Material grinding issues

[AHMAD_UCD 0]

Hello everyone,

I'm facing some persistent issues with my 3D printer when attempting to print new car models that have curved surfaces. Initially, my prints with flat-bottomed models went smoothly. However, with these new curved designs, despite adding supports, the printer frequently fails, grinding the material.

Here are the steps I've tried so far:

Lowering the retraction speed to 35mm/s
Cleaning the feeder and the wheel

Cleaning the bowden tube

Hot and cold pulls (core cleaning)
Adjusting the tension on the spring screw by loosening it incrementally
Experimenting with printing speeds of 90-100 m/s. 
Setting the core temperature to 215 degrees Celsius
Adjusting Z-hop height to 2mm

 

Despite these efforts, I continue to face under-extrusion problems followed by an error message that says something along the lines "problem with extruder one, check if the spool is empty." I'm using a new spool of tough white PLA filament, and my layer height is set at 0.4 mm and  I am running the fan at 100% speed (default value).

I would greatly appreciate any advice or suggestions on how to tackle this issue. Is there a specific technique for models with curved geometries, or could there be another factor I'm overlooking?

[gr5 2,189]

I don't recommend z hop on ultimaker printers - that's the first thing that I noticed.  zhop works well on delta printers (a very few non delta printers can benefit but not ultimaker) (google images of delta printers if you don't know what they are - they are niche).  But that probably has nothing to do with grinding.

 

I number things because people often skip over things otherwise and we don't get back to something for weeks and that sometimes is the most important thing.

 

1) Could you include photos please?  One person's "grinding" is another person's "collisions".  Photos help decrease misunderstandings.

 

2) These are single material prints?  PLA only?

 

3) Lowering retraction speed shouldn't make any difference other than reducing the overall quality of the print.

 

4) Check the front fan.  What you describe is surprisingly a common symptom of the front fan (not the 2 side fans) on the print head not spinning which is pretty common as it can get jammed or just simply fail.  The front fan should be spinning anytime either nozzle is over 60C.

 

A) It's common to get grinding when the same filament goes in and out of the feeder > 20 times.  This is super common on certain unusual models.  And super rare on most models. If you don't know what to look for, two models might look identical but one will have issues. There are settings that fix this.

 

B)It's also common to get grinding if you are pushing too much volume of filament through too small a nozzle at too cold of a temperature.  This could be as simple as your layers are too thick for your print speed.

 

If you post your project file I can see if you have issues with A or B.

 

 

[AHMAD_UCD 0]

Hi.

 

Thank you for the prompt response. 

 

1. Please find attached the photos. I had over 10 failed attempts so the pictures are from various attempts. With the latest settings, the bite marks/grinding are not very deep, however, the printing will stop every a few minutes.

2. I am using only one extruder, the one that comes with the Ultimaker 5s. The filament is PLA Tough White/black 2.85mm.

3. Thanks for clarifying about the retractions, I just read it in another post in the community and followed. 

4.  The front fan works fine. I've checked. 

 

I have included some pictures of failed attempts. The bottom one-to-a-few layers print fine sometimes, before it starts giving errors or messes up everything.

 

Please find attached the recent project file too. 

 

I turned off the sensor to have a go, some of the lines are too thin, and some lines remained incomplete (marked light blue in the picture). The top and bottom are mostly fine. 

simple van basic all straight.3mf

[gr5 2,189]

The feeder tension is set to the weakest pressure as shown in your photo above.  Do you move it back to the center position after you re-assemble the feeder?  Your symptom could exactly be explained by forgetting that step.  Again - you do want it at the weakest setting while putting the back of the feeder back on.  But then you want that "stick" to be half way down the slot.  Not at the top as it is in this photo.

[AHMAD_UCD 0]

Hi,

Thank you for the response.

I put it at the center after assembling the feeder. I have tried it moving a few turns up but still it grinds, as mentioned in the initial post.

 

Going through various posts I think the speed settings are too quick. Can you please check, I have attached the project file in the above post, or if you want any details, I shall gladly provide.

 

once again, thank you for the prompt response.

 

 

 

 

 

 

[gr5 2,189]

You have top/bottom thickness set to 15mm!  The default is 1.2mm.  Changing that to default of 1.5mm saves you almost 2 days printing time from 2 days 14 hours to just 20 hours.  Why did you make it so thick?  Did you want it to feel heavy?  You can instead insert some sand in the print when it is 1/3 done.  You can pause the print or use the "pause at layer" plugin.

 

I didn't see anything that looked like it was printing too fast.  .4mm lines, .2 layers and 50mm/sec.  That's not particularly fast.  You could cut the print time in half by using a 0.8mm nozzle which is what I would do.  I'd keep the same speed and layer height but the lines should switch to .8mm thick and it will print twice the volume.  Also this will put less strain (2x) on the feeder because a .8mm nozzle can pass 4X as much volume of filament per second and you would only be printing 2x (volume wise) faster.

 

Also you don't have excessive retractions.

