Micro Swiss hot end stringing

[stejan 1]

I recently upgraded my Ender 5 Pro hot end to the Micro Swiss all metal Hotend (thanks to GregValiant for the recommendation) and i am very pleased with the difference it has made to my prints. The only problem i have now is more stringing then before.

This is due to having to reduce the retraction distance from 6.5mm to 3.5mm on the recommendation of Micro Swiss to stop any potential PLA clogs.

Is there another way to help control the stringing, i have tried lowering the temp a little but hasnt really helped?

 

 

[GregValiant 1,344]

When you changed the hot end you had to change the thermistor?  Did you run the Auto-Tune routine and adjust the PID settings?

The recommended retract distance wasn't sufficient for me either.  I did back down my retractions and at 5.0 for PLA it's been fine.  When I print PETG I run the retraction distance at 6.5 and that hasn't been a real problem either.  I do clean out the hot end prior to long prints just in case and I dropped my PETG temp by 10° and that helped as well.

If you have not calibrated your E-steps, then that would need to be done.  Over-extrusion can make stringing worse as the pressure in the nozzle is higher and so it takes longer to bleed off.

In the Cura Marketplace is a plugin for Calibration Shapes.  It adds different models and then you select the Cura post-processor for any model and the setting will change at the layers you pick.  There is a retraction tower available as well as a temperature tower.

[stejan 1]

Hello Greg

I didnt have to change the thermistor or the heater cartridge. The hotend was just a straight swap for the original one.

I checked the e-steps and its actually slightly under extruding, so i have left that has its easier to deal with then over extrusion. I will try upping the retraction distance to 4.5-5mm and try a few calibration shapes that you have suggested.

Thanks again

[GregValiant 1,344]

If you watch the bowden tube where it goes into the locking fitting on the hot end while you move the print head back and forth along the X beam by hand, you will see the bowden rotating at least a little bit.  That is an unavoidable problem as the bowden would twist if it didn't rotate.

Within the fitting are knife blades that cut into the bowden to keep it from backing out of the fitting.

As the bowden rotates, those little knife blades cut deeper into the tube.  That causes the tube to loosen and a gap eventually forms between the end of the bowden and the heat break.  In your new hot end that is well above where the gap used to form at the back of the nozzle.

What I do about it is every 30 to 35 hours of print time I take the hot end apart and clean it out good, and trim 4 or 5mm off the end of the tube and then re-assemble it.  I do the same just before I start any longish print.

These machines run for hours at a time and they don't complain much.  Some preventative maintenance can go a long ways towards keeping the complaints to a minimum.