I took shop class, I made a chess board that I remain proud of to this day, and I used a metal lathe CNC to make chess pieces- also, a really lovely decorative shelf.

And I just can't disagree with you strongly enough.

Just recently, using the MakerBot2 at my university library, I was able to replace this: https://i.ytimg.com/vi/1nePU5mz8Z4/maxresdefault.jpg. (The large, central gear that overlaps the metal framework close to the screwdriver). (I got this Jumping Sumo Drone for free in a broken state, and 3D printed the central gear for less than 4 dollars, and that's with a 300% markup on materials to use the school's 3D printer)

Now, I know that it'd be hard to merely repair the damage, or remake that gear from scratch because I spent several weeks and a lot of spare time trying. The 3D printed gear has stood up repeatedly to the same behavior the originally broke the central gear (attempting a jump on a soft surface), and is still going strong despite my having let my nieces and nephews run the battery down half a dozen times over Thanksgiving break (I want them to be excited to robotics, programming, etc.- I figured if they broke the free Sumo I had fixed, it would be a worthy sacrifice- incidentally, I didn't actually mean to test the jump on a soft surface again and specifically warned them against it, but- ah- well- they average age 9 right now, I knew shenanigans would ensue when I set out! :) )

Some parts are really hard to make, 3D printers help a lot. Don't you cheapen that, jdietrich, 3D printing is a fantastic stride for makers everywhere, and the materials science is an obstacle made of tissue paper- as in, we're already blowing through it handily. I don't know what you're printing with, but I'm already making more than tchotchkies, and I am dang glad I didn't encounter your sentiment before I tried it myself.

I might have been too negative, but only by a hair. FDM printers do have their uses, but it's a very niche technology that is difficult and time-consuming to learn. Lots of really cheap and easy fabrication methods are almost totally ignored by the maker community, while 3D printing is put forward as the glimmering future of manufacturing.

Your story is very positive, but it falls a long way short of justifying the purchase of an expensive machine and the investment of many days of effort in learning how to use it. How many people have a burning need to produce hundreds of dollars worth of spare parts for toys?

>the materials science is an obstacle made of tissue paper- as in, we're already blowing through it handily. I don't know what you're printing with

I've seen test results from the absolute best case scenario - professionally designed parts printed on a $200k Stratasys machine using ULTEM 1010. The material properties just about match injection molded ABS. Parts made on consumer machines using ABS or PLA filament are generally an order of magnitude worse.

If you tailor the use-case to one a consumer 3D printer can't match, then you can certainly show that the materials science won't allow the consumer-grade machine to compete- the issue here is one of imagination and applicability. Like the other fellow here says, what you're saying has deep shades of the same "why would I even WANT a computer, green monochrome, blocky text, stupid games?" Arguments I had the misfortune to deal with personally, and the good fortune to avoid being swayed by. It's very much still a hobbyist's game, and just as it was then, when it would be substantially less time-consuming for most hobbyists to just, I dunno, modify their spreadsheets by hand and do calculations with a slide-rule than to program a computer to modify the order some little blinking lights came on.

So powerfully, we don't really disagree- I concur that my use case (replacement parts for toy robots) doesn't justify even a 500$ 3D printer- but the communal one we share at university was extremely valuable (did I mention the quotes from services like Shapeways for the part were in the 17-25 dollar range, where I was charged 3-4 bucks?). Moreso, the REAL value here is in all the crazy designs I've been concocting since then, like the adjustable desk I've been toying with building for ages, but always found my toolbox, workspace, and expertise somewhat short to make the gear setup- the portion of the project that intimidated me would be trivial and cheap with this 3D printer- and this printer, it's one of the ones that really sucks! This breaks that barrier right down, and that's all technology is really for, anyway- to help us make our visions into realities.

You obviously know more about materials than I do, but I think that your perspective is skewed by upper limits- you're trying to decide this technology by comparing it to other tech that it has zero need and zero business trying to compete with- when we DIY guys require materials that strong, then maybe we can talk (not saying it wouldn't be nice, and break down more barriers, I'm saying that it sounds like you're saying that unless it can compete with injection molded ABS plastic, it's not worthwhile, and I hotly contested that assertion), until then, you're trying to shortchange our moon rockets because they won't get us to Mars, and that's pretty silly, in my book, even if it's true.

So, indeed, hobbyists machine- someone purchasing this as an appliance like a refrigerator- meant for convenience and time-savings, I can agree that they'll be disappointed. In the meantime, hobbyists who only want to give the vision-to-reality ratio a boost are going to continue to be tickled pink at their 3D printers, and I suspect that their enthusiasm will drive enough interest and investment in the technology to maybe deliver some of those high-quality, cheap Laser sinterers you mentioned before- all possible as long as there's an enthusiast market to consume the hobbyist level iterations along the way! :D

I'm thinking if I want to spend a bit of money on a computer-controlled making gadget I'd probably do better with a laser cutter. That covers a lot of cases (e.g. a gear should be just as easy on one of those as with a 3D printer, right?), and my impression is that the people I know with those tend to make more useful things than those with 3D printers, largely because of the material flexibility. Am I missing something?

Very much so. At my local hack space there's a week long waiting list to use the laser cutter, while the 3D printer gathers dust.

