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Ask Slashdot: Economical Lego-Compatible 3-D Printer? 165

Wycliffe writes: There are plenty of high end 3d printers which allow high precision and large prints. There are also plenty of economical 3d printers but most of them don't have high enough precision for printing good Lego pieces. What is a good economical printer for printing small Lego pieces? Build size is not important as most Lego pieces are tiny but precision and quality prints are very important. What is a good, cheap 3D printer that can reliably print tiny Lego pieces? What is the best bang for the buck when you want a small printer and don't care about large prints?
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Ask Slashdot: Economical Lego-Compatible 3-D Printer?

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  • by Anonymous Coward

    I wonder if this is even legal?

    • Re:Copyright (Score:5, Insightful)

      by ShanghaiBill ( 739463 ) on Friday January 29, 2016 @02:07PM (#51397357)

      I wonder if this is even legal?

      As long as you don't print the LEGO trademark on them, it is legal. But it is not possible, at least on a cheap 3D-printer. Legos are made in custom injection molds with 0.005mm precision. A 3D printer is not going to even get close to that. Making Lego Bricks [].

      • Re:Copyright (Score:5, Insightful)

        by markus ( 2264 ) on Friday January 29, 2016 @02:14PM (#51397419) Homepage

        That's the reason why many people who own LEGO bricks are scared of MegaBloks. MegaBloks makes generic bricks that are nominally compatible with LEGO bricks. But in practice, they are built to lower quality standards and tend to attach much more poorly. As small number of MegaBloks in a collection of LEGO bricks can cause a lot of havoc and result in LEGO models that keep falling apart.

        And as the bricks look so similar, they are hard to remove from the collection of bricks, once the infestation has happened.

        Having said that, I can definitely understand why OP would love to have a 3D printer that can output LEGO-compatible bricks. Every so often, it would be nice to build special-purpose adapter pieces that allow integrating non-LEGO hardware (e.g. a cell phone) into LEGO models. Perfect fit wouldn't necessarily be a strict requirement. And as the adapter is going to look quite unique, there isn't much risk of it accidentally getting confused with a genuine LEGO part.

        • Re:Copyright (Score:5, Interesting)

          by NJRoadfan ( 1254248 ) on Friday January 29, 2016 @02:20PM (#51397477)
          TYCO used to make their own LEGO clone called "Super Blocks" that caused havoc. They were easy to pick out of the pile though since the pieces were noticeably more "glossy" than the genuine LEGO bricks.
          • IIRC, it was relatively easy to tell TYCO blocks apart because they tended to be different colors than LEGO blocks (at least, the ones I had) and the plates were thicker -- 1/2 the thickness of blocks, instead of 1/3.

        • by vux984 ( 928602 )

          Every so often, it would be nice to build special-purpose adapter pieces

          Lots of models for these adapters exist, including to adapt them to other building systems.

          As you noted the tolerances can't currently be met, but if you plan ahead it can work. (e.g. don't plan on having your 3d printed part just connect to lego, instead plan around having real lego sandwich the interface above and below (better still have multiple interface points each sandwiched) . Or do it technics style with multiple axles and bushes to lock it into place.

        • Indisious MegaBloks (Score:5, Informative)

          by Jodka ( 520060 ) on Friday January 29, 2016 @02:54PM (#51397813)

          MegaBloks makes generic bricks that are nominally compatible with LEGO bricks. But in practice, they are built to lower quality standards and tend to attach much more poorly. As small number of MegaBloks in a collection of LEGO bricks can cause a lot of havoc and result in LEGO models that keep falling apart.

          Yes, and even worse, in my experience, MegaBloks are dimensionally unstable over a decade or less, Legos are stable for at least 4 decades.

          About 10 years ago I gave my nephews a set of MegaBloks and patted myself on the back because I had given an enormous set of "Legos" for so cheap. When new, they worked just as well as Legos. My nephews have long-since outgrown those MegaBloks but my own kids were visiting recently and we dragged them out. They do not stay together at all now.

          I still have the real Legos which I had as a kid in the 1970's, and they hold together just like new.

