Are you a teacher (or a professor), deino?
What do you teach?
If I had to guess, journalism.
J-20 5th Gen Fighter Thread IV (Closed to posting)
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If I had to guess, journalism.
Upps, just a short break with Internet-connection. 
Yepp. I'm a teacher on a regular Gymnasium (via Wiki: In its current meaning, it usually refers to secondary schools focused on preparing students to enter a university for advanced academic study.)where I teach Chemistry, Sports and Geography.
To admit that sounds a lot, but in Germany a teacher has to study two subjects - and in some cases if both are not main topics like Math, German or English/France (as language) You need to add a third one. This rule was later changed to only two but long, long ago, when I was at the University (and needed maybe even a bit longer ... to enjoy a student's live !) I had to take three.
Currently I only teach Chemistry and since about four years a new commom subjec called "Nature science" for the small ones in class 5 und 6.
To admit journalism is really not my subject and I'm sure I'm not a good journalist at all even if I work in this area right now as a hobby. I see myslf more as an information-hamster, who collects data, information and images and tries to put together short summaries on certain themes.
Anyway thanks for Your interest, sorry for being off-topic ... and now CAC, let the show begin !
Deino
Are you a teacher (or a professor), deino?
What do you teach?
Yepp. I'm a teacher on a regular Gymnasium (via Wiki: In its current meaning, it usually refers to secondary schools focused on preparing students to enter a university for advanced academic study.)where I teach Chemistry, Sports and Geography.
To admit that sounds a lot, but in Germany a teacher has to study two subjects - and in some cases if both are not main topics like Math, German or English/France (as language) You need to add a third one. This rule was later changed to only two but long, long ago, when I was at the University (and needed maybe even a bit longer ... to enjoy a student's live !
) I had to take three.Currently I only teach Chemistry and since about four years a new commom subjec called "Nature science" for the small ones in class 5 und 6.
To admit journalism is really not my subject and I'm sure I'm not a good journalist at all even if I work in this area right now as a hobby. I see myslf more as an information-hamster, who collects data, information and images and tries to put together short summaries on certain themes.
Anyway thanks for Your interest, sorry for being off-topic ... and now CAC, let the show begin !
Deino
You lack the influence of forging on the structure of the metal but you are able to vary the alloy over the product and can influence the structure that way. I imagine you print under an Argon atmosphere. A small amount of powder is heated by lasers and fuses with the previously added metal before the next amount or, probably, a line of powder is deposited and then fused to the metal. You probably end up with metal that is nearly as good as forged metal while the shape can be much better optimized. You end up with a product that is much lighter than was earlier possible and also you can change the shape for the next iteration by adapting the computer program which is much faster and cheaper than having to produce new molds ( which might be necessary for a new forged shape ) and then machining your forging to the new shape.
broadsword
Brigadier
At what point is it cheaper to use molds? If it is about making for 200 jets, isn't it cheaper to use molds rather than laser sintering?
Molds are often extremely expensive and you have to pay for them upfront. And you have to pay for them again if you change your design and need new ones.
The cost per aircraft changes a lot between building 200 aircraft in three years or twelve.
But I'm in favor of using molds whenever applicable. You might use molds to make a base from which you not only take away by machining but to which you also add by laser sintering.
plawolf
Lieutenant General
Do those pontificating about the supposed weakness of printed parts have any actual experience with printed metal parts, or even a basic understanding of how metal printing works?
Ask any expert in the field and they will tell you that not only can printed metal parts match the strength of forged ones, printed ones are in fact likely to be stronger, or at least more reliable in that they are less likely to have hidden internal flaws.
And this is only the very first steps of using 3D printing to make parts commercially. Already scientists are producing brand new alloys previously impossible to make, or at least extremely difficult and costly because of the different melting points of various metals.
A step further on would be to print parts with integrated structures embedded in them, maybe made of a different materials, to give the overall structure greater strength and/or other characteristics that a hemogenous block of the standard material would not have. Think of steel support struts in concrete or the steel mesh embedded in wired safety glass or even chobrum armour if we want to bring this back into the military field.
