Welcome! Log In Create A New Profile Recent Messages


additive machining for lenno's cylinder ?

Posted by jethro 
additive machining for lenno's cylinder ?
February 08, 2011 12:35AM
Was reading some of thread about Lenno's problem of having to do sand cores for a steam cylinder and the fantastic cost and
effort to do !
I was reading in a rescent issue of aviation week and space tech. about a new process called additive machining.
It is similar to the process called rapid prototyping except that instead of simply producing a plastic model of the part,
you actualy get THE ACTUAL part. It mentioned that they had made titaneium fan blades (jet engines) which had as much
total strength as the forged+machined or investment cast ones which are the strongest possible to be made. It also mentioned
that the steel parts were as strong as forged. It said that basicly no one in usa is doing this process yet - being done in europe.
Appierently we only do the version where the output is a model of the product.
For the cost of casting in sand some clever guys could build the machine to do this new process ! And if Jay wanted to fund
the machine he could do outside work for lots of folks !

Just an idea !
Re: additive machining for lenno's cylinder ?
February 08, 2011 05:11AM
Isn't that the process where they use powdered material spread over very thin layers and then a laser melts the pattern into slices?

Re: additive machining for lenno's cylinder ?
February 08, 2011 09:26AM
can you link to the article? which issue?

Re: additive machining for lenno's cylinder ?
February 08, 2011 09:35AM
I've had some prototype made by this method. SLM (selective laser melting) can produce very complex parts and is used in the medical industry to create replacement bone sections.

It is not a cheap process and I'm only aware of machines to make relatively small parts. A steam car cylinder block would bo out of the question for both of these reasons.

I still keep an eye on the devolpment of the process from time to time. If prices drop like they have for rapid prototype processes, it might be more attractive to the hobby builder.
Re: additive machining for lenno's cylinder ?
February 08, 2011 12:22PM

Testing a printed hand sized stainless steel rocket motor. Earlier posts talk about the manufacture and problems that were overcome. Only available in small sizes I think
Re: additive machining for lenno's cylinder ?
February 09, 2011 12:57AM
I have the issue here somewhere If I can find it ...... may be in the car. It has been in the last 3 or 4 months I think. I will try to
find it tomorrow.
It mentioned there were about 4 or 5 different senarios on how the material was deposited. One used a metal foil somehow which was laser
melted. another used powder shot through a nozzle and lasered on the fly into substrate.
Will find the issue so yall can read it - great article.
The main thing I can't get is how the machine keeps track of the geometry of what it has just laid down in order to adjust for the next pass.
Might use a ccd for x and Y but what about the depth axis ???????????

would be a neat machine to build !
Re: additive machining for lenno's cylinder ?
March 07, 2011 08:11PM
I've seen it done at Southern Methodist U a few years ago. Prof Kovacevic was doing this with several techniques, using plain old welding guns on a six axis robot arm, and laser welding, up to vacuum electron beam melting with robot manipulators.. He had a solid printing setup, like the plastic model one, that used titanium. The robot welder was using H12 tool steel wire, and the results were remarkable. Hollow tubes with walls .040" thick, with all sorts of twists and turns. He welded up a helical spring that has just as good fatigue properties as a normal one.

The end use he wants is on-site fabrication. Say you're on a carrier, and you break a landing gear part. Instead of days or weeks getting one from Stateside or a ton of machining in the shop, you make one from a CAD model and finish machine it. I was looking to do stamping die details, welded on carbon steel armatures. Cut steel costs by half, cut machining time by 80%. My boss wasn't interested.
Sorry, only registered users may post in this forum.

Click here to login