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First Printing Problems  

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christoph.r2
(@christoph-r2)
Active Member
First Printing Problems

Hello Everybody,

my wife and I got our Prusa Kit last week. We assembled it and "passed" all the calibrations. We did some printings, and well... we are happy, that the printer is working, but they could look better!

At first our prints didn't stick to the bed. So we did some live-z calibration and I think we are now using values around 0.300. The frog (pic1) turned out quite well. But the bottom looks totally wrong (pic2). We are not sure if this is because z-axis is too low (and the material can't come out of the noozle) or if the z-axis is too high.

We then printed a kitty-ring (pic3) and noticed that the first and last layer (if it is horizontal) look so strange.

We did another printing of a self designed wall-part and had the same effect (pic4 and pic5). In addition the print didn't stick correctly to the bed (pic6).

Thank you very much for helping of pointing me to another thread, where I can find some help!

Veröffentlicht : 29/08/2017 8:07 pm
christoph.r2
(@christoph-r2)
Active Member
Themenstarter answered:
Re: First Printing Problems

Here are the other three pictures!

Veröffentlicht : 29/08/2017 8:08 pm
JeffJordan
(@jeffjordan)
Mitglied Moderator
Re: First Printing Problems

still a first layer issue ! have a look at this thread.

dem inscheniör is' nix zu schwör...

Veröffentlicht : 29/08/2017 8:57 pm
AJS
 AJS
(@ajs)
Noble Member
Re: First Printing Problems

Yes, the curling, and issues are related to the first layer. Try these steps:

http://shop.prusa3d.com/forum/prusa-i3-kit-building-calibrating-first-print-main-f6/-before-you-ask-troubleshooting-video-updated--t472.html#p39190

If that does not help, please comment back here and we can see what we can figure out.

Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage or loss. If you solve your problem, please post the solution…

Veröffentlicht : 30/08/2017 1:59 am
christoph.r2
(@christoph-r2)
Active Member
Themenstarter answered:
Re: First Printing Problems

So thanks for your help. We did some calibration and worked out some Live-Z-Adjustment where the first layer looks way better thank before.

I have added one photo of the bottom of a part that I just printed. The problem is, the outer ring come off from the bed after roughly 70% of the model is printed. But the inner square sticks so well to the bed, that I am afraid to damage the bed, when removing the model. This also causes the whole model to come out of shape, which makes it pretty useless.

We were also not able to get better resulsts for the final top layer. It still has holes. Any chance that it will look like the bottom layer I just posted?

Veröffentlicht : 03/09/2017 1:50 pm
AJS
 AJS
(@ajs)
Noble Member
Re: First Printing Problems

That first layer looks okay to me (but it is hard to tell from a picture).

For cases where you have small surface area, add BRIM to the print. That will keep it stuck to the bed, and will require a little bit of post print cleanup.

The holes on top look like an extruder issue. Either a small clog, or a bad calibration, or a slipping pulley, or constrained filament that causes resistance, or ...

Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage or loss. If you solve your problem, please post the solution…

Veröffentlicht : 03/09/2017 5:03 pm
christoph.r2
(@christoph-r2)
Active Member
Themenstarter answered:
Re: First Printing Problems

Thanks for your help aaron!

Top Layer Holes
I changed the top layer infill width from 0.4 to 0.3 and it Looks much better now. But I only tested it on a calibration cube. Not sure if this applies to only the final layer, or every horizontal layer.

Print loosening from the bed
I remember some learning Video from Josef, where he was saying only to use glue if your model is very tall and has a small surface. The model I printed is about 5x5cm and only 1cm tall. Almost the complete first layer has contact with the heatbedbed. If I need to glue this model, I will need glue for every print.
Additionally, like I've already said before: Everything that sticks to the heatbedbed, is incredibly hard to remove! I had to twist the print above as hard as I could, before it came off the bed. I don't like the idea to add glue!
Another thing is, I alway thought the heatbed would cool down, as more and more layers are added. But it just stays at 55°. Even if you print 100layers on top. So if you have printed 100 layers, let's say layer 50 already cooled down completely, but layer 1 still has 55°. I'm not an expert, but isn't that temperature difference already enough to deform the print and cause it to come of the heatbed on some places? The print above started to come off the heatbed when alread 0.8cm of the print were finished. So it's not like, it's not sticking to the heatbed at all.

Veröffentlicht : 04/09/2017 9:19 am
AJS
 AJS
(@ajs)
Noble Member
Re: First Printing Problems

1) You do really want them to stick good, and you don't want to remove them by twisting the model 😯 you want to get under them with a tool and pry them up. There are tools for sale for this purpose, but they are just very thin spatulas with rounded corners (to prevent gouging the PEI surface). Some people say hard plastic to prevent PEI damage, other say use metal with care. Some people use dental floss. This will help you a lot.

