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Cura G-code problems


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Posted · Cura G-code problems

So I am relatively new in this 3D printing stuff. I learn new things every day. But I primarily depend on Cura for my G-code and I am just lost on some really odd decisions when it comes to Cura creating the path that the print head will follow aka G-code. I am printing with PLA on a Tevo Tornado and use mainly stl and obj files from Blender, MeshMixer, Tinkercad.

Do mind that I fully understand that this is a free software and I have no "right" to complain. I din't come here to nag anyone, or to claim that I understand what is going on, or that I know how it can be made better! I came here to ask for help or guidance. I lay down the problem that annoys me and then I ask the question HOW? Nobody owns me anything and nobody is responsible for my troubles. It is the troubles that pain me and cause me grief and not the developers of the program. So chill. (this is for those who take it quite personal. I had that before.)

So what exactly is my problem?

1.

Let's print something. Anything. I open Cura, make my adjustments, save to card. On the printer - the head makes it trough the first layer - maybe we will have a successful print! It prints the object walls and it prints supports, THEN THE HEAD MOVES DIAGONALLY TROUGH THE WHOLE PRINT AT MAXIMUM SPEED WITHOUT LIFTING AND MAKES A TERRIBLE SOUND AS IT TRIES TO RIP OFF THE SUPPORT! Which eventually it does and it my print is destroyed.

So I go trough the settings and all the Youtube videos and I find that I must use Z hop and also avoid support when traveling. I wonder why is it not ON by default, but never mind. Easy - I try again, and it makes NO DIFFERENCE! So I look some more and find out that Z hop only works over the print walls, but not the supports??? And avoiding means the head travel to the side of the printed areas... So I look some more and I find that I must use combing mode within infill.. And I now I have the world's most annoying sawing machine that goes up and down on every single dot that it tries to fill.

So why does Cura create a G-code path that elevates a layer and then tries to run the head right trough it to go to the other end of the print by default? And how do people get over that?

2.

Path optimization. Right off the first layer throughout the whole print it is easy to see that the path is ...not ideal. It prints to some extent and then goes all the way back to the start to print the rest. And more - When I printed my first benchy there was a small mid-layer shift  - I thought something is off with the printer. It wasn't bad. But my next benchy printed EXACTLY the same. So the printer was fine - the G-code was making it look weird. After reading some and watching some and following the print head simulation I found that it must be the way Cura decides where a new layer begins  There are options on deciding how it should approach that decision, but they all work equally as weird. Right now I am printing a sphere to test my fan shroud and I am baffled on why such a simple model can't just follow a circle after circle, but instead it goes to some point and then skips a portion, goes all the way around and then goes back to fill in the gap it left before. It is slower, leaves artifacts on the outside and stringing on the inside. And I can't understand why it prints outside walls first (where it has no support) and then some inside walls, and then fills the gap between them. The top portion of the sphere looks better than the lower for that reason, and the part where it skips and goes back to fill up the gap looks bad from top to bottom. That looks like tiny square gaps that I now identify in my previous prints. Now I know that is also Cura's fault.

I just don't understand why it acts that way and can I stop the skipping and use a more orderly fashion of laying the filament? There is an option for that as well in Cura, but it doesn't seem to optimize the travel in every print- otherwise it would be standard.

3.

Printing non manifold objects? No problem! We are just going to stitch the openings for you!

Why? Can't I turn it off? Non manifold objects (corrected by Cura) print just fine if you remove top and bottom layers. But that also removes every single top and bottom layer in the print. And if I give up and let Cura stitch up up the openings my print becomes useless to me, or it just becomes extremely wasteful in print time and material. Why? Because that opening that I don't need is now a huge flat surface that needs support. And then I have to cut all that plus the massive supports away! So I'm left with the extremes - either print everything or nothing!

Cura has absolutely no problem in generating code for non manifolds! But for some reason that is hindered. How can I get around that problem? Make Cura just print whatever I gave it and not care if it is correct or not? Or have an option to select the very top and very bottom layer TO NOT BE PRINTED. Which is incredibly useful for multi part objects that should be opened in the middle.

 

If anyone knows how to deal with these problems, thank you brother! So far my success/fail ratio is pretty bad. And when when the print fails after 24Hrs.... it hurts.

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    Posted · Cura G-code problems

    Hello @id104335409, you have described various problems. To better understand what is happening it would be very useful if you could create a project file and attach it to this thread with a description of what is wrong with that particular project. If you have multiple problems it's better if you create a project per problem. We can then load up those projects and see if the settings could be adjusted to get a better result or if there really is a problem with Cura. Thanks.

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