Surface Finish Problems - Ridges & Gaps.

[dcp360 0]

Hello all,

I am having problems with the surface finish on my prints. Finished prints either have gaps or large ridges at regular intervals.

The printer is Ultimaker Original Plus.

I have done some research on other threads and forums and tried everything, still having problems.

Any help would be amazing! I have attatched an image of some example prints.

Thank you.

[Nicolinux 288]

Hi,

This looks like good old under-extrusion. Here some ideas:

 

• temperature readings are incorrect and filament can't extrude properly
  
• partially clogged nozzle
  
• filament diameter inconsistent
  

 

What did you try so far (so we can rule out some things first)?

[dcp360 0]

Originally I had some pronounced ridging on the surface of the prints. So I thought it might be something to do with the Z - Axis. I have greased and moved it up and down to check for any bad signs and I can't see any. Also, tightening the screws.

I have tried a range of different temperatures and settings in Cura and tried the atomic method. Im presuming the filament is good quality, so it will not have an inconsistent diameter.

[Nicolinux 288]

You can measure the filament to be sure.

Ok, next I would check the temperature. This is somewhat hard to do if you don't have an adequate thermometer. You could try the "water boiling test". Heat up to 90°. put a drop of water on a flat surface and carefully let it touch the nozzle. If you see small bubbles moving up then it means the temperature more or less fine. This is not an accurate test - by far, but better than nothing without a thermometer.

[dcp360 0]

Checked the diameter and it seems to be okay throughout the roll.

90degrees, nothing happens.

100degrees - nothing happens

approx 110degrees it bubbles.

[Nicolinux 288]

Ok, this indicates that the temp sensor is not accurate. You could perform PID-Autotuning next:

https://ultimaker.com/en/community/18625-solved-um2-pid-autotune-failed

[dcp360 0]

I followed what you did...

[01mT:149>[00m M301 P0.00 I0.00 D0.00

SENDING:M301 P0.00 I0.00 D0.00

ok p:0.00 i:0.00 d:0.00 c:1.00

[01mT:108>[00m M303 S150

SENDING:M303 S150

PID Autotune start

bias: 43 d: 43 min: 148.91 max: 155.78

bias: 41 d: 41 min: 148.44 max: 151.72

bias: 40 d: 40 min: 148.83 max: 151.09

Ku: 44.96 Tu: 22.68

Classic PID m

Kp: 26.98 m

Ki: 2.38 m

Kd: 76.46 m

bias: 40 d: 40 min: 148.98 max: 151.48

Ku: 40.74 Tu: 22.81

Classic PID m

Kp: 24.45 m

Ki: 2.14 m

Kd: 69.69 m

bias: 38 d: 38 min: 149.06 max: 151.33

Ku: 42.71 Tu: 21.76

Classic PID m

Kp: 25.63 m

Ki: 2.36 m

Kd: 69.70 m

PID Autotune finished! Put the last Kp, Ki and Kd constants from above into Configuration.h

How do I store them?

[dcp360 0]

I stored them

P = 27.94

I = 2.46

D = 79.19

Max was about 155? is that max temperature? abit low?

[Nicolinux 288]

Did you follow these steps?

https://ultimaker.com/en/community/18625-solved-um2-pid-autotune-failed#featured

150 was the temperature that I have chosen to run the PID-Autotune.

[dcp360 0]

I have followed those steps, I'll test it out now.

[dcp360 0]

Very inconsistant surface finish and the infill was poor quality too.

Edited March 27, 2016 by Guest

[neotko 1,417]

On one of my UMO+ I had to run the PID like 8 times until it was perfectly tuned.

You must wait to the hotend to be cold (20-50C) so start the PID again. (I might be wrong about this btw).

I did my PID to S210 since it's the temp I use the most.

[Nicolinux 288]

 

@neotko: Good tip about PID-Autotuning at the most used temp... I didn't think of it...

[dcp360 0]

That makes sense, I will try this when I have the time.

Is there anything else which I could try?

[gr5 2,178]

dcp360 you have underextrusion. Most likely you are printing too fast. Check ALL speeds including the infill speed. Your temp is probably fine but you know it's not fine if it cycles by more than +/- 5C while printing.

CAUSES FOR UNDEREXTRUSION AND HOW TO TEST FOR THEM AND REMEDY THEM

As far as underextrusion causes - there's just so damn many. none of the issues seem to cause more than 20% of problems so you need to know the top 5 issues to cover 75% of the possibilities and 1/4 people still won't have the right issue. Some of the top issues:

1) Print slower and hotter! Here are top recommended speeds for .2mm layers (twice as fast for .1mm layers) and .4mm nozzle:

20mm/sec at 200C

30mm/sec at 210C

40mm/sec at 225C

50mm/sec at 240C

The printer can do double these speeds but with huge difficulty and usually with a loss in part quality due to underextrusion. Different colors print best at quite different temperatures and due to imperfect temp sensors, some printers print 10C cool so use these values as an initial starting guideline and if you are still underextruding try raising the temp. But don't go over 240C with PLA.

2) Shell width confusion. Shell width must be a multiple of nozzle size. If nozzle size is .4mm and shell width is 1mm cura will make the printer do 2 passes with .5mm line width which is possible but requires you slow down much more to make a .5mm line out of a .4mm nozzle. If you really want this then set nozzle size to .5mm so it's clear what you are asking Cura to do for you.

3) Isolator - this is most common if you've printed extra hot (>240C) for a few hours or regular temps (220C) for 500 hours. It warps. It's the white part touching the heater block. Test it by removing it and passing filament though it by hand. Also if you notice parts of it are very soft then it's too old and needs replacing.

4) Curved filament at end of spool - if you are past half way on spool, try a fresh spool as a test.

5) curved angle feeding into feeder - put the filament on the floor -makes a MASSIVE difference.

6) Head too tight? Bizarrely MANY people loosen the 4 screws on the head by just a bit maybe 1/2 mm and suddenly they can print just fine! Has to do with pressure on the white teflon isolator.

5b) Bowden pushing too hard - for the same reason you don't want the bowden pushing too hard on the isolator.

5c) Spring pushing too hard. Although you want a gap you want as small as possible a gap between teflon isolator and steel isolator nut such that the spring is compressed as little as possible.

7) clogged nozzle - the number one problem of course - even if it seems clear. There can be build up on the inside of the nozzle that only burning with a flame can turn to ash and remove. Sometimes a grain of sand gets in there but that's more obvious (it just won't print). Atomic method (cold pull) helps but occasionally you need to remove the entire heater block/nozzle assembly and use flame. Or soak it in acetone overnight (after removing 90% of the material with cold pull).

8) Temp Sensor bad - even the good ones vary by +/- 5C and bad ones can be any amount off - they usually read high and a working sensor can fail high slowly over time. Meaning the sensor thinks you are at 220C but actually you are at 170C. At 170C the plastic is so viscous it can barely get out of the nozzle. You can verify your temp sensor using this simple video at youtube - on you tube search for this: mrZbX-SfftU

9) feeder spring issues - too tight, too loose

10) Other feeder issues, one of the nuts holding machine together often interferes with the feeder motor tilting it enough so that it still works but not very well. Other things that tilt the feeder motor, sleeve misaligned so it doesn't get a good grip. Gunk clogging the mechanism in there.

11) Filament diameter too big - 3mm is too much. 3mm filament is usually 2.85mm nominal or sometimes 2.9mm +/- .05. But some manufacturers (especially in china) make true 3.0mm filament with a tolerance of .1mm which is useless in an Ultimaker. It will print for a few meters and then clog so tight in the bowden you will have to remove the bowden from both ends to get the filament out. Throw that filament in the trash! It will save you weeks of pain

11b) Something wedged in with the filament. I was setting up 5 printers at once and ran filament change on all of them. One was slowly moving the filament through the tube and was almost to the head when I pushed the button and it sped up and ground the filament badly. I didn't think it was a problem and went ahead and printed something but there was a ground up spot followed by a flap of filament that got jammed in the bowden tube. Having the "plus" upgrade or using the IRobertI feeder helps you feel this with your hand by sliding the filament through the bowden a bit to see if it is stuck.

12) Hot weather. If air is above 30C or even possibly 25C, the air temperature combined with the extruder temperature can soften the filament inside the feeder such that it is getting squeezed flat as it passes through the feeder - this is obvious as you can see the problem in the bowden. The fix is to add a desk fan blowing on the back of the printer. Not an issue on the UM2 "plus" series.

13) Crimped bowden. At least one person had an issue where the bowden was crimped a bit too much at the feeder and although the printer worked fine when new it eventually got worse and had underextrusion on random layers. it's easy to pull the bowden out of the feeder end and examine it.

[dcp360 0]

Thank you for the replies.

neotko- I simply do not have the time to do the procedure 8+ times and testing it. I need the printer to work to prototype designs for university (final year).

gr5 - I have done all of these things without success. It must be either the quality of the parts or I am missing something really really obvious.

The printer is still in warranty - so I am asking Ultimaker (3DGBIRE) for replacement parts for the main assembles which I think are causing the problems.

Thank you for your help!