          So you might think you are getting a deal with MegaBloks, but not so much, if you plan on them lasting.

          • by larkost ( 79011 )

            As a side note: we just purchased a good sized collection of Duplo for our toddler son from a seller on craigslist. We put them in the bathtub for cleaning, and now have a much larger collection for not a lot of money. In looking for these I saw a number of similar notices for regular Lego, and will probably go that route when our children get a bit older.

      • Your link is nothing to do with what you claimed.

      • by Rei ( 128717 )

        For some reason I doubt that you need that sort of precision. I mean, five microns? The details inside the 8086 processor were 1,5 to 3 microns. Why would you ever need that kind of resolution for a plastic piece?

        Lego interconnectors are 4,8mm across. 0,005mm would mean accurate to 0,1%. Looking at iMaterialize's printing options, one could use ABS like legos and get 0,3mm resolution, or high detail (UV cured) resin and get as low as 0,2mm resolution (but no colour options). Polyamide would also offer

        • by Rei ( 128717 )

          Hmm, just checked Shapeways, looks like their "frosted ultra-detail plastic" has a 0,1mm resolution. Sounds like the best option so far (if you don't mind it not being from ABS)

          I suppose you could take the totally opposite route and choose Shapeways or iMaterialize's rubber/elastic type materials, to deliberately add extra flex into your connector at a cost of lower resolution.

          • While you're in checking mode, perhaps you could research uncountable nouns.

            • While you're in checking mode, perhaps you could research uncountable nouns.

              1. You don't add any value to the current conversation

              2. Also, you're wrong : it's correct to use the plural :

              I suppose you could take the totally opposite route and choose Shapeways or iMaterialize's rubber/elastic type materials

              It might surprise you, but there are clearly more than one type of material that is flexible (e.g.: flexible nylon and printable rubber, just to cite the first 2 of the top on my head).
              As the poster is referring to different types of material, rather then a bigger quantity of material, the usage of plural is correct.

      • Re:Copyright (Score:5, Insightful)

        by thoromyr ( 673646 ) on Friday January 29, 2016 @04:30PM (#51398607)

        It really depends on what the goals of the person are. You don't actually need the precision that lego does in order to create an interoperable part and I have done that with a consumer-grade 3d printer.


        You will have nowhere near the durability of a lego part. Not just in terms of strength, but in terms of wear. It will not last.

        You will spend a *lot* more money per brick. Its been a while since I've done the calculation, but I'm pretty sure its at least an order of magnitude more expensive to print your own. Especially if you aren't using a consumer-grade printer (stratasys ABS is stupid brittle and very weak, completely unsuitable for the task, and absurdly expensive on top of that).

        So why do it? Maybe for giggles (I've done a variety of 3d prints that are not really serious, but just to see if it can be done). Maybe for one-off pieces. It may be worthwhile to print an occasional piece that Lego does not. I've done a variety of those.

        Bottom line: any reasonable printer should be able to do it, but *no* 3d printer can match Lego injection molding for quality, durability, price, etc.

        • by Rei ( 128717 )

          What sort of filament were you using, out of curiosity? Were you using ABS? It's a lot more durable than, say, polyamide. Also, if they wanted, they could (unlike legos) add internal structural supports.

          Also, my impresson was indeed that they wanted to print legos not to save money, but to make parts that don't exist elsewhere.

      • by Guspaz ( 556486 )

        You really don't need 0.005mm precision to get two plastic bricks to mate. Higher resolution 3D printers like the Form2 have a 25 micron layer height with a 140 micron laser spot. That's already overkill to make a LEGO-compatible brick.

      • Just because the mold has 0.005 mm precision (which is difficult in steel, from which the molds are made - probably needs EDM or some other expensive, high-end method), doesn't mean that bricks themselves are anywhere near that. There are a variety of considerations (shrink, draft, wall thickness, etc.) that play a roll and limit the accuracy of the bricks. 3D-printers approach 0.05 mm accuracy, which might be enough. SLA gets even better results.

        Short of anyone actually trying and measuring the result,
    • by Anonymous Coward

      Lego's Patents started expired in the early 2000's. Lego tried trademarking the design, but they have been losing those cases.

