THP Entry: An Affordable Metal 3D Printer

metalFor years now, people have been trying to develop an affordable, RepRap-derived 3D printer that will create objects in metal. There has been a lot of work with crazy devices like high-powered lasers, and electron beams, but so far no one has yet developed a machine that can print metal objects easily, cheaply and safely. For The Hackaday Prize, [Sagar] is taking a different tack for his metal 3D printer: he’s extruding low temperature alloys just like a normal 3D printer would extrude plastic.

[Sagar]‘s printer is pretty much a carbon copy of one of the many ‘plastic-only’ 3D printers out there, the only change being in the extruder and hot end. As a material, he’s using an alloy of 95.8% tin, 4% copper, and 0.2% silver in a 3mm diameter spool. This alloy melts at 235° C, about the same temperature as the ABS plastic these printers normally use.

The only real problems with this build are the extruder and nozzle. [Sagar] is milling his own nozzle and hot end out of stainless steel; a challenging bit of machining, but still within the realm of a hobbyist. He has some doubts about the RepRap derived plastic geared extruder being able to handle metal, so he’s also looking at designing a new version and milling that out of stainless as well.

It’s an awesome project, and we hope we’ll be seeing some updates to the project shortly. While a 3D printer that produces objects out of a low temperature alloy won’t be building rocket engines any time soon, it could be a great way to fabricate some reasonably high-strength parts at home.


SpaceWrencherThe project featured in this post is an entry in The Hackaday Prize. Build something awesome and win a trip to space or hundreds of other prizes.

Servo Stock, The Future Of 3D Printers

printerIf you think about it, the RepRaps and other commercial 3D printers we have today are nothing like the printers that will be found in the workshops of the future. They’re more expensive than they need to be, and despite the RepRap project being around for a few years now, no one has cracked the nut of closed loop control yet. [mad hephaestus], [Alex], and [Will] over on the Hackaday Projects site are working on the future of 3D printing with the Servo Stock, a delta printer using servos and closed loop control to build a printer for about a quarter of the price as a traditional 3D printer.

The printer itself is a Kossel derivative that is highly modified to show off some interesting tech. Instead of steppers, the printer has three axes controlled by servos. On each axis is a small board containing a magnetic encoder, and a continuous rotation servo. With this setup, the guys are able to get 4096 steps per revolution with closed loop control that can drive the servo to with ±2 ticks.

The electronics and firmware are a clean sheet redesign of the usual 3D printer loadout. The motherboard uses a Pic32 running at 80MHz. Even the communication between the host and printer has been completely redesigned. Instead of Gcode, the team is using the Bowler protocol, a system of sending packets over serial, TCP/IP, or just about any other communications protocol you can think of.

Below is a video of the ServoStock interpreting Gcode on a computer and sending the codes and kinematics to the printer. It seems to work well, and using cheap servos and cut down electronics means this project might just be the first to break the $200 barrier for a ready to run 3D printer.

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The Hour of the 3D Printed Clock Draws Nigh

clock_3d_printed_display_large

Many have tried, but [Christoph Laimer] has succeeded in designing a working, (relatively) accurate clock nearly completely from 3D printed parts. Every gear, pulley, wheel and hand of [Christoph's] clock is printed. Only a few screws, axles, a weight, and a string are non-printed. Even the crank to wind the clock is a 3D printed part.

[Christoph] designed his clock in Blender. It took quite a bit of design work to create parts that would work and be printable. Even more work was involved in printing over 100 failed prototype parts.

One might think that [Christoph] is using the latest  printers from the likes of Makerbot or Utimaker to achieve this feat. It turns out he’s using a discontinued Rapman 3.2 printer. Further proof that even “older” printers are capable of great things! [Christoph] does run his printer rather slowly. Printing a single gear with 0.125 mm layers and a 0.4 mm nozzle takes him 2 or 3 hours.

Mechanically, the clock is gravity powered with an anchor escapement. Rather than a pendulum, [Christoph] chose to use a balance wheel and hairspring assembly to govern the escapement.  Even the spring is printed from standard PLA. The weight is suspended from a pulley block. The clock isn’t particularly efficient. 70cm of height will run the clock for only 2 hours.

[Christoph's] clock has proven to be accurate to within 1/4 second per hour. He hasn’t provided temperature stability data – but being PLA, we’d suggest not getting it too hot!

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The Hackaday Prize: Thinking Really, Really Big

Dome

In case you’ve been living under a rock for a few weeks, we’re giving away a trip to space for the best, most grandiose connected hardware project. [coxrandy], a.k.a. [Phillip Cox] realized the best way to build something awesome was to think big, and his plan for building a 1km dome (yes, 1000 meters) is the most ambitious project we’ve ever seen.

