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gbr1

Trying to run before I can walk!?

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HI All,

So I only got the printer on Friday, had a few successful prints so was pretty happy. I was just printing using the quick print (Normal quality) and got OK results, my main issue was with (not sure of the term) but looks like small over prints or excess PLA when moving from one object to another.

So reading through here I decided to enable the expert settings and with reading through a few posts edit some of my settings to have a starting base.

So when I now try and print (using Ultimaker provided blue PLA) it doesn't look like it laying any (or not enough by a long shot) of filament for the base layer. With the same object if I go back to non expert mode and re slice it it prints fine.

Temps are the same between the two and print speed is the same, I know there are plenty of other factors but all I really changed was the 2 settings in retraction to zero and increase the retraction height to 5.5 as was suggested.

Another 2 quick ones for you guys (sorry). I had an SD card error, so I simply plugged my computer in and did a install default firmware which went fine, but due to my first layer prints looking funny I went to re level the bed and now the print head moves over the glass holders at the front, which i guess should not happen!?

Second is the print time between the cura print time and what it says on the UM2 screen are very different, even when I make print speed to 100%? Not that this is a show stopper just confusing.

Thanks for you help in advance..

GBR1

 

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The was a bed leveling issue that I thought got fixed in later firmware. Are you using Cura 13.11.2? That has updated firmware for the UM2.

It sounds like your first layer height is off when you are using the full settings. I'd be inclined to set it to at least 0.2mm, maybe even 0.3 for the first layer to help it stick, and give you some margin for error in bed levelling. Also, you need to be sure that retraction is enabled on the first tab of the full settings if you want it to be used, irrespective of what you set for retraction on the second tab.

When you switch from quickprint to full settings, the settings do not carry over. So you need to review all the settings and make sure they are what you want.

Print times are a known weak point at the moment. The head accelerates and decelerates at each corner in the print, so the times can be off quite a lot compared to the estimates in Cura which assume constant rate printing, and all at full speed.

 

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Hi illuminarti, gr5

I followed you advise and changed the first layer height to 0.3 and it was the ok. I will continue to play with the settings and see if I can get better prints.

The soft wear is 13.11.2 so confused about the glass plate holders.

With PLA approx what temps are you running for the heated bed, I have been printing at 60 and it seems ok but I did have some small curling. This may have been to poorly prepped bed though using the glue provided!?

Thanks all..

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Second is the print time between the cura print time and what it says on the UM2 screen are very different, even when I make print speed to 100%? Not that this is a show stopper just confusing.

 

Print times in Cura and on the machine are currently inaccurate. It's on my big-items to-do list to do after my current changes (tighter packing of multiple objects) and adding better support for multiple printer connections (to support network printing and improve USB printing).

It's a complex problem, but I know I can solve it, just takes time.

 

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With PLA approx what temps are you running for the heated bed

I'm still a novice. Before the UM2 came out, experts recommend 70C and that is what I used with UM1.

My understanding is if you only care about sticking - 60C is plenty. But if you have curling at the edges - this is a warping effect due to shrinkage, then you need to add "brim" feature in Cura and also 70C is better.

The "glass" temperature for PLA is around 55-65C (depending on color and brand of PLA):

http://en.wikipedia.org/wiki/Polylactic_acid#Chemical_and_physical_properties

and if you can keep the bottom 5mm of your part above 65C then you won't get much lifting because it is too soft to pull up. I think this is why the new Cura keeps the fan off for much more than 1 layer now.

Just make sure the bed cools to 50C before removing your part.

 

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Evening all..

So today has been a day of head scratching. So I mentioned the print bed levelling issue with the glass plate holders, so I decide to delete my copy of Cura and re install and straight away re install the firmware this time with my mac. So it still had the glass plate issue but now when aborting a print I had to manually lower the print bed and home the extruder.

I then re installed the firmware from my PC and it still had the bed level issue but not the abort issue!

I have been having a few issues with the base layer but have posted that in another thread.

gr5 its funny you mention curling as I had this today quite badly. I was printing with bed temp at 60 deg and having issue I also printed at 75 had the same issue..

I was printing this.. http://www.thingiverse.com/thing:53451

I printed one the other day and it came out well (on “normal” quick print), I have scaled it up now to 1.5x’s and the outside ring was fine, it was the middle cogs that had the lift/curling.

I am trying again now but with slowing down the first layer hoping to get a better adhesion.

Added is a photo, been having a few of these issues, maybe its simply what happens but would be good to remove at print if possible. I am not sure if this is a retraction issue or not? I have retraction on and the 2 relevant settings to 0 (zero) and on the UM2 have increased the height to 5.5mm.

Any advise welcome!

Many thanks

GBR1

sample

 

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I just filed a bug last night that Cura doesn't do retractions when moving between islands that are less than 1cm apart. Could that be the case here? It doesn't really look like it's trying to retract. You should be able to hear the distinct chirp of the retraction and de-retraction as it jumps between the parts. Or look at the gcode in Repetier Host or a text editor, and see if there are G10/G11 commands where it moves back and forth between the two.

Daid has already fixed the bug for the next release of Cura.

Are you using gluestick for the gears print? I printed it with glue and on a 75º bed I think, and got no warping at all. It really shouldn't warp much - those gears are pretty small. My guess would be that you didn't get very good adhesion to begin with. Yesterday I printed a fairly large flat box, with glue at 60º and didn't get any warping. I recommend spreading the glue around evenly with a wet cloth, so it gives a thin even coat for the print to adhere to. I generally print the first layer at 50mm/s or more on my UM2.

Regarding the firmwares... it's possible that the two versions include different binaries, I guess. I'll check that.

 

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Added is a photo, been having a few of these issues, maybe its simply what happens but would be good to remove at print if possible. I am not sure if this is a retraction issue or not? I have retraction on and the 2 relevant settings to 0 (zero) and on the UM2 have increased the height to 5.5mm.

Any advise welcome!

Many thanks

GBR1

It looks like in this photo you started printing a bit high. See how the skirt has moved and not been squished down flat onto the glass.

 

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No, I checked... they're byte for byte the same UM2 firmware binaries in the 13.11.2 Cura for Win and Mac. Are you sure you had the same version of Cura in both cases?

Yep, both 13.11.2.

I am having to print much slower than you are to get a good print. Currently base layer I am having to print at 15mms and then main part at 50 otherwise it looks like not enough filament is going down!

Should I try printing faster and increasing flow rate maybe?

Yep, printing with the glue, I tired at 60 and had some curling, then printed again at 75 and had the same. I will try spreading the glue with the cloth as well, I am sure lots of these little tricks add up to a better print..

Saying this I changed the filament and am now printing the same part at 60 base plate temp and it's going well!

Cheers

GBR1

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My guess would be that you didn't get very good adhesion to begin with.

 

I agree. You do not need to change speed. You are already using glue. Your ONLY problem related to curling now is that you are printing too high off the bed. Two of us have mentioned this now. Leveling properly is really really important. The PLA should be SQUISHED into the glass somewhat.

 

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Evening,

So had a good day. I re-levelled the bed with a touch more friction but also spent most of the day printing with Form futura’s PET.

This seemed to go well, I had really good bed adhesion with a bed temp of 60deg and the prints came out well.

Felling bullish I tried (one of) the bridge test.

Blue is with the Ultimaker PLA and clear is the PET.

Bridge test with PLA

Bridge test

Visually I think the PET printed better (bar the 2 strands that hung down), it is certainly the stiffer of the two. Both were printed at the same speed of 50mms and same temp of 220deg C. Only difference was I had the bed temp at 65 for the PLA and for the PET at 60.

Both could get better, I am guessing speed is the key figure here?

Thanks for all the advice.

GBR1

 

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In this case probably more temperature (see post #17). Can you go lower temp for the pet?

 

Hi gr5,

So I did a few more tests with the pet (as in filament and not small furry animal)..

As you can see from the photos I went down to 180degC, it printed and the actual bridge part was OK but generally it was the worst overall.

The 210 bridge was in torsion the strongest. This was done by simply holding and twisting, there was enough of a difference to feel between the temps!

200 was the best surface finish and it got worse form there. BUT as you can see they all printed pretty well compared to other images I have seen so I am happy with my setting for this material.

220

210

200

190

180

What was also good was by lowering the temperature I didn’t get what I assumed were retraction issues. I now think at 220 the filament was almost oozing out by gravity (if that's possible) and causing some of the stringing between objects.

Thanks again

GBR1

 

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Nice experiments! Yes, 220 is too hot. The rest look reasonable. Going by these pictures 190 looks quite good but often with colder temps you get bad adhesion between layers so I would recommend some destructive testing now that you have taken your pictures.

 

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