      Canadian trademark ruling in 2005 []

      European trademark ruling in 2008 []

      • Re: (Score:2, Insightful)

        by Anonymous Coward

        But Lego wins on quality and nothing beats Lego. Everything else is a cheap knock off. Lego blocks are nearly indestructible and will last forever, so costing a little bit more for something you can continue to pass down through many generations of your off spring isn't that bad of an investment.

        • by TWX ( 665546 )

          But Lego wins on quality and nothing beats Lego. Everything else is a cheap knock off. Lego blocks are nearly indestructible and will last forever, so costing a little bit more for something you can continue to pass down through many generations of your off spring isn't that bad of an investment.

          Lasting forever, from the supplier's perspective, is not necessarily a good thing as there's the possibiltiy of the market peaking and a decline in demand due to saturation. That's probably why Lego continually works on theme sets and tie-ins with movies and the like.

          As for nothing beating Lego, tha only works so long as Lego continues to maintain its own quality. Those molds are considered good for a set number of batches. That number is very, very high, but there is a limit. If Lego finds itself in

          • Re:Copyright (Score:4, Informative)

            by njnnja ( 2833511 ) on Friday January 29, 2016 @02:51PM (#51397781)

            What Lego could do for me would be to offer kits of bulk pieces that are not intended to build something specific, at a good price. Older kits were a lot more like that

            They do have those, appropriately named Lego Classic []. And they are about the same price as any other Lego, around 6-8 cents/brick.

          • In addition to the Lego Classic line mentioned above you may want to check out the Creator line. They do have specialty pieces, hinges, those triangle wing pieces but they are used in new and interesting ways. The amount of part reuse of late has really surprised me, and is a good thing. Also the difference between when I was little and now is that there is a lot more building with plates instead of bricks. This as well as making generic pieces for side building (SNOT) has greatly added to the detail and co
          • Yeah, they do. Go look at their website. They offer bricks in pretty much any optional packaging you can imagine, from singles to large packages of one type, to large assortments of generic bricks.
      • by Holi ( 250190 )
        Yeah, the courts tend to frown on using trademarks as a patent extension.
    • Re:Copyright (Score:5, Informative)

      by zarmanto ( 884704 ) on Friday January 29, 2016 @02:50PM (#51397769) Journal

      I wonder if this is even legal?

      It's technically legal to produce the basic bricks, since the applicable patents expired in 1989 []. As for trademarked Lego properties (like the mini-figures, for example) or any which are covered by more recent patents, you can still get away with it as long as you're only producing toys for personal use, and make no attempt to sell them.

      But back to the OP's topic: The feasibility of making Lego compatible bricks [] with cheap 3D printers isn't actually the only question that you're going to have to face; you also need to take into account materials cost. Sure, the "Ultimaker 3D Printer" itself is quite expensive at US $2K -- but even if you gave up on cheaper options and decided to cough up that chunk of change, you also have to keep in mind that the plastic filament to feed the beast also costs money, to the tune of $20 to $80 per spool, depending upon what you're doing. On top of that, not every "printed" component comes out quite right... so you're likely to blow plenty of cash on ultimately wasted filament. Mind you, there are also so many other really cool things you could do with a 3D printer, besides making Lego bricks... but those things will just require that much more filament, and ultimately accomplish the opposite of your stated goal, that of saving money.

      So the bottom line is, if you're going to get into 3D printing at all, you really need to do it "for the love of the game" as they say, not to save money. If all you want is cheaper Lego compatible bricks... then you'll probably be better off in the long run just buying generic brand bricks.

  • A little more detail might help....

    "Tiny" is not an accurate description when looking for actual tolerances in a printer.

    • How about "wee"?

    • Half a unicorn mane hair width.

      I understand wanting the cheap one, I do. I don't understand wanting the cheap one to be precise. Fast, good, cheap; choose two. Accepting very slow can only get you to average precision if you already chose cheap.

      He should probably make do with making larger, not-lego-format blocks that have a similar usage style but need a little clear tape on the outside to keep it snug. That is more doable next to "cheap." Or, plan to spend up to mid-range.

