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Print quality?  

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SteveS
(@steves)
Trusted Member
Print quality?

Beginning to think it is a waste of money! Printing a simple flat part albeit with a fair few holes in it. On the original printer, sliced the stl, almost perfect print.

Been at this for near ten prints so far and getting nowhere near the quality. The last two attempts it didn't even stick to the bed! Using the same temps as on the original printer for PLA, 210 for both and bed at 60. 

Most of my work will likely be single colour but decided to get this to save mucking about with drums. its p*****g me off. 

Veröffentlicht : 24/09/2020 7:50 pm
jsw
 jsw
(@jsw)
Famed Member
RE: Print quality?

Please post photos of your failed prints, along with what filament you are using.

Is this a new printer, or was it working fine and then quit working fine?  What is the 'original printer'?

Most print issues have solutions that those here can identify.

Veröffentlicht : 24/09/2020 8:40 pm
SteveS
(@steves)
Trusted Member
Themenstarter answered:
RE: Print quality?

@jsw

the printer is an i3 MK3S that was built from a kit a few months ago. once set up its printed great with very few issues. Built the MMU2 kit on it start of the week and just started printing with it (setting up). Using the exact filaments i was using previously. Obviously had to change the printer type in Slicer and jig the settings i had. Carried out a First Layer cal that resulted in a reasonable change. 

Attached is apic of the plate that I'm trying. Fairly simple but with a few wee holes and slots in that make it a tricky print. The one on the left with the extra bit fitted (another print part glued) is from the original printer. moving to the right are various trials. Tried slicing it as a single and also with all elements (only two loaded just now). 

Had some issues where the extruder swiped the first layer bolt hole circles off the bed. Think that is sorted with adding 0.05 to the Z on the First layer. You can see its a progression but the last print on the right is marginally thinner than the original. Been using the same STL file so should be the same thickness.

If had read all the issues people have might have not bothered as most prints are single colour but bought the MMU as a toy to have. But if it cant even print my original parts in single colour to the same ease/quality as the standalone printer 🙁 its not worth having. 

I'll keep playing for a while but ..... 

Veröffentlicht : 25/09/2020 9:52 am
jsw
 jsw
(@jsw)
Famed Member
RE: Print quality?

That kind of a bracket should print very cleanly with your machine, with nice clean holes and no wild strings.

One suggestion, from one who has the MMU2S, for routine single-color prints, just operate it as a single-filament printer.  I have a switch to cut the power to the MMU and I just feed the filament directly into the extruder most of the time.

I see a few issues in your prints.  First and most obvious are those blobs or 'boogers' hanging onto prints 2 and 3.  There appears to be some scorching on the blob on print 3, which could be caused by a blob that was sticking to the nozzle breaking away.

Another looks like it may be underextrusion.  Lots of 'holidays' (to use a naval term) in the layer of the print that's facing the viewer.

Also some general inconsistency from print to print, which again may be underextrusion.  Your printer should definitely be able to produce prints that are not visibly different from each other.

As to 'last two attempts it didn't even stick to the bed!', this is most likely an adhesion issue (non-obvious contamination on the bed) or a Z calibration issue.

I would suggest running an in-depth Z calibration, using one of those 3x3 Z calibration files or equivalent (seen below).  All solid squares should be filled in smoothly with no significant difference from square to square across the plate.

Also, and sorry if this sounds pedantic, please be sure that the print bed is Really Most Sincerely Clean, which is very easy to overlook.

Maybe some of the others here will give their opinions as well.

 

Veröffentlicht : 25/09/2020 5:32 pm
SteveS gefällt das
SteveS
(@steves)
Trusted Member
Themenstarter answered:
RE: Print quality?

@jsw

thanks for the sage words of advice.

I ran another first layer cal and used digital callipers to measure the thickness and adjusted on that to get 0.2mm. I did note that there was a load of crud hanging underneath so did a heat up and cleaned as much of as i could with tweezers.

I then printed off a 20x20x20 X, Y, Z cube. Pictures attached.  measured between 19.99 and 20.01 so quite happy with that. 

Now back to dealing with stringing but reckon its temperature rather than extrusion flow. 

Cheers

Diese r Beitrag wurde geändert Vor 4 years von SteveS
Veröffentlicht : 26/09/2020 1:56 pm
jsw
 jsw
(@jsw)
Famed Member
RE: Print quality?

If you have a significant amount of filament residue on the nozzle, you can usually heat it up above the normal temperature of the filaments you are using, and let it sit a while.  Some of it may just drop off, and the rest can easily be removed with a soft wire brush.

I'm in the habit of routinely brushing off the nozzle area with a brass brush just before most (well, almost) prints.

Veröffentlicht : 26/09/2020 3:36 pm
SteveS gefällt das
SteveS
(@steves)
Trusted Member
Themenstarter answered:
RE: Print quality?

@jsw

good tip, will look at doing that in future.

Sorted stringing issues (wish i had taken a before pic, looked a mess!) by dropping from 215 to 210 for first layer and then 205 for the rest. Hardly a string in sight on reprint 🙂

Veröffentlicht : 26/09/2020 7:48 pm
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