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Filament flow % (UM1)

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Is there any guideline to calibrate the flow % of filament? Thanks.

My problem is when printing in 0.05mm layer height, it seems the printer output too much filament. The symptom is the surface facing Y=0 is smooth, the surface facing Y=200 is very rough. It seems to me that there is excessive filament was output and left on the surface facing Y=200.

Any input is much welcome.


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Do you have a picture? um1 or um2?

The first layer is very difficult to get perfect because having the bed flat *and* level is hard. I recommend the first layer be .3mm if you can. You need a first layer Z height accuracy of about 1/3 the height of the first layer. So if your first layer is .3mm then you need to level plus or minus .1mm error (the width of a sheet of paper). But if you print the first layer .05mm - well then you need accuracy of plus or minus about .02mm. That's pretty much impossible with the plastic bed as it has warps in it larger than that. So it just can't be done unless you have glass or MIC6 aluminum.

Anyway you probably need to relevel after every print or at least once per day.

Here is my levelling procedure for UM1:

How to level:

leveling here is defined as setting the Z height and also leveling. It's one procedure that does both at once.

Optionally heat up the nozzle to 180C because a cold nozzle shrinks and you will be setting the bed to the wrong height. Make sure tip of nozzle doesn't have any plastic on it or you may level to the wrong height. I usually prefer to level with a cold nozzle but if you want extra accuracy then use hot nozzle. If you have a heated bed that should also be warm for the same reason.

Home the z axis only. If you must home all 3 then you need to disable the steppers once it's done so you can move the print head by hand. Move the head as close as possible to each of the 4 screws in turn. Once at a screw tighten the screw and then slip a piece of paper between the nozzle and the print bed. Make sure the paper slides very freeley. Then loosen the screw until the paper gets slightly stuck. You want the paper to easily be able to slide in and out under the nozzle with one hand pushing the paper. If the paper gets stuck it's probably too tight under there. While levelling try rocking the bed across both opposite diagonals to see if one of the screws isn't touching the bed and to see if the bed is "hung up" or stuck on the threads of a screw instead of on the screw head.

Repeat this procedure for the other 3 screws. Then go back to the first screw and repeat on all 4 screws again. Then repeat on all 4 screws again. Then again. It may take you 20 minutes to do this the first time but the second time you do this it should take much less time because you are both better at it, faster at it, and because there isn't much to adjust the second time.

Note that the act of putting the screwdriver in the head can apply weight to the bed and change the height. You have to be careful to put as little weight as possible when testing with the paper.

If you leveled with a cold nozzle you are done. If you leveled with a hot nozzle you should then loosen the 4 screws 1/8 of a turn to compensate for the thickness of the paper.

Once done leveling rotate the z screw by hand to keep the nozzle off your bed. This makes it less likely to damage your bed surface and gives the nozzle room to leak.

On a new ultimaker repeat this procedure before every print (at least every hour) because the print bed can move/droop like a new guitar string. After many months the droop slows down.



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Sounds like a cooling/temperature problems, as the left side has better cooling due to the fan being on that side.

Which temperature are you printing at? And lower it to 200 for example.


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I also thought it may be a cooling issue.

Perhaps if you have an Ultimaker Original you need to adjust the adjustable part of the fan duct (near the nozzle)

Aim it in a way that it guides the air just underneath the nozzle.


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