Bronzefill help - layering issues?  

RE: Bronzefill help - layering issues?

So I just did the thing you're not supposed to do and made adjustments while it was printing. I reduced flow factor to 95% from 100% and the marks instantly disappeared. Have I solved my problem permanently? I hope so

RE: Bronzefill help - layering issues?

3d Printing is a process with a lot of interacting options. 
Ideally the initial slicer results will be correct, however raising the nozzle temperature may make your filament flow more easily which can result in over extrusion. whilst giving good interlayer adhesion. 
Lowering your nozzle temperature can make the filament flow less easily and can lead to poor inter layer adhesion, reduced flow and a dull appearance to your model surface

Over extrusion is usually more apparent on solid layers. on layers with less than 100% infill, any over extrusion can effectively squeeze out sideways and make the walls of the model slightly wider (which can spoil the look of the sides of your model) 
However, on top solid layers there is nowhere for this extra filament to go, so it tends to squeeze up and around the tip of your nozzle. leaving furrows in the surface of the model. 
With PLA these furrows are simply a nuisance which makes the top surface of the model look ugly.  with PETG the nozzle tends to collect tiny amounts of the filament that it is trying to push out of the way, building up small blobs of filament stuck to the nozzle. after a while these blobs reach a size where they are unable to remain stuck to the nozzle, and they become detached an fall into your model (Usually at the most inopportune moment) these blobs may have discoloured, over a period of time, or may be remnants of a different filament colour.  so they are visually unwelcome, but they may also become lumps in the extrusion path, that the nozzle will crash into on later passes, Causing deflections in the filament path, or collisions which can knock the part off the build plate, or stall the printer motors and cause a layer shift. 
The hot end thermistor is not a thermometer, it is a simple sensor, which reacts with an input on your XBuddy controller, to estimate the temperature of your nozzle. 
and generally it does a pretty decent job. however it is very unlikely to be holding the nozzle temperature at exactly the displayed temperature. 
If you can accept that as a reality, and you are aware that the actual temperature of the nozzle will affect the performance of the filament then you may become more comfortable with changing parameters, to improve print performance
in the case of your bronze fill, it would appear that reducing your flow rate, improved the surface finish. (that is fine... and if you remember to reduce the flow rate next time, your next print will be improved too...   but one day, you will forget...!)
you could change the amount of filament extruded by changing either the extrusion multiplier in the slicer filament settings, or by changing the flow rate in the slicer 'Custom Gcode Start Gcode' in either printer settings or filament settings (which is more effort and less easy to manage) 
once you have changed the  slicer you can save the settings as a personal profile for use in the future... 
I Don't know how much you changed the flow rate, but for example, if reducing the flow rate by 5% improved the surface finish, next time you use the same filament try slicing with an extrusion multiplier of 0.95 instead of the default extrusion multiplier of 1  this should have a similar effect. You could then save the filament profile as say 'Bronzefill PLA 95pc' or some other name that will remind you what you have changed in the profile. then next time you prepare to slice the same filament, you can select that profile. 

Note reducing the temperature may give a similar result as reducing the extrusion multiplier. 
A worn nozzle may reduce back pressure in the extruder and increase actual filament flow 

Stringing may be caused by higher nozzle temperatures, most people address stringing by increasing retraction,  if you use too much retraction, you can run into issues with heat creep. different nozzle materials can cause more or less heat transfer to the filament in the nozzle...  your thermistor in the hotend, estimates the temperature of the heatblock where it is located, it cannot estimate the actual temperature of the filament leaving the nozzle. 

All of these factors and more can affect the performance of your printer, and the quality of the prints you produce is, to some degree controlled by your mastery of the various factors before or during the print process. 

You say that you did something you are not supposed to do... (Changing flow rate during a print, in this case...)  
If you hadn't changed the flow rate, you would not have noticed that doing so improved the surface finish.  and you wouldn't have made your post, and I woudn't have suggested that you change the extrusion multiplier
This is a hobby, you are allowed to experiment. 

Last night I was getting some stringing on a print, so I lowered the nozzle temperature during the print and the stringing stopped.  I would have had to abandon the print, adjust the retraction and re slice, to see if increased retraction would have helped. (From my experience adjusting retraction often doesn't help with stringing)
typically the Prusa default is 0.7 to 0.8mm for PLA and PETG, I usually use 0.4mm (this can reduce heat creep) 

Build plate cleanliness is a major factor in adhesion... general belief is to wipe the build plate with Isopropyl alcohol (IPA),  I Find that washing the removable build plate with dish soap and Hot water,  then rinsing with hot water and drying immediately, works better for me...  I find that IPA tends to spread grease more evenly across the build plate and then evaporate, leaving the grease behind...    Your mileage may vary

I run my heatbed at 65 to 70C for PLA, because I get better adhesion... (this may be a factor of the inaccuracy of my heatbed thermistor  (but it works for all four of my FDM Printers))

lots of people will offer, often conflicting advice. 

I Suggest you consider all advice, apply it to YOUR Use case, try the advice if it looks likely to work, ignore unlikely options, but keep them in mind for future occasions. 
Be aware that there may be more than one possible solution to an issue, and which ever one works best for you, is the best solution at that time, for you. 

Above all... HAPPY Printing! 

Joan

RE: Bronzefill help - layering issues?

Joan, thank you for this incredibly informative and insightful response. I only glanced over it because I am working at this moment, but it looks like some of the things I have learned are confirmed here and some might not be so accurate or completely the way I thought I understood it. I'm saving this whole response to be referenced later multiple times. I spent so long looking for a good amount of information about printing with this material. I managed to patch together some bits of info from many different posts on many different forums, but none were as high value or thorough as your response here. Honestly this should be sticky and reference to anyone who is challenged with this material

Bronze (and copper) filled filaments are more heat conductive than regular filaments.  At 100% you are draining heat away from the deposition point far faster than the presets are intended work.  Try slowing the print and perhaps increasing the nozzle temperature.

100% fill is almost always a mistake, Even 90% will print more cleanly as there is somewhere for flow irregularities to smooth out.  For small toys you will often find 20% and two or three perimeters sufficient.

Cheerio,

RE: Bronzefill help - layering issues?

Diem, this is also very illuminating to me. And it totally makes sense. I'm kicking myself right now because I feel like I read somewhere that you are supposed to run it rectilinear at 100%. And so I thought I had the opposite issue, maybe it was flying out too quickly haha. This is why lowering the flow rate helped I guess, lowering the speed would produce a similar effect? And of course I was hearing occasional clicking sounds which I now understand to be jamming which is also related to excessive cooling. It's kind of insane how you can look at all this information, but assembling it properly takes so much effort until someone just presents it to you. I'm very grateful to you and other members who have assisted me here.

I think I will still choose a high density as I would like these to be dense and premium feeling in the hands. Thank you very much 

RE: Bronzefill help - layering issues?

Hi Jeremy, 
100% infill can be a bit of an issue. and often gives poor results.
however if you set enough bottom layers and top layers to completely fill the model with top and bottom layers, you effectively end up with 100% but no problem with infill...   

regards Joan

RE: Bronzefill help - layering issues?

Excellent, thank you. I should be able to figure out how to do that pretty quickly in the slicer or something I'm sure. An interesting observation I made is that the bronze color fab is set to a value of 1.12 by default

RE: Bronzefill help - layering issues?

Profiles are only guidelines, don't feel bad about changing them!

Joan