Comment by adrianmonk | Hacker News Reader

Comment by adrianmonk | Hacker News Reader

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> 3D printing is magnitudes slower than forging

Suppose you wanted to mass produce 3D printed parts as cheaply as possible. Would there be opportunities to scale up the speed of printing?

One thought is to steal an idea from traditional (2D, paper) printers. A traditional dot matrix printer has a head which sweeps side to side, but there are much faster printers called line matrix printers (https://en.wikipedia.org/wiki/Line_matrix_printer) which essentially have a head the width of the entire page, so it prints one entire row of pixels in one fell swoop. (One such printer is the IBM 6400. Video here: https://www.youtube.com/watch?v=KnPBWru2Ecg#t=6m57s)

One could imagine a similar approach with 3D printing with a wide print head that prints an entire row at once instead of a point.

Maybe there could be other optimizations or economies of scale as well.

Obviously R&D costs would be high, so you'd probably only do it if you could use for more than just pistons in one low-volume model of car.

You can already see some relatively high-volume components produced with additive processes, but we still need to address part strength/integrity and process reliability.

In my (admittedly limited) experience and leaving aside cost considerations, process reliability is the biggest thing holding us back from widespread adoption of AM in mass production. If you could just leave the machines running lights out with confidence that you’ll get good parts in the end, then individual process speed wouldn’t be a huge issue. We aren’t there yet, though.

I imagine this is where mass CNC machining processes were ~30 years ago.

For some types of 3d printing where the material is laid down in a bead, the path of the nozzle has an effect on the resulting part. So having a wide row of nozzles would give you less flexibility in the design. But this may have less of an effect on certain metal 3d printing technologies. For example, that could work very well for some metal sintering methods.

https://en.wikipedia.org/wiki/Selective_laser_sintering

What I find facinating about 3d printing is how much unexplored area of research there is. Not only is there so much more to explore, a lot of it is very accessable without lots of money or technology. This is especially true on the sofware/gcode/slicing side of things.

No one is talking about what Forging does to the grain boundaries and consequently increasing the strength of the material.

There is also shot peening which is like case hardening but with little balls of steel. Usually done on piston rods and turbine blades.

I don't think 3D printing can do these things, but I hope to be proven wrong some day.

I don't understand the point of this comment. No one is saying that 3D printing will make forging obsolete. There's always a balance of trade offs. It's up to the designer/engineer to decide how something should be made. Developing more options, and better understanding those options is part of engineering progress. It may be good to temper expectations (no pun intended) to avoid overhype, but at the same time I think it's also good to let people's imaginations run wild because that's where creative developments come from.

For example, I'm sure people will come up with ways to have more control over grain boundary and other material properties of the 3D printed material through the use of heated chambers, annealing, new alloys created for specific processes, etc.

>What I find facinating about 3d printing is how much unexplored area of research there is.

I spent about 2 years working on manufacturability analysis software during grad school. We were looking at machining, 3d printing, casting, and die casting, with the intent to give feedback to the design engineer.

There are indeed an incredible number of opportunities when it comes to additive manufacturing. And when you start dealing with integrated CNC/AM machines, you get an order of magnitude more possibilities.

The lab I worked in got one of these machines and I toured the lab last year. They were working on things including:

* Fast 3d printing of big parts. A demo part ~24x12x3 inches was printed in about 2 hours, which would have typically taken a couple days. The nozzle was much larger than most 3d printers, high precision and accuracy weren't required, but the demo part wasn't easy to manufacture with traditional subtractive methods

* Switching materials mid-print, enabling plastic and metal to be integrated in way which are otherwise prohibitively expensive or impossible.

* Integrating machining and 3d printing. Fixturing is traditionally a big challenge with machining, and every time you reset the part in a machine, you add variability to the part. 3d printing features then machining flat surfaces (for later use as datums or functionally) really cleans things up for better assembly, part function, and later fixturing.

Manufacturing capability is growing very fast in neat ways, and I'm excited to see how things will be in 5, 10, and 50 years.

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