 

Those circled areas I'm guessing are underextrusion?  If so then I'd get rid of non-retracting moves (also called combing moves).  So I would probably turn off combing moves.  If you leave it on, there is no retraction and on your large part, with long travel moves, some plastic will ooze/leak out and cause the next printed portion (possibly those circled areas) to be under extruded.

 

So I really don't know why you are grinding your filament.  You could test the feeder - use the MOVE command on your S5 touch screen and then fight the feeder by reaching around and pulling down on the filament while the feeder is pulling up.  Pull quite hard.  I broke a feeder and noticed today and it took about 2 ounces of pressure to fight the feeder.  Usually an S5 feeder can pull 10-15 pounds (6-9kg).  You could try lifting a 10 pounds weight to compare the force.  It's a lot of force.

[AHMAD_UCD 0]

Hi gr5,

 

Thank you for the response.

I have to drill and tighten some screws at the bottom of the model for the experiment, and hence the thick bottom. 

 

I am not sure why it's 50mm/s and taking 2 days. The speed I set was 100mm/s and the rest of the settings remain the same. It takes about a day. Is the speed fine at 100mm/s or could that be the reason? please check the attached picture.

 

I will keep the thickness of the bottom at 1.5 mm/s, pause, and glue an already printed block using the pause at layer plugin. Thank you for the useful tip, it would surely save time and also using an 0.8 mm nozzle would be better. Thank you

 

I will update you with the latest results by turning off the "combing" and the "z-hop". 

 

 

 

 

 

 

[gr5 2,189]

100mm/sec*0.4mm*.2mm layers is 8 mm^3/sec

 

8 is up there for a 0.4mm nozzle.  Yeah maybe that's a problem.  I've printed that fast but that's close to the limit.  And I had raised the temp a bit.

 

Again, a .8mm nozzle can print 4X the volume (4x the area of the hole).  So printing 16 mm^3/sec for a 0.8mm nozzle is not a problem for the extruder.

 

I have a chart somewhere of max speeds on some older printer but it still is relevant...

[gr5 2,189]

Okay so this is ancient - this was 11 years ago and I think on a UM2 with the old, weaker feeder and a 0.4mm nozzle.  The S5 can probably do 2X faster volume.  Note that you can print much faster if you increase the temp a bit.  This is for PLA.

 

The quality tends to get better at lower temps - better overhangs.

 

 

[gr5 2,189]

Are you screwing from below and have to make sure hit the right spot?  With wood screws?

 

Rather than inserting something with the "pause at layer" plugin, and rather than making the entire bottom 15mm thick for screws, maybe just model holes in the bottom?  Also you can make it solid infill in selected regions and normal infill in the other.  Watch this video or similar on how to use "mesh modifiers" to modify settings in just certain spots.  You can actually create the meshes in CAD instead of manually as shown in the video.  That way you can position the thicker meshes at precise location e.g. exactly 10cm apart or something so you know where to drill?  Maybe.

 

 

[AHMAD_UCD 0]

Hi,

 

Thanks for the tips.

I have to use the models for various experiments and attach them to force balances. 

I have used the blocking supports and they are good.

 

I attached a new filament, PLA black tough, turned off z hop and combing. I have increased the temperature to 220 too. 

 

The first 6 hours went smooth before it started giving me the material empty error again. Checked feeder and there's NO grinding at all. Tried running it two-three times but in vain. Unload the material, something seems off at the tip. Please check the picture. Loaded it again and it was smooth and consistent, picture attached. Working fine for the last 30 minutes.

 

 

Thank you again.  Will update about the progress.

 

 

[AHMAD_UCD 0]

and I have decreased the printing speed too. 

[gr5 2,189]

I see nothing suspicious about the tip of the removed filament.  It looks typical to me I think?  You'll get more defined, useful information from a cold pull which should be a perfect mold of your heater block and nozzle.

 

But your printer has successfully printed 8^3mm/sec which tells me it is in pretty good shape.  But something is either on the edge or intermittent.

 

Make sure to check the front fan each time you check other things.  Maybe with a flashlight?  Or you can use the TUNE menu to turn off the side fans briefly and then it's obvious if you can still hear the front fan spinning.

 

If it were me I'd replace the print core.  It's cheap (compared to the cost of filament) and easy to do and I'm sure you have more important things to do with your time - so that's a quick thing to try.

[gr5 2,189]

I guess I'm wondering if the "material empty" issue is now caused by all that earlier dust in the feeder sensor and that it's printing just fine?  Seems unlikely but maybe one error causes the other?

 

I don't recommend this but FYI you can disable the filament sensor.

 

If you put in the IP address of your printer in a web browser and click "temperature graph" you can see the filament sensor readings.  They are confusing but possibly helpful.  It only shows the last 10 minutes or so but if you keep that window up in your browser it will accumulate "forever".

[AHMAD_UCD 0]

Switching off the filament sensor worked. A few spots needed sanding but it printed well. 

Going to start printing some more models and will post if any issue occurs.

 

 

Thank you.