The household economics of 3-D printers

I have been a skeptic about the import of this new technology, but I am happy to pass along estimates to the contrary.  This is from a new paper by Wittbrodt,

The recent development of open-source 3-D printers makes scaling of distributed additive-based manufacturing of high-value objects technically feasible.  These self-replicating rapid prototypers (RepRaps) can manufacture approximately half of their own parts from sequential fused deposition of polymer feed stocks. RepRaps have been proposed and demonstrated to be useful for conventional prototyping and engineering, customizing scientific equipment, and appropriate technology-related manufacturing for sustainable development.  However, in order for this technology to proliferate like 2-D electronic printers have, it must be economically viable for a typical household. This study reports on the life-cycle economic analysis (LCEA) of RepRap technology for an average U.S. household.  A new low-cost RepRap is described and the costs of materials and time to construct it are quantified.  The economic costs of a selection of twenty open-source printable designs (representing less than 0.04% of those available), are typical of products that a household might purchase, are quantified for print time, energy, and filament consumption and compared to low and high Internet market prices for similar products without shipping costs.  The results show that even making the extremely conservative assumption that the household would only use the printer to make the selected twenty products a year the avoided purchase cost savings would range from about $300 to $2000/year.  Assuming the 25 hours of necessary printing for the selected products is evenly distributed throughout the year these savings provide a simple payback time for the RepRap in 4 months to 2 years and provide an ROI between>200% and >40%.  As both upgrades and the components that are most likely to wear out in the RepRap can be printed and thus the lifetime of the distributing manufacturing can be substantially increased the unavoidable conclusion from this study is that the RepRap is an economically attractive investment for the average U.S. household already. It appears clear that as RepRaps improve in reliability, continue to decline in cost and both the number and assumed utility of open-source designs continues growing exponentially, open-source 3-D printers will become a mass-market mechatronic device.

I don’t see the twenty products a year as coming true, given the current limitations of the printers, plus there are significant start-up costs for learning how to run and fix the printers.  I still despair at the paper printer we own, which breaks periodically in a non-transparent manner.  What does it cost to have a plumber remove a simple hair stoppage in a drain these days?  And how much does one have to pay for the IP rights for what one prints?

Still, I am happy to reproduce one economic case for the import of the technology.

For the pointer I thank Sami Varma.


As an owner of two printers of the rep-rap lineage and having used a few others, I don't think that 3D printing for consumption will be mainstream for quite some time. For one, the rep-rap printers in particular have proven to be highly unreliable (I would say that I get about a 30% success rate after starting a print--a full 2/3 fail during the print). The FDM (plastic extrusion) process is pretty unreliable and requires quite a bit of tweaking to get right. There are better FDM printers, but I am highly skeptical that the process can be made reliable enough for mainstream American households.
That leaves stereolithography (ala Form1) and laser sintering which both have fairly high material costs. I continue to believe that the value of 3D printing comes in education. It will be an invaluable tool for learning to design and visualize. I could be the wood and metal shop of the future.

The glittering gem of this paper is its Table 1. The list of those 20 products that he mentions as "typical of products that a household might purchase" is quite esoteric: It has three (yes three) iphone docks, a iphone tripod, a ipad stand, a jewellery organizer, a spoon stand, a train track toy, a Pierogi mold, a key hanger etc.

Basically, assorted, non-load bearing, non-critical trinkets. Wonder what he used as his prototype of a typical household.

That. For most households the scrap in Table 1 is useless. However, I think pirated legos/toys will make it viable for households with kids. That is the only useful purpose I can imagine.

Finally! I don't have to purchase my annual set of iPhone accessories and Pierogi molds in a costly dollar store... I can print them out at home in my OWN FREE TIME for only PENNIES A DAY!

Brilliant. I love 3D printing, but this table made me laugh and laugh.

Far better ways to conceive of its value are in making (pirated or other) toys, as one commenter suggests, in the educational experience of learning to build and use the device itself, or *very* occasionally in replacing a broken part from another device that would be costly or impossible to replace... The latter value of course is readily undermined as an argument for buying a home printer by the ease of getting a much higher-quality print from a service like Shapeways.

A plumber might charge you anywhere from nothing to over $100 for the stopped up drain--around the same rates as in-the-flesh IT support or repair. Given that a 2-D printer can be purchased for less than $80 there isn't much incentive to repair them in this country. Besides, HP and others make their money on the ink--and the 3-D printer companies will likewise expect to make their money on selling tubes of the polymer equivalent.

