Upgrading Prusa Mendel

Hi,

I would appreciate a bit of help. I think I have the first model of Prusa Mendel I purchased a couple of years ago. It's been a project on it's own and I haven't used it much, but now I need to print some good and consistant 3D objects and I face a few problems.

Printer prints 3mm ABS, has a 0.5 mm nozzle. The extruder (and actually the whole printer) looks like the one here:

www.nextdayreprap.co.uk/extruder-and-hot-end-assembly-reprap-prusa-mendel-build-manual/

I can print 0.4 layer height fine, but the objects look quite crude. I also can't print anything tiny, because the hot end smudges as it's spherical instead of cone shaped. I need to print a slightly better quality prints and I was looking at extruders and nozzles, but I'm a bit at a loss right now. I would like to print ABS or PLA with 1.75/3mm fillament and 0.35 nozzle, but don't have a clue where to look for parts to upgrade my setup to get a higher quality. Maybe it's not even worth upgrading and I should just get an i3 kit and build it?

I would appreciate any help.

Regards,
Arvydas

An improved hot end would definitely help. I like the E3D all-metal hotend.

You could also stabilise the frame - Y direction is OK thanks to the a-frame, but you can get some wobble when you're moving fast in the X direction. Thingiverse has some stabilisers: http://www.thingiverse.com/thing:34214

Posting an image of the prints you're currently getting would help with identifying opportunities for upgrades and improvements.

Thanks 3dkarma for quick response. I've looked at E3D hotends and they look great. I don't think I will be able to put it into the current extruder housing. Any tips where I could find parts to print housing that would suit my printer?

I will definitelly have a look at stabilizing X axis. Thank you very much for the tip.

Here is one example of the print:

[twitter.com]

At the very top the print gets ruined, because the fan working can't cool quickly enough and the previous layer does not get cool enough to keep the shape so the spherical hot end smudges it.

Also, I can print at 0.2mm layer height, but the print gets this yellowish color. Not sure why this happens and I could live with my current setup if I could get this issue sorted.

It's been a lot of Slic3r parameter tweaking until I got to the point where I can make shapes even though the walls are not very even.

Have you tried changing the the "Slow down if layer print time is below t seconds" settings in Slic3r?

adavidm

Hi adavidm,

I tried so many things that I don't even rememeber :-) What would be your suggestion? Should I disable it alltoghether?

I currently have "Slow down if layer print time is below" 30 seconds
Min print speed: 10 mm/s

Arvy

The easiest way to improve printing small details at the top of a print is to print two of them side-by-side, or print a column at least the same height as the object you want printed well, at the same time. It gives each layer time enough to cool before printing the next.

Re printing at 0.2mm layer height, it sounds like there's too much heat getting to the print. Maybe increase the speed, or lower the print temperature.

Re mounting an E3D, what kind of extruder do you have? A greg's hinged accessible works well and the scad can be modified readily to suit an e3d. If you let me know what you currently have (a picture would help) I'll see if I can find / sort something out for you.