I wrote a long post about fan blades the other day. In it I pointed out that fan blades on the front of turbofan jet engines (the ones on commercial jets) are really difficult to make. They spin fast (providing most the thrust for the plane). And they have to deal with bird strikes (which are surprisingly common). And finally they are not allowed to penetrate the engine casing if one were to fly off.
Fan blades have taken a surprising amount of material science to develop. They really are "cutting edge" stuff.
I talked a bit about Alcoa (AA, Financial) supplying the fan blades on the Pratt & Whitney geared turbofan (GTF) engine. Indeed I showed an Alcoa video of the project.
Well it turns out that these fan blades are the main reason for the GTF engine being slow to deliver.
The FT is running a story about how Pratt & Whitney are cutting engine production targets. It is not good news and they are blaming Alcoa.
Mr Hayes said front fan blades were among about five engine parts “that are causing us pain” by slowing deliveries. The company is continuing to build the engines, since fan blades go on at the end of assembly...
The fan blade, developed with Alcoa, is made of aluminium-lithium alloy and tipped with titanium on the leading edge. Efforts to speed up blade manufacturing have taken longer than expected, leaving Pratt with fewer units than it expected by now, according to people familiar with the process.
This year, we talked about delivering about 200 engines,” Mr Hayes told investors. “As I stand here today, I think that number is probably plus or minus 100 — more like 150 engines for the full year...
I encourage reading the article.
That said an analyst on the United Technologies conference call couldn't resist the chance to get in their question about 3D printing. 3D printing has uses - one is to make really complicated parts. But it is not much use in making really strong parts (like fan blades)* because there is in weaknesses where the product is added rather than made (say in a cast/forge process) as a whole piece from inception.
Enjoy the question and the none-to-subtle put down:
Nigel Coe - Morgan Stanley - Analyst
Obviously, GE (GE, Financial) is making a big play in additive manufacturing. Why couldn't you print out these fan blades -- what -- easy, right? It's simple. What is your play is additive? Is that a potential for Pratt?
Greg Hayes - United Technologies Corp. (UTX, Financial) - Chairman, CEO
It's a potential for Pratt. It's probably a bigger potential maybe even with -- at the Aerospace Systems business. If you think about where additive really gives you the advantage, think about a fuel pump today, which is essentially a piece of aluminum or nickel that you hog out, you put all of these passages and cavities in, very, very difficult to machine. Where we see the opportunity there is through additive to be able to build these up 1/10,000 of a layer at a time, and build these cavities right in.
John
*I simplify a little here. Additive manufacturing (aka 3D printing) is of great use in making the moulds for casting. You can cheaply and easily print very complicated designs which you then use for making moulds. 3D printing has its place but nobody has yet come up with a way of actually printing the super-strong cast elements.