    • Lego claim 10 micrometres. In Imperial, that's about a tenth of an RCH [].

      • by fermion ( 181285 )
        The tolerance on Legos are really good. I have done activities where kids have practice mechanical drawing by measuring and modeling Legos, and I could often could not measure a difference between block using a really good caliper. This tolerance is very believable. From what I can tell, a normal $5,000 3d printer has a resolution of 100 to 1000 times this. I would think that a 3d printer with a 50 micron resolution would provide acceptable parts, but that may be getting to $10k. I know there are some s
        • by xaxa ( 988988 )


          1500 pieces, mostly bricks but enough windows, wheels etc. And lots more colours than there used to be.

          That's the largest, but there are a few sizes of the same thing, and in a Lego shop you can buy individual bricks by volume. I don't see what more they could do — there'd be no point having 50 no-particular-theme sets.

        • I do miss the older style supplemental sets that they had in the 80s, I seem to remember they had smaller sets where it was a pile of gears and axles, a sets of about 100 assorted [color] pieces, sets of accessories, sets of plates, etc. that you could mail order from the catalog in that was included in the sets that were above $20. That appears to have been replaced by the pick a brick option on their website but there doesn't appear to be a good way to get a pile of new bricks of a specific type like ther
    • The tolerances of a Lego brick pretty well defines the problem space. A snippit [] but I cannot find wthe article it referes to.

      It looks like a height tolerance of 40 microns (max). Not sure about the XY tolerances.

    • Oops, looks like XY tolerances are here []

  • by Malenx ( 1453851 ) on Friday January 29, 2016 @02:08PM (#51397363)

    Duplo block might be as close as your going to get with the current precision of 3d printers.

    • Re:Doesn't exist yet (Score:4, Interesting)

      by samkass ( 174571 ) on Friday January 29, 2016 @02:42PM (#51397681) Homepage Journal

      This is true-- there is no home 3D printer that can print a reasonable LEGO brick.

      However, LEGO makes a lot of other ancillary pieces that you CAN print. Replacement heads for mini-figs, clip-on attachments to things, little flowers, buckets, etc. In addition, the LEGO Technic straight brackets (the long ones with the holes and plusses) are not too hard to print, and you can create your own configuration of those holes. (I have a customizable one up on ThingiVerse here: []).

      So a 3D printer is not going to keep you from buying LEGO, but it might make playing and building with LEGO more fun.

  • by enjar ( 249223 ) on Friday January 29, 2016 @02:09PM (#51397373) Homepage

    Depending on how many parts you are having made, consider sending them to a company with a good machine. I had to have a few parts made for a work project. I sent the parts, they sent me a quote, the price was reasonable and I got my parts quickly. I don't do this every day, so for me I wanted the parts in my grubby little hands rather than the machine to make the parts.

  • by BubbaDave ( 1352535 ) on Friday January 29, 2016 @02:10PM (#51397387)

    How about LEGO gets a high-end 3D printer and customers can submit CAD files for custom pieces that then could be avail. in low quantities to everyone?

    • How about LEGO gets a high-end 3D printer and customers can submit CAD files for custom pieces that then could be avail. in low quantities to everyone?

      Great idea. Also, why can't anyone else do it? What IP Law protects LEGO-type bricks?

      It can't be Patents — those only last 20 years. Utility, Design, all of them.
      Copyright — how would that apply to a 3D object?
      Trademark — Don't use their Trade Dress or Logo – anywhere. It is unclear how the functional part of LEGOs could be protected by Trademark.

      In short (and keeping in mind that IANAL), just find a "3D Print to Order" company on the web.

      Better yet, come to the realization

  • My experience ... (Score:2, Insightful)

    by Anonymous Coward

    The most economical solution that I found was to simply buy used, good-quality Lego off of Ebay. The price is typically in the neighborhood of $17-$23USD per pound of used Lego (non-broken, washed, and sanitized).

    A decent, high-quality, but non-commercial 3D printer costs $2500USD (for an Ultimaker 2). That's a lot of Lego.

