JohnFox
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Posts posted by JohnFox
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I assume you have done some Atomic cleans? Can you see through the hole in the nozzle after a clean? Just wondering if you have a large bit of junk floating around somewhere.
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A set of needle files.
Wet and dry emery paper, grades from 120 to 400 mesh size.
I also use a woodworkers belt and disc sander. Runs rather too fast but with care it can smooth the surfaces quickly. ( the items I am making tend to be regular solids with flat sides ).
I like the waste paper basket suggested by |Robert|
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Could also be a problem with the PTFE coupler, simply worn out.
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I have a UM2, so it may not be exactly the same but try moving the cables in the area of the head to see if anything happens during a test print. If you get an error when you move them, you have found the problem.
this is something on nozzle changing
Okay....
I'm new with this wich wire is it? And how can I change the nozzle?
Thanks!!
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After a print, the head is free and can be moved around by hand. Occasionally it parks and it still under control then you can't move it, it simply feels solid.
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The first layer being wider is called 'elephants foot'.
This is caused by the nozzle being a bit too close to the bed and the material is over extruded beyond the correct area. Lower the bed by about 1/4 of a turn on the screws and try again.
I have just been doing some tests of this problem and the main cause of 1st layer problems is the bed height. I use the Cura default of 0.3mm 1st layer thickness, I suspect with 0.4mm it is trying to extrude too much material.
Do you use PVA glue on the bed? I use a small amount of PritStick, then a tiny sponge with a few drops of water to spread it around, ( goes milky then dries). Never had PLA coming off the bed with this.
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Yes, I now think curling was the main problem. Trying to spread the material too wide.
The bed leveling (read also the absolute difference between nozzle and platform) plays a big role on the first layer. If the bed is too close the amount of material coming out the nozzle is too much so it will go somewhere. If it can not go to the side (one side has already printed material) it will curl up. And this is what it looks like curled up lines at certain places.
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Sounds like a suspect connector on the temperature sensor cable. I had a bad sensor wire, only fixed by changing the whole thing.
Thanks! One more question... Do you know what it can be when I'm printing something that takes about 10 hours so after 5 hours the temperatur will drop rom 210C to about 40 - 60 c for about 10sec and then back to 210 c and again and a again until the machine says stop...
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Just done some tests, no dramatic results.
I modified the first two layers of a test square, then went back to defaults afterwards. Printing PLA.
No visible difference between 20mm/sec and 30mm/sec
Possible change between 220C and 210C, (default)
No obvious improvement between 100%(default) and 110% extrusion rate
No obvious change between 60C bed( default) and 70C bed.
A minor improvement when using 225C nozzle AND 70C bed.
Similar result with 225C nozzle, 70C bed and 110% extrusion rate.
The biggest effect on the print quality was any alteration to bed height, with less than 1/4 turn of the screws making an obvious difference.
How does the UM2 zero the Z axis? Any minor fluctuation here would alter the quality of the first layer.
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Just in the throes of doing some controlled tests on the bottom layer.
I'll try the 65C idea, makes some sense.
Not bothered about the elephants foot effect, it's the grooving that is the trouble.
And, printing thin layers is difficult for the 1st layer - set your 1st to .300 and once you have perfected it then if you need to go thinner give it a try.
I run my 1st layer at 20mm/s; go faster at your peril. Once the first layer is printed turn your bed temp down. I normally print my 1st layer at 65c and turn down to 50c, I have seen others that go lower. I assume you have your fans turned off for 1st layer.
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I use a 0.3mm first layer as well.
Would it help to have a slower print speed for the first layer?
This problem on the bottom layer is my biggest problem at the moment. It takes quite a bit of work to sand away the grooves. The top layer is fine.
To me it looks like the platform was a little to close to the nozzle. It starts putting too much material and then the material start to curl up on the sides.
It is not so easy to have the platform just right. That is why I use 0.3mm first layer but even then this might happen.
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Any suggestions for improving the first layer, ( the object is shown upside down)? I watched the perimeter being printed and that looked OK but didn't see the rest of it.
Also what could be causing the oddities at the two corners?
I think the PLA is being squished down OK judging by the amount that is being pushed beyond the layer.
PLA, 210C, 0.12mm layer, bottom layer speed 30mm/sec
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That's rather impressive.
Were the windows glued into place? What glue did you use?
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Have you tried changing the material, taking it out and putting it back again? It's possible that the tip of the filament has got stuck in the PTFE coupler.
At some point, you may have to remove the end of the Bowden tube to see what state the tip of the filament is in.
