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shurik

Prints quality improvements

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First of all, I'm happy to say that my UM2 arrived yesterday, and even with some stickers with it. :p

 

The machine is superb, running smoothly and quietly for many hours, real pleasure.

Using UM Blue PLA, I print on glass, 75C and it sticks excellently.

Now, to the business.

Yesterday, 4-hours print of a toothbrush head holder run perfectly - cannot be better.

Then, I left another build overnight - Brim, 0.1mm, 50mm/s, 75C bed, 210C head (I think - the default setting).

 

  1. Is it a leveling issue:
    IMAG0396
    IMAG0393
    ?
     

  2.  
    Why did it get so much underextrusion from the middle of the print?
    IMG 7893
    IMG 7894
     
    Much appreciate your help.
     
     
     

 

 

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first of all in my tame irish manner..... YIPPPPEEEEE you got your cool new ultimaker 2 !!!

yes I know i get over excited about these things but they make me very happy so why not... ;)

so to your question

yes do your leveling again... that wont help that your pla cant get out of your nozzle on the left and then drop everything down on the right... that wont help. easy thing to reallign in your setup.

little tip, screw all 3 screws of the bed clockwise so they are up.

then do the setup. and screw anticlockwise down a tiny bit so you get your paper thickness.

that should help

About the under extrusion between openings... my friend Iv had enough fun with this.

The problem is, the standard rate of retraction is a little to high for this type of printing.

try either lowering the amount and distance of retraction that goes on. Cura settings !!

or option 2... turn off retraction all together, you will get much better print quality and after the print. just take a sharp knife and cut the tiny treads away in about 1 second... thats what i do often so i know the walls are 100 percent perfect !

Ian :-)

 

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He-he, "YIPPPPEEEEE" is not enough of the word... It is just like sci-fi came alive in front of me, it is unbelievable... To the best of my knowledge, the very first UM2 in Israel or among the very first ones, at least. I'm proud of myself. :D

Many thanks for the inputs, will certainly try them.

Leveling - yes, making leveling with flu fever is not going to get any good results. They should've mention this in the manual. :smile:

About the retraction - do you refer to these settings:

retraction

?

Would you recommend to put zeroes there?

What about speed/temperature? Are they good as they are?

Again, many thanks!

P.S. Just FYI - I left you a message a while again, still shows as "unread" by you... Maybe, just missed it.

 

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The underextrusion is worst between the windows where it has to stop and start extruding. This means the pressures are pretty high in the nozzle and it takes a while for the PLA to come out of the nozzle and by the time the PLA starts coming out it is already past the the wall-between-windows and onto the next spot.

So you need to either raise the temperature or slow down. I recommend raising the temperature to 220C. Or even 230C. Also you should do shell thickness at least .8mm. That way it prints the inside first and gets up to speed on the extruder before doing the outer (visible) wall. Are you doing shell .4? Or shell .8?

 

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gr5 - I appreciate your advice. It seems like you're always here to help.

So, to combine both Ian's and your suggestions:

 

  • Put zero on all two retraction settings and uncheck "Enable combing" (not sure what it will do, please confirm)
  • Raise temperature to 220C - I could already see on other prints tried yesterday and today that it seems to be the optimum temperature for UM Blue
  • The shell thickness was unchanged, so it is 0.8mm by default
  • The speed is left on default 50mm/s

One more thing - on some of the prints there is some curving inside, even like on this test:

IMG 7898

 

Is there a way to get rid of these?

 

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Is there a way to get rid of these?

 

I don't totally understand what causes that shrinking but it has to do with temperature. People usually get rid of it by modifying fan speeds and bed temp. 75C is a bit high for PLA. Try 65C or 70C. I usually do 70C.

I'm not sure what's better for this low level shrinkage:

more fan

less fan

more bed heat

less bed heat

But I'm pretty sure those are the 4 things that affect this. By default the fans come on to 100% by 5mm height and they come on gradually each layer. So at 2.5mm they are at 50%.

Bringing the fans on too suddenly causes the nozzle to cool too fast and you often get underextrusion. The PID temperature controller in Marlin compensates within about 30 seconds. So bringing the fans on at 30%, then 60% then 100% is probably the fastest you want to do it.

100% fan helps many many other things besides this: bridging, sides with good quality, overhangs.

 

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...

 

  • Put zero on all two retraction settings and uncheck "Enable combing" (not sure what it will do, please confirm)

 

 

Don't put in zeroes. If I remember correctly, that causes major problems.

