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3D Solex Hardcore keeps clogging with PLA

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I have bought a 3D Solex Hardcore Pro and an Hardcore PVA some months ago, and I have a slot to set them up on my UM3E. I already have Bondtech QR3.0 extruders since the beginning, so not grinding...


I am currently printing some ColorFabb PLA Economy with the Hardcore - 0,4 nozzle, using Cura PLA settings for 0,15 layer height with some minor mods (first layer width, infill speed). The part is quite simple, being a plate (150 * 150 * 4 mm) with a text carved into it on 2 mm depth.

The print starts well, but as soon as it prints the letters, I have a clogging, then grinding and ruined print. I've done it twice, always the same results.

Then the PLA is really stuck into the print core


I have printed it with the legacy AA 0,4 printcore, no issue at all.


To me it looks like the retraction is too high with 2mm and there is molten PLA going on the cold zone during retraction. Or a manufacturing defect on the Hardcore.


Can anybody share his retraction settings on an Hardcore  ?


BTW, I'd like to have the email of 3d solex support team.


Any help appreciated.

Thanks in advance 


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I have and sell hardcores.  I help Carl with support for them.  I'm hearing maybe 2 issues?


1) There was a problem with some hardcores where after the print is over it won't retract the filament out of the hardcore.  Carl knows about this now and all newer hardcores don't have this issue - basically the upper portion of the hardcore (on some - I think maybe 10%?) was too small - smaller than the ptfe inner diameter - such that the melted filament has a larger diameter, then solidifies, then won't retract more than 10 or 20mm before getting stuck in the "trumpet" or in the top few mm of the heatsink.  If you have this issue I'd send it back and get a replacement.  In USA contact me at thegr5store@gmail.com.  In the rest of the world you can contact 3dsolex or contact your reseller.  3dsolex is just carl and one or two assistants who don't know much about 3d printing.  So really it's carl you'd be talking to if you contact them.  If this is an issue it's very obvious - you can't get the damn filament out - you can't get the damn core out.  One solution is to use a hot knife and cut it off just above the trumpet (heat exacto knife with flame).  Another solution is to remove the bowden, cut the filament, and with the nozzle hot push it downwards with some tool until it is inside the trumpet so you can remove the core.


2) The other issue is where it consistently stops printing during your print.  This *might* be due to excessive retractions which makes sense as it starts happening when it starts the letters.  Every printer is different and it matters how tight your bondtech is but typically the same spot of filament should be safe to go through the feeder 10 times.  20 times and you have a very good chance of it grinding to dust and failing.  Try restricting retractions to 5X on any give spot of the filament.  To do this you have to know your retraction distance which I think defaults to 6.5mm but just type "retraction" into the search above settings and look at what that value is.  Then copy that value to "minimum extrusion distance" and then set "maximum retraction count" to 10 (no more than 10 times - same piece of filament through extruder).


2b) Or it could be 100 other issues but retractions seems most likely


3) Note that the default 6.5mm retraction works quite well with hardcore so I recommend sticking with that.


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Hi gr5


Thanks for your valuable feedback.


The issue is not at the end of the print, so I don't think it's the old gen of hardcore. I've bought them (Hardcore Pro 4 + PVA BB) in September '17, they are recognized as "Hardcore" by the printer / Cura


First my settings regarding retraction are 2 mm retraction @25mm/s, and a max count of 25, no retraction between layers, no coasting, no extra prime amount. It's the same profile as the Ultimaker PLA.


If I use the Ultimaker AA Printcore, I've got no issue with that particular print. See the pic of the completed part and the failed one.

Failed print with Hardcore.jpgSuccessful print with Ultimaker Printcore.jpg

I've got Bondtech extruders on another printer for more than a year and half and I am pretty sure there's no grinding during that print on my UM3E.

I have made the tests with another spool of the same grade of PLA (ColorFabb Economy), same results.


I have done retraction tests using a different part with 8 retractions per layers, to avoid excessive number of retractions. At 1,5 mm it worked and failed at 1,75 mm. See pics.

It's similar with the issues I've got when having too much retraction on a full metal hot end (I'm using E3D V6 on my other printer).

Retraction test @1,5mm.jpgRetraction test @1,6mm.jpg

So I believe there's something wrong with the ptfe lining of the hardcore....


I'm based in France and bought my hardcores at 3D Jake, so I believe I need to contact Carl.

Edited by V3DPrinting

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That does not look like a print with excessive retractions.  Is it possible you sliced for 0.4mm but have a 0.25mm or 0.5mm steel nozzle on there instead?  As that would explain it right there.


I would try removing the nozzle and the bowden and with the hot end hot - manually feed some filament through the core to see how much back pressure there is.  On the UM2 the teflon would fail due to being at high temps for hundreds of hours - it would get soft and then when compressed it would squeeze the filament and add lots of friction.


On the Um3 the teflon should never get above 100C so it shouldn't deteriorate.  Ever.  But maybe it was always bad from the start.  It could be that Carl cut the teflon a fraction of a mm too long and when compressed in the core it squeezes the filament too much.  This would be obvious if you do my test.


Another possibility: the temp sensor is reading high and the nozzle is 20C cooler than we think it is.


That's all I can think of right now.  This is not a common problem - at least no one is reporting what you describe.  So far.  with many hundreds shipped.  But doing this quick test would be helpful and informative.  If you were in USA I'd have you ship it to me and I'd do the test myself.  Carl is pretty crazy busy keeping up with shipments.

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Agreed, the print is pretty much simple.

I've just checked the nozzle on the hardcore, it's a 0,4mm.


My Hardcore is brand new, less than 20 hours printing with PLA at 235°C max, so I don't think the teflon had been degraded by excessive heat.


I have another set of Hardcores, brand new for my second UM3E - which is currently back at Ultimaker, chassis had been twisted during shipping -.

I have bought them in December '17 at 3D Jake too.


I've just started to print a retraction test with the same spool of silver PLA Economy and the new Hardcore, using the retraction settings above (2mm retraction).

I'll let you now the result.


I'll do the suggested test without any nozzle too.


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I have successfully printed my retraction test with 2 mm retraction (Ultimaker PLA settings) with my second Hardcore. Just some slight banding linked with temperature a bit low due to the run in period of the Hardcore (220°C max for 2 hours).


I have done the suggested tests with the faulty Hardcore and temperature tests looks good.

However the test done without any nozzle is showing some difficulties to go through the core with the filament, as soon as it softens and expands. Reaching 3,1 mm diameter, the filament gets stucked in the core, close to the heatbreak.

So the problem definitely seems to be on the ptfe tubing.

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@tonydg - if it won't retract after a print this is a known issue and you should send it back.  It looks like you are in USA.  Send an email to thegr5store@gmail.com and I can ship you a new one with a return mailer.  It doesn't matter if you bought the original from me or some other reseller - I can send you a new one.  It takes me just 2 minutes to fix it.

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@V3DPrinting - I'll contact 3dsolex for you - I'm not sure what's going on here but I'm sure Carl aka @swordriff will send you a free replacement if you want.  Who did you buy yours from?


This test with no nozzle was with the block at 200C?


You kind of have to do the no-nozzle test above 180C because you can get a cylinder of pla in the heat break after a print is over but this warms up and comes loose when you start a new print.


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9 hours ago, gr5 said:

This test with no nozzle was with the block at 200C?


You kind of have to do the no-nozzle test above 180C because you can get a cylinder of pla in the heat break after a print is over but this warms up and comes loose when you start a new print.


Hi gr5.


Yes nozzle was at the working temp for the material 220 °C. And the jamming occurs when the PLA softens.

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