I fail to see the hype of 3D printing. We have milling machines for ages. As I understand it, what printing brings to the table is good niche applications where the shapes would be difficult for traditional machinery. Or when the printers are so cheap that "everyone" can afford them (not really there yet). For most applications it seems more a "because we can" than actually solving a problem people have.
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Well this particular use seems a bit weird. But in general 3D printers are extremely useful, mainly as time savers. Yes you can machine most shapes that you'd want, and you'd probably end up with a nicer result. But it's far more difficult, expensive and time consuming.
1. You have to manually do all the work, or at least set up tool paths which is a pain (and good software for this is even rarer than good solid modelling software).
2. You can't do as complicated shapes. I'm not talking fractals, I mean can you mill a plastic latch as easily as I can 3D print one? No way.
3. It just takes longer. Once I've done my CAD with 3D printing the work is basically done. With machining it's only just beginning.
4. If I make a mistake in my model and have to make a change, it is extremely quick to just do the modifications and reprint it.
5. If I want more than one of them I just click print again.
You're right that good 3D printers are still quite expensive (FDM ones aren't really worth it, but there are SLA printers for a few grand now). However good milling machines cost a similar amount, and CNC milling machines cost more.
The image problem with 3D printers is because all the cool and actually useful uses are one-off and in companies so they don't get talked about as much trinkets and jewellery. For example I made a mount at work that attaches a stepper motor to a linear slide. Can't release it to the world though.
Counter points to all of that:
1. All of the software that creates printing paths is a derivative of the work done to turn solid models into milling machine tool paths. That software has existed for well over 30 years, and the proprietary stuff is excellent.
2. This is the big advantage of 3D printing. Arbitrarily complex shapes don't increase the cost. That said, you can do some insane things with a 5-11 axis machining center.
3. It's impossible to say as a general rule which one takes longer. If you have a shape that is relatively close to the full volume of the stock, then mills will be faster than 3D printing. If you are spending a lot of time cutting down stock to get close to the final shape, then 3D printing might be faster. Either way I would expect finishing steps.
4. Either way you are starting from scratch, this goes back to #3. No one really wants to do rework unless you are building very expensive industrial parts in low quantities, and at that scale you are unquestionably milling.
5. CNC mills are exactly the same. Actually most of the ones in a factory take the raw feedstock in and spit out finished parts, no human intervention required. 3D printers generally don't do this yet.
I get the impression you haven't worked with advanced CNC machining centers. I've worked with $50,000 mills (and $500,000 mills). I've also worked with $50,000 3D printers. The $50,000 mill beats the pants off the $50,000 3D printer every day of the week.
At the hobbyist level and a budget of $2,000 things are different, but serious industrial production is definitely better done on CNC milling machines. If you are comparing manual mills to CNC 3D printers, that is pretty apples to oranges. That would be like comparing a CNC mill to a guy holding a hot glue gun.
Source: I've been a mechanical engineer designing manufacturing systems for medical devices & nuclear submarines.
I am pretty sure 3D metallic sinter machines will replace many (not all) CNC mills/turns (incl 5 axis) machines in the industry in a few years. Some car manufacturers of expensive sport cars already use them to create whole parts of the cars engine and its exhaust system. It allows them to print them complex metallic parts including moving gears all in one step without any assembly or finishing step at all - something that would require multiple parts and many human work hours using CNC mills/turns.
Source: I have background in these field as well.
3D printing will be awesome for small shops and DIY stuff around the house, but large manufacturers have already solved the problems you've listed. CATIA and NX are great for creating tooling paths, change management, etc.
I wish i could find the article - it was circa 2010. Without proof i guess it's just a story, but i think a believable one.
So, there was this factory. A part broke, it would take 2 days to get the part from the supplier, but the whole line was dependent on the machine. They had a laser scintering 3d printer. they made a poor quality, but good enough for a few days use replacement. I think it was a broken tooth on a cog, the kind of thing that would be tough to mill without some decent expertise on hand.
In any case, i think that's more or less the future usage. If things are worth repairing, any parts made after the initial run would probably just be printed off. Pretty easy to imagine in a utility truck, or auto part warehouse.
I don't think that temporary part fabrication for critical assembly lines qualifies as overhyping 3d printing. That seems super reasonable :) A 3d printer in every house, completely removing the need for centralized manufacture or distribution, a bit moreso.
Of course this is at its infancy. However, I think we can bring about a Roddenberry economy if we can survive long enough to perfect it.
First thing, we'll need unlimited, cheap power. A Mr. Fusion in your basement, or at least on your block, is not too much to hope for.
Second is ubiquitous printers. Whether by nano assembly, transmogrification of elements (unlimited power means you can make any element or molecule), or some other means, imagine throwing dirt in one end and getting out a Rolex or an I-beam or a steak dinner.
Given those, anything you'd want to buy with money from working, you'd just print. Material possessions would become meaningless, as would needing to work to afford them. Manufacturing, transporting, and retailing of material goods, restaurants, etc would go away. Service jobs can be largely automated away also.
So all that's left are thinking and creating type jobs, which might just pay the same as sitting on the couch but be more rewarding.
I understand your scepticism, I shared it. What changed it for me was prototyping electronics.[1] If you're prototyping something there are things you use to hold them together, but when you look at something like the LMB catalog [2] there are a bunch of boxes of certain shapes with certain properties, and mixes of those properties to try and maximize the chance they will have a box that is useful to you. Often you can get close, but it is to expensive for any distributor to stock their whole line so when you found your enclosure you had to order it and it had to come from the factory. Change the project so it doesn't fit any more and order the next bigger box, wait, and move forward.
ABS though is reasonably strong (and it is used in a lot of plastic cases) so if you can "print" the enclosure you just do. After postage its about the same cost, and from a time basis it is a lot cheaper. My daughter built a yardage counter out of an arduino, a hall effect sensor, an LCD display, and a printed "wheel" which carries the yarn and rotates carrying inside a small magnet that passes the hall effect sensor. All of the case work is custom and can be printed.
I wanted a 'universal' mount to hold various small eval/demo boards. The base is defined and the board holders are custom printed (basically a flat sheet with posts that can be drilled and tapped in various places) so every board just drops into the holder. Easy sauce.
Prior to printing things I have a Sherline Mill and Lathe. Great for a lot of materials and you can make things the old fashioned way by grinding off the stuff you don't need, but aluminum is expensive (even at scrap prices) when you need a bigger block that mostly is going to become chips. So while I love the VESA 200 -> 100 mount adapter I machined out of a 1/2" thick piece of aluminium, you can do it in structured ABS for less money and less time. And a lot less waste. (That said I'd love an affordable laser sintering system).
So kind of like programming, its neat and all but what ever and then suddenly it clicks into your brain where solutions to problems come from and you start seeing all sorts of things you can do now that you didn't think was possible.
[1] A short digression, I had the same scepticism for Evernote, but once it reached a critical mass of information it became HUGELY valuable to me, much more than the sum of the information contained.
3d printing in general is not just about different shapes, but different materials as well.
3d printing of organs and tissues is something that can't be done with traditional machinery and is showing lots of promise.
The hype is less about present practicality and more about the future. Within just the last few years print resolution and available print materials have skyrocketed while printer prices have dropped enough that you can even find them on some store shelves. If that trend should continue, it may well supplant "traditional machinery" in some areas.
Until then, we have hobbyists and artists working to improve the industry and bring attention to the potential it can have for the future.