Think about how retraction works, respectively what it is used for:

If the printhead has to "travel", meaning switch it's position quickly from one point to another, without printing in between, then it can do that by either just moving fast and stopping the extruder. That will cause some oozing and make a thin strain along the travel path.

The other possibility is to retract the filament for the travelling distance and then "reinsert" it again. That usually gets rid of the oozing.

Now, if you specify "0" as the travel distance where the printer should start retracting, then it may retract even if there is no travel at all (because "0" is no travel at all).

One important thing about retraction is, that every time you retract, you apply extra stress on the filament where it is going through the knurled bolt (in the extruder drive). Depending on the hardness of your filament and the spring tension of the extruder drive, the knurled bolt may grind the filament and fail to push it further. That will lead to a failed print.

So, usually, you don't want to have too many retractions but only retract where it makes sense. One thing is minimum travel (expert settings). It usually doesn't make sense to retract for just a very small travel distance but only the longer bits. That depends on what you're trying to acheive - play with this setting and you'll see how it changes the result. There are many suitable test models for that purpose.

The "minimal extrusion before retracting" (expert settings) is necessary only if you have the problem that the knurled bolt grinds your filament too much. Usually, it is set to a very small value (*), but if you set it for example to "1", there will only be one retraction for every 1 mm of filament going through the knurled bolt. Note that 1 mm extrusion is not the same as 1 mm of printhead movement!

The advanced settings tab also has something about retraction. I never played with this before, but the retraction distance is also an important thing: if you lower that value, you make the retraction less effective, but also less stressful for the filament. You can fine-tune that, lowering the value more and more as long as the retraction still works well (no oozing while travelling with retraction).

This is a lot or work however - and it depends on the type of filament you're using, as well as printing speed and temperature. You change any of these - you'll have to redo the fine-tuning.

I always stuck with the standard settings so far - it always worked fine enough for me.

(*)

For some reason, this is set to 0.02 and not 0, even though that doesn't make any physical difference. Maybe setting it to 0 causes bugs (division by 0 maybe?). So, I'd leave it at 0.02 or increase it if necessary.

 

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(*)

For some reason, this is set to 0.02 and not 0, even though that doesn't make any physical difference. Maybe setting it to 0 causes bugs (division by 0 maybe?). So, I'd leave it at 0.02 or increase it if necessary.

 

Actually, 0.02 just prevents massive amount of retraction on very small islands. For example, the Eiffel-tower has lots of tiny pillars, the 0.02 prevents that the filament is totally grind down on this print, without preventing a lot of retraction.

 

Now, if you specify "0" as the travel distance where the printer should start retracting, then it may retract even if there is no travel at all (because "0" is no travel at all).

 

It will only retract on travel. However, during solid infills, it does travel from line to line, and do you want retractions there on every move?

 

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Hi Shurik,

Congratulations for the new shiny UM2, and what a machine...

I am printing with sucess, with this setup:

speed: 40mm/s

Temp: 230ºC

Bed: 60ºC

Fans: 100%

Retraction: enable (Basic Menu - Quality parameters)

retraction lenght: 5.50mm

retraction speed: 35mm/s and sometimes 40mm/s

You can also try, for superior print quality,

Speed: 20mm/s -30mm/s

temp: 221º-230ºC

I never printed in blue PLA but already tested different PLA colors and it seems that 230ºC is a good starting point. I also never print a house, so I will follow Ian's advice because he has enough experience printing houses. If the underextrusion does not disappear even at low speed and at higher temperatures to reduce the pressure inside the nozzle, it seems to me an excellent tip to try.

Be shure that your bed is well calibrated. repeat the bed calibration several times until perfection. I changed the inicial layers to 0,1mm and gave the final touch to the bed calibration. Now it's on the magical spot.

Have fun , you lucky israeli...

...and don´t forget to print the rose for the wife... ;)

 

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I disagree with Johnny. I have set this to 0 for all my prints and not had any trouble. .02 is a reasonable value - any larger and it won't retract as much as I want. If your retraction distance is set to 4.5mm (many people use 5.5) then the same filament may pass back and forth through your extruder no more than 4.5/.02 or 225 times. That is kind of a lot but my extruder seems to be gentle enough that this works for me. I actually printed the Eiffel tower last week and it came out fine with no filament grinding. And again, this was set to 0. I counted the quantity of retractions in the top section of the tower and it ended up averaging such that each piece of filament went back and forth through the extruder about 10 times. But that was the average - some sections were much higher.

