3D Printing Giant LEGO-Like Blocks To Build Big Toys

[Ivan Miranda] is all about big 3D prints. He’s now set about printing giant blocks in the vein of LEGO Technic to build himself a full-sized rideable go kart. The project is still in progress, but [Ivan] has made great progress with his design.

The benefit of 3D printing giant blocks like this is that they open up the possibilities for rapid prototyping of big projects. It’s already easy to snap together a little LEGO tank, boat, or car at the small scale. Bigger blocks would make that possible for larger builds, too. Plus, once you’ve got plenty of blocks, there’s no need to wait for the 3D printer to churn out parts. You can just play with your toolbox of existing components.

[Ivan]’s design has faced some teething problems along the way. He struggled to solve various coupling problems for joining the blocks in various orientations, and made iterative changes to solve the issue. Eventually, he realized if he just eliminated an offset between the top and side holes of his beam design, everything would neatly work out. Plus, he learned that he could print a tiny scale version of his big blocks in order to test out designs without using as much plastic.

We love the idea of having a garage full of adult-sized LEGO-style blocks for big projects. The only caveat is that you really need a giant printer like [Ivan’s] to make them. Continue reading “3D Printing Giant LEGO-Like Blocks To Build Big Toys”

Large Format 3D Printer Is A Serious Engineering Challenge

When you want to build a large format 3D printer, you can’t just scale up the design of a desktop machine. In an excellent four-part build series (videos after the break), [Dr. D-Flo] takes us through all the engineering challenges he had to contend with when building a 3D printer with a 4x4x4 ft (1.2 m cube) print volume.

For such a large print volume you won’t be printing with a 0.4 mm nozzle. The heart of the printer is a commercial Massive Dimension MDPH2 pellet extruder, capable of extruding ~1 kg of plastic per hour through 1.5 mm to 5 mm nozzles. To feed the extruder, [Dr. D-Flo] used a Venturi vacuum system to periodically suck pellets from a large hopper. The system is driven by compressed air, which can introduce moisture back into the carefully dried pellets. To reduce the humidity levels, the compressed air passes through a series of vertical aluminum tubes to allow moisture to condense and drain out the bottom.

At 8.4 kg, it needs a powerful motion platform to move it. [Dr. D-Flo] went with a stationary bed design, with the extruder pushed around by seven high torque NEMA23 motors on a large gantry built from C-beam aluminum extrusions. A machine this size needs to be very rigid with well-fitting parts, so [Dr. D-Flo] made heavy use of CNC machined aluminum parts.

To allow dynamic bed leveling, [Dr. D-Flow] made use of a Quad Gantry Leveling (GQL) scheme. This means that each of the four Z-actuators will dynamically adjust its position based on inputs from the leveling probe. The avoid stressing the corner mountings that hold the X-Y gantry to the Z carriage plates, he used radial spherical bearings at the mounting points to allow a few degrees of play.

The build plate consists of an aluminum plate bolted onto the base in 25 positions with springs for adjustability. A massive 6000 watt 220 V heating pad sticks to the bottom, while the actual printing surface is a large sheet of borosilicate glass. One major concern was the deflection of the build plate when heated to working temperature, but with all the adjustment options [Dr. D-Flo] was able to get height variation down to about 0.25 mm. This is within the acceptable range when printing with layer heights of 1 mm or more.

We’ve featured large scale 3D printers in the past, but none are quite as big the University of Maine’s building-sized 3D printer that can print a motorboat in one piece.

Continue reading “Large Format 3D Printer Is A Serious Engineering Challenge”

Giant 3D Prints Piece-by-Piece

While FDM printers have gotten bigger lately, there’s almost always going to be a part that is bigger than your bed. The answer? Break your design into parts and assemble them after printing. However, the exact method to do this is a bit of a personal choice. A mechanical engineering student wrote:

After researching the state of the art as well as your ideas here on reddit, I realized, that there are almost no universal approaches to divide a large part and join the pieces which maintain mechanical strength, precisely position each segment, and also counteract tolerances due to the FDM-process.

Therefore I tried to develop a universal method to segment large trim parts, additively manufacture each segment and finally join those segments to form the desired overall part.

The result is a research paper you can download for free. The method focuses on thin parts intended as automotive trim, but could probably be applied to other cases.

You can read about the thought process, but the final result was a joggle — a joint made with a rabbet and tongue. Adhesive holds it together, but the joint offers advantages in constraining the final product and the transmission of force in the assembly. Judging by the picture, the process works well. It would be interesting to see slicer software develop the capability to segment a large model using this or a similar technique.

Of course, you can just build a bigger printer, at least to a point. It seems, though, that that point is pretty big.

Electric Skateboard With Tank Tracks, From A Big 3D Printer

One of the basic truths of ground vehicles is that they are always cooler with tank tracks. Maybe not better, but definitely cooler. [Ivan Miranda] takes this to heart, and is arguably the king of 3D printed tank projects on YouTube. He has built a giant 3D printed electric skateboard with tank tracks with the latest version of his giant 3D printer. Videos after the break.

