Hello all,
So I was hoping for some advice on where I should go with my printer.
I currently have an old Prusa i2 frame that I had started to build a few years ago - I'd shelved the project due to hot-end issues but I've just recently finished it off and got it printing. As I'm sure most of you know the i2 is about as rigid as a wet piece of pasta and is really limited in build volume, therefore I went with the bowden route which gained some Z height and reduced a lot of the X carriage mass. Due to the age of the frame, it has T5 belts and M8 threaded rod "leadscrews" so print quality is limited in a number of ways. (Although the z banding I get isn't
too bad, all things considered.) As it has the horizontal X bars, there's very little space for cooling fans - I currently have two 40mm fans angled down but they are a bit far away from the hot end and they reduce my X travel to around 130mm.
I do have some decent parts in my current printer that I'd like to retain in a new printer:
- An E3D Titan Extruder
- An E3D V6 hot-end
- A Duet Wifi control board
- A DC42 IR sensor for Z probing (Not fitted to the current printer, but I already have it)
I was initially thinking about a CoreXY build with Chinese linear rails on all axes and rolled ballscrews for the Z axes. Having seen the P3 Steel and Prusa i3 MK2 however, I'm considering basing my design off of these. I'd like to use a direct extruder setup to allow for flexible filament, which I think would defeat the point of building a CoreXY.
One thing I'd quite like about the i3-based designs is that the rails are out of the way and there's a lot of parts available on Thingiverse. I also really like the way that the P3 Steel (and Mendel90) keep the X and Y axes aligned. One thing that does concern me is the rigidity of the unsupported 8mm rails that are often used in these designs - I'm thinking that a single 15mm linear rail would be a better option for the X axis and double linear rails for the other axes. Is this likely to be a worthwhile upgrade ? It would mean moving away from a lot of the carriage designs available and would mean I'd have to design something myself ?
If I was to go with the i3-based route, I'd probably build a cross between the Prusa i3 MK2 (But with this carriage: [
www.thingiverse.com], modified to use real cable chains and the IR sensor) and the P3 Steel frame. (Modified for a larger build volume and using 12mm ballscrews rather than M5 threaded rod) Sadly the i3 MK2 heatbed is only 12V, so I'd probably go with the E3D varipower heatbed for an even larger print volume: [
www.filastruder.com] I'd also go with 10mm GT2 belt to reduce stretching.
I'm tempted to drive both Z ballscrews with a single NEMA 17 motor and a large belt across the top, although this does add belt stretch to the Z axis.
So essentially I'm looking for ideas and advice. I'd love to be able to take a kit such as the Prusa i3 MK2 and just modify the X carriage to suit my parts, but sadly the heatbed is an odd size and not 24V so I can't use theirs and I can't find a replacement without reducing the build volume - I'd also have to add some bracing to tie the X/Z sheet of metal to the Y axis as that's mostly unsupported out of the box. There are a number of designs out there that are nearly right, but just not quite there in my opinion. Another option would be to build a Prusa i3 MK2 style frame out of aluminium extrusion which may end up being more rigid and would allow for a different heatbed: [
www.thingiverse.com]
Edited 2 time(s). Last edit at 03/03/2017 08:23PM by yngndrw.