J-20 5th Gen Fighter Thread VIII

[siegecrossbow]

Weight and structural improvements aren’t even the most important aspects of using 3D printing. The main structure is titanium and without additive processing, you need to carve them from a large block of solid titanium. If you screw up a little bit, the whole thing is wasted. And even if you don’t, the stuff you shave off likely cannot be reused.

 

[enroger]

I think they did really mean a 38% overall weight reduction, but just the fuselage itself. The original text just said "weight reduction (减重)" with no specific keywords indicating that it's structural weight.

38% overall weight reduction is just insane, it would mean cutting structural weight to almost nothing, I'd have to read the paper

 

[plawolf]

Weight and structural improvements aren’t even the most important aspects of using 3D printing. The main structure is titanium and without additive processing, you need to carve them from a large block of solid titanium. If you screw up a little bit, the whole thing is wasted. And even if you don’t, the stuff you shave off likely cannot be reused.

They should be able to recycle the titanium shavings, so it won’t be totally wasted, but what savings you get from that will be a tiny fraction of the material cost of the titanium block. On top of that, titanium will probably wear out drill bits pretty damn fast.

The biggest weight savings are from the ability to redesign structures without needed to factor in the limitations of CNC machines’ ability to reach areas to machine.

Other potentially important considerations would be manufacturing time differences and failure rates. Depending on which way those differences swing, it could potentially also impact on production rates.

 

[Alfa_Particle]

38% overall weight reduction is just insane, it would mean cutting structural weight to almost nothing, I'd have to read the paper

It's from this page, fourth paragraph (right side).

 

[enroger]

It's from this page, fourth paragraph (right side).
View attachment 150862

Thx! Reading that sentence carefully I believe they meant weight reduction of 38% for this particular structural part (frame-wing beam 翼梁整体件), compared to traditional separate piece wing and frame weld together approach

 

[FriedRiceNSpice]

And even if you don’t, the stuff you shave off likely cannot be reused

Can't be remelted to form another block?

 

[siegecrossbow]

They should be able to recycle the titanium shavings, so it won’t be totally wasted, but what savings you get from that will be a tiny fraction of the material cost of the titanium block. On top of that, titanium will probably wear out drill bits pretty damn fast.

The biggest weight savings are from the ability to redesign structures without needed to factor in the limitations of CNC machines’ ability to reach areas to machine.

Other potentially important considerations would be manufacturing time differences and failure rates. Depending on which way those differences swing, it could potentially also impact on production rates.

From what I’ve read it is not trivial to recycle the titanium shavings (which is an alloy). It is a lot more complicated than melting it down.

 

[manqiangrexue]

Can't be remelted to form another block?

From what I’ve read it is not trivial to recycle the titanium shavings (which is an alloy). It is a lot more complicated than melting it down.

Guys, what are we talkin' about here? Are we talking about how to save a couple dollars recycling metal shavings or are we talking about how to make fighter aircraft lighter? We're not HAL with their ugly ass bare metal prison chair made from recycled crap while looking at China fly two 6th gens.

 

[siegecrossbow]

Guys, what are we talkin' about here? Are we talking about how to save a couple dollars recycling metal shavings or are we talking about how to make fighter aircraft lighter? We're not HAL with their ugly ass bare metal prison chair made from recycled crap while looking at China fly two 6th gens.

The cost saving is significant, as per 601’s paper documenting laser based 3D printing. Structural strength and reduced weight are added bonus.

 

[manqiangrexue]

The cost saving is significant, as per 601’s paper documenting laser based 3D printing. Structural strength and reduced weight are added bonus.

And I absolutely fully support enhancing production methods for any benefit, but clearly, the added strength and reduced weight are the goal, and any cost savings are a small bonus. But you guys were talking about melting titanium shavings. That's a traditional method before the 3D printing method, right? How much could you possibly save melting metal shavings compared to the >$100M price tag of a J-20??