[AR] Re: [AR] Re: Open Source Igniter / Rocket
- From: "" <dmarc-noreply@xxxxxxxxxxxxx> (Redacted sender "gnsortino@xxxxxxxxx" for DMARC)
- To: "arocket@xxxxxxxxxxxxx" <arocket@xxxxxxxxxxxxx>
- Date: Thu, 12 Feb 2015 15:35:49 +0000
It’s ben a while since I tested but I mainly do soap bubble testing and I don’t
recall there being any leakage. I’ve also hot-fired shapeways 3d printed
engines and have not seen any issues with leakage. I will re-test again in the
next few weeks and report back to the list.
I read through a lot of Paul’s comments about Shapeways and I haven’t had many
of the same issues. I suspect that since he was such an early adopter that he
experienced more problems while Shapeways worked out the kinks. A friend of
mine used to be a 3d printing engineer at Shapeways and he worked a lot on
improving their build quality. The two issues that I have are printing internal
geometry and the material does rust/oxidize when exposed to water.
If anyone does try printing anything sophisticated I’d strongly suggest going
through ExOne rather than Shapeways. They are about the same price as Shapeways
but will have an engineer manually review designs before printing. This catches
a lot of printability issues. I also find for some reason that prints come out
much better with ExOne versus shapeways. Not sure exactly why this is the case
but I suspect they have more stringent quality controls. The downside of ExOne
is that their service is not as streamlined and user friendly as Shapeways
For example, my latest engine is regenerative and the injector has pretty small
diameter holes so I had those parts by ExOne. Something simple like my igniter
I can just print on shapeways.
igniter: http://shpws.me/ER6i
injector: http://shpws.me/ER6e
engine: http://shpws.me/ER6b
From: RM
Sent: Thursday, February 12, 2015 9:29 AM
To: arocket@xxxxxxxxxxxxx
They must have improved their process then. See paul's experience below.
http://unreasonablerocket.blogspot.com/2010/08/getting-back-to-rockets.html
How are you measuring pressure tightness? Did you try submerging the entire
part in water to see if it bubbled?
-RM
On Thu, Feb 12, 2015 at 4:34 AM, Redacted sender gnsortino@xxxxxxxxx for DMARC
<dmarc-noreply@xxxxxxxxxxxxx> wrote:
Shapeways SS is not porous. I’ve pressure tested it up to 2000psi without
noticing any leaking. The challenge is building internal geometry as the 2 step
printing process leaves a powder residue that if not cleared out will sinter
and block internal passageways. The SLS process is very good and quite cheap
for simple parts like igniters.
From: RM
Sent: Wednesday, February 11, 2015 9:49 PM
To: arocket@xxxxxxxxxxxxx
$15 is pretty darned attractive. How did it work? I think I recall that Paul
Breed found that the Shapeways sintered/infused stainless was too porous for
his liking.
On Tue, Feb 10, 2015 at 2:37 PM, Lloyd Droppers <ldroppers@xxxxxxxxx> wrote:
I did see your pr56 igniter, and I like it. Frankly I like the work on your
website from the valves to the 3d printed chamber, and you we're one of the
inspirations for me to post my own open source rocket work.
I had initially looked at making the igniter conventionally machine, but when I
looked at Shapeways with a $15.00 price and 2 week leadtime for the igniter I
had to give that a try first.
Lloyd
On Tue, Feb 10, 2015 at 1:36 PM, RM <rocketmoonlighter@xxxxxxxxx> wrote:
Very cool Lloyd.
I posted my latest design iteration of my igniter a few months back
http://www.rocketmoonlighting.com/projects/pr56-igniter
It looks similar in design to yours, but the body is conventionally machined.
The fully dimensioned drawing is on the page for download. I've tested it
with gox/propane, gox/kerosene, and n20/propane.
I have an extra body ready to go if anyone would like to try it out
RM
On Friday, February 6, 2015, Lloyd Droppers <ldroppers@xxxxxxxxx> wrote:
Hi aRocket, you've been pretty quiet lately so I thought I would add something
to the mix. I've been working for the past couple months on an open source
liquid powered rocket , and I thought the list might be interested.
- 3d printedGOX / IPA igniter up and running
- All the igniter documentation (CAD / Arduino / P&ID) and some design codes
are on the website
- I'm doing a once a day Instagram (ProcectEarendel) for various rocket doodles
and project related picture
- And a Kickstarter to try to build a suborbital test vehicle.
Hope that you all find it interesting, after 10 years building rockets for
other people, it is fun to do my own thing that I can share.
Lloyd
Other related posts: