Problems getting started with my Ultimaker 2

[CrownGirl 0]

Hey all,

I semi-recently purchased a higher mileage Ultimaker 2 that I haven't been able to get a great print from. I'm new to 3d printing outside of downloading STLs from the web and making minor tweaks to the slicer. I've also played with a bunch of settings and replaced a bunch of different parts. My prints are getting substantially better from when I first started, but I think there might be something I'm missing. From the pictures (and video), I think I'm having problems with stringing and poor bridging from what I can tell. In the helix video, you can see that it looks like its consistently bumping the print as it moves. In some of the pictures, you can also see where it looks like it is almost dragging the nozzle. I've also noticed that the filament also tends to curl up on the nozzle. Infill also doesn't completely connect, but this only started recently happening. I think this is due to a slicer setting.

 

Things I've done:

I've adjusted the temp up and down +/- 5-10 degrees as well as played a little bit with the speed with no success. I've also replaced the complete hotend, bowden tube, and upgraded the feeder to the Ultimaker 2+ feeder. When I upgraded the feeder, I did calibrate the e steps several times and believe it is within 1mm .The printer has over 1400 hours on it, and seems to be in decent condition. One of the belts does squeak, which I plan on replacing at a later date. I have also performed many atomic pulls, even with the new nozzles.

Slicer settings:

Latest Cura using the "normal" profile (0.15 IIRC). Have messed with retraction distance and speed, with no real improvements.

Filament:

I WAS using Ultimaker PLA Red, but have switched to Ultrafuse 2.85 in order to rule out filament (Ultimaker PLA is all several years old). Filament is kept in mylor bags, and is preheated to 55c for two hours prior to printing.

 

I feel like I've hit a brick wall with 3d printing. Any advice for me on what to test or check?

Video:
https://imgur.com/a/AcmIdgA
 

[CrownGirl 0]

Just my luck, received a nozzle temp error today.

Ordered a new one off Amazon, we will see if this was related.

[gr5 2,178]

I wouldn't recommend preheating PLA.  I print old PLA all the time.  Some brands will get brittle if you leave them unspooled for a day or two but only the portion of the filament that was unspooled.  It has to do with the mechanical stress of straightening the filament.  I think it probably gets microcracks which simulates brittleness.

 

I'm not sure if your parts are typicall of what is expected or not.  But I think your printer is probably working fine.  Not certain but it looks okay.

 

Did you order a new sensor or heater?  More often it is the sensor the breaks but it's possible for the heater to break as well.

[CrownGirl 0]

Hey, and thanks for the reply.

I replaced the nozzle/hotend as I broke it during disassembly.The factory UM2 feeder had constant problems with grinding filament, so I swapped it out for the UM2+ one. Since then I haven't had any problems.

I swapped the temp sensor for the bed before I ordered it to test. Replacement sensor hasn't had any issues.

Same issue with new sensor unfortunately.

[gr5 2,178]

11 hours ago, CrownGirl said:

Same issue with new sensor

What issue exactly?  You aren't happy with the quality?  Maybe you should be more specific.

 

For example in the arcing area - underneath the arc.  That looks typical.  It's difficult to print overhangs like that.  It's normal for the quality to be worse under overhangs like that.  the arc shows how steep you can print up to (looks like you can print right to the end!  Very good.)  and the other shows "bridging" which looks reasonable there.  You can probably do better by tweaking some things in cura.  And printing farther from the print bed might help as the heat might be part of the problem (not sure).

[CrownGirl 0]

Hey again,

I'm overall very happy with the quality of my prints compared to where I started. I believe I'm still having issues with bridging and or possibly overextruding. I've printed several temperature towers, with varying improvement based on my slicer settings, but most still don't look nearly like any of the tests I'm seeing online. Mine seems to have a lot of "spaghetti" if you will:

 

[gr5 2,178]

Well in this last picture I'd be worried about the quality of those walls first.  Bridging is indeed tough but...

 

Okay my thoughts:

1) Bridging is tough but first you need to get the walls perfect - the walls should be much nicer.

2) The walls looked fine in the first pictures - maybe it's just printed too fast?  Did you mess with the speed?

3) Are 2 the side fans turning on?

4) Okay that looks like Z issues maybe and it was stated that this is an old printer so...

 

I think you might have Z issues.  Maybe not - hard to tell from the photos but let's talk about that.

 

The Z screw.  In the back of the printer.  By now I assume it's dirty?  Dirt mixed in the grease causes the bed to move less consistently so each level has a bit of random error and you get horizontal banding, bumps, holes, and so on.  Clean it with WD40.  I recommend removing it - it is permanently attached to the stepper which has a cable under the panel so you have to remove 2 or so screws to get the bottom panel off then unplug the Z stepper, then undo the 4 screws that hold the Z stepper, then it just slides out.  It's a little tricky as it has to spin to come out but you just pull pretty hard and the screw will spin and the whole assembly pops out.  Then you can put it on newspapers and clean with WD40 and a tooth brush getting in all the cracks.  Then add one drop of grease and reassemble.

