The Midwest RepRap Festival – Awesome Stuff in the Middle of Nowhere

It’s time once again to venture out to Goshen, Indiana for the Midwest RepRap Festival. It is the largest 3D printing con in the entire world where no one is trying to sell you anything. With a qualifier like that, it doesn’t have to be very big, but last year over 1,500 people showed up to the Elkhart county farm show complex and this year many more people are expected.

On the list of attendees is Taulman 3D, makers of fine, odd filament, Lulzbot, [Johnny] of Ultimachine, creator of the RAMBo board, MakerJuice, the FirePick Delta – the most skulled project on hackaday.io, and dozens of other people who make a living with 3D printing.

Of the expected attendees that are not specifically involved with 3D printing, I’m told [Ben Heck] will be there, along with someone from Adafruit and Make. The EFF might have a booth. A local radio station is doing a remote, and the servers at Wings, Etc. — one of the few area pubs — are going to clean up this weekend.

The event officially starts at 4:00pm today, Friday, March 20th. If you won’t be going the entire weekend, I’d suggest showing up on Saturday or Sunday. There will be far too many people there, and I’m slightly agoraphobic. We’ll be posting updates from the MRRF later on.

3D Printering: Induction Heating

Every filament-based 3D printer you’ll find today heats plastic with resistive heaters – either heater cartridges or big ‘ol power resistors. It’s efficient, but that will only get you so far. Given these heaters can suck down only so many Watts, they can only heat up so fast. That’s a problem, and if you’re trying to make a fast printer, it’s also a limitation.

Instead of dumping 12 or 24 VDC into a resistive heater, induction heaters passes high-frequency AC through a wire that’s inductively coupled to a core. It’s also very efficient, but it’s also very fast. No high-temperature insulation is required, and if it’s designed right, there’s less thermal mass. All great properties for fast heating of plastic.

A few years ago, [SB] over on the RepRap blog designed an induction heater for a Master’s project. The hot end was a normal brass nozzle attached to a mild steel sleeve. A laminated core was attached to the hot end, and an induction coil wrapped around the core. It worked, but there wasn’t any real progress for turning this into a proper nozzle and hot end. It was, after all, just a project.

Finally, after several years, people are squirting plastic out of an induction heated nozzle. [Z], or [Bulent Unalmis], posted a project to the RepRap forums where he is extruding plastic that has been heated with an induction heater. It’s a direct drive system, and mechanically, it’s a simpler system than the fancy hot ends we’re using now.

Electronically, it’s much more complex. While the electronics for a resistive heater are just a beefy power supply and a MOSFET, [Z] is using 160 kHz AC at 30 V. That’s a much more difficult circuit to stuff on a printer controller board.

This could be viewed as just a way of getting around the common 24V limitation of common controller boards; shove more power into a resistor, and it’s going to heat faster. This may not be the answer to hot ends that heat up quicker, but at the very least it’s a very neat project, and something we’d like to see more of.

You can see [Z]’s video demo of his inductive hot end below. Thanks [Matt] for the tip.

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New RepRap With Integrated Case, Oddly Called Case-Rap

The great thing about RepRaps are that there are so many to choose from! No matter what features or design intent you could want, there is probably a RepRap for that. Even so, there has been a recent addition to the RepRap family. Creator [jlguil] calls it the Case-Rap, and for good reason, the frame of the printer folds up into a suitcase.

The Case-Rap is inspired by the Mendel90 which tries to improve on the original Mendel by replacing the threaded rods for a more rigid sheet material frame with bracing to keep the X, Y and Z axes perpendicular to each other. The Case-Rap goes a little further with the design to have the frame also perform double duty as a travel case.

Check out the video after the break, the printer is actually built in 2 complete separate assemblies. The X and Z axes are mounted in a 4-sided wooded frame. The Y axis and the electronics are mounted on a 2-sided wooden frame. When the frame pieces are latched together in one orientation, they conceal the printer inside a suitcase-sized box. The latch positions were thoughtfully placed so the frame pieces could also be latched together in ‘printer mode’. Setting up and breaking down the printer takes all of 30 seconds.

You may think a super portable printer has to be small… but you’d be wrong. The Case-Rap has a commendable 8x8x8 inch print area. According to [jlguil], the total DIY cost comes in around 350$ CAD, which is not too bad for a 3D printer, and pretty good for one that is unique, portable and capable.

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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.