Great brainstorming session these past few days on additive manufacture of
rocket thrust chamber assemblies, Bob Truax would be in awe.
So who's going to print the first LR-101 Vernier TCA hypoid drill a nozzle?
K
On Thu, Aug 13, 2020 at 12:15 PM Elliot Robert <elliotr@xxxxxxxxx> wrote:
I'm just reposting this because the conversation has made it more relevant
and I think some on here missed it. I don't think metal 3d printed exists
that's cheaper than this but it's really more of a sand casting method that
takes the human out of it.
Iro3d <https://youtu.be/IDl57RmASyA>
On Thu, Aug 13, 2020 at 2:56 PM Joe Bowen <joe.b.bowen@xxxxxxxxx> wrote:
The Virtual Foundry is a little bit more than just a printing service,
although they do that too. But the way I came across them is that you can
use your own cheap plastic 3D printer and their filament to print out your
part, and then you send it to them to sinter. It probably wouldn't take
too much to build a specialized kiln so you could sinter your own parts, I
think it's just a standard ceramics kiln with specialized gas shielding
(maybe it would be as simple as just pumping in some gas from an argon
tank). They're just using existing technology developed for injection
molded metal parts (https://en.wikipedia.org/wiki/Metal_injection_molding),
so you could probably even make your own filament using cheaper bulk pellet
stock.
And if you're really daring and want to risk frying your eyes out,
there's always this: https://reprap.org/wiki/MetalicaRap
Joe
On Thu, Aug 13, 2020 at 12:45 PM ken mason <laserpro1234@xxxxxxxxx>
wrote:
If this is indeed a viable/affordable option then it needs to be
exploited. I immediately fell in love at first sight in seeing 3D laser
sintering/melting. This was corroborated upon reading about the Australian
rocket launch company, Rocket Lab's Electron rocket with their printed
Rutherford rocket engine.
Again I ask, will Peter Beck offer insights to us at aR about how we can
apply the technology to our rockets. Nothing patented that I can see.
I have the laser, a brand new 1KW 1070nm single mode fiber laser that
runs on 220 VAC single phase 30 amp service like a clothes dryer at home.
You young budding rocket scientist geeks, check it out.
Ken
On Thu, Aug 13, 2020 at 11:34 AM Tyler Adkison <tyler.adkison@xxxxxxxxx>
wrote:
In my personal experience you pay by the pound and by the inch.
Optimizing for mass is obvious, but at least the service I used as part of
a college research project puts a heavy premium on how tall the object is
because that is what determines how long the print job takes when done
layer by layer. Out of curiosity, we requested quotes for two objects of
the same mass and floor profile, just different internal geometry and
height. The one that was twice as high cost a little over 30% more. This of
course can vary dramatically by company, material, printer tech, etc. so
don't put too much stock on it.
I think a good amateur engine would have to be printed by a service
(owning one just won't be practical for at least another 5 years even for
the best-off amateur). I think a machined engine would still be cheaper,
but the 3-d printed engine could have an edge with convenience. I think one
would first want to develop a heavily optimized design in terms of mass and
length using heat-sink engines before considering moving the design over to
metal 3-d printing.
On Thu, Aug 13, 2020 at 11:11 AM ken mason <laserpro1234@xxxxxxxxx>
wrote:
6-7 figures is prohibitive for all but the most well off amature. Even
when I was making 6 figures/yr for 20 years I couldn't afford nor justify
that kind of expenditure.
But a printing service would be a horse of a different color like the
one just posted by Joe. Needs further investigation.
K.
On Thu, Aug 13, 2020 at 11:00 AM Tyler Adkison <
tyler.adkison@xxxxxxxxx> wrote:
Most don't even use a 1KW fiber laser. Sure, some like the EOS M400
do, but I would say the majority tend to use lasers in the 250watt range.
The cheapest systems (usually some sort of major limitation) start at
about
$100,000. I'd say the more common price range is the $350,000 to
$1,000,000.
On Thu, Aug 13, 2020 at 10:39 AM roxanna Mason <
rocketmaster.ken@xxxxxxxxx> wrote:
The caveat though is cost. This is an amature site so by nature has
cost limitations. What is the cost of a laser sintering printer anyway?