The BuckyBot, as [Phil] is calling his build, relies on the ideas of the great [Buckmister Fuller] and his idea to build a huge geodesic dome covering all midtown Manhattan. [Fuller] didn’t have the resources to build a structure this large in the 1950s, and to be honest, we don’t have the resources to build it nowIt would be a ludicrous effort to build something like this one beam at a time, and [Phil] concludes that to build something this big, we need to think small.

Instead of thousand ton cranes and several thousand vehicles trucking in building supplies, [Phil]‘s idea uses small “BuckyBots” – a combination 3D printer and robot – that builds one structural cell of a giant dome at a time. These BuckyBots climb around the structure, build the internal and support structure, slowly climbing to the skies on their fractal-inspired creation.

The Hackaday Prize contest will end far before [Phil]‘s BuckyBots will have the ability to build a kilometer-wide dome, so the current plans are to modify his RepRap Mendel to crawl. Once that’s done, he’ll have his newly built BuckyBot build a 2 meter hemisphere in his garage. From there, construction moves to the back yard where a 10 meter dome will be built.

Even if this project never makes it past the planning stages, it’s an awesome example of thinking big, something you’re going to need if you’re trying to win a trip to space.

Heated Build Chambers Don’t Have to be That Complex

800px-HBC_open_door_view

Looking to improve the quality of your 3D prints? Worried about peeling, warping, and de-laminating layers? All you need is to do is make a heated build chamber!

The heated build chamber is one of the patents that the big 3D printer company owns (we won’t point any fingers), and that’s why you don’t see it as a feature on any of the “consumer” grade 3D printers. But that won’t stop people from making their own!

[Repkid] just finished a wiki page on this topic, and it’s a great way to build a heated chamber — if you have the space for it! He’s built a large wooden enclosure for his RepRap out of MDF sheets. Double-ply cardboard is used as thin insulation, although we imagine if you’re building something this large you might as well use some commercial insulation.

The chamber is heated by a blow dryer which is mounted off the back of the box, and the heat is controlled by changing the speed setting of the dryer. A laser cut vent allows for further adjustment. If you want to get really fancy, it would be very easy to install a thermostat PID controller that could regulate the temperature more accurately. To prevent overheating the electronics, all the control boards are also outside of the box.

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Ask Hackaday: Auto Bed Leveling And High Temperature Force Sensitive Resistors

FSR

[Johann] over on the RepRap wiki has an ingenious solution for making sure a borosilicate glass bed is completely level before printing anything on his Kossel printer: take three force sensitive resistors, put them under the build platform, and wire them in parallel, and connect them to a thermistor input on an electronics board. The calibration is simply a bit of code in the Marlin firmware that touches the nozzle to the bed until the thermistor input maxes out. When it does, the firmware knows the print head has zeroed out and can calculate the precise position and tilt of the bed.

Great, huh? A solution to bed leveling that doesn’t require a Z-probe, uses minimal (and cheap) hardware, and can be retrofitted into just about any existing printer. There’s a problem, though: these force sensitive resistors are only good to 70° C, making the whole setup unusable for anything with a heated bed. Your challenge: figure out a way to use this trick with a heated bed.

The force sensitive resistors used – here’s a link provided by [Johann] – have a maximum operating temperature of 70° C, while the bed temperature when printing with ABS is around 130° C. The FSRs are sensitive to temperature, as well, making this a very interesting problem.

Anyone with any ideas is welcome to comment here, on the RepRap forums, the IRC, or anywhere else. One idea includes putting an FSR in the x carriage, but we’re thinking some sort of specialized heat sink underneath the bed and on top of the FSRs would be a better solution.

Video of the auto bed leveling trick in action below.

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MRRF: ARM-Based CNC Controllers

smoothie

8-bit microcontrollers are the standard for RepRap electronics, but eventually something better must come along. There has been a great deal of progress with ARM-based solutions, and of course a few of these made a showing at the Midwest RepRap Festival.

First up is [Mark Cooper], creator of Smoothieboard, the ultimate RepRap and CNC controller. It’s an ARM Cortex-M3 microcontroller with Ethernet, SD card, and up to five stepper drivers. It had a Kickstarter late last year and has just finished shipping all the rewards to the backers. In our video interview, [Mark] goes over the functions of Smoothieboard and tells us about some upcoming projects: the upcoming Smoothiepanel will feature a graphic LCD, SD card, rotary encoder and buttons, all controlled over USB by the Smoothieboard.

Next up is [Charles] with a whole bunch of CNC capes for the Beaglebone. By far the most impressive board was a huge I/O expander, motor driver, and everything controller for a Beaglebone featuring – get this – three parallel port interfaces. This was a one-off board costing thousands of dollars, but [Charles] did show off a few smaller and more practical boards for Beaglebone CNC control. Here’s a link to [Charles]‘ capes.

Videos below.

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