    • On local Craigstlist, I can sell LEGO for around $8 a pound (or up to like $12 a pound if it's mostly Star Wars pieces).

      LEGO pops up pretty regularly at the Goodwill Outlet, where they dump unsorted donations in giant bins and you can take anything you want for $1.29 a pound. It's a good hobby and side income when I have time to spend a few hours digging through rubbish, and there are other interesting and valuable things besides just LEGO.

    • by Rei ( 128717 )

      My presumption is that they're not trying to save money, that they're wanting to make parts that you can't get elsewhere (such as connectors to various types of real-world objects)

  • by roman_mir ( 125474 ) on Friday January 29, 2016 @02:12PM (#51397397) Homepage Journal

    With so much demand for lego pieces isn't it time to start thinking the right way? Forget a 3D printer, how about building a lego pieces making machine? A cutting machine, a moulding machine for home use as opposed to a 3D printer, which will probably not work well enough to make high quality pieces anyway.

    • by OnceWas ( 187243 )

      Good luck with that. The precision of Lego's molding process is beyond what can be done at home. []


      The moulds are permitted a tolerance of up to two micrometres...

      To put that two micrometers tolerance into perspective:
      - 1–10 m — diameter of a typical bacterium.
      - 3–4 m — size of a typical yeast cell.

  • Now in terms of price you will probably be better off just buying the pieces you need. If you need some sort of custom piece, then you are probably cheating in what you are making. Lego creations for the most part are limited to the design of legos basic parts. They are some custom parts but not so many. The challange for the hobby is to build based on the lego design.

    • Having recently gotten back into Lego (kids) I have been pleasantly surprised by how even the "special" pieces get reused to create interesting designs and details. I will say that the push that some people have made for some more unique but generic parts like additional sizes of the idler gears that are engaged by the driving ring. The justification is that it allows complex gearing in a more compact layout which I can see being useful. Also I wouldn't mind if Lego created some ring gears that weren't the
  • Ultimaker 2 (Score:1, Interesting)

    by Anonymous Coward

    Works OK but the glass effect on the first layer can be a pain.

  • RepRap Pro Ormerod (Score:1, Interesting)

    by Anonymous Coward

    I have been successfully printing lego parts with an RepRapPro Ormerod and a 0.3mm nozzle. It needs fine tuning of the print parameters and PLA was a little harder than ABS (i have not used) but the parts are working.

  • I know this is a maker question and it's not really about cost, though the OP mentions "bang for the buck" as a requirement, but I think it's better to go to the Lego Pick-a-Brick store to buy individual pieces. It's like McMaster-Carr for Legos. I agree with others that there is no way a 3D printer will come anywhere close to meeting the tolerances you need to make Lego-compatible bricks. Other options include buying bulk bags of Legos on eBay or other web sites. We did that years ago and our 14- and 11-ye
    • You can also search Brink Link [] to find the pieces you want. I did this recently and wound up buying more bricks than I immediately needed because the per piece pricing and shipping cost were so low.

  • None. (Score:5, Informative)

    by daid303 ( 843777 ) on Friday January 29, 2016 @02:39PM (#51397655)

    As someone in this industry (Ultimaker)

    I will tell you. There no single printer you can buy that will do Lego level of quality. The precision of lego is just beyond of what current 3D print tech can do. The molds Lego uses to make their bricks are already on the extreme level.

    Now, if you want to replace 1 brick. You most likely can get away with any printer, as 1 imprecise brick in a build isn't an issue. But 5 in a row are.

    Your best bet would most likely be a small SLA printer. Like the a Formlabs or a Autodesk Amber.

    If you don't want the dirty bits of SLA. You're stuck with an FDM printer. Not the best option for what you are looking for. But no chemicals. I would look at an option that has a 0.25mm nozzle option. There are a few. Our latest iteration has it. But that's most certainly not the cheapest machine.

    • Re:None. (Score:4, Informative)

      by jbeaupre ( 752124 ) on Friday January 29, 2016 @03:57PM (#51398361)

      Depending on the type of part, FDM can work. Many of the Technic parts are functional from FDM. I've had good luck making custom gears. For holes, you make them a bit undersized, then drill or ream them. Shaft splines tend to be forgiving. The teeth aren't too bad.