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That all makes sense, those *&%@$£! Z bearings are causing a lot of problems recently. I suspect that their tolerances aren't compatible with the pillars.
the play is in the z-nut on the bed. Did also try the advice on this page: https://ultimaker.com/en/community/11123-z-axis-layer-error?page=last#lastreply
to loosen the screws on the bottom, but that didn't do anything.
This is a combination of the play in the z-nut and some friction in the bearings. When the bed comes to a spot with friction it lifts the bed up until the play of the z-nut drops it again.
To proof this I put a weight of about 500 grams on the bed and printed the same file again.
right: without weight, left: with extra weight.
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I would NOT advise lubricating the Z guide columns. That can cause problems.
Hi. first i test the temperature, and do the same.
Then i i lubricate the Z guide columns with the spesific oil, the Z screw was good. The tests after this are good.
Thanks for all.
Quicu
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Not sure where the software people have got to, they usually reply pretty quickly.
I think it's a conflict between nozzle and wall size. Probably trying to make two 0.4mm walls in a 0.5mm space.
A thought!
In Cura, (Advanced settings), try setting the nozzle size to 0.5mm. It may then just do the one pass over the circles.
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That is very interesting indeed.
Looks like something out of alignment, most probably the stepper drive. I think the two pillars are quite tight fitting.
Although I am trying not to be too enthusiastic about it, a guy in a german UM Facebook group pointed me to a possible solution of the Z Layer problem. Seeing it is a fix that can be tried within minutes I am going to share it.
First you clean the axis and the driveshaft of the z axis thoroughly and apply fresh grease to the driveshaft. What you then do is run the table to the top and unplug your Ultimaker. You then loosen these eight screws by about two turns and run the table gently up and down manually a couple of times (15 times in my case).
You will notice the motor and axis might move slightly. After moving the table a couple of times I tightened the screws again.
Not expecting much, I started the Benchy3D print. The silver one is before, the blue one after the "tweak" (cant even call it that)...
SInce then I have printed three objects that had a missing layer every single time... They are all perfect now. I guess its worth a try
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It looks like you have the layer skipping problem, where the build plate drops down too much.
My theory is that the bearings on the Z axis are sticking.
Clean the two Z axis rods so there is no oil on them. Keep them oil free.
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That looks like a lot of play on the print bed.
Can you raise the print bed and check the 4 bolts holding the Z nut. Wonder if they are slack.
gr5: do you mean this? on my new UM2Go, I had banding from the start, after cleaning the rods it got a little better but there is still something at the same spot.
after cleaning the rods:
before cleaning the rods:
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I noted that you didn't comment on the divorce option.
Apart from the fans, I get a lot of noise when it does a retraction AND moves on the Y axis. It's a sort of grinding sound, never been able to find out where it comes from, the retraction itself is quiet but the motion is noisy. Does't happen during normal printing.
earplugs start to hurt after a few hours so no option
it's definitely the sound the motor we are hearing, the sounds is not transmitted through my desk or wall I'm afraid.
Even with a top-cover and front-door you can still hear it too loud.
But this will be all solved with the updated Ultimaker release within a few months.
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Have a look at the comments in the Thingiverse page. It says that the objects should be scaled by a factor of 10, they made a mistake.
It's not you - it's them!
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Just seen an image of your print, it's in your profile as 'uploads'.
Some of it is due to under extrusion, the skirt around the print is really thin and wobbly, it should be a clearly defined band. What is the temperature?
The bits of filament from circle to circle is stringing, caused when the nozzle moves across the print in a non-print move. Have you got 'Enable retraction' on? In Cura, Layer view, the blue lines show the travel and retractions.
Part of the problem may be the 0.5mm walls when the nozzle size is 0.4mm. It may be trying to print a wider layer than it should.
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Ear plugs?
Divorce?
Is some of the sound being transmitted via the table to the floor or wall? Just wondered if mounting the whole printer onto foam would help.
Yip that's good.
Ok order completed, I'll print your fan shroud too when I'm going to assemble the rear fan. Curious about the improvements tbh.
Still my wife hears only the "beep beeps" of the retraction when we are in bed. The printer is located 2 rooms further... And I got a front-door and top cover on my UM2 but still she hears it...
So no night prints for me for now until the beep-beeps are solved.
Sometimes one z-level is not printed
in UltiMaker Cura
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Suspect it is the dreaded Z axis bearing problem that quite a few of us have hit.
In my case the bearings would periodically lock up, causing the missing layer. I eventually replaced the bearings but I think the underlying cause is lubrication on the Z pillars. Any oil on the pillars makes the balls slide, rather than roll and this causes the lock up.
Some time ago I tested this by oiling the pillars and the fault occurred. When I removed all trace of the oil the fault cleared and hasn't returned ( yet ).
Use kleenex to remove all lubrication from the pillars, move the bed up and down a few times and repeat the wiping.