One extension of household printing is third party printing. Through websites like 3D printer owners use their printers to make and sell products to others, and those less technically inclined don't have to worry about trying to figure out how to use and repair printers. The thing I can see them becoming useful for are for printing replacement parts for other devices with plastic parts that break around your house (e.g., battery covers on remote controls). Rather than throwing something out or trying to buy the part from the manufacturer, you could make it yourself, or have someone else make it for you.

Compare 3d printing as a manufacturing process to the internet as a publishing medium. The equivalent of a blog in a pre-internet blog is an irregular newsletter that is hard to subscribe to , and expensive to reply to. Instead, we were stuck with magazines. Making small scale publishing cheap means that a whole lot more content can be created, because the barrier of entry is very small.

People providing content that is interesting to a lot of people still organize themselves in ways that resemble newspapers or magazines, but would something like this blog even exist if it had to be a newsletter?

3d printing does not have as good an economy of scale as the internet, but it should make it far easier to create objects only a few people want. A new shell for a mouse, custom decorations, spare parts. Nothing that should revolutionize the world, but it does bring value. The less standard you are, the higher the value.

Sure, but what does "interesting" constitute when it comes to monomaterial objects subject to strict color & geometry restrictions? Figurines? The internet of the mid-90's could still produce a "good enough" approximation of most magazine or other published content, but current 3d printers are nowhere near that benchmark. I think, in time-- measured in decades-- it will get there, but not soon.

'And how much does one have to pay for the IP rights for what one prints?'

Well, the IP rights for the software I use is basically covered by the GPL. It is reasonable to assume that a similar expenditure of time and talent will be found around 3D printing - I would happily post a link to the physibles site, but that is not allowed.

I predict the breakthrough for wide deployment of 3D printers will be the availability of a rich variety of downloadable IP for porn.

I think it might be worthwhile to register

I was thinking more along the lines of erotic figurines.

People championing 3D printers tend to follow this chain of thought:

1. 3D printers are important, like personal computers!
2. Personal computers became so widespread that essentially everyone had one.
3. So eventually everyone will have a 3D printer

Or replace "personal computer" with "smart phone" or whatever. The thing is, they aren't wrong about 3D printers being important, they're wrong that the path of every important technology is massive democratization. Micro-manufacturing is important, but its path isn't one of everyone having a 3D printer at home, it's probably important in terms of shortening supply chains.

Most people don't really need enough physical things that a home-based 3D printer could produce, to have the need to buy one. But if Amazon or whoever could make a warehouse-sized omni-factory in your hometown that could produce 1,000 different products that are commonly bought by 50,000 people in your hometown, without factory workers, then they can save costs on flying those items cross-country and still deliver them the day or the day after you order them.

Look around you and count the number of different metals, plastics and composites in use. Now think of the number of materials a 3D printer is capable of printing in.

There must have been a good reason we use so many materials, right? I think the 3D-printer revolutionaries ignore this ground reality.

Definitely. Which is part of the reason that the technology of 3d printers is important, but the ultra low-end household models are not.

If you have toured a modern machine shop or manufacturing facility, you will quickly see that this technology is important. That's why it already exists in just about every machine shop. Multiaxis machining has been around for a while now. The cost of the machines is dropping quickly and the cost of the service is dropping as well. Hobbyists are now having parts milled from aluminum to their specs. People who restore old items have obsolete parts recreated from drawings or existing originals.

As far as home use, this reminds me of self-printing books. Back in the olden times when Barnes & Noble and Borders were using free money to build bookstores on every corner, the "future" was self printing books. Instead of a warehouse full of originals, shoppers would print their copy as a bargain on the stores high speed printers. In the same way, we will look back a decade or so from now and laugh at the idea of printing your own bric-a-brac and plastic jewelry.

The real innovation is multi axes CNC, laser machining etc. The plastic printing is over-hyped.

The plastic printing is over-hyped.

Yes, it's definitely over-hyped. That being said, it's quite possible that 3-D printers will become more sophisticated and take on many of the features of various mills.

There's no reason that they can't have a 3-D plastic printing process for additive manufacturing, but a laser/milling process for finishing work. And then another 3-D ink printing process for final painting.

If you had 3 refrigerator sized machines that sequentially did one of those processes and the end result could supply 80% of the items that populate your house, what would be the value?

Why does home use have to come first? Offices were full of printers and fax machines before they started coming home....

Think about the advent of smartphones, or pre-smartphone cell phones, or the Internet, along with pdfs and youtube videos. Who needs this stuff? What would we do with it? And then all of a sudden life is forever changed.

