Old school machinists, listen up, a newly developed technique for creating ceramic molds to a foundry-ready state for investment casting of intricate metal parts may disrupt the current process in a big way.
We’re confident that our approach can lower costs by at least 25 percent and reduce the number of unusable waste parts by more than 90 percent, while eliminating 100 percent of the tooling. (emphasis added)
Molds for relatively simple pieces can be produced without a problem using methods developed over, literally, thousands of years, but today’s precision parts have pushed the boundaries of the old processes to such a degree that the time necessary to create production ready molds along with a high scrap rate can make some kinds of parts extremely expensive.
The new process, developed at Georgia Tech, called Large Area Maskless Photopolymerization or (LAMP), is a form of 3D printing.
The technique places one 100-micron layer on top of another until the structure is complete. After the mold is formed, the cured resin is removed through binder burnout and the remaining ceramic is sintered in a furnace. The result is a fully ceramic structure into which molten metal – such as nickel-based superalloys or titanium-based alloys – are poured, producing a highly accurate casting.
“The LAMP process lowers the time required to turn a CAD design into a test-worthy part from a year to about a week,†Das said. “We eliminate the scrap and the tooling, and each digitally manufactured mold is identical to the others.â€
Although the current work focuses on turbine-engine airfoils, Das believes the LAMP technique will be effective in the production of many types of intricate metal parts. He envisions a scenario in which companies could send out part designs to digital foundries and receive test castings within a short time, much as integrated-circuit designers send CAD plans to chip foundries today.
As demands continue to grow for pieces like these along with ever more complex parts for any number of uses, the old methods which have served so well for so long, may find it difficult to keep pace.
Digital foundries, … cool!
Link: Georgia Tech via PhysOrg
Related: Production ready rapid prototyping
Mean Monkey says
@ Paul Crowe
Oh man, this process is way too good! Worked in a casting shop years ago making lost-wax molds for GE jet turbine blades. If this reduces the scrap parts by a third, the savings will significant.
mean monkey says
What I was trying to say…….That if this process eliminates scrap parts by at least a third, the savings will be significant.
Perhaps I should be sleeping rather than typing.
petermac says
Wonderful stuff.
I read a story a few years ago in an Architectural magazine, about a guy here in Italy, in Pisa if I’m correct, who was printing very large forms as a demonstration as to how one could “print” a full scale building. His machine was basically a huge inkjet printer in concept and sprayed layer upon layer of plaster material to build up the 3D shape.
Truely amazing to think this CAD process has gotten so much future use. 3D humans here we come……!!!
Jim P. says
I am not familiar with this area of manufacturing. I have often wondered about the casting process such as producing a multi-cylinder engine block. Is it necessary to make a separate “lost wax modelâ€, mold, and casting for every part manufactured? And is the mold destroyed with each casting? If so then I can see that the method being developed at Ga. Tech (and probably elsewhere) would revolutionize this industry. I do have a question regarding the molding/casting process. If the mold is made of a ceramic, or any other material, how are internal portions of the mold removed such as the oil galleys in an engine block? I realize this question may be outside the scope of this article but it would help in realizing the impact on manufacturing.
Mean Monkey says
@Jim P.,
The “lost-wax” AKA “lost-investment” casting process with I had worked used a metal die, hot wax injection machine to make the wax ‘positive’ mold. The waxes were removed from the die and chilled. They were assembled by hand with a heat knife onto ‘trees’ made of wax bars that became the gates and sprues of the mold. The ‘trees’ were dipped into ceramic slip (liquid), dried, and dipped again, building up a thick coating. The mold assembly was baked in a kiln which melted out the wax and hardened the ceramic. Still glowing-red hot, the mold went to the foundry room to pour the molten metal. Then while very hot, to the shaker tables where the ceramic was vibrated off the metal castings. The potential labor savings alone from this new molding process going to be huge and as mentioned in the article, prototyping will speed up, too. I’m sure the ol’ Kneeslider is as excited about it as I am .
Paul Crowe - "The Kneeslider" says
This process is truly amazing, but this story has so many entry points for even more new knowledge. As I was writing this, I had to come to grips with the term “single crystal superalloys,” which I had never heard of, and off I went, digging up some info just so I could figure out what that was all about, but that’s a topic for another day.
