Midwest RepRap Festival, March 20-22nd

Right now there are two emails in my inbox inviting me to 3D printer conventions. If you’re not familiar with how these cons go, here’s a quick recap: a bunch of 3D printer manufacturers set up their booths the day before, put a printer behind an acrylic enclosure, start a very complex print, and come back the next day. This printer finally completes the print sometime Sunday afternoon, a bunch of people walk by the booths, and the entire venue is filled with enough morose faces as to be comparable to one of the higher circles of hell.

The Midwest RepRap Festival is not this con. It is, to the best of my knowledge, the only 3D printing convention that isn’t a trade show. It’s a blast, it’s March 20th through the 22nd, and we’re going to be there.

This will be our second expedition to the MRRF. Last year we saw 3D printed resin molds, and a strange Core XZ printer from [Nicholas Seward], the mind that brought you the odd Reprap Wally and Simpson. The most interesting man in the universe was there with a Smoothieboard. There were talks on 3D Bioprinting by [Jordan Miller] from Rice University, and everyone ate 3D printed waffles. If you’re looking for the possibilities 3D printing offers, this is the con to go to. If you’re looking for people to sell you stuff, look elsewhere.

This event is organized by the folks at SeeMeCNC, and it will be held on their home turf of Goshen, Indiana. Yes, you will be passing Amish buggies on the way to the event. Even though the MRRF is being held in the middle of nowhere, it was absolutely shocking how many people turned up last year and how good the con was. To put this in perspective, I’m driving nine hours to MRRF, and going to Maker Faire NYC takes me four hours. If I had to choose one 3D printing event to go to, this would be the one. That’s not just because I’m told there will be a t-shirt cannon at MRRF.

The event is free and open to everybody. You can just show up, although it would be a good idea to register. You’ll see the World’s Largest 3D Printed Trash Can. Yes, I’m serious. Call Guinness.

Closed Loop Control For 3D Printers

One of the bigger problems with any CNC machine or 3D printer is the issue of missed steps when moving the toolhead. If a stepper motor misses a step, the entire layer of the print – and every layer thereafter – will be off by just a tiny bit. Miss a few more steps, and that print will eventually make its way into the garbage. [Misan] has the solution to this: closed loop control of DC motors for a 3D printer.

Most printer firmwares use an open loop control system for moving their motors around. Step a few times in one direction, and you know where the nozzle of a 3D printer will be. Missed steps confound the problem, and there’s no way for the firmware to know if the nozzle is where it should be at any one time.

[Misan]’s solution to this was a DC motor coupled to an optical encoder. Both the motor and the encoder are connected to an Arduino Pro Mini which receives step and direction commands from the printer controller. The controller takes care of telling the motor where to go, the Arduino takes care of making sure it gets there.

The entire build is heavily derived from ServoStrap, but [Misan] has a very cool demo of his hardware: during a print, he can force the X and Y axes to either side, and the Arduino in each motor will move the print head back to where it needs to be. You can check that out below.

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Wait, a 3D Printed Lawn mower?

Well, we have to admit, we never saw this coming… A 3D printed lawn mower? What? Why? Huh? How? Those were at least a few of the thoughts running through our head when we saw this come in on the tips line.

[Hans Fouche] has a giant 3D printer that takes up most of the space in his garage, and after printing several large vases, a briefcase, bowls, and even a wind turbine blade — he decided to try printing a lawnmower. A freaking lawnmower.

To do so, he reverse engineered his old rusty lawn mower, and redesigned it to be printable. Apart from the steel axles, some fastening hardware, and of course the motor and blade, the entire thing is 3D printed. And it looks like it works pretty good too.

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Hackaday Links: January 4, 2015

Chips as furniture is now a thing. It started off with a 555 footstool from Evil Mad Scientist and moved on to an EPROM coffee table. Now [msvm] over on the War Thunder forums has constructed a Nixie tube driver table. It’s based on the K155, and as a neat little addition, he’s included a real vintage chip under glass in the table.

Have some tongs, an anvil, and a blowtorch? Make some bottle openers out of framing nails. There’s a lot of variety here in the shapes of the bottle openers.

[Stephen] used a solid state relay he found on eBay to drive some Christmas lights. The SSR failed. That meant it was time to see inside of this relay looked like. The short answer is, ‘a lot of goop and epoxy’, but the traces look big enough to support the current it’s rated for.

Imagine a part of your 3D printer breaks. That’s alright, just print another…. oh, yeah. Well, I guess it’s time to make a bearing bracket out of wood.

The Electronica MK-54 and MK-61 (actually the Электроника МК-54) were incredibly popular Soviet programmable calculators. Now there’s an emulator for them.

[Rue Mohr] found a very cheap TFT display on an Arduino shield. The chip for the display was an SPF5408, a chip that isn’t supported by the most common libraries. He eventually got it to work after emailing the seller, getting some libraries, and renaming and moving a bunch of stuff. If you have one of these displays, [Rue] just saved you a bunch of time.

Interview With A Printer

The Hackaday European tour continues, this time in Prague with Josef Průša (Google translate), core developer in the RepRap project, feature at all the Maker Faires and cons, and creator of his namesake, the Prusa Mendel and i3 printers.

[Prusa]’s involvement with the RepRap project started with a RepRap Mendel, the second iteration of RepRap hardware, but the first popular and easy to build version. [Jo] found the Mendel rather difficult to build, so he loaded OpenSCAD and started to design his own version of the hardware. This version became the de facto standard RepRap for a few years, with many inspired by and derivative printers making their way to hackerspaces and workshops around the world.

The first Prusa printer, derived from the RepRap Mendel.
The first Prusa printer, derived from the RepRap Mendel.

A few years ago, [Prusa] was one of the first to make a complete break with the traditional ‘threaded rod and nut’ construction of RepRaps with the introduction of the Prusa i3. This was the first model that had a metal plate as the frame, another feature that would be seen in dozens of other models. It’s not something that was without controversy, either; using a metal plate for the frame doesn’t allow for as much self-replication, something that’s a core value of the RepRap project. That didn’t matter to the community; the Prusa i3 or a similar design is the third most popular printer on 3Dhubs.

The first Prusa printer showing off its Makerbot heritage
The first Prusa printer showing off its Makerbot heritage

What’s the future of the Prusa name? There is an i4 in the works, and I’m pretty sure that’s all I can tell you. Someone already bought the Prusai4 domain, so there may be a name change.

In the interview below, [Prusa] goes over his involvement with the RepRap project, his business, what he considers to be the latest advances in 3D printing for the past year, what the worst things about the 3D printing scene is (it’s Kickstarter), the state of the RepRap project, and thoughts on SLS, DLP, and SLA printing technologies. Video below.

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Printing In Metal with a MIG Welder

Whenever the question of metal 3D printers comes up, someone always chimes in that a MIG welder connected to a normal 3D printer would work great. A bit of research would tell this person that’s already been done, but some confirmation and replication is nice. A few students at TU Delft University strapped a welder to a normal, off-the-shelf 3D printer and made a few simple shapes.

This project builds on the work of [Joshua Pearce] et al. at Michigan Tech where an MIG welder and delta bot was used to lay down rather complex shapes on a metal plate substrate. The team at TU Delft used a cartesian bot – a Prusa i3 – for their replication because of the sheer mass of moving a metal build plate, firebricks, and welder around.

In the first few prints on their machine, the team was able to lay down enough metal to build a vertical wall. It’s not much, and to turn this into a finished part would require some machining, but these are only the beginning steps of what could become a legitimate way of creating metal parts. Video below.

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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.