Fine-Tuning Print Parameters

[last updated: 2022-11-21]
3d printing home page
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On this page...
• Calibrate Printer to Filament
• Reduce Stringing
• Set live-z (squish)
• Reduce globbing
• Get good first layer PETG adhesion
• Reduce warping on print bed
• Make supports easy to remove

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• (link to:) Great tutorial from Simplify3D
• (link to:) all3dp.com

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• Calibrate Printer to Filament:
• Use digital calipers (resolution at least .02mm) and measure filament diameter at several places and average
• Enter diameter value in PS: Filament Settings > Filament: Diameter
• from forum: " 50mm/s retract and 25mm/s de-retract speeds "
• Reduce Stringing:
• Short version: reduce temperature; increase retraction;
  reducing temperature may require lowering print speed to prevent under-extrusion.
  (link to:) Matter Hacker tutorial.
  (link to:) YouTube - 3D Printing 101: on fine-tuning retraction, speeds, etc.
• Change/set retraction in Slic3r PE:
  Printer Settings > Extruder 1 (or whatever)
  enter desired Retraction Length
  (from MH tutorial) "In general, it’s unlikely you should need more than 5mm or less than 1mm."
• Change/set speed for non-print moves to high/max:
  Print Settings > Speed
  Speed for non-print moves: Travel 180 mm/sec default
• Evaluate the amount of stringing on a standardized part:
  Two 10mm cubes, 20mm spacing between them
• Set live-z: (squish):
• Live-Z: more negative = more squish
• I modeled an stl and sliced to gcode of a model with a single, ie. 0.2mm height, and 75x75mm filled layer.
  (got the idea from a nice post on prusa forum, but have lost the link)
• I start printