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Hello!

 

As you can see in my picture(s) i have bad overhang at the bottom of my prints. If i would design a model, where you wouldn 't  even notice it was there, there would be no problem. But.. . what if the disign requires to look good at both sides of the print. I have had contact with the designer of this model and, he gave me some tips about tuning my pids. But i don't think i can do that. Can anyone help me please?

 

Greet Raimon

20180917_124406.jpg

20180917_124506.jpg

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50 minutes ago, RaimonElctrncs said:

I have had contact with the designer of this model and, he gave me some tips about tuning my pids. But i don't think i can do that. Can anyone help me please?

 

Why do you think you can't do that and what tips did you get?

 

I would say, print cooler and you want to cool the layer as fast as possible, so check fan speeds.

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Hello Smithy,

 

I want to thank you for your fast reply. Great!

 

The tips i get were in this guide he made himself: https://3dnation504795197.wordpress.com/guide/#pidautotune

I'm just a simple man who can't (and won't) change g-code, because i don't know what i'm doing in that way. 

 

My fan speed is at 100%. And i'm printing with Ultimaker material  at 210 degree Celcius.

 

Don't get me wrong, actualy i'm pretty happy with the result i have with this test. I was just wondering if there was a way to fix the bottom overhang at 80 degree (as shown in the picture). But the answer i got was to complicated for me. So.. . printing lower than 210 degree using PLA is a good tip. Using my old printer i printed PLA  at 200 degree celcius. So i wil try that out.

 

Thanks

 

Greet Raimon

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I can sometimes even go as low as 182degrees with pla but thats pushing it. Quality gets better, but its the balance of printing as low as you can with good layer adhesion is what you are after...experimentation. i now print everything at 200 btw... but i feel ill go lower on my next job...

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I generally use the same settings for all pla, maybe dropping or raising a few degrees here and there but i mainly use colorfabb pla/pha and use an ultimaker2 and ultimaker s5. Same temps on both machines. I never print pla above 200. But then again I almost exclusively print at 0.06 layer height! Even at 0.1 layer height 200 should be fine at 30mm/s, you might even get away with lower. Internal wall i print at 70mm/s though, having an overall higher temp to balance the speed difference. Large objects may not fair so well doing these vast speed changes though but i have had no real issues so far, just quicker prints. 

 

I print outerwalls slow to avoid ringing as much as i can btw! 20mm/s on the um2 30mm/s on the s5.

Edited by cloakfiend
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No problem! and i know a lot of people may disagree here, but i find those overhang and bridging test prints kind of pointless. In reality youll never print that kind of stuff for a client and the shape of an object plays a large part in how it prints so you learn from experience where things go better or worse than expected.

 

The first test and in my experience the only real test you NEED to do is to kick of a print and to SLOWLY decrease the temps until issues arise, (basically 1 degree at a time). 

 

That will tell you the minimum temp for your particular layer height and speed you are using. Any time you increase speed or alter the layer height, simply repeat this procedure and youll soon find a general ball park of where you can play around in. 

 

But take you time and dont rush the temp drops. Also make sure you are starting with a perfect unblocked nozzle and perfectly functioning machine otherwise things may eventually go into random territory where other factors start playing a part. And from a testing point of view you only want to be adjusting one setting at a time!

 

....and thouroughly examine your model afterwards for poor layers as sometimes they look deceptively perfect!

Edited by cloakfiend
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Hello cloakfiend!

 

Yes i totally agree with you that the way  testprints are designed, you won't find that kind of stuff in daily 3D models. I have filed your tips in my computer (on my desktop); i can easily acces them this way. 

 

Greet Raimon.

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Concerning this testprint: undersides of overhangs are printed half in the air, so they partially sag or fall down. You can not totally avoid this without support. Printing cooler and slower, and using thicker layers, will somewhat reduce the effect, but not eliminate it. But thicker layers reduce details.

 

I agree with cloakfind that this test print may not be representative for the real print. Optimal print settings often depend on the actual model. Test prints like these are very good to find the limitations of the printer, and to try the effect of different settings (fast/slow, hot/cool). You should do them to gain better understanding of the printing process and of all variables that play a role.

 

And then, based on this understanding, select the best parameters for the real print.

 

If you are still unsure, try this: cut out the most critical parts of the model in your 3D-editor (such as overhangs and fine details), and save them into a new model. And then only print these difficult parts with different settings to try which works best. In thisway you don't waste too much time and material.

 

Or design your own test model that exactly mimics the critical parts in the real model. Make sure layer printing time (and thus layer cooling time) is similar to that of the real model, this has an effect on quality for small models.

 

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Hello,

 

I posted this topic because, the given solution to the problem of my print in the picture was too diffucult to understand for me. Something about tuning pids and g-code (my english isn't the best). So i had this idea of posting it on this forum. And i found out that there is a easier explanation. This to solve the problem if there was one in the first place; because this testprint isn't real printing-life.

 

So i want to thank all of you for your answers. They were more than welcome and, i definitely learn something.

 

Greet Raimon

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....as for support, im veering on giving up on it totally. Just cant trust it amymore. Time to go manual or hope cura gets smarter about it. As the current support methods are completely unreliable as 'support' once they reach a certain height using high resolutions. Ill post my easy manual support fixes once i get out of bed, i've been ill for the past few days. It came out ok-ish but im getting a bit fed up of seeing this on the regular. 

 

....I might just be annoyed as ive been ill for so long and been bedbound. But i still dislike these tall unsupported supports. Its just asking for failure.

20181001_115847.jpg

Edited by cloakfiend
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Try the conical and tower options. Basically, get a bigger base that tapers. Even when I use PLA I do not get the failures I see here. And, PVA is a flimsier material and I only get failures on moisture invasion.

 

As for overhang tests, they  do offer decent information such as what angle your printer starts to fail on the underside. If I know what angle things fail, I know what angle to use as the default before supports are generated. Also, you do find a lot of information that can be used in real world situations, especially if doing organic modeling that changes angles constantly.

 

When putting in an angle in the support section, the red area that lights up is falling within the gamut of failure.

 

At lest I derive information from them.

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After pulling the stick out for a while then putting it back....the files mysteriously work again???  A short in and out didnt work.... I guess the files are referenced in memory somewhere that got temporarily corrupted? I dont know whatever...they work now.

20181001_140011.jpg

Edited by cloakfiend

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Ill still post some nice overhang support helpers that are light on material and easy to remove....ish lol. Sorry for the hijack and going off topic!!!! I tend to do it a lot without realising!!!

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