How to improve the quality of a print? Ultimaker 2+

federico3 · 2016-06-30T17:18:39.000Z

20% infill. The filament looks like really fine, so I won’t say that’s the cause of the imperfection.

Jamburger · 2016-06-30T17:19:36.000Z

Thanks, I’ll take a look at this and post some screenshots.

glad to help!

federico3 · 2016-06-30T17:23:00.000Z

Take all the time that you need, I’m not in a rush. It is just curiosity and willingness to learn
And, if you find out any issue with the Gcode, can I ask to point me where is it? I’m trying to learn how Gcode it’s working and it’s always nice to have see the point of view of someone else

remcokatz · 2016-06-30T17:42:37.000Z

Hi @federico3,

Please check these 4 things:

1. Consistency of the filament diameter
2. Temperature variation; What is the off-set on your hot-end? 230 on your screen could be 215 or 245 etc. in real life with your machine

3. Are you certain that your PTFE is still in good condition (no brown parts when you open the hot-end assembly on the white PTFE part)?

4. How well is your machine performing at this point mechanically? Are all the belts tightened etc?

I’m suspicious of option 1. and 3. but let’s see what you can tell us

federico3 · 2016-06-30T17:52:16.000Z

Hey Remcokatz,

Now I’m at home and tomorrow I’m not in the office, in any case, I’ll ask someone else to check it.
1&3. The material should be fine: the filament is completely new (I opened the plastic bag just one day ago) and I didn’t have any problems with other prints.
4. Mechanically speaking, the machine is perfect.
3. I’ll try to run again the code and I’ll let you know what was the temperature

Thanks for your help

MattG · 2016-06-30T17:53:58.000Z

Had a quick look at the gcode nothing glaringling obvious, the reason I was suggesting something mechanical rather than cooling or setting related is just because of the localisation of the problem, it doesn’t appear to be at the beginning or end of a tool path either. When you say this happened at two points, at different heights, were they in roughly the same location in x-y?

The hottend is moving freely… there’s nothing snagging, restricting the bowden tube at a certain point / extreme is there?

Curious to see the cause of this one!

remcokatz · 2016-06-30T18:10:18.000Z

Alright looking forward to the feedback!

Regarding point 1; Even cheap filament can look great but what you don’t see if it has diameter tolerance issues. Therefore you would have to measure it at several points on the spool with a caliper. So you can never say that filament is fine just by looking at it (even new spools). If you need help how to properly measure I can give some more info.

If you havent gotten any problems with the same spool and different prints then we can just move forward to solve your issue.

P.s. your retraction speed seems a bit aggressive but i’m not sure what the standard is for the 2+

MattG · 2016-06-30T18:19:51.000Z

Seems unlikely to be a filament issue doesn’t it? What’s the odds on the filament having an issue at exactly the same section of the print for what must be about 100 layers? If I’ve had an under extrusion issue because of inconsistent filament is usually just drops a layer.

remcokatz · 2016-06-30T18:27:04.000Z

Oh it’s just an extra check to make sure that there’s no issues at all with the filament but I agree that this is not going to solve the issues alone :). I work in the filament industry so I kinda have a standard list of like 30 points that I work through group-wise to pin down where the issues are.

Model3D · 2016-07-01T07:40:54.000Z

I think it is a problem of temperature.

Perry_1 · 2016-07-01T14:50:04.000Z

This is an error in your retraction or pausing when you change layers. That is why it is occuring at the same area on the print, because that is where the zaxis is moving up. This is also why the error is occuring elsewhere on the print, but NOT in the same layers.

One of two things.

1. Your layer height retraction number is screwy. You are retracting so far that the head moves up, the next layer starts, but it takes awhile for the plastic to get out of the extruder.

2. Or more likely, you have a mechanical issue. The extruder pauses, the z axis moves up to the next layer, and when the extruder unpauses, it is slipping, jamming, etc. As more and more plastic is pushed into the extruder, it finally builds up enough push to continue printing.

3. This could also be caused by a worn, difigured, burned PTFE extruder lining, that it needs much pressure to get going after a pause, zaxis move.

All the other temperature, speed, gust of wind, etc. posts are simply not realistic.

I will bet you a candy bar that if you watch the print as it is happening, it will be exactly where you printer is changing layer height.

Perry

MattG · 2016-07-01T15:14:05.000Z

Agree with everything here, but when I looked at the gcode for the area of the problem, the layer height appears to change at a different position for each layer???

Perry_1 · 2016-07-01T15:30:49.000Z

In looking at the gcode, I am going to stay with my original analysis.

federico3 · 2016-07-02T11:43:05.000Z

Hi Perry_1,

Thanks for your answer. On Monday, I’ll check if there is any mechanical issue with the printer but I’d say that the printer is working smoothly. I’ll also try to run again the same gcode file, in order to understand if the problem is due to an external factor or to a problem in the code/printer/material.

Federico

federico3 · 2016-07-04T15:50:11.000Z

@remcokatz I’ve measured the filament in three random spots, the results are quite regular: 2.90, 2.87, 2.92 mm

federico3 · 2016-07-04T15:54:11.000Z

The two imperfection are on two different points in two completely different positions on the x-y-z axis.
I’ll check if there is any mechanical problem as soon as the printer will finish the print that is doing.

MattG · 2016-07-04T16:00:09.000Z

Good luck with figuring this one out, let us know any developments! I know how frustrating troubleshooting can be, particularly less obvious symptoms, and especially when it ruins long runs!

danilius · 2016-07-06T16:57:30.000Z

If the print was sitting inside the printer as per the second photo you printed, then that suggests that the failed part was at the back, so localised heating issues would seem to be unlikely. Also, only one leaf appears to suffer from this issue.

So, the only thing I can think of at the moment it to use the “cut off bottom object” feature of Cura (15.0x) and start printing from just below where the problem started, and then watch what’s going on. Ideally, video it as well, and make the video very steady. Then we might be able to diagnose the problem from that, or you might do so yourself just by observing what’s going on.

n23d · 2016-07-07T01:36:11.000Z

I’ve looked at the G code and there are no extruder retracts or Z hops near the locations where the defect is. The extrusion proceeds smoothly from the

sides right across the face where the defect is. The print looks like the extruder is starved of material in that zone of the print. Since it does not seem to

occur randomly but repeatedly in that one zone it might have something to do with the filament binding when the head moves into that particular location in

that particular direction at that particular height. Once the head is out of that zone the filament moves freely again and the starved extruder issue goes

away. My guess is the wire cable is stuck behind the filament spool and is causing drag on the spool and/or the filament path where it should not be. See the picture.

n23d · 2016-07-07T01:38:53.000Z

I drew a red circle on the picture but its hard to see.