However not all UM2's are the same and you might have a different experience. Your extruder might grind up filament often. I think a better description of this parameter might be "Maximum retractions over the same area of filament" and it could default to 200. Unfortunately, retraction length is set in Marlin and so Cura doesn't know what this is. Alternatively when you enter .02 in this box it could let you know that it will retract no more than 225 times on a given part of the filament if your retraction is 4.5mm.

edit: Also some filaments might not handle repeated retraction as well. I don't know if the harder or softer filaments would have more trouble but I'd guess the harder filaments would grind to dust more easily.

 

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edit: Also some filaments might not handle repeated retraction as well. I don't know if the harder or softer filaments would have more trouble but I'd guess the harder filaments would grind to dust more easily.

 

I can confirm that. The rather hard "Raven Super Premium PLA" from qu-bd (anyone wonders who bought all of the spools they had in stock - I'm totally innocent) was the first and until now only filament that ground up badly when I did too many retractions.

 

...

Be shure that your bed is well calibrated. repeat the bed calibration several times until perfection. I changed the inicial layers to 0,1mm and gave the final touch to the bed calibration. Now it's on the magical spot.

...

 

One side note on that:

Don't forget that a thinner initial layer also makes your brim thinner which makes it easier for larger parts to warp.

I only print with 0.3mm initial layer thickness, otherwise all of my prints would warp.

 

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OK guys, that's quite a bit of the information to digest and to try.

Really, this forum is one of the reasons to choose the Ultimaker.

Just have to say to Mr. Waldorf - my luck is relative. :mellow: I only got blue filament, the UM didn't care to update me in advance that other colors are out of the stock, so we will resort to the regular roses meanwhile. :wub:

So far, lowering the bed temperature to 60C did the trick - no more deformations!

Will set the retraction settings as you suggest.

In the recent prints there is still some irregular underextrusion - lines of holes in the walss here and there. Even at the sale height, i.e. - layer they might appear from one of the sides of the model. Will try to print with 230C to see if it helps.

I really do not want to lower the printing speed from the current 50mm/s, on contrary - the printing times are already too high. Will attempt to reach some acceptable compromise at this speed, if possible.

 

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One side note on that:

Don't forget that a thinner initial layer also makes your brim thinner which makes it easier for larger parts to warp.

I only print with 0.3mm initial layer thickness, otherwise all of my prints would warp.

 

Hum...No warps over here, so i suppose that you need a very well calibrated bed to avoid that. Maybe 0.2mm inicial layer suits better to you. I realy like the bottom finish with 0,1mm layer...

 

Just have to say to Mr. Waldorf - my luck is relative. :mellow: I only got blue filament, the UM didn't care to update me in advance that other colors are out of the stock, so we will resort to the regular roses meanwhile. :wub:

 

I am sorry Shurik, I may have some guilt, has perhaps helped to deplete the red. :oops:

I'm kidding, but it seems that ultimaker has serious problems with filament stocks. I ordered with my UM2, 3 months ago, some filaments and I'm still waiting. Next fillament order I will buy in other place than Ulti.

 

I really do not want to lower the printing speed from the current 50mm/s, on contrary - the printing times are already too high. Will attempt to reach some acceptable compromise at this speed, if possible.

 

For this speed (50mm/s) I would try 240ºC. Don't change everything at the same time, otherwise will be more difficult to understand what works better for the print. Play a litle bit with nozzle temps to achieve a good extrusion rate and when you get rid of the underextrusion, you can play with retraction values.

You should check the tightness of most screws because my UM2 came completely loose and poorly fitted. You must check the material feeder, that tiny screw that tights the knurled part to the motor shaft, because if it is loosened as mine was, you will also have underextrusion problems. When I received my UM2, I noticed that I have visibly loosened bolts, so I disassemble everything and went back to assemble everything correctly. During this process I came to fix various problems of poor fitting, the wires on the bed were not tightened to the controller board, the ventilation wires were disconnected, some wires were crushed in the side covers, that extruder knurled piece was loosened, has 90% of the screws, and all this even before connecting the power.

After some tweaking and tuning my UM2 is working like a charm, but still with underextrusion problems at higher speeds, however it seems that the problem is widespread and entire community is reporting this problem.

I just ended a 22H print and its just a perfect one...

Layer: 0,1mm

Speed: 30mm/s

temp: 230ºC

Bed: 60ºC

fan: 100%

retraction speed: 35mm/s

retraction lenght: 5,50mm

 

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OK, next step.

