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Z-Hop and retraction settings question  

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Grendelrt
(@grendelrt)
Eminent Member
Z-Hop and retraction settings question

Stringing started to become an issue on a lot of my prints. So I played with retraction settings for the first time. I found that the Z hop and retraction speed affected the stringing the most even after dropping temps 10C. My question is, the stock profile Z Hop is .6mm ,  Z length is .8mm and retraction speed is 35mm/s. I was thinking of changing my default printer setting (and using filament profiles for fine tuning) to .2mm z hop, .2mm z length, and 50mm/s retraction speed. I am using .1 zhop right now on a print no issues on this specific print. But my main concern is, what are some of the issues that may arise from dropping the default settings in general, are there any specific use cases where I need the much higher values?

Postato : 21/11/2020 6:10 pm
Neophyl
(@neophyl)
Illustrious Member
RE: Z-Hop and retraction settings question

With sloping thin sections on some prints you can get those edges curling up slightly, on those sorts of prints a low z hop can hit the curled up bit and potentially knock the print about. That said I run with the lowest z hop I can.  It also has the side effect of decreasing print time. I can’t compare my retract speed as I’ve got a geared extruder mod  but mine is set to 70mm and deretract of 35mm. 

Also if you are using one of the manual mmu techniques to do things like plates with different coloured letters in the first few layers then those need a higher z hop to skip over the already laid down sections. 

Postato : 21/11/2020 6:40 pm
Grendelrt
(@grendelrt)
Eminent Member
Topic starter answered:
RE: Z-Hop and retraction settings question
Posted by: @neophyl

With sloping thin sections on some prints you can get those edges curling up slightly, on those sorts of prints a low z hop can hit the curled up bit and potentially knock the print about. That said I run with the lowest z hop I can.  It also has the side effect of decreasing print time. I can’t compare my retract speed as I’ve got a geared extruder mod  but mine is set to 70mm and deretract of 35mm. 

Also if you are using one of the manual mmu techniques to do things like plates with different coloured letters in the first few layers then those need a higher z hop to skip over the already laid down sections. 

Thanks, do you have a default Z hop you keep as a starting point, .6mm seems a little high to me. What are the advantages of doing the deretract speed, you are the second person I have seen quote a 50% retract speed for their deretract.

Postato : 21/11/2020 6:53 pm
Neophyl
(@neophyl)
Illustrious Member
RE: Z-Hop and retraction settings question

I like my z hop to be around 2 layers high so as I do the majority of my printing in 0.2 my z hop is set to 0.4.  On my cr10 with 0.6 nozzle that I use for larger/draft prints I do a lot of 0.3mm layers, the z hop is set to 0.5 on that printer.

On the retract/de-retract speed I once saw it explained like using a straw, if you 'suck' the filament back quickly its more likely to cleanly remove the molten plastic and a de-retract is basically an extrusion so while its probably going to still be warmer you don't want to try and force it out too quickly, you want that process to be more measured.

Don't know if that analogy is true but it seems to work and kind of makes sense.  Of course if someone wants to do some proper scientific testing and prove it one way or another then great.

Postato : 24/11/2020 7:38 am
Grendelrt
(@grendelrt)
Eminent Member
Topic starter answered:
RE: Z-Hop and retraction settings question
Posted by: @neophyl

I like my z hop to be around 2 layers high so as I do the majority of my printing in 0.2 my z hop is set to 0.4.  On my cr10 with 0.6 nozzle that I use for larger/draft prints I do a lot of 0.3mm layers, the z hop is set to 0.5 on that printer.

On the retract/de-retract speed I once saw it explained like using a straw, if you 'suck' the filament back quickly its more likely to cleanly remove the molten plastic and a de-retract is basically an extrusion so while its probably going to still be warmer you don't want to try and force it out too quickly, you want that process to be more measured.

Don't know if that analogy is true but it seems to work and kind of makes sense.  Of course if someone wants to do some proper scientific testing and prove it one way or another then great.

Thanks for the reply! I like your 2 layer thought process =)

Postato : 24/11/2020 1:52 pm
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