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Pancake Dies: My Further Adventures


#1

You might think that with some spare time over Christmas I’d have
taken it easy and worked on music or laid around and eaten candy all
day (ok I did a fair amount of all that) but it seemed like a good
time to get around to some important documentation of my
experimental exploits. Also, since the 1/2 HP gearmotor I found
wasn’t here yet, more attempts at pushing the little Pepe rolling
mill to the brink of it’s doom would have to wait.

So much earlier this year I had gotten the (maybe not so ) bright
idea to make an elaborate, 2 part, cut and form, pancake die set,
just for the purpose of show & tell about how to do it. I had cut
the pancake die, a funky flaming- sun shape 4.75" in diameter, with
the expectation of making it into a 3-D ornamental sun-face project.
It was a busy year, so it waited until now to go any further, and I
made a sculpey clay sun and used it as the model for an aluminum
sand-cast punch component that would attach to the pancake die. The
other part of the die set is a female mold, cast in plastic steel,
using a sheet metal shell (that’s made by getting formed around the
sand cast punch) as the model.

I wanted to make the sun with a face on it, but found the level of
my small-scale artistic sculpting abilities to be sadly lacking, so a
plain, faceless sun it would have to be. Unless…

It kept bugging me, because for one, a plain sun probably wouldn’t
even require a female mold to form ; it would probably work as a
one-piece die, with the cast punch attached to the die, but simply
pressed into a thick urethane pad for forming and cutting. It was
bugging me, so on the night of the 23rd I looked around online and
found some flexible molds for clay that looked like they had some
potentially usable faces, and ordered a couple. Then came Christmas
Eve morning, and being obsessed as I obviously was at that point, I
just couldn’t wait, and went to a crafts supply store and found a
similar mold and took it home to proceed.

Obsessed, impatient, but with a plan, I quickly made a little clay
face and cooked it. Then I simply made a little mound of sifted
casting sand and pushed the face into it to make a cavity to cast
into. I used silver, and then ground the back down so that it would
fit onto the flat spot I had sanded on my plain sun. Not a perfect
joint, and being the 25th at about 3 am by then, I wasn’t going to
be able to go get any plastic steel, and I was obsessed. So I did
what any normal, calm, rational, obsessed person would do in this
situation : I swept up some metal dust from around the sanders,
mixed it with some epoxy, and patched together the sun and sun face.
Now it was a SUN FACE !!! YIPEE !!!.

Now, a few days later, the project is nearing completion, and I took
detailed notes -for of course there were new twists and turns that
previous similar projects didn’t take – and lots and lots of
pictures. None of the pix are developed yet, and it may be some time
before I post the step-by-step and pix in a formal way, but it feels
good to have started working towards documenting my infamous
escapades. Chipping away at it like this, there’s a good chance that
I will leave behind a decipherable record of my practical/functional
obsessions. Oh, and the gearmotor came today. Pepe, my friend… say
your prayers !. (No, I will not destroy my rolling mill. I will not
destroy my rolling mill. I will not…)

I did scan the shell made by pressing the cast punch into rubber,
urethane, and plastic.

Stay tuned,
Dar
sheltech.net


#2

Here is a scan of the finished piece. One interesting thing that I
had not thought of or tried before, and is very cool for a couple of
reasons, is pre-forming the part before loading it into the cutting
die. This is done using the 3-D, cast-aluminum punch that’s attached
to the cutting die, but done without loading the metal into the die
for cutting. After pre-forming and then loading, the loaded die sets
on the base plate (with cast plastic-steel female mold built-in) much
better, and it takes very little pressure (or almost none after
blanking, if you’ve done your pre-forming at high pressure ) to
finish forming, which allows the delicate parts of the plastic steel
mold to wear much much better.

This particular sample piece was pre-formed at 40 tons into (first)
3/4" of 95 a urethane, and (second)3/4" of (Sanalite) polypropylene.
The part is 4.75" in diameter and about 1/2" deep at the nose, and
about up to 1/4" deep along the flames. This latter forming step did
all the forming of the face, and did more forming than did 20 tons
with the die and solid mold. This tells us, among other things, that
some designs are suited to full forming before the blanking stage and
that attaching the forming punch to the cutting die itself isn’t
always necessary or best.

This die was started with the intent of being a one-step die, and I
finished it that way. But to make it last longer in the delicate face
area, I will most likely never actually use it in the one-step
capacity. This one, unlike many similar ones I’ve made in the past,
is
not built with the option of using a thin urethane pad insert in the
plastic steel mold to cushion the metal as the forming punch and
cutting edge force a flat piece of metal down into it. That could be
added after the fact, and does make the one-step function go more
smoothly, literally.

It was started with the intent of being just like those other ones,
but after I made the shell shown in the earlier picture (done the
same way as pre-forming , but before the forming punch was attached
to the cutting die) I realized that this design would work perfectly
and the face area of the plastic-steel mold would last longer if I
went the pre-forming route. It’s also less stressful on the cutting
die itself when all it has to do is… cut the part!. Which opens
the
door for the option and possibility that attaching the forming punch
to the die isn’t even necessary… and so it isn’t, always.

Of course, for certain designs it’s perfect, and when you want
one-step efficiency and speed (which I absolutely had to have with
those other ones) it’s the way to go.

I understand that much of this is hard to follow without pictures of
the dies and the steps done in making them, which is exactly why I
took so many shots and notes. So eventually I’ll get that all sorted
out for further explaining. But here’s the scan of the final cut
piece.

Dar Shelton
sheltech.net


#3

There’s the link to my photobucket site with the scans of the Sun
Face. I got the real pix back today and will begin procrastinating
the process of formalizing the written how-to steps to go with pix.

DS
sheltech.net


#4

Taking a break from rolling mill adventures to do my real job, or at
least talk about doing my real job, I give you some more pictures of
the Sun Face Project, posted over on the Bonny Doon forum:
http://www.bonnydoonengineering.com/ceilidh/ceilidh.html#4709

Dar
sheltech.net