First prints! how to improve my prints?  

RE: First prints! how to improve my prints?

Then I have tried other prints :

The frog :

And the Benchy :

I find that the prints are well but not perfect.

I have some strings effect , some marks, I am not able to read the "3D benchy" at the rear of the boat.

Do you know what I can do now to improve my prints ?

Do you think a bed level correction may have an effect on that ?

Thank you

Ben

RE: First prints! how to improve my prints?

Your new first layer looks to squeezed to me. In my opinion, your first try was better.

Your top surface is over extruded. Try to reduce the extrusion multiplier filament setting by 2% (advanced setting).

RE: First prints! how to improve my prints?

I like the second Layer-1 best. First is a bit underextruded.  Prusa plaque is looking good. If it were PETG and not PLA, then I may say the first image is slightly better; but it'd depend on brand of PETG. Benchy layer 1 is looking a bit thick.

Live-Z a bit too high; best; a bit too low

Make sure you have your settings mesh leveling set to 7x7;  and I'd avoid the bed correction offsets - that mechanism is really designed for the 3x3 cal, and has been deprecated and now not very useful (I've turned mine off because I believe it adds problems). 

The swirls you've circled are wipes - done to reduce spiderwebs/stringing when the nozzle is moved to a different location.  

Top layers on the Prusa Logo and Benchy look good to me.  The only model I see an issue with is the frog; it looks like a very slight over extrusion on all layers.  And if that is the SD card 0.05 mm Treefrog gcode, you might try slicing it yourself and reprinting, and lowering the extrusion multiplier a few percent, or use the LCD menu Tune to reduce Flow from 100% down to 95%.

You'll find if you ask 10 people the same question, you may get 10 different answers.  We all have bias based on our own experiences.  

ps: you might check to make sure your Bondtech gear is accurately centered in the filament path... any offset to a side will cause over extrusion.

RE: First prints! how to improve my prints?

Thank you very much for your replies and advices!

I will do more prints/tests tomorrow with the 7x7 mesh leveling setting and with a lower flow of extrusion.

Posted by: Tim

ps: you might check to make sure your Bondtech gear is accurately centered in the filament path... any offset to a side will cause over extrusion.

l have check the bondtech gear and it is align with the filament path in one axis (front view) but in the other axis the filament is rounded due to the bontech gear. Do you think this cause over extrusion ?

Thanks

Ben

RE: First prints! how to improve my prints?

I have tried to draw this in order to explain my last question 😉 !

RE: First prints! how to improve my prints?

This positional error is a Prusa design flaw in the extruder housing.  A few people have redesigned the extruder housing to correct the misalignment, but so far the main issue has only been soft TPU like filaments are sometimes a problem to load.

RE: First prints! how to improve my prints?

Posted by: Tim

This positional error is a Prusa design flaw in the extruder housing.  A few people have redesigned the extruder housing to correct the misalignment, but so far the main issue has only been soft TPU like filaments are sometimes a problem to load.

 

Thank you! 

RE: First prints! how to improve my prints?

Hello everyone!

I have done more tests this weekend on my prusa ! I have followed your advices and used the cube to adjust the Extrusion Multiplier !

After few test I have found that 0.97 may be fine to me :

For me the top layer is better now! what do you think?

But I have layers that seem to be shifting at some locations: 

RE: First prints! how to improve my prints?

Then I have tried a more complex objet :

But I have some troubles in some points :

I have used the 0.97 Extrusion Multiplier that I have found previously to do the print and all default settings from prusaslicer (PLA, 0.15mm, 15%infill)

Do you think this problem come from extrusion multipier ? in-fill ?

What parameters can I change to improve the prints?

Thank you

Ben

RE: First prints! how to improve my prints?

Bridging.   When printing bridges, especially a layer that has circular structure, you often need supports. The printer cannot print in free air.  Enable Detect Bridging Perimeters then inspect your model in slicer after it's completed the slice.  Look for any bridged regions - there is where you'll see problems you may have to prevent with supports or changes to the model.

On you part, the slicer tries printing the perimeters first.  If that perimeter has nothing below it, the plastic droops down to where ever it lands.

RE: First prints! how to improve my prints?

Posted by: Tim

Bridging.   When printing bridges, especially a layer that has circular structure, you often need supports. The printer cannot print in free air.  Enable Detect Bridging Perimeters then inspect your model in slicer after it's completed the slice.  Look for any bridged regions - there is where you'll see problems you may have to prevent with supports or changes to the model.

On you part, the slicer tries printing the perimeters first.  If that perimeter has nothing below it, the plastic droops down to where ever it lands.

Thank you very much tim-m30 for your reply! I will try to improve that 😉

Is it normal that during preheat PLA is going off the extruder (slowly but continously) and then during the z calibration just before printing some depot of PLA go on the steel bed?

RE: First prints! how to improve my prints?

Ooze is part of printing.  I haven't heard of any sure cure to prevent it from happening with all filaments.  Gravity and fluids is part of the problem, and that's a difficult one to solve.

Most of us use custom gcode, and preheat the nozzle before calibration. This minimizes ooze yet still achieves a good cal.

Here's how I do it.  And there are 50 different ways if you ask 50 different people.

M115 U3.7.1 ; tell printer latest fw version
G90 ; use absolute coordinates
M83 ; extruder relative mode

; preheat things to a low temp, , get nozzle plastic mushy before driving into the bed with G28
M140 S[first_layer_bed_temperature] ; set bed temp so it starts warming up while we do other things
M109 S185 ; wait for extruder temp
G28 W ; home all without mesh bed level

; soak PINDA then level
G0 X50 Y50 Z1 F3000; this is a good PINDA heating position
M190 S[first_layer_bed_temperature] ; set & wait for bed temp to hit target
M860 S40 ; now wait until PINDA is >= 40C
G80 N7 R5; mesh bed leveling

; heat to extrude temp
G0 X0 Y-3.0 Z10 F3000; this is a good nozzle heating position
M109 S[first_layer_temperature] ; set & wait extruder temp

; purge
G1 Y-3.0 Z0.15 F1000.0 ; go outside print area
G92 E0.0
G1 X60.0 E9.0 F1000.0 ; intro line
G1 X100.0 E12.5 F1000.0 ; intro line
G92 E0.0
M221 S{if layer_height<0.075}100{else}95{endif}

RE: First prints! how to improve my prints?

Also with bridging, tick the Detect Bridging Perimeters in Print Settings  / Layers and perimeters and in Advanced  /Bridge Flow Rate, try reducing the 0.95 down to as low as 0.8, but you will have to download and try some bridging test pieces, these settings affect the initial first bridge string, too high (0.95) and your strand will sag, too low and it will break, get the speed, temperature cooling  and flow rate just right and you can pull surprisingly long flat bridges.

It really is a case of playing with settings and testing and make notes, it's very easy to lose track of what worked best.

Unfortunately, Slicer is not actually the best at bridging and sometime whatever you try, just doesn't seem to work, then you really are down a rabbit hole with linearity correction, jerk values, acceleration etc, but start with the first lot of settings to adjust to begin with and see how you get on.

Remember the bridge flow rate basically adjusts how taught your first bridge pull is, if it is too thin, then you may have to bring the flow rate back up a little and increase cooling.

Keep a notebook for settings for different filaments and also keep your filament dry.