time to write
about my work, but will attempt to chip away at it over time. In what
will no doubt appear a random and disjointed manner. As things seem
to happen…

I have a particular blanking die with a wire design soldered on; it’s
a star about 3.5" by 2", with a spiral (2 complete windings, in 18 ga
rd. nickel silver ) in the middle. Normally it’s done in 24 ga. copper
and takes about 20 tons to emboss nicely, in something a bit harder
than 95a durometer urethane. It works well with 75-d duro, or a very
softer ,somewhat mushy plastic ; “Sanalite” is a brand name I have
piles of and use a lot.

The new problem was that I got sent some 22 ga. Cu, and the 25 tons
of my small press wasn’t enough and I simply didn’t want to use the
50 tonner. I instinctively thought of (and dismissed at first ,because
of the time and trouble involved) a female conforming die. Building a
setup using Plastic Steel was out of the question for a short run, as
was using the die itself to melt a depression into nylon or
polyethylene ; just too much of a pain for this quickie. Yes, I
understand I could’ve used the 50 ton press and been done with it,
but I then thought of something I wanted to try.

Exactly what I thought of ended up working perfectly, and this is it.
I took the die and set it on a piece of 1/4" polycarbonate (Lexan)
sheet, taped down some metal strips onto the sheet, snug against the
sides and top edge of the die, to function as a locating jig for the
die. Then, leaving the die right there, located, I pressed it into the
Lexan in the 50 tonner, then took a previously cut (and formed) part
from the die, put it into the die and pressed again at 50 tons.

So there I had it, a solid (more or less, and good enough for quite a
few parts, I suspect) female conforming mold, formed exactly by a
part from the die itself, complete with locating strips. The result
was a setup that formed parts that were more defined, at a much lower
pressure, and out of a thicker gage, and was extremely easy to use.

I’ll get some pix up soon ; this was a spontaneous development ; no
camera handy this morning.

Dar Shelton
www.sheltech.net