I
know how much my 1KW fiber laser cost, mid 5 digits. And that's one
kilowatt, how about 5 or 10KW's?
K
On Thu, Aug 13, 2020 at 8:02 AM David Gregory <
david.c.gregory@xxxxxxxxx> wrote:
Nearly every rocket engine developed in the last five years
incorporates SLM parts on it, including several built by people on this
list.
On Wed, Aug 12, 2020 at 3:35 PM roxanna Mason <
rocketmaster.ken@xxxxxxxxx> wrote:
Technology advancement is great, I hear that the Rutherford engine
for the Electron launch vehicle is 3D printed.
If you need a 1KW fiber laser for your printer I have a brand new
one still under warranty.
Thanks Carl,
K
On Wed, Aug 12, 2020 at 12:51 PM Carl Tedesco <
ctedesco@xxxxxxxxxxxxxx> wrote:
Ken, when I designed the printable LR-101 injector, the state of
the art DLS printer were all EOS and they did not have the build
volume to
do an LR-101. I designed several “mini-LR-101’s”, but never was able
to
have them printed since at that time the cost was always
prohibitive. In 3D
printing, the bigger the z-axis, the longer the run time = $$$.
Since then the SDSU students I advise have made 3D printed motors
in parts (as Henry S. has suggested), so the tall z-axis problem
goes away.
There is a seal involved, but it wasn’t a show stopper. I also did a
100
lbf. LOX/LCH4 100 lbf printed motor (attached pic), but it was
small, ~8”
tall. That was about $2500. The injector was 3D printed too, but it
is
proprietary, so I cannot show it.
--- Carl
*From:* arocket-bounce@xxxxxxxxxxxxx <
arocket-bounce@xxxxxxxxxxxxx> *On Behalf Of *ken mason
*Sent:* Wednesday, August 12, 2020 10:48 AM
*To:* arocket@xxxxxxxxxxxxx
*Subject:* [AR] Re: LR-101 injector
Interesting Carl, have you looked into a printed TCA too? Since I
first heard about SLS,Selective Laser Sintering, the LR-101
immediately came to mind. Though the injector wasn't part of that
since
it's a 'straightforward' lathe/mill job all made of simple aluminum.
The bottom line, is there a demand/market for a 'cheap' LR-101
beyond limited amature use?
Nice work,
Thanks,
Ken
On Wed, Aug 12, 2020 at 10:31 AM Carl Tedesco <
ctedesco@xxxxxxxxxxxxxx> wrote:
Barry,
Those images are of reproduction LR-101 injectors I had made. I
contracted out the machining to a friend of mine, but I made the FOD
screen
myself. Some tips my machinist used on these injectors:
1. Leave 0.040”-0.60: of extra material on the injector face,
that way you can add a small countersink for the angled orifices
to avoid
drill “wandering”. After all orifices are drilled you can machine
away the
extra material. This will also minimize burrs.
2. Sharp drill bits are a must, so replace them often. They
are small drill bits and inexpensive, so it is not prohibitive to
use 4-6
per injector.
3. The machinist intentional ground a score line around each
drill bit shank. That way if they broke off in the injector, the
break
point was outside the material, and the broken part of the drill
bit could
be removed with pliers.
At one point I made a 3-D printable version of this injector. The
vendor printed the sample shown in the attached images. The surface
finish
of the small orifices is NOT great. The orifices diameters were
printed
0.010” undersized, with the intention of using a precision reamer
to get a
nice clean, smooth orifice. A lot of material goes away, so it was a
very
light part. A complete printed injector never materialized, since
the price
per weight savings didn’t merit it. Maybe I will revisit this design
some
day on a larger motor.
--- Carl
*From:* arocket-bounce@xxxxxxxxxxxxx <
arocket-bounce@xxxxxxxxxxxxx> *On Behalf Of *1bcjolly
*Sent:* Tuesday, August 11, 2020 4:25 PM
*To:* arocket@xxxxxxxxxxxxx
*Subject:* [AR] LR-101 injector
Some pictures of LR-101 injector
Sent from my Sprint Tablet.