I recall riding in the back seat of a Suburban with a US investor in a certain Latin American country, in 1995, with the Nokia 2120.

He said, "Look at that screen, in a few years, you'll be able to play games or watch vidoes on on it."

It will be interesting to see if product designers and software developers can make this high-cost, low-volume, low-flexibility, highly distributed paradigm work somehow. Highly customized designs might drive some demand, but I'm also reminded of Mao having people forge iron at home.

Brilliant analogy.

I'm also reminded of the movement from having cottage industries to scaled-up production in factories. Seems like 3D printing is pushing us back towards the former. One argument against 3D printing is that most common items have a large enough customer base that they can be produced and distributed at scale, which still tends to be cheaper than 3D printing in single-unit quantities. Until 3D printing gets cheap enough to flatten out the supply curve I don't see how it can compete, given that a customer willing to wait a few days can get the same item shipped to him/her at greatly reduced cost.

This of course ignores material properties, which is the elephant in the room, but the 3D printing folks seem keen on ignoring that issue.

"Highly customized designs might drive some demand, but I’m also reminded of Mao having people forge iron at home. "

Is music and book publishing today akin to Mao's home-made pig iron?

Or is it a result of technology liberating the creativity of millions of people who couldn't or wouldn't pursue record and book contracts with traditional publishers.

Manufacturing is a very complex, expensive and time-consuming process that is often dependent on cheap labor in faraway lands. The incentives to make 3D printing - and local robotic factories - work are powerful and history teaches us that when powerful incentives join with rapidly improving technology and pricing, then the changes can be significant to say the least.

False analogy. Books and music have almost zero marginal cost (in the presence of computers, kindles, and MP3 players) - producing another eBook or MP3 costs almost no time nor resources. In the case of 3D printed stuff, the marginal cost is still quite high. Just because the distribution system has been made simpler does not mean total cost is decreased.

Furthermore, material properties! The examples of things that can be 3D printed today are sad. Semiconductors will never be 3D printed. Heat-treated steel and aluminum will never be 3D printed. And 2 by 4s are unlikely to be cheaper to 3D print than to make from trees and distribute.

No. What matters is the relative cost.

So the difference in cost from making a book of paper to one of bits is significant.

But it is also significant between making something in China, shipping it here, pushing it through the supply network with its associated costs of rent and retail staff; and printing it at home or at a nearby printing company.

Actually the cost savings may be greater.

And your point still didn't address the liberating decentralization of the manufacturing process

These could be essential for rebuilding things if we have a Carrington event or a comet hit, provided that the thing isn't fried and a supply of raw materials is on hand. May be more valuable than almost anything else.

The nice thing about this study is it is easy to replicate for yourself -- look at the hundreds of thousands of free designs on thingiverse find 20 you would want -- and compare printing costs of $1/item to what you would normally pay for -- if anything this study was wrong the other way - I print way more than 20 things a year and obviously saved more than the study suggests!

I don't want everyone to own a 3D printer today, I want the demand for them, tech progress, and cost curve to continue on the same timeline as dot matrix printing to wide format printing has.

Today, my wife still can't digitally print a 15 yard bolt of canvas in our home, but that day is coming.

Give it time boys and girls, give it time.

"Today, my wife still can’t digitally print a 15 yard bolt of canvas in our home, but that day is coming."
I'm not sure how you think this will work - canvas is made of long organic fibers in a plain weave. How would you synthesize that using an additive process? You would need some kind of "molecular printing."

I assume he means printed canvas, such as in a decorative pattern.

What's bothered me about 3D printers from the start is how much more expensive its outputs are, relative to a manufacturing facility that benefits from economies of scale.

For example, how much would a 3D generated Eiffel Tower cost, vs the price for a 4 inch high metal Eiffel Tower, 7 dollars, free shipping, from Amazon.

In my industry there are whole lines that are not longer being manufactured. Useful things that the very large companies who have bought up all the small manufacturers won't make anymore. I'm certain other industries are running into the same problem. This technology isn't about me making something, it is about prototyping something then getting it made by someone with a cnc machine. The economics are whether I replace the whole system or spend 3-4 times redesigning it to work another way, or spend non commodity prices for something that works, has worked for a long time but simply wore out.

Economies of scale work just fine, but there are serious numbers of things that are needed where economies of scale don't apply.

What percentage of your expenditures are on parts that aren't produced anymore, and are feasible to produce (due to material properties) via 3D printing?