The skateboard consists of a large steel frame, with tracked bogies on either end. Most of the bogie components are 3D printed, including the wheels and tracks, and each bogie is driven by a brushless motor via a belt. Some bends were added to the steel frame with just 3D printed inserts for his bench vice. The bogies are mounted to the frame with a standard skateboard truck, which allows it to steer like a normal skateboard, by tilting the deck. It looks as though this works well on a smooth concrete floor, but we suspect that turning will be harder on rough surface where the tracks can’t slide. We’ll have to wait for the next video for a full field test.

The large components for this skateboard were printed on [Ivan]’s MK3 version of his giant 3D printer. Although it’s very similar to the previous version, improvements were made in key areas. The sliding bed frame’s weight was reduced by almost 50%, and the wheels were rotated, so they ride on top of the extrusion below it, instead of on it’s side, which helps the longevity of the wheels. This also allows bed levelling to be done by turning the eccentric spacers on each of the wheels. The rigidity of base frame and x-axis beam were increased by adding more aluminium extrusions. Although he doesn’t explicitly mention the print volume, it looks to be the same as the previous version, which was 800x500x500. For materials other than PLA, we suspect a heated build chamber will be required have any chance of making big prints without excessive warping.

[Ivan] really likes big prints, with a number of 3D printed tanks, a giant nerf gun, and a sand drawing bot. Continue reading “Electric Skateboard With Tank Tracks, From A Big 3D Printer”

Giant 3D Printer For Giant Projects

Established FDM 3D printers designs generally lead themselves well to being scaled up, as long as you keep frame stiffness, alignment and movement in mind. [Ivan Miranda] needed a big printer for his big projects (videos below), so he built his own i3 style printer with a 800 mm × 500 mm usable print bed and about 500 mm vertical print height.

The frame of the new machine is built using 20×20 and 20×40 aluminium V-slot extrusions with some square tubing for reinforcement. To move all the weight, all 3 axes are driven by double NEMA17 steppers, via a DUET3D board with an expansion board for the extra motors. The extruder is the new E3D Hemera with a 0.8 mm nozzle. The print bed is a mirror, on top of the aluminium plate, headed by a large silicone heat pad. The first bed version used a smaller heat pad directly on the back of the mirror, but it heated up unevenly and the mirror ended up cracking. Look out for the ingeniously lightweight and simple cable management to the extruder. When all was said and done he printed a 800 mm long size 66 wrench as a test piece with zero warp, which is pretty good even for PLA. This project is also a perfect example of the power of 3D printing for rapid iterative development, as lot of the printed fittings went through multiple versions.

Although [Ivan] received most of the components for free, a printer like this is still within reach of the rest of us. We look forward to a lot of big prints by [Ivan] in his signature red, like a massive nerf gun and the ridable tank he is currently working on. Continue reading “Giant 3D Printer For Giant Projects”

Humongous 3D Printer Produces Boat And Challenges

We’ve seen some pretty big polymer 3D printers, but nothing quite as big as the University of Maine’s 3D printer with a 22,000 ft³  (623 m³) build volume. It holds the Guinness World Record for the largest polymer 3D printer, and with that size comes some interesting challenges and advantages.

You might have already seen the video of it printing an entire patrol boat hull in a single piece, and would have noticed how it printed at a 45° angle. Due to the sheer weight and thermal mass of the print bead, it cannot bridge more than an inch, since it’ll just sag. A 45° overhang angle is about all it can manage, but since the layers can be tilted at that angle, it ends up being able to print horizontal roofs with no support. A 10 mm nozzle is used and the extruded line ends up being 12.5 mm in diameter with a 5 mm layer height. The boat mentioned above was printed with carbon ABS, but it can reportedly use almost any thermoplastic. It looks like the extruder is a screw extruder from an injection moulding machine, and is likely fed with pellets, which is a lot more practical than filament at this scale. Check out the video below by [Paul Bussiere] who works in the Advanced Structures & Composites Center at the University. He also does a very interesting interview with his boss, [James M. Anderson].

The 45° layer angle is very similar to how some infinite build volume 3D printers work. For something more within the reach of the average hacker, check out the tool changing Jubilee.
Continue reading “Humongous 3D Printer Produces Boat And Challenges”

3D Printing Houses From Concrete

We’ve seen 3D-printed houses before, but most make use of prefabricated chunks. This hurricane and tornado resistant hotel suite in the Philippines was printed in one shot.

Sound familiar? This is the work of [Andrey Rudenko], who started by building a concrete 3D printer in his garage 2 years ago, moved on to 3D printing his kids a concrete castle in his backyard later that year and now appears to have a full-blown company offering commercial 3D printed houses. Way to go [Andrey]!

The building was designed in Sketchup no less, and the printer makes use of Pronterface for the control software. It’s absolutely fascinating to see this built at full-scale. We want one. Continue reading “3D Printing Houses From Concrete”