But all of that all misses the real point, and problem that I have with the position those who keep droning on about the mystical weakness of printed parts - which is, just exactly what relevance does the question of whether or not printed parts are indeed weaker than forged ones have to do with anything?
The implied accusation is that the J20 and other Chinese aircraft that use printed parts (notice how the question of whether printed parts are weaker never seem to come up when discussion western aircraft that are also starting to use printed parts) are somehow inherently flawed because they use printed parts, and also that Chinese scientists and engineers are somehow so incompetent they would not think to test to make sure the strength and reliability of said printed parts are adequate for their intended role before installing them on their aircraft.
Ask any expert in the field and they will tell you that not only can printed metal parts match the strength of forged ones, printed ones are in fact likely to be stronger, or at least more reliable in that they are less likely to have hidden internal flaws.
And this is only the very first steps of using 3D printing to make parts commercially. Already scientists are producing brand new alloys previously impossible to make, or at least extremely difficult and costly because of the different melting points of various metals.
A step further on would be to print parts with integrated structures embedded in them, maybe made of a different materials, to give the overall structure greater strength and/or other characteristics that a hemogenous block of the standard material would not have. Think of steel support struts in concrete or the steel mesh embedded in wired safety glass or even chobrum armour if we want to bring this back into the military field.
But all of that all misses the real point, and problem that I have with the position those who keep droning on about the mystical weakness of printed parts - which is, just exactly what relevance does the question of whether or not printed parts are indeed weaker than forged ones have to do with anything?
The implied accusation is that the J20 and other Chinese aircraft that use printed parts (notice how the question of whether printed parts are weaker never seem to come up when discussion western aircraft that are also starting to use printed parts) are somehow inherently flawed because they use printed parts, and also that Chinese scientists and engineers are somehow so incompetent they would not think to test to make sure the strength and reliability of said printed parts are adequate for their intended role before installing them on their aircraft.
Forget proof, that level of metallurgical knowledge would probably be beyond comprehension for most on here anyway, but what are you basing your conjectures on? Some sort of scientific reasoning would be nice. For example, does 3D printing result in a less pure product? Are the crystal lattices formed different? I honestly don't know. If the same elements form the same bonds, then it should theoretically result in the same product, no?
1. 3D printing seems to limit the sizes of crystals to the size of the granules used in the print.
2. It would seem to be a serious challenge to shape or orient the crystals to maximize strength in the printed product
3. Making the granules adhere would seem to require serious heating that would further effect control over existent crystals in the granules.
4. It would seem to be challenging to control the void spaces between granules.
I tend to agree with Chuck at this stage of development, although Delft does have a point as well, so IMHO, take this for what its costing you?????
A forging is "always" going to be stronger due to being "hammered" into shape, that strength is more "universal" or multi axis than a casting, or a printing. Casting is "cheaper", although in order to achieve the desired strength, it is likely a little heavier, printing is also cheaper, or more expedient...... most firearms "barrels" are forged.....period, as are the slides on most "self-loading pistols", Browning HP, Colt 1911, Smith and Wessons, Sigs, and even Glocks. Frames may be forged or cast, from metals?? steel/aluminum, or polymers. But the tough bits, barrel and slides are forged and machined for superior strength, most jet engine turbine blades are cast and machined to shape....so the best material to use is the material with the strength, properties, and shape you need, in addition many parts require hardening/tempering, to meet the requirements of the job at hand... Yes, I have worked on aircraft, automotive, farm machinery, firearms, and I have "broken" far more cast tools than forged tools in the process.
Now, composites and 3d printing in particular do offer advantages, primarily requiring much less finishing in order to produce a final and usable part, sometime at significant weight savings. In addition some primary aircraft structures, fuselage/wing box are now being welded to produce a stronger junction and reduce stress in critical "attach" points???
Skywatcher
Captain
You could make a 3D printed titanium part on par with a forged equivalent, but then you'd require complex machinery (like a somewhat decent semiconductor fab) and a lot of time, to the point that you'd probably be better off with the forge.
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