2014 - projects, plans, updates...

Hi all. January is almost behind us, so I thought it was past time I write something new here. I'll go through some of the stuff I'm working on and some I plan to work on this year. Also I hope this post will answer some questions I get asked frequently on Thingiverse and elsewhere. So let's get started...

NanoBlock extruder

[It doesn't look like this anymore :)]

This is something I've spent countless hours on. The whole project started I think almost two years back, when my friend Bruno and I were contemplating alternative extruders for our Ultimakers, since retraction didn't really work back then and all our prints were full of strings because of it. We wanted to try out a head mounted extruder, but also to keep it lightweight. We didn't want to lose the benefits of UM's super light printhead. 

The first thing we tried was a worm-gear based extruder run via a flex shaft. It was super-small. And super-lousy. Although we expected hysteresis to be present in the system, we didn't expect that much of it, but at least we had proof the flex shaft approach was flawed.

Since we realized we will need a motor to run the extruder directly, I ordered some NEMA8 and NEMA11 motors to test. The NEMA 8s  proved unreliable. The NEMA11s were awesome. 

And that's where all of it began. I've done countless revisions of the design, and I'm closing to what I think will be a really cool, powerful extruder, in a really small and light package. Although I like the simplicity of bowden extruders, I think there are a lot of issues with them. Flexible filaments are a big problem for example, and they're much more sensitive to filament diameter changes, or low quality filament. Also, they need lots of retraction which can slow down complex prints. Basically I'm looking for a best-of-both-worlds solution. Something with the performance of a direct driven extruder, but with more torque, and weight-wise in between bowden and non-bowden print heads.

There is one drawback of this extruder and that is a lot of special parts. It's really hard to cram everything in a 4x4x4cm or similar envelope so some creative usage of parts was necessary. Some micro bearings, worm and worm gear, custom bolts and whatnot, but I hope it will be worth it in the end. 

I have just received the last part of the puzzle, which are my custom machined drive bolts. I am hoping they will help me simplify the design even more, and provide optimal filament grip. So I hope I will be able to finish and publish this soon. (And usually when I say SOON, somehow a year goes by, lets hope it's not the case this time...) Props go to Calum Douglas who helped me immensely with the whole custom machined bolts adventure - thank you!

H4 Extruder

Well, I promised you guys this one a long time ago. The H3 has had 18K views,  more than 14K combined downloads, and some very nice makes in these one and a half years since it was made. I'm really happy it turned out to be as good as it was. But the design is showing its age now, especially in my eyes. I've learned a lot about designing functional parts in the last two years, and I see lots of areas that can be improved. 

I've been working the next version, the H4, on and off for quite a while. I'm still not sure about some of the features, but some are already there. It will have internal gears. It's pretty, much more comfortable for manual extrusion, and it seems to be quieter. Did I mention it's pretty? Optionally you can then print out the outer gear with a solid outer face (ie. without spokes) so it's more child-proof. 

There will also be a mount for filament cleaners/straighteners or such, but no quick release for bolt cleaning, since the UM V3 bolt pretty much takes care of that by itself. I'll need somebody who actually owns a V3 bolt to do an accurate drawing of it though, so if you're reading this and have one, it would be much appreciated.

 I have been using the various H4 prototypes to research various ways of applying pressure on the filament, and had some pretty cool results. I'm just not sure yet what to use in the final design. I want the main features of this extruder to be ease of use and reliability. 

DD-1 - Ultimaker Direct drive

Ok, this is in eternal beta, even though I've been using it for quite a while now. The problem with this thing is that the little side "wings" which hold the motor in place have snap fittings, which tend to break. Another problem is the fact that this design only caters to one specific length of NEMA17 motor. Which sucks.

One of the good aspects is that with this design you only need one additional linear rod, and no spacers or similar gimmicks. I made it primarily because I had a single longer 8mm rod laying around, and I wanted something that looked nicer than the printed variants. (Speaking of which, Calum Douglas aka Snowygrouch originally came up with the idea to remove the short belts in the Ultimaker, to reduce backlash and other issues.)

In the meantime I solved all of those problems, and made it really simple to dismount the motors if necessary. I've also included a nice mount for 40mm fans to cool the motors if necessary. The design is a combo of lasercut and printed parts now, but I'm trying to make it completely printable. I'm using the new version now, but there's still some tweaks to do before publishing (like always). I'll finish this as soon as my UM starts printing again. I somehow managed to fry the darlington transistor which controls the fans twice in a week, so I have to replace it again.

SmoothieBoard, Megatronics V3.0, UBIS hotend...

When I bought my UM, it came with a rev. 1.5.3 PCB which is a bit outdated now,  and I fried several things on it already, so it's in kind of a sorry state right now. Also I never liked the fact it has to be covered, the fan makes noise, and it's a hassle to disassemble. So I decided to replace it with RepRapWorld's Megatronics V3.0. I like it because it's an integrated solution but the stepper drivers are still separate. And it also supports the newer DRV8825 drivers based on Texas Instruments' chips, which have higher current capabilities and 1\32 micro stepping. It should arrive in a week so expect a review/tutorial here. I was also lucky to get my hand on one of the last 3mm UBIS ceramic hotends from printrbot. I kept hearing how it's the best hotend for printing PLA available right now, and to tell the truth, I was kinda tired of the E3D and it's active cooling. Those little 30mm fans suck, they're noisy as hell, vibrate a lot, and take up valuable space. The E3D is a great hotend, mind you. It's really well designed and well made, but since I am basically printing only PLA, I wanted a simpler solution for now. I will also do a blog post on that too, after I install the new electronics.

Finally I also kickstarted a SmoothieBoard, a 32bit ARM based CNC controller board. That is something I plan to use for a completely new 3d printer I've been working on for a while now. I started work on the first prototype, but there is an insane amount of details left to be done before it's complete. 
All in all, 2014 looks promising.

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