 

Or you can do it in situ.  Protect the glass bed from any oils (best to remove it and also place newspaper or something on the bed).  Clean with wd-40 and toothbrush.  Wipe as dry as possible getting in the cracks of the triple helix thread (if you stick a paper towel and toothpick or something in one thread and spin you only get one of the 3 helixes).  Add one drop of grease if you have it - any grease will do.  You don't need high temp grease.  You don't need silicone grease. Any grease.  Just a tiny bit.  See if this makes the walls of your parts much better.

 

Try printing something you actually need or want.  Maybe something around the house.  Walk around your apartment or house or a friends place and look around until you see a need that can be solved by something plastic.  Print that and if you don't like the quality *then* it's easier to talk about improving it.  Printing test prints is trickier as they are designed to be nearly impossible.

[CrownGirl 0]

Hey again,

Speed - I'm tried varying the speeds during my helix test prints . I have the speed at 50 mm/s. I have varied it from 30-60mm/s with no change.

Fan: Fans are on, 100%

Here are my slicer settings. They are the default for the "Normal" profile.

Speed:
Print Speed 50 mm/s

Infill speed 50 mm/s

Outer wall speed 32 mm/s

Inner wall speed 42 mm/s

Top/Bottom speed 25 mm/s

Travel  150 mm/s

Initial later speed 25 mm/s

Initial later speed 25 mm/s

Initial later print speed 25 mm/s

Initial Later Travel speed 75 mm/s

 

Walls:
Layer height: 0.15mm

Initial later height 0.27mm

Line width 0.35 mm

Wall line width 0.35mm

Outer wall Line Width 0.35mm

Inner Walls Line Width 0.35mm

Top/Bottom Line Width 0.35mm

Infill Line Width 0.35mm

Initial Layer Line Width 100%

So, the z screw...

I took the z screw assembly out,  cleaned it in my parts washer, and applied a light coat of light weight machine oil. The lead screw was was coated in a heavy grease, kinda like wheel bearing grease if you are a car person. I figured for the heck of it, I should take the z bearing out and clean/oil it as well. After cleaning it, I checked for play and think it might be out of spec. Using my dial indicator, I measured around .010" backlash. This seems a bit excessive, and want to bring it up. As for the rest of the build plate, it moves smoothly without any binding. The bearings sound a little loud, but I wasn't able to feel any play. 

I've printed several things with it, and generally don't have any issues unless there is some sort of unsupported area. With supports and areas that would generally be bridged are rough after the support is removed. I can post pictures of it if needed. Generally speaking, I really only use this printer to print brackets and stuff for car projects. Most of what I print is usable, as aesthetics are not that important to me when the part is behind my dash or out of view. I've been asked though a few times to print things/figurines for friends, and feel embarrassed by the quality of the print. Most of the time I'll have to sand or work on it after before giving it to them. Hoping I can cut down on my post print work

Thanks again for the help

[gr5 2,178]

grease

 

The z screw is different in that it is supposed to have grease, not oil.  Just a pea sized drop.  Wheel bearing grease is great.

 

z nut

 

Yeah there can be a lot more play than that even.  The printer partly relies on the weight of the bed to avoid backlash issues and partly it relies on only ever moving the bed down during a print (never upwards)  (so try to avoid using the "hop" feature on an ultimaker - in fact it's pretty much only meant for delta printers - a completely different design).

 

speed and line width

 

I don't like those to vary.  Ever.  That's important.  There is a big delay between changing speeds and when the pressure in the nozzle equalizes.  The pressures are pretty high: 150 to 250 psi is common.  Anyway whenever you slow down extrusion it overextrudes for a little bit and then when you speed up again it under extrudes for a second.  Bridging may be an exception where you might want to change flow for that.  Anyway, so keep all your speeds the same if reasonable (infill, inner shell, outer shell) and keep your travel speed high - like 250mm/sec on a UM2 should be fine (I think it defaults to 150mm).

 

Same with line width - if you are doing one shell at 0.4mm line width and the next at 0.2mm line width you are going to get under/overextrusion at the flow changes.  Try to make the wall width a multiple of the line width.  For example 0.4mm line width and 1.2mm wall width.  So the lines are the same thickness.

 

Fans at 100% - good.  That's what you want for PLA.  The more fan the better.  Some people add cross flow fans or even put a window fan blowing into the printer.  The improvements in quality are typically pretty small as the side fans are usually enough.

 

There are a ton of bridging features in cura.  Type "bridge" in the settings search box and you will see them all.  I have no recommendations but many other people do.  Maybe search for posts by burtoogle as he has experimented a lot with bridge settings and he is the one who got many of those settings added to cura (he is not an Ultimaker employee and doesn't own an Ultimaker printer but he has been a significant contributor to Cura features and bug fixes).