According to someone on this forum the j-head fit (but loosely) in lawsy's mk4 extruder replacement.

Edit: I have no idea if a 0.5 mm nozzle might be better. I ordered mine with 0.35 mm nozzle.

Spent so much time trying to improve it, get things tuned, etc, and I can't get any correct print anymore.
I even switched back to stock extruder, but after 10 minutes or so it doesn't extrude anymore, rip the filament and mess up everything.

I'm just fed up, there is always something wrong.

Thomas.

Seems nice ... but what nozzle size to order?

SD stock is 0.35mm, but it seems J-head standard is 0.5mm, is it better ? (increased flow ???).
The thinnest wall I design are 1mm, is 0.5mm ok ?

Do you know where to find them in stock in EU ?

I'd have to design a new holder to fit them.

Thomas.

Hello,

I'd be very interested to play with better hot ends (reducting the hot chamber size seems a good idea, less melted plastic, but on the other hand you have to melt it faster).

What are those j-heads everybody is talking about ?

Thomas.

Here's some information about the j-head hot ends: http://reprap.org/wiki/J_Head_Nozzle
On the RepRapWiki there's also a list of supplies.

I'd be very interested to play with better hot ends (reducting the hot chamber size seems a good idea, less melted plastic, but on the other hand you have to melt it faster).

What are those j-heads everybody is talking about ?

Thomas.

Thanks for the writeup Otatiaro!

Also: I'd recommend thingiverse to upload the STL and maybe the source CAD files for your mount.

The limit on speed is more about the extruder at this point than the XY movement.  It has to be able to push the filament through that much faster to keep up with the XY speeds.  That means melting the filament quickly.  You can do that with higher temperatures, but you have an upper safe limit, and extruding too hot can reduce print quality if you can't get the filament cooled down quick enough.  Or you can design the hot end in a way that the melt zone is small- less filament has to be melted at a time, and the solid filament has less squishy melted plastic to push against so it can drive the extrusion more effectively.   The stock nozzle on the SD may not be the best for high speeds, so once you have the Bowden working the way you want, it would be worth experimenting with some other hot ends.

Hello,

Here are my Slic3r speed settings :

And the result :

Thomas.

Very nice looking print.

For the bowden :

- print airstripper (modified) extruder
- get the screws (fixnvis) / bearings (1001roulements) / PTFE tube + connectors (reprapworld.com)
- print my hot end holder + accessories (don't know where to put the files though, and what format do you prefer?)
- disassemble the normal extruder, take the motor, hot end / thermistor, etc, and put it on the airstripper extruder
- print

No need to update firmware or anything ... just a few settings to tune on retraction.

The TI drivers : http://www.pololu.com/catalog/product/2133
Drop in replacement for the stock (allegro) ones ... it's a nice upgrade, if you know what you are doing with the current setting (pretty much needed for the bowden extruder, at least on the extruder axis, the bowden tube is a bit harder to drive than the normal extruder for the stepper, with stock driver I got some missing steps).

Don't touch the Y axis sliders if it's working correctly ... it's a nice mod (I still have to replace the other end of the belt with bearings), but it requires quite a lot of work and you can definitely destroy your SD with the dremel.

The bowden mod is nice, you get a much better finish with good print times, but it's also a bit more difficult to operate efficiently, do it if you know what ou are doing.

I find the bowden mod a lot easier to maintain though than the stock extruder, 2 screws to remove the whole hot end bloc, more visibility, etc.

I'm using my bowdendoodle for work for I needed a certain level of precision, that's why I did these mods. If your new to 3D printing, my advice is to get used to the techniques, know how everything works, play a lot with settings, etc, then you'll know what mods you need. I also wanted to mess with it as much as possible because I plan to use it to design something quite similar (not a 3D printer, but XYZ movement too, just with a different head) so it was experiments on the possibilities of the steppers, etc (the NEMA11 on the X axis is a mistake, should have been a NEMA17 ... mine runs at more than 100°C !).

I think the final cost of my solidoodle with the mods is above 1k€ ... that's a lot for hobby use, but well ... it's already paid with the few things I did with it.

Thomas.

printed new extruder head and brackets
moved extruder to back of SD and mounted stepper motor and motor frame
mounted existing nozzle to new extruder head
ran temp and heater leads back to extruder (new sensors or just extended old ones?)
then tubing and couplings for filament

just update firmware for new settings?

what is all this TI allegro stuff? You replace your Ardunio?

then you also upgraded the y axis linear bearings?

you have a parts list

thanks sorry for questions

Jim

Here are my Slic3r speed settings :

And the result :

Thomas.