Nice, did you put the 3d model of the gear on Thingiverse? To me, the access to a large database of useful 3d objects that you can print easily is another huge advantage of 3d printers.

<mumbles something nearly unintelligible about having started modeling it himself, but then having checked Thingiverse, he got it off of Thingiverse because someone had already done a fantastic job of modelling the piece. :D >

Realistically it takes my 3D printer about 90 seconds to warm up and while it's printing I can be doing other things.

I, too, love manual subtractive fabrication. But while the tools are not necessarily that expensive, they do take up far more space on the shop bench. While I'm temporarily an apartment dweller, I just don't have the space to set up my lathe or a mill.

The technologies are perfectly complementary. For example, often I'll 3D print something with undersized holes and then drill and tap them to size.

To a degree this is true, but a perfect example I just ran into today is this: I've got 3 sonar range finders to mount on my robot chassis which has been made from aluminum- I could painstakingly hand craft three holders out of wood or metal, spending at least an hour or two per holder, or I can find a model on the Internet, modify it to fit my application and print all three at once in under 90 minutes. You shouldn't be 3D printing everything, but it is INCREDIBLY useful for small part fabrication.

It took me at least 6 prototypes to get everything right and get this as a result - http://www.amazon.com/dp/B019JK8AQM

And by prototype I am not saying just slightly different positions of pieces, but rather different designs. I would be dead tired at the time i am working on 3rd prototype using "drill, tap, saw and file" :) And I would certainly not be able to share design online or sell it.

There is place for these tools, and there is place for 3D printer tool.

At the end of the day, a 3D printer is just another tool in the shop. It has its place like all the other tools, but it doesn't replace them. Some objects are more appropriate in plastic and easier to design and print than machine. I use my 3d printer all the time, for useful objects I design.

Do you have a 3d printer? If you don't have, your urging advice is pointless.

I know how to measure, drill and tap, saw and file. Everything you said I do, and do well, and probably much better than you do.

I have also lots of 3d printers, I volunteer to teach children the basic making techniques and also 3d printers.

One of the best thing of 3d printers is printing tools. I can print a vice accessory so I could adapt a 6 euro vice to aluminium plates.

Doing so with only metal will take 8 times the work and time. I could design a piece and multiply it by 100, and not spend 100x the time doing it, the 3d printer as a robot does it.

My professional jigsaw machine's motor died, so I replaced it with the entire assembly of a hand drill tool that I bought for 1/10 the price the original manufacturer asked me. I designed and 3d printed the support-adapter to the saw in ABS and aluminium. It took me 2 hours cutting and reusing the old axis in the new machine. The original motor had to be imported and was very expensive to transport because f the volume and weight.

Now the machine works much better, as the motor weights 6 times less, is smaller, is inverter, with variable velocity, and more powerful.

I 3d print my own 3d presses and my own CNC machine: http://www.thingiverse.com/thing:724999

I also use 3d printers for prototyping parts in plastic before they are in metal. I only cut small pieces myself, it takes a lot of time to do it manually,and I have great tools.

I send it to laser or water cutting, but the design must be perfect before sending and 3d printers are great tools for that.

"Until then, no amount of clever technology will overcome the basic materials science that prevents FDM machines from being useful."

Until then, your prejudices will blind you.

Lots of the great things of 3d printers have nothing to do with technology, but with people.

I teach children, and every one of them could create as I do. I teach them the jigsaw hack and the next week they surprise me with their own hacks, inspired by me but done entirely by them.

Not only that, but I can download their designs and replicate it with zero effort, I just press "print" and go take a nap, when I wake up, the thing is done.

Is an incredible tool for collaboration.

To me that sounds like I should do math and figure things out on paper instead of writing a program to do it for me. Fuck that noise.

I'm no artist, have no skill, little manual dexterity. I basically suck in every physical way. But I am powerful because I know how to get machines to do my bidding.

This sort of comment is exactly why I rag on 3D printing. A 3D printer isn't a magical tchotchke machine, it's a shop tool. You need knowledge and skill to design a part and successfully print it.

You can learn an awful lot of practical making skills in the time it takes to get to the 3D printing equivalent of "hello world".

Same was true back when computers were programmed with toggle switches. I'm glad early engineers stuck with them instead of just going back to slide-rules, logarithm books, and doing it by hand.

I wholeheartedly agree. I think part of it has to do with the "everyone must go to college" movement that looks down upon manual labor and blue collar jobs. People have that yearning to build (or "make") something but don't even think of using hand tools.

You can't drill a curved hole.

It's trivial to drill gently curved holes in wood using a Forstner bit or a suitably shaped spade bit. You can cut the workpiece in half, rout or mill a curved channel in both halves and fasten the two halves back together. You can use a curved electrode with electrochemical or electrical discharge machining. Of course, the best option is to design the part without a curved hole in the first place.

Electrical discharge machining, seriously? Not even well equipped machine shops are likely to have such specialized equipment.

I think you're proving his point that subtractive fabrication technologies have their limits (as do additive).

https://en.wikipedia.org/wiki/End_mill ?

3D printing is great for molds (lost plastic / lost wax process), for the things you won't be able to make with your simple tools. It is also great for making and adapting tools.