Right now nothing. I don't think that the output of these printers would be any more than prototypes to test the ideas or fit. The actual low volume manufacturing would be done by a shop set up to do that with materials to suit. I regularly get stuff repaired or made up by a machine shop. If I needed a few of something it would be worth my while to get a drawing made up suitable for a cnc machine. Mistakes would be cheaper if done in plastic.

I view this akin to the tools available to me on my mobile platform. Large national companies have had IT resources available to them for remote access, remote monitoring and remote access to resources for their businesses. They spent millions of dollars to build and roll out these systems. Now I have almost the same capacity available to me for the price of a data plan, a few apps and maybe a software subscription. All my guys can access it with their phones, we have access at the office, I can look at it from home or if I'm travelling. I would never have considered getting into the prototyping and manufacturing business because of the resources needed to even think about it. These printers open up possibilities. There is still a need for skills specific to what you want to make, but the capital investment required to start poking around is far less. Another comparable thing is the arduino platform for electronic devices. How many serious products were started by prototyping on that platform? Over the years I've looked at stuff like that, but I remember it costing thousands just to get what you needed to start. Now I can get a kit to start testing an idea for $55.

I don't think that this stuff is revolutionary as a means of mass production. It is more another tool made available at a lower cost. I suspect that as time goes on the actual accomplishments will be almost invisible to most people.

Agree completely. I've seen 3D printed stuff work out great for prototypes and physical mock-ups, so that a company would have a "real-world" faux-product for prospective customers to handle. I think we're in agreement that the benefit of this is marginal and it is unlikely to displace stamping, milling, extrusion, or even CNC work.

Agreed, but i'll say the number of cases where an engineer actually needs a plastic prototype is fairly limited. In most cases engineering drawings, and today even better computer generated isometrics or even computer verified fits and non-interference will do the job.

The real useful innovation in the use-case you describe seems CNC and laser machining etc. because they will actually produce strong, robust metallic parts that will actually work.

The fellow who invented the Palm Pilot wandered around with wooden mock ups to get all the details right. I wouldn't underestimate the benefits of making the iterative process of design cheaper.

Mockups / prototypes have had huge utility for industrial design. Agreed.

Somehow aesthetics & ergonomics are hard to get a feel from an engineering drawing.

"Somehow aesthetics & ergonomics are hard to get a feel from an engineering drawing."

Pun intended?

There are plenty of game developers who only ever order one production run of a game. Usually, it's not economical to run less than a thousand prints. So they design a game, purchase one print run from China, and then go onto designing a new game. As a result, there are plenty of games that sell for hundred's of dollars above the original selling price, because their out of print and you can't buy them in the store.

Certainly that's a niche market, but there are a lot of niche markets. I suspect the aggregate total for items that aren't worth retooling a factory line for and yet there is market demand for, is pretty large.

How big is the custom car part market? The model airplane market? Etc.

I think there is a substantial market. But I don't think the current 3-D printers are good enough to address that market however.

Is this better, cheaper, and faster than injection molding? Will it ever be better, cheaper and faster?

Sure, I see it replacing a lot of unskilled labor at some point. The question is what that labor will do.

Lower total cost. Injection molding has a five-figure NRE last time I checked.

Injection molding needs a new die / mold every time a design changes.

I could buy into printing molds, but still only for R&D.

How do I short this? Or anything else I hear about on NPR for that matter?

Pay for the IP that one prints?

I thought one of the major benefits was that the down and out regions of the world could in principle begin to access and actually make use of all that history of human knowledge, and fuggedabout the IP.

Of course in wealthy countries, those with IP rights can operate more transparently and will probably be able to operate more all-round successful businesses ... but really, do you think anyone in Asia, Africa, Latin America who could prospectively use these technologies will feel the remotest obligation, outside of the weight of the law, to send IP rights money to various Western IP holders?

Advanced IP holders will have to stay miles ahead of the game: reverse engineering just got that much easier. It is not a natural thing to lock up knowledge in IP ... it is natural that the IP developer will want protection, but technology and knowledge "want" to be diffused, as proven by the fact that people copy good ideas.

I think a lot of the hype on 3D printers is the potential everyone see in them. Because most people aren't able to get hold of them and actually see what they can actually do and how useful they are it remains to be seen how effective they will be in the near future.

However, over time we will definitely see it grow into something that could change the way manufacturing is done. I remember how the internet was back in the late 80's and early 90's when all you could do was communicate with text on the screens and graphics was composed of creatively typing the letters and numbers.

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