Anyone interested in how things are made can launch from any one of those bits and keep digging and learning as far as he or she wants. I just don’t understand how anyone can avoid being fascinated by how the world around us works.
So much to learn, so little time and still, so many wasting their lives doing nothing.
B*A*M*F says
Historically, large cast items like engines were made by sand casting. Typically, a pattern is created, basically the same item you want to cast. It is then put into a large box shaped mold, which is then filled with a special sand that has been treated to stick together with the application of heat and pressure. From there, the hardened sand comes out of the box, as does the pattern. When the various sand parts are put back together, liquid metal can be poured into them.
It’s a bit more complex than that, and things like coolant passages, cylinder bores, and such require the use of core pieces.
Tirapop says
Engines have also been made with lost-foam casting, a variation on lost-wax investment casting. Foam preforms are made in metal dies to have precise shapes. Complex geometry can be made by using multiple foam preforms. In some cases they’re stacked like Legos. The foam preforms can be dipped in ceramic investment to form the actual mold. I think for some applications they can use casting sand with binding agents rammed around the foam preforms. Instead of being burned out of the molds like wax in the lost wax process, foam can be vaporized by the metal being cast.
Egeek says
As someone who signed a non-disclosure agreement when dinosaurs walked the earth on Single Crystal Airfoils some of what is here is not new. Since those days, what I got to see was a story in the likes of Popular Science but with that as a background the “LAMP” portion of the process looks new vs. the male mold product which they made the female ceramic crucible out of. Now all that requires other molds and tools and personnel to literally handle and assemble it. This is where he savings maybe, by eliminating the personnel and the other tooling. Other parts of the single crystal process are time consuming and expensive and are centric to the entire technology, if they have changed they are not discussed here…
Dano says
Paul, we developed “single crystal” blades at Pratt & Whitney in the “70′ and ’80’s. As a tool maker I worked on the multi slide wax injection molds for years, very complicated.
The process of chilling the casting “grows” the crystal in the ceramic shell. We developed copper chill plates and incorporated a wax pigtail onto the wax blade form prior to ceramic dipping and shelling. This was and still is a monumental break through for blade technology at the time. Today these blades along w/ some of our propietary coatings are allowing for unheard of temperatures and speeds in developing jet engines.
Our P&W Middletown, CT facility had a foundry for manufacturing them for years, Automated Casting Facility or ACS. We have since licensed our blade suppliers to manufacture them for us.
Some of our rapid prototyping systems are incorporating technologies like LAMP at this time.
Paul Crowe - "The Kneeslider" says
You know, I’ve often thought the best vacation a techno-geek could have is going to several factories, like a P&W, manufacturing the newest and most high tech products and components and spending the day with a guide who was intimately familiar with the processes involved.
Of course, these days, with terrorism and intellectual property concerns, it would be a lot harder to arrange, but contrast seeing this sort of process take place and learning how it works with a trip to one of those mind numbing tourist destinations. “Look Honey, it says here this is the world’s largest ball of yarn.” 😯
Floyd says
This process has some very interesting possibilities. I’ve spent a bit of time looking to see if it has been commercialized yet. All I can find on the internet are white papers and academics working with it. Does anyone know of a company that is currently offering it to customers? If so, please post it here.
Gearhead says
Sweet !! Now somebody please take this retail,,please.
Imagine having a one off antique part laser scanned and the Big Brown Truck delivering a duplicate six weeks later or sending a CAD file for the custom part you want or need for that wild to mild build.
Jim Kunselman says
–Gearhead
I recently stumbled upon the public access machine shop (www.techshop.ws) while cruising through Instructables.com. So, I did a search for TechShop on Kneeslider and found that Paul has covered them several times already. So much for trying to be the smart guy w/ the hot info. At any rate, the digital mold process machine would be great addition to their shop inventory. The Detroit location is nearest to me (about 3 hours away), I’d like to take a techno-geek day trip this summer to visit the shop.
mARK says
Just as i’m training to become a machinist >.>
Pathetiq Kphretiq says
Same here. The first thing I thought when I saw those was: “ready for acid etch”.