      It's making parts that will snap together that gets sketchy.

    • by Misagon ( 1135 )

      It is not just the extreme quality of LEGO's moulds. LEGO are also using a higher-quality process compared to regular run-of-the-mill injection moudling so as to reduce shrinkage/warping and avoid other defects.
      For instance, the injection inlets are heated so that there are no sprues left when demolding.

    • Your best bet would most likely be a small SLA printer. Like the a Formlabs or a Autodesk Amber.

      We tried printing LEGO form-factor bricks with a (now older) Stratasys mid-range SLA. The results were marginal for plates, ie topside-only, and flat-out unacceptable for the bottoms of blocks. Blocks that were correctly dimensioned to snap onto a lower block, and thin enough to snap in beside another block, broke during use. We had to make fat blocks -- increase wall thickness -- that couldn't nest in beside other blocks to get ones durable enough to survive a dozen attach cycles.

  • I'm going to assume that you're not trying to save money from buying Legos, because that's kind of foolish, but instead trying to make custom parts to fit within the Lego system. Your best bet may be to use, at a minimum, 1x1 lego plates (round or square) for the attachment points and use a cheaper 3D printer with a material that bonds to that plastic (ABS, I think).
    You can use other Legos to build supporting structures for the printer to build around and keep the 1x1 plates in place and aligned during the

  • by nam37 ( 517083 )
    I would look into resin 3D printers like: []
  • LEGO Strength (Score:2, Interesting)

    by chewtoy-11 ( 448560 )

    I could be wrong, but I think the injection molding process used to manufacture LEGO bricks is the reason they are so strong. Most 3D printers use PLA or ABS, and while ABS should be sufficient, PLA is a softer plastic that just won't have that "LEGO grip". Because of the layering technique used by 3D printers, there will always be more flex in the end product than the rigidity of a dense brick made with a highly-pressurized injection system.

    I'm sure in the future these problems will be dealt with, but fo

  • CNC Mill (Score:4, Insightful)

    by Anonymous Coward on Friday January 29, 2016 @02:52PM (#51397789)

    I know 3D printers are all the rage these days, but low cost CNC mills will give you far far better results than low cost 3D printers.

    • I know 3D printers are all the rage these days, but low cost CNC mills will give you far far better results than low cost 3D printers.

      Any specific recommendations?

      • I'm going to argue with the OP. Most retrofit cnc kits won't give you 0.002" repeatability because the lead screws are too sloppy. LEGO bricks are built to 0.0002". A Tormach 440 cnc, cost $5K, with ballscrews rather than leadscrews, still quotes positional accuracy at 0.0013". Prices rise quickly from there. The Haas minimill, at $34K, appears to claim positional accuracy of 0.0005", although it's not obvious that its repeatability is that high.

  • The bumps on the top and the receptacles on the bottom are high accuracy, the bit in between probably less so, I imagine the brick could be a lot more that 5um out of square or height and still attach firmly if the top and bottom connecting surfaces were accurate.

    So maybe you could buy a bunch of those thin bricks and simply glue them onto whatever you print.

    That may not be good for replicating everything, but you could certainly create a lot of new types of blocks that way

  • Wanhao Duplicator I3 runs around $399

    Info Link []

    Forum []

    Info on 3D printing and Duplicator Calibration and mods from JetGuy []

    This is from a guy (JetGuy) That build a 4 X 4 X4 FOOT ed Printer

  • The shrink rate is higher than the tolerances of Lego.
    How much it shrinks each print can change based on formula, environment, filament size, etc... The only way Lego gets around this is by using a high pressure mold, something you cannot do free form.

    By the time you count electricity and time, it's cheaper to buy the Lego off the shelf. That's before you even buy the printer.
  • 3D printers may never get there. Lego bricks are injection-molded to very tight tolerances -- 2 to 20 microns, depending on the source you read. (0.0008 to 0.00008 inches) Google "lego tolerance" to learn more. Even 20 microns is still less than a thousandth of an inch. Warm, freestanding plastic isn't currently close. Even if a printer can put down a 20-micron-thick layer of plastic, that doesn't mean you can build a vertical wall and maintain that precision the whole way.

