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MK3S and RAFT issue  

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kankan
(@kankan)
Active Member
MK3S and RAFT issue

Hello

I am trying to print some game figurines.

As those are little, i created a 1 layer raft with a 0,2 Z distance.

PLA, fst layer : 220° then 210
Bed : 70 / 60

I reduced manually raft printing to 40mm/s

Calibration is fine.

As raft begins to print, all is ok, but after few minutes it looks like some PLA sticks to the nozzle and raft goes wrong. (see attached screen).

I have no issue after 1st layer printing, all goes ok but i am not able to print a correct raft.

Any advices ?

Thanks for you help and support.

This topic was modified 4 years ago 2 times by kankan
Posted : 29/07/2020 6:52 pm
bobstro
(@bobstro)
Illustrious Member
RE: MK3S and RAFT issue

Looks like your Live-Z is too low (too negative) and the nozzle is so low that filament can barely squeeze out on the first layer.

If you have not already done so, try using Jeff Jordan's "Life Adjust" procedure for calibrating your Live-Z setting. It is much easier to use and understand than the on-board routine and much easier to make mid-print adjustments accurately with. In general, start high (less negative) and work lower (more negative) in large increments (e.g. 0.1mm) until the filament starts to stick on its own. When you've got your Live-Z setting adjusted properly, you should be able to gently rub the extruded lines on the PEI surface without dislodging them.  Then start lowering (more negative) the level until there are no gaps between layers. You should not be able to peel the lines apart after printing, but the top should be regular. 
 
Once you get your Live-Z set properly (and the bed properly clean), you most likely will not need rafts at all, even for fine miniatures. Here's a sample of miniatures being printed with support with a 0.25mm nozzle:
 
 
My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Posted : 29/07/2020 7:07 pm
Andrew liked
kankan
(@kankan)
Active Member
Topic starter answered:
RE: MK3S and RAFT issue

Thank you @bobstro, i will have a look at this solution.

Regards

Posted : 29/07/2020 7:12 pm
kankan
(@kankan)
Active Member
Topic starter answered:
RE: MK3S and RAFT issue

I manage to get a proper square and homogeneous layers with this test.

Despite, when printing my file, i am still facing issues with raft.
If i don't use raft, support layers do not print properly.
At the beginning, print is doing well, but after a certain time, printed lines are curled an PLA sticks to the nozzle.

I do not understand what i am doing wrong.

Strange thing is that i already printed this file correctly before, but i do not manage to do it do again.
In between, i printed some ABS and Wood.. would that be possible that it stucked the hotend ?

I attached my gcode but forums system seems not handling it :/

Thanks for helping.

This post was modified 4 years ago 4 times by kankan
Posted : 29/07/2020 8:34 pm
kankan
(@kankan)
Active Member
Topic starter answered:
RE: MK3S and RAFT issue

Typically :

First layers on the right : ok
Then second layers on the left : KO :/

 

Posted : 29/07/2020 8:45 pm
bobstro
(@bobstro)
Illustrious Member
RE: MK3S and RAFT issue

Before doing too much else, I'd recommend a good clean of the PEI sheet. This will eliminate adhesion issues. Even if you don't think this is the cause, it's always a good idea to make sure your PEI surface is clean before trying any other fixes. If it's a smooth PEI sheet, take it to the kitchen sink and give it a good dunk with Dawn (original formula, no vinegar or hand softener variants) dishwashing soap or your local equivalent (e.g. Fairy in UK). Use a clean paper towel to clean it off, and another to dry it. Avoid using any sponge or cloth that has been in contact with grease. Above all else, avoid touching the PEI print surface. Once it's good and clean, you should be able to use 91%+ isopropyl alcohol between prints, 100% acetone when that fails , and another dunk when acetone fails. Worst-case, use a 3M 7445 ScotchBrite pad or equivalent on smooth PEI to give it a very light buff, but only infrequently. If you've got a textured powder-coated PEI print surface, the official instructions are to use 91%+ isopropyl alcohol on it only. Rumors persist that some tribes deep in the jungle have had good luck getting started with these sheets by giving them a wipe with 100% acetone and a dunk with Dawn. Either way, there's no real warranty on these sheets. YMMV.

My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Posted : 29/07/2020 8:53 pm
Neophyl
(@neophyl)
Illustrious Member
RE: MK3S and RAFT issue

I think the one on the right looks slightly to low, not alot but a bit.

Posted : 29/07/2020 9:07 pm
kankan
(@kankan)
Active Member
Topic starter answered:
RE: MK3S and RAFT issue

Just to give a return
A proper bed cleaning solved the issue.
The raft is now very clean 🙂
Thanks bobstro for advices.

This post was modified 4 years ago 3 times by kankan
Posted : 31/07/2020 8:35 am
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