Yep, mais Il faut 2 alims : une de 5V sur la pin Logic supply et une de 30V max sur Load supply les deux pôles négatif étant connectés sur GND.
Un moteur pas à pas se pilote en position, une impulsion sur "STEP" = 1 pas ou plutôt 1/8 de pas sur ton driver, pour faire varier la vitesse, il suffit de faire varier la fréquence des impulsions "STEP".
merci pour ça je vais tester et je reposterai ici (je n'ai pas encore reçu ma carte arduino)
je vais deja me preparer une alim et un pc avec les outils necessaires installés en attendant.
pour les extrudeurs as tu vu ceci?:
[spoil]Triffid Hunter
On Fri, Dec 16, 2011 at 8:01 PM, glaes...@debitel.net
<glaes...@debitel.net> wrote:
> I would be thankfull if some could point out (or point to sources off)
> some design thougts about extruder heads....
The extruder/hot-end is the heart of our 3d printers. All else being
equal, the extruder/hot-end can easily be the difference between a
terrible printer and a fantastic one.
One of the most critical parameters is structural integrity.
Originally, hot-ends used PTFE (teflon) as a structural element, and
would frequently fail because PTFE "creeps" (slips over itself) under
load. Now we're mostly using the much more expensive PEEK. Don't get
me wrong - PTFE has its place. It makes a fine sleeve for the cold end
of the barrel where friction can be problematic, but it cannot be used
to hold anything in place.
All-metal and mostly-metal hot-end designs are starting to appear,
such as the arcol v4 and the makergear with SS barrel. These hot-ends
exploit stainless steel's relatively poor thermal conductivity to
create a sharp thermal transition while retaining the strength of
steel all the way up to a section that's cool enough for normal
plastics to handle.
It is also critically important that the heat does not go too far up
the barrel. Makergear's standard hot-ends have a brass/PTFE junction
inside the PEEK "groovemount" to prevent heat going too high, and all
hot-ends benefit from a small fan to help keep the top end cool.
Nozzle diameter affects print quality, and the length of the
constriction is important too- too long and your extruder must exert a
lot of force, risking jams and stripping filament, but too short and
you get lots of ooze. I believe this parameter is only starting to be
explored.
As for the extruder, there's a few designs around. Since our extruder
runs a lot (10-300x!) slower than our feedrate, can also require
surprising amounts of torque, and needs to be quite precise for
certain prints, we get a lot of advantage from some gear reduction.
Direct drive does work, but since the motor shaft is only 5mm in
diameter it doesn't have a large contact area with the filament and so
can't impart as much force to it as a geared extruder with a larger
diameter drive member. Putting a large pulley on the motor shaft means
that you simply don't have the precision in terms of steps per mm for
fine detail prints.
Wade's and variants with 4:1 to 5:1 gear ratios and an M8 bolt seem to
hit a sweet spot, and MakerGear's geared stepper (13.6:1) with ~12mm
pulley seems to work as well.
Basically you're going for an overall result of 500 to 1500 steps per
mm of filament. Much lower and you lose useful precision, and much
higher and you'll have difficulty retracting quickly.
Another important parameter are the teeth that grip the filament. If
the teeth are too small, they fill with plastic dust easily, giving
ruined prints. Too large and you can't transmit as much force as there
simply aren't enough teeth contacting the plastic. You also don't want
to bite all the way through the filament! We usually use a tap to cut
teeth into the side of a bolt or whatever, M6 (1mm pitch) seems to
work really well. M3 (0.5mm pitch) is definitely too small. I'm told
that M4 (0.7mm pitch) works, but it's a bit small for my liking.
1mm length of 3mm diameter filament has a volume of 7mm^3. With
extrusion width of 0.5mm and a layer height of 0.05mm, that's enough
plastic to draw a segment (or series of segments) 280mm long! FWIW,
I've successfully printed with those settings using my Greg's
Accessible Wade's, 51:11 gear ratio, a bolt hobbed with an M6 tap and
a Makergear hot-end with 0.35mm nozzle.
SO in summary, the ideal hot-end is very strong and is only hot for
the bottom 10-15mm, above which it cools rapidly. The extruder has
appropriately sized teeth, and a gear ratio that gives a good balance
of precision and speed.
Hope this helps![/spoil]
posté sur le google group de thingiverse,
je trouve ce qu'il dit plutot censé et il te rejoins pour les extrudeurs en prise directe.
je vois bien l'intérêt d'une démultiplication a deux étages mais cela risque aussi d'augmenter le jeu a moins peut etre de passer par de petites courroies, comme celles ci que j'ai récupérées aussi:
[spoil]
[/spoil]
si un nema14 avec la bonne démultiplication fonctionne bien, ça ouvre la voie a de beaux dualheads! (voire trois
)