Tried these over the last day and night, still underextrusion. Layers were 0.2mm, speed - 50mm/s. First, 230C:

IMG 7904

Then, 240C:

IMG 7905

Since these horisontal lines didn't go away, I set the feeder to 120% at some point, but apparently with no effect.

First case, retraction length was 5.5mm and retraction speed - 35mm/s. For the 2nd try these were reset to the defaults - 4.5mm, 25mm/s. Should I play with these settings?

Another thing was the clicks of the feeder. Normally, there is only slight squeaking of the filament roll as it turns slowly. From time to time, the feeder runs the filament back and forth, nnothing special again. But as it seems, there are some "clacks" from the feeder when it runs the filament back, and then - a stroke of the underextrusion. Not sure though, but I tried to follow this pattern for a while.

All in all, there is need to provide consistent walls of acceptable quality. Any ideas are welcome.

On the bright side, there's no slightest sign of warping or curved edges at 60C bed, brim or raft.

Update - it's definitely the feeder. Set to print stretchlet at 0.2mm, 50mm/s. Very soon, the "clacks" come. When I put my fingers on the filament going into the feeder, I can normally feel it slowly going in. Then, all the sudden, the "clack" comes, instantly setting the filament a few centimeters back and causing the immediate underextrusion. What is it and how it can be avoided?

My respects,

Alexander

P.S. Now run the stretchlet at 0.1mm, 50mm/s. I had to set the speed to 130% and the flow - to 60% in order to get rid of the clacks and the underextrusion. There were some formulas to try and determine the optimum flow rate, who can help me to set these correctly please? I'm a bit limited in time right now...

 

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Hi Shurik,

Last night I printed a house just for testing...

I was able to print without underextrusion with the folowing setup:

layer: 0,1mm

speed: 50mm/s

temp: 240ºC

bed: 60ºC

retraction speed: 25mm/s

retraction lenght: 4.5mm

flow: 100%

fan: 100%

PLA: Gold

I'am not shure if 50mm/s isn't to much for 0,2mm layer

 

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There were some formulas to try and determine the optimum flow rate, who can help me to set these correctly please? I'm a bit limited in time right now...

 

please see Illuminarti's post: http://umforum.ultimaker.com/index.php?/topic/4171-ultimaker2-axis-squeeknoise-solved/page-2

and also Gr5 awesome posts: http://umforum.ultimaker.com/index.php?/topic/3418-um2-extrusion-rates/

http://umforum.ultimaker.com/index.php?/topic/4127-um2-extrusion-rates-revisited/

 

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Hi Shurik, I have been doing a lot of architectural printing and am well aware of your under-extrusion problem!!!

Your 1st pic looks as if it may be at 1:200 architectural scale, but anyway you have a short distance between the windows. IMHO you are printing too fast. For 1:200 I print at 20 m/s, 100 microns and between 200-210 degrees depending on the filament. Bed temp at 60.

I am working on a large 1:100 project at the moment (70+ pieces to assemble on completion), which fills the print bed with one or two mm to spare. For this I am printing at 200 microns to keep the print times down and at 30m/s for the larger pieces but 15-20 m/s for stuff like window frames and balconies.

I have been tempted to push to 40 m/s to reduce print times but I have also experienced that higher speeds affect the sharpness of the corners; filament affects this too. My standard white, Faberdashery Arctic white, gives good 90 degree corners but my benchmark filament, Colourfabb Dutch orange, gives scintillatingly fantastic corners. A variety of others have given less good corners at the same speeds.

At the end of the day if you are extruding too much and going too fast you will get small blobs left at the corner which will grow, then potentially stay soft for the next pass , resulting in a rough corner. Slowing down and reducing extruder temp. will fix that

 

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Mr. Waldorf, yellowshark - thanks so much for your help!

Mr. Waldorf - Yes, I was referring to these links by Gr5. He did a very impressive job. However, the results are confusing for such a newbee like me. It seems like we can print 0.1mm layers at 120mm/s on 210C, which is unfortunately, not very realistic. I probably miss the point there, such a noob of me...

yellowshark - it wasn't any particular scale, just a very first test on the brand new machine, to see how it works out. It seems that my prints will be probably the maximum size of the buildplate, bringing the total print time to 14-16 hours. :wacko:

At the moment, I use the only available UM Blue, but ordered Colorfabb White which already passed the customs and should be here by tomorrow.

