[hoss2006]

pardon me if this has already be asked but do you plan on using flex couplers?

if so, do you think you will have issues with Z resolution due to the springy nature of the coupler and all the weight from above?

when I built my Prusa i2 I swaped out the printed (nophead) couplers for these and found them to be too springy and added thrust bearings below the coupler to stop it along with a motor lift thingy I made to hold it all. see pic

yes I pretty much have the same couplers ordered.
Difference between this printer and the prusa is the coupler's at the bottom so the normal mode of operation will be to crush the coupler.
If it still feels springy Ill either make solid ones again or epoxy these so they can't compress.
Hoss

[hoss2006]

Machined the lower Y axis carriage today and it fits.
Ordered some 62 oz/in steppers too for the x,y and z's.
I have some 48 oz/in like on the prusa but I'll use them for the extruders.
Hoss


[ame=http://www.youtube.com/watch?v=Wo42Zz2BKag]OB14 3D Printer Assembly Part 3 Y Carriage - YouTube[/ame]

[Xnaron]

Machined the lower Y axis carriage today and it fits.
Ordered some 62 oz/in steppers too for the x,y and z's.
I have some 48 oz/in like on the prusa but I'll use them for the extruders.
Hoss


OB14 3D Printer Assembly Part 3 Y Carriage - YouTube

Looks great Hoss! IMHO you really don't need the middle rail in the Y sled. There are really no forces acting on it and I doubt that the aluminum you used would sag.

[hoss2006]

The 3rd rail is for more support for the rails themselves.
The 8mm rails that long do have some sag so tying 3 together will be stronger.
If I were to redesign the frame I'd make it to use 10mm rod like the Z, they are much stiffer.
Hoss

[hoss2006]

Now that I look at it I ordered some more 10mm rod and bearings for the Y before I get in too deep.
Hoss

[arizonavideo]

I grabbed 4 of the 62oz steppers with the .9 degree (400 count) stepping angle and they are surprisingly powerful. The were running on a G251 at the full 2.2A 50V

I did find a new driver chip that will plug into the Pololu socket. They rate it at over 2A RMS. It is still so tiny but it should be better that the around 1A you get from the the A4988 chip.

Pololu - DRV8825 Stepper Motor Driver Carrier, High Current

I have the driver but can't test yet as my Mega board is not here yet. I have no idea if you need more power to run these things.

[Xnaron]

The 3rd rail is for more support for the rails themselves.
The 8mm rails that long do have some sag so tying 3 together will be stronger.
If I were to redesign the frame I'd make it to use 10mm rod like the Z, they are much stiffer.
Hoss

Yeah I used 10mm on the Behemoth for the Y.

[diyengineer]

Machined the lower Y axis carriage today and it fits.
Ordered some 62 oz/in steppers too for the x,y and z's.
I have some 48 oz/in like on the prusa but I'll use them for the extruders.
Hoss


OB14 3D Printer Assembly Part 3 Y Carriage - YouTube

Where did you grab your kit from? Since yours is larger, will you have the plans on your website?

[hoss2006]

The "kit" is on thingiverse.
OB1.4 open beam 3D printer by Wired1 - Thingiverse
He just posted it last month and is still a work in progress.
I'll share my specs when I'm finished, I've already remodeled several parts as I go to tweak them.
Hoss

[Fastest1]

Hoss, I have been having nothing but fun with my RepStrap

[hoss2006]

I can see that, congrats!
Hoss

[Fastest1]

Thanks. I was curious, the print in that picture I posted was running a .5mm nozzle with a .36 layer height in Slic3r 0.7 @216-220C (Black ABS) bed at 75-85C. I am running the nozzle .06-.08mm above the heated bed. The bottom is perfect, almost looks like CF. The sides and tops though bonded well, leave a little room for improvement. The sides get an almost geometric effect in the pattern. Is this due to too low extruder heat? The swirling as it is leaving the nozzle cause this? It doesnt seem to change with speed. Of course each layer is very visible as I would expect with any layered deposition technique but I am searching for improvement in all areas. I have been needing to calibrate the extruder but I cant seem to turn it off long enough as it is very close now. The stringing has been almost non existent. Thanks

[hoss2006]

Could be resonance from the steppers, try changing the microstepping.
Is this a model you made yourself?
I know with Aibre I can adjust the stl output for normal deviation, a small number gives high resolution but big files,
a higher number gives a more faceted look but smaller file size.
Hoss

[Fastest1]

I will look into the microstepping. I am running 1/2 microstepping on a direct drive Nema 23. This is my A2ZCNC mill with RepStrap (read a combo of everybodies) extruder head. Btw it flows very smoothly in the air at all temps between 190-220C.

[hoss2006]

Looks very cool!
Yeah, I run 1/8 microstepping with the ramps.
Hoss

[hoss2006]

The X and Z axis endstops are made.
I changed the x trigger to a sold bolt, doesn't need to be adjustable like the z with a spring.
Hoss

[ame=http://www.youtube.com/watch?v=CllnjvoZfr4]OB14 3D Printer X and Z Axis Endstops - YouTube[/ame]

[hoss2006]

Made supports for the Z leadscrews since the helical couplers are just squishy springs and to take any load off of the steppers.
Using a typical 8x8 heatbed till the 12x12's get in stock.
Got the bed pretty much done, it's getting close.
Good because I have a couple micro printer ideas I want to do next.
Hoss

[ame="http://www.youtube.com/watch?v=H9hdEz-Ytmo"]OB14 3D Printer Z Leadscrew Supports and Heatbed - YouTube[/ame]

[SixOfOne]

Looks like a solid fix for the springy-ness of the couplers.. nicely done Hoss

[hoss2006]

Thanks, you were right about those couplers, not much good without supporting the leadscrew with bearings.
Hoss

[hoss2006]

Anyone interested in the files for this printer can get them on my thingiverse page.
Hossmachine OB14 3D Printer by Hossmachine - Thingiverse
Hoss