3d Solex Hardcore jamming when ironing

[V3DPrinting 11]

Dear community

 

I have an issue when performing an ironing on a flat surface, highest layer only, with PLA.

The hardcore is jammed due to heat creep.

 

I use ironing feature from time to time, but it's the first time I have heat creep.

 

I made larger prints on an S5 with a 0.8 mm Hardcore, ironing nearly the build plate surface was without any problem.

I made lots of prints on UM3E with UM AA 0.4 print core without any problem when ironing.

 

But these prints with a 0.6 mm Hardcore are jamming, on both UM3E when ironing.

 

I have checked the printhead cooling fans, no issue on that side.

PLA is a standard ColorFabb PLA Economy which performs very well.

 

BTW Cura is version 4.2.1.

 

Thanks for your feedback

`David

Edited February 27, 2020 by V3DPrinting

[V3DPrinting 11]

I have done some more testing, with a 0,8 mm nozzle on the same Hardcore, expecting the heat creep would be less severe due to higher flow. No success.

 

Then I reverted back to the UM print core and realized that not only the ironing was creating heat creep due to the very low flow, but also the standard printing.

 

I found out that the print core cooling fan was not running at the right speed, not cooling enough.

 

The issue is a accumulation of strings around the axis of the fan motor, creating some friction and slowing down the fan.

 

I have replaced the fan and done a successful print with the 3d Solex Hardcore and a 0,8 nozzle. No jamming nor heat creep.

I am currently printing multiple parts.

 

The 3d Solex Hardcores are working very well in fact.

 

Bad news is my other UM3 is also having the same issue, but I don't have any spare fan left and broke the faulty ones when trying to clean them.

Edited February 28, 2020 by V3DPrinting

[V3DPrinting 11]

I've been too quick ...

 

Printing multiple parts has reproduced the problem, even with a brand new cooling fan.

Again heat creep and the print core jammed with a 3d Solex Hardcore + 0,8 mm nozzle.

[Torgeir 280]

Hi David,

 

Very interesting this, first I do not have an S5 and neither an UM3 E. But I have a "custom" made UM2..

I've never seen this issue as you explain here, however all what you said make sense and happen.

When you said "heat creep", I'll suppose the cold side of the extruder is not cold enough. Sure it is possible, -but this can also be a sign of another problem, the feeder. The problem I've seen is that when printing first levels and ironing, the pressure in the bowden tube increase. For an UM3 this will increase the drag forces, when the filament is pressed upward in the bowden tube.

An S5 do not have much of this problem and this is because of the "track line" made by the knurled wheel is on the underside of the looped filament in this printer, while the UM3 types have the "track line" going on the to of the looped filament. This make a huge difference when printing with high pressure in the feeding system. 

I've many times been thinking, it mus be possible to just swap the two feeder units in order to have same feeding properties as an S5. Just leave the feeder motor (stepper) and swap just the feeder unit(?). This would not change anything in software or whatever, but just improve your UM3 allot..  Well, I do not if ultimaker already made this modification. 

Well, I did this in 2015 when I built my printer and been used the "inner track" all the time without any issues!

 

Wish you good luck and hope you will have more inputs from the community about this problem.

 

Thanks

 

Torgeir

 

 

 

 

 

 

 

[V3DPrinting 11]

18 hours ago, Torgeir said:

When you said "heat creep", I'll suppose the cold side of the extruder is not cold enough. Sure it is possible, -but this can also be a sign of another problem, the feeder. The problem I've seen is that when printing first levels and ironing, the pressure in the bowden tube increase. For an UM3 this will increase the drag forces, when the filament is pressed upward in the bowden tube.

 

Very accurate analysis of the problem.

In fact it seems at the first look to be an heat creep.

But after replacing the printcore cooling fan and printing successfully the same part without ironing, even with multiple parts, it is more an excessive pressure in the print core, having the filament softened too much.

It is easy with PLA to soften it @55°C or just above.

 

I have changed the PTFE lining of the Hardcore and ensured that the filament path is cleaned, it hasn't change much the issue or the symptoms.

 

BTW I have Bondtech QR3.0 extruders on my two UM3E, so I am sure that the filament is properly extruded (FW have been tweaked accordingly with Bondtech specs).

 

I am currently doing a test on my S5 with the same part, similar Hardcore, same slicing parameters, with ironing enabled.

 

18 hours ago, Torgeir said:

I've many times been thinking, it mus be possible to just swap the two feeder units in order to have same feeding properties as an S5. Just leave the feeder motor (stepper) and swap just the feeder unit(?). This would not change anything in software or whatever, but just improve your UM3 allot..  Well, I do not if ultimaker already made this modification. 

 

I would rather change my S5 extruders by Bondtech extruders, as the UM extruders are grinding quite easily the filament and a bit of a pain to clean. Only showstopper at the moment, no filament sensor integrated on the Bondtech extruders.

 

If you have the opportunity to swap to Bondtech on your UM2, don't hesitate.

Edited February 29, 2020 by V3DPrinting