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J'ai oublié : il faut proscrire le ventilateur axial pour pousser dans un tuyau : il ne permet pas une pression suffisante ; le ventilateur radial (tangentiel) est bien mieux. C'est ce genre de ventilo qu'on trouve dans les hottes, les VMC, etc...
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fma
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RepRap Groupe d'Utilisateurs Francophone
Salut,
Le montage que j'avais publié sur Thingiverse fonctionnait, mais était mécaniquement trop faible, et n'a pas duré bien longtemps.
Par contre, la pompe d'aquarium fonctionne pas mal, mais il ne faut pas vouloir refroidir comme un bourrin ! En fait, j'avais étudié ce genre de solution pour l'ABS, où il faut justement éviter de refroidir toute la pièce, au risque de la voir se décoller à ca
by
fma
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RepRap Groupe d'Utilisateurs Francophone
Thanks for this complete answer! If I go that way, I will use a dedicated board to monitor the FSR, like John's trinket board.
Did anyone tried to mount the FSR on the hotend, instead of the bed? This is something I wanted to try for years, but never did... The problem is to maintain the hotend, and allow it to change the resistor of the FSR when hitting the bed.
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fma
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Delta Machines
Yes, sure. But is it a reliable method? Or does it introduce some issues?
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fma
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Delta Machines
Is the FSR (Force Sensor Resistor) under the bed a good solution for bed leveling (and printer calibration)? What are the pros/cons?
I like the fact that this is the hotend itself which is used to touch the bed, instead of an external switch/optical/inductive/capacitive/whatever sensor, introducing error... No more problems when chnaging nozzle, or when you just remove the hotend after jamming o
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fma
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Delta Machines
QuotehercekThat seems to be what people seem to call forward for reasons I newer understood. Why it should be called forward when the direction we primarily need is the other one?
Well, forward is defined from actuators to cartesian space; same notation is used for robots. But your're right, this is mainly the IK we are interested in.
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fma
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Delta Machines
Quotedougal1957If you can wait till later today or early tomorrow I can sketch one out for you with some measurements on the sketch for you?
That would be great! It is not urgent at all, so, I can wait longer...
Thanks.
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fma
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Delta Machines
Thanks!
I think what is important is the position of the concurrent points of the horizontal arms relative to the center of the vertical arm (upper and lower dimension on the drawing).
by
fma
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Delta Machines
Hi!
I plan to use metal corners to build my future Delta 3D printer, from robotdigg company.
Unfortunately, they don't provide any top view of there products, which is a little bit strange, as it is mandatory to determine horizontal length profiles.
So, does anyone have top view (as DXF or just image with dimensions) of these products:
(for both NEM17 and NEMA23, but I think they are the sa
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fma
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Delta Machines
Nice maths!
Are there curves, somewhere, showing the resulting errors on the movements, depending on the different errors that can be encounters, as described above (for standard vertical towers, not titlted ones)? I've no idea of the order of magnitude of all this...
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fma
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Delta Machines
Compared to the standard profiles, like 2020 Motedis I-profile, is Openbuilds profile better? It has maybe a better contact whith the wheel?
BTW, I also plan to use excentrics...
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fma
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Delta Machines
Quotefma
Like these?
Are these profiles better, in combination with the above wheels?
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fma
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Delta Machines
QuotefmaWith tilted towers, it seems that arms remains more // to the towers in every point (didin't check with maths), so accuracy should not change as much as with vertical tower, from center to edge of bed.
This may also be better to prevent effector tilt? Especially under lateral load (spindle usage)?
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fma
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Delta Machines
So, it will be more a calibration machine than a 3D printer
With tilted towers, it seems that arms remains more // to the towers in every point (didin't check with maths), so accuracy should not change as much as with vertical tower, from center to edge of bed. But as you explained, other problems make this point irelevent.
I agree with metal corners; I will also use them, rather than printed
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fma
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Delta Machines
Quotehercek[...]If you are very advantageous then go for about Ø 1.5 mm steel cable. But in this case you need big diameter drums to minimize impact of the errors because of varying position on drum. And that means you probably need a speed reduction from stepper to the drum.
What accuracy do we need on the axis?
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fma
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Delta Machines
Quotedc42I have only even used Delrin wheels on aluminium profiles, and they work well for me.
Like these?
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fma
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Delta Machines
Thanks, DC42; I'll dig that solution...
O_lampe, I plan to use 40x20 aluminium extrusion as vertical arms, and put the rods on each side of the 40mm lenght. So, I will have more than 80mm between rods...
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fma
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Delta Machines
I'm wondering: does this design reduce the non-linearity, and so simplify the tuning?
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fma
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Delta Machines
What are the feedbacks on the linear systems using plastic wheels on aluminium profiles? I see that on some commercial 3D printers, but I wonder if it provides good long term accuracy...
It is a very simple design, and very cheap compared to rods/ball bushing.
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fma
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Delta Machines
Quotehercek
In my opinion, the only reason to prefer delta to coreXY is the high printing speed. Otherwise delta has only disadvantages. It needs more powerful/expensive controller, it is harder to calibrate, and it is taller. But if you want a delta for the fun/challenge of it then go on
Well, I find it simpler to design: only 1 axis, repeated 3 times. About controller, I'm waiting for a Repli
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fma
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Delta Machines
Quotedougal1957The Arms should not be less than 20 degrees to the bed at the farthest extent of there travel and should be as wide apart as you can get but aim for no less than 45mm (that is around 40 mm wide fixing points on the effector/carriages which is the std for the Kossel if you can go wider then you will have greater rigidity)
Thanks for the tips!
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fma
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Delta Machines