2) Glue Stick is an interesting thing. It ADDS adhesion when you have too low an adhesion, but it reduces adhesion when you have bonding since it is a barrier layer. For example when printing PETG it will absolutely FUSE to the PEI. Semi-permanantly. Glue prevents that. You might want to try it, but frankly, with a good clean bed you should really not need it with PLA unless the model has a very small base and is tall. I like the Elmer's purple.

3) It sounds like you have some parts sticking, and other parts are not. Which makes me think it is a contaminant on the bed. But your prior discussions indicate that you did a real good cleaning. I recommend very pure IPA, but in cases like this I do windex followed by acetone followed by IPA. But I know you read that in the other thread.

4) Are you printing with Z-Hop or Z-Lift (two names, same thing)? Is there anything that might be BUMPING the print? e.g. PINDA probe too low, or Extruder cable bundle hanging too low?

5) Adding Brim (or Mickey Mouse Ears) is also a good way to get adhesion increase on models who's geometry just wants to contract and pop off.

6) I think Jeff has commented that prints with many walls and solid infill tend to shrink more and cause curling which can pop them off the bed. What are the wall and infill settings on your model?

Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage or loss. If you solve your problem, please post the solution…

Veröffentlicht : 04/09/2017 3:38 pm
christoph.r2
(@christoph-r2)
Active Member
Themenstarter answered:
Re: First Printing Problems


[...] Some people use dental floss. This will help you a lot.

Well, don't know why I didn't think about that. Thank you for the tip. Will try it on the next print.


2) Glue Stick is an interesting thing. It ADDS adhesion when you have too low an adhesion, but it reduces adhesion when you have bonding since it is a barrier layer.

Sounds about as logical as your first point. For now I will try to prevent glue, but it will probably need your tip at some point of time.


3) It sounds like you have some parts sticking, and other parts are not. Which makes me think it is a contaminant on the bed. But your prior discussions indicate that you did a real good cleaning.

Are you sure, you don't confuse me with somebody else? I have never participated actively in any other discussion in this forum. But we do use small wipes, that are infused with IPA. I could also try some windows cleaner before that. I will also test this on one of the next prints!


4) Are you printing with Z-Hop or Z-Lift (two names, same thing)? Is there anything that might be BUMPING the print? e.g. PINDA probe too low, or Extruder cable bundle hanging too low?

We are using Lift Z "0.5mm". I didn't change that value, so it is probably a standard value in the Prusa Slic3r. Should I change it?
The Pinda Probe is higher than the extruder tip. We calibrated it like in the tutorial video. (Putting a zip tie between the probe and the heatbed). I also think the cables are okay, but I need to check them moving during a print.


6) I think Jeff has commented that prints with many walls and solid infill tend to shrink more and cause curling which can pop them off the bed. What are the wall and infill settings on your model?

Perimeters is "2" - this was already set in the Prusa Slic3r, although it says standard is "3"
Top and Bottom Shell was "6" and "5". I lowered both to "3" (as this was the standard) with no visible effect.
Infill settings were 20%. I lowered it to 15% but that caused some small defects on the edges on the calibration cube.

Thank you for your help! I really appreciate the effort you put into this!

Veröffentlicht : 04/09/2017 9:25 pm
AJS
 AJS
(@ajs)
Noble Member
Re: First Printing Problems

Yes, I was confusing you with a different thread. Sorry. My bad.

I have NOT found the little wipes with IPA to be effective. I use a bottle of IPA (as PURE as you can get - the other additive may leave a residue which can prevent adhesion) and some paper towels. IF there are oils or other contaminates, I clean with Windex, then acetone, then IPA. This really gets the PEI back to new. I re-use the paper towel for quite a while. Helps to rub well.

Yes, that Z-Lift is fine.

Those model parameters seem fine too.

Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage or loss. If you solve your problem, please post the solution…

Veröffentlicht : 04/09/2017 10:23 pm
christoph.r2
(@christoph-r2)
Active Member
Themenstarter answered:
Re: First Printing Problems

I did another print of the above model. I did the following:

- changed the infill from 15 to 25%
- changed the infill for horizontal surfaces from I think 0.4 to 0.3
- I cleaned the heatbed with glass-cleaner, then with IPA-wipes
- And I also used the variable layer height

Again the model was incredible hard to remove from the heatbed, but it only lifted a little on the corners during the print. I tried to remove it with some sewing thread, and managed to damage the film a little bit with it. Should have used dental floss...
The top surface (it's some stone-floor-template for tabletop gaming) looks really good. It's a little bit bended, because it came off on the edges, but I am more than happy with the result. I will try glue on the next print and I will buy some scraper and some dental floss, for removing the model.

But right now I think the printer runs fine.

I just noticed one last small thing. During retraction of the nozzle, the printer leaves some small "tail" of filament. I would have added a picture, but it is really hard to see on a photo. Can I do something about it?

Once again - thanks for helping!

Veröffentlicht : 06/09/2017 12:55 pm
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