problem of part geometry

[GRIZET]

Hello, I am a professor of mechanics at ENIT (National School of Engineers of Tarbes) in France
I have a Rodstock Delta since juanury
For the moment, it does not print quite good geometry. That's about it I'm looking for help on this forum.
I do not know too much or post my request on this forum (especially since English is not my first language ... and I'm not familiar with forums)
I can illustrate my problem, I hope you will guide me to the forum
The best thing is to show you my picture problem: I have the outline of my pieces that do not follow the fill area. I think the filling area is right but the outline is slightly separated by place and it's not going right
Is anyone has any idea why this default?
Thank you for your help
Francois

[Polygonhell]

Looks like something somewhere is binding, or you have a tremendous amount of slop somewhere.
First thing to look at if this is a V1 are the UJoints, they tend to seize if they weren't lubricated during assembly, testing them all is something of pain since it involves removing each end of each arm and checking for easy motion.
The next thing to check is belt tension, this is IMO hard to describe! it needs to be tight enough to take the slop out of change in direction without being too tight so as to excessively load the bearings in the stepper motor.
Cheap skates need to be just tight enough to take out the slop without compressing the extrusions.
I find with mechanical issues like this the easiest way to diagnose is to move every thing by hand and see if there is unexpected slop, or resistance.

I just re-read your post, is this an original rostock or a rostock max, if the former, you can ignore most of the above, because most of the mechanical components are different.

[GRIZET]

It is indeed a Rodstock max.
Thank you for your reply, I will try to relax the belt and lubricate shafts.
It is possible that the rails are set incorrectly because it seems to me that there is a lot of freedom.
I did not follow the assembly of the machine (I told students in a project), I do not think U joints were lubricated, should we do it? and with what?
Sorry for my english, it's not so easy for me to talk about technicals problems en english.

[Polygonhell]

I used lithium grease on the shafts, but almost anything that prevents seizing should be fine.
The cheapskates should be free to move vertically, but without play in the other axis, people tend to over tighten them because they don't understand how easy it is to deform Aluminum. If they are overnight, you can end up with tight spots in the motion, because part of the extrusion is deformed, just loosen them off a little and run them up and down by hand to even out the motion.

[GRIZET]

ok, thank you very much, I'll try it as soon as possible

[GRIZET]

Hello there,
Here is the latest news of my Delta printer.
I removed all the links and I lubricated This greatly arranged geometry as can be seen in these two pictures (front and back of my test piece Free)
There is still the defaults notament in the corners. and the quality of the layer laid on the glass.

[GRIZET]

Then I did it again the adjustment of zero (which is very difficult on the entire bed) to ensure that the first layer is good, then I re-tensioned belts because I seemed that the problem of defaults in the corners were due to a lack of precision in the catch-up game Finally, I used a fan which further improves printing. So here is the result that satisfies me. I do not expect to arrive at a better result with this machine. In any ca thank you again "polygonhell" for advice, it's a bit thanks to you that I came to this result.