What you say about the printing speeds echoing some of the advices here and it is depressing because of the printing times. Given your and others experience, it might be the only way. :( However, I run a test print yesterday-today with the following settings:

Layer: 0.1mm

Bed: 60C

Shell: 0.8mm

Head temp: 240C

Speed: 60mm/s

Flow: 100%

Retraction length: 4.5mm

Retration speed: 25mm/s

with very acceptable results.

The results were even slightly better when the speed was 100% (=50mm/s) and the flow was 80%. There were no underextrusions with these settings, and overall quality was excellent.

I would love to try the Faberdashery filaments but their shipping costs are outrageously high, the Colorfabb and UM have much more sane pricings.

Bottom line - it seems like I will end up using your suggestions. In the meantime, I will struggle a bit, trying to keep up the speeds a bit higher, in a hope to find an acceptable compromise.

Your help is most appreciated!

 

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It seems like we can print 0.1mm layers at 120mm/s on 210C, which is unfortunately, not very realistic.

Yes - I can barely print that fast. Without severe underextrusion. But that's right at the limit so quality is better at slower speeds.

- George

 

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My good friends,

There is still hope for printing at higher speeds with a quite acceptable quality.

Makes about a month since my UM2 arrived and has not stopped since day one. I Always print at lower speeds to achieve better quality and never printed anything up to 50mm/s for thinking that the quality would be much reduced and had already seen intermittent problems of underextrusion above the 50mm/s, so wrongly I established that this speed was an acceptable limit.

This week in an attempt to help Shurik and others decided to print my first house and also experience the higher speeds. I Printed a house at 50mm/s, 230°C and underextrusion didn't happened but it seemed that was bound to happen at some spots, but still a very good print. After this print I went to exchange filament and noticed that it was quite stretched and folded on the entrance of feeder material and on that filament guide thing, so after a brief analysis I decided to improve the filament entrance, because it seemed he was doing a lot of friction in that stock filament guide and with a very wrong entrance angles in to the material feeder.

WP 000142

After a 50mm/s print

 

In my underextrusion experiences I have noted that at higher speeds the knurled wheel was chewing and spitting filament so baddly that caused jams, sometimes inside of the material feeder and other times on the teflon coupler. Also found once that dust caused a little underextrusion too...

So less talk and lets fix the damn thing...

This is what I did with some RC parts (traxxas revo steering system) that seemed to be designed on purpose for the UM2

WP 000149

 

small Anodized tube which acts as a bearing

 

WP 000158

 

No holes, I used the existing hole and longer screw

 

WP 000157

With the dust filter...

and this is my third consecutive print without underextrusion at 100mm/s

 

WP 000161

 

after some cleaning...

 

WP 000163

WP 000162

WP 000164

Have to change bottom/top to 1.6mm!

 

So before this I couldn't go over 50mm/s without underextrusion, and now I am printing consistently at 100mm/s. The UM2 rear became much more quieter and smother, no more vibrations, clicks, clacks or bangs.

 

I managed to find that gold PLA, works very nice at 250ºC-100mm/s and I don't advise to go lower on the temp since I noticed that were single underextrusion spots on the more tight corners at 245ºC.

 

So, yes we can print fast, and with a damn good quality. I am very pleased and suprised. There will be a litle stringing, due to the high temp but very easy to remove and doesn't affect so much the final print quality.

 

 

Pardon my french but I am portuguese so ignore my english errors

 

 

 

 

Now I will return to my 20 and 30mm/s prints, because I just love them :wub:

 

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Bonjour,

 

J'ai aussi remarqué l'attaque en entrée du filament est de trop mauvais angle. Je vois ce que je peux faire pour faire la même chose que vous.

 

En effet, il ya un effet de ressort supplémentaire désagréable sur le principe d'origine.

 

J'ajoute juste ajouter une poulie sur le roulement à billes et plus sur votre mécanisme.

 

Beau travail pour améliorer :)

 

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Merci beacoup,

L'angle s'aggrave avec la vitesse, il est extrêmement important que le filament entre droit pour éviter les frottements. Les améliorations ont été immédiate et sensible, Je suis très satisfait, cependant je vais revenir à des vitesses inférieures parce que j'aime les impressions de qualité supérieure

Salut

 

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Exact :)

Tien, dans mon précédent écrit j'ai oublier la traduction :oops:

Permettez moi de la rajouté ici !

 

Hello,

 

I also noticed the attack input filament is too bad angle. I know what I can do to do the same thing as you.

 

Indeed, there is an additional spring unpleasant effect on the origin principle.

 

I just added add a pulley on the ball bearing and more on your mechanism.

 

Nice work to improve :)

 

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