    And you can't even make a slightly

  • It's not going to happen - not even close. I'm looking at a reprap i3 right now and its printed parts. Forget about reaching anything close to the type of tolerance that LEGO has. Maybe a photosensitive resin printer using a 4k DLP chip could get close for small parts, but the photo resin isn't like the ABS that LEGO uses... it'll be brittle unless new chemistry comes along.

    The whole point of a 3d printer is that you make the part directly. If you need something bigger or with geometry that the printers

  • Precision manufacturing and economies of scale work against you.

    The making of a Lego brick requires very high temperatures and enormous pieces of equipment, so machines, rather than people handle most of their creation.

    When the ABS granules arrive at Lego manufacturing facilities, they're vacuumed into several storage silos. The average Lego plant has about fourteen silos, and each can hold about 33 tons of ABS granules. When production begins, the granules travel through tubes to the injection molding machines. The machines use very accurate molds --- their precision tolerance is often as little as 0.002 millimeters.

    How Lego Bricks Work []

  • Just print up whatever piece you like with appropriately-sized empty pockets where you can glue original Lego bricks (available as small as 1x1) or plates that will mate with the other bricks in your project. Tight tolerances and the right kind of plastic only really matter for the actual pins and sockets which must mate with the other blocks. And, there's always sandpaper if the body of a printed piece is a shade too large. That is how real manufacturers typically do things: they use high-precision or high

  • by Anonymous Coward

    I see above a number of references to the high precision of Lego molds -- in the 0.001 mm range -- which is nigh impossible to achieve with FDM printers.

    True enough. But take a look at a Lego block. Note that each little locking knob has the word LEGO embossed on it. That right there is why you need the ridiculously high tolerance on the moulds, so you can get that word looking like the LEGO trademark and not some random hieroglyph. You still need pretty good tolerances to fit the pieces together,

  • As many have pointed out, you won't find a 3d-printer with the necessary precision.
    Do what I did as a kid:
    Make your custom part - I did it with plain old ABS and wood (without a printer, obviously) - and spare holes for the original LEGO parts.
    Then you place your "connection" parts on a Lego board, put glue in your custom part, fix it on your connection pieces (waiting on the board) and done.
    This will give you the precision for distances many pins apart if needed.
    Nowadays use any decent 3D printer for
  • It might be best to weigh the relative cost in time and money:

    1 Of buying the blocks you want
    - vs -
    2 Of buying, tuning, programming, material cost etc of printing the same blocks.

    You don't explain your desire to print blocks. Are you planning to compete with Lego by pirating their designs? Is there some configuration you must have that they don't offer? These considerations are part of the economic equation too. Of course if you are just an adult playing with commercial toys, maybe you don't value t

  • This is starting out with the wrong assumptions.

    Design a brick system that can be produced with 3-D printers, and will hold together when fabricated within the tolerances of an SLA printer. Forget FDM, it's too low precision and SLA is already achieving an equal or lower cost of manufacture compared with FDM.

    LEGO is manufactured to astonishingly high precision, but I am not convinced that this is the only way to make a brick system.

  • None of them can hit the tolerances. The only place I could see it being workable would be printing out track for a large lego layout, because the track parts are expensive and fairly limited (the curve radii is great for a kids playset, not so great for a real model), but don't need to integrate so tightly with the rest of the system. Don't say use the Lego flextrack, I've got that and find it a huge disappointment. It is useful as an official 1/2 length straight, and not much else.

    PS: This is news for ner

  • printing conventional bricks. Even as expensive as Lego bricks are, 3D printed bricks are crazy expensive when you factor in the machine's cost and the time required to print.

    What does make sense is to print stuff that Lego doesn't make or is very difficult to obtain from Lego. As for compatibility, any crappy printer can print things to which you glue real Lego bricks to get absolute compatibility. You can print things with flat surfaces to which the smooth sides or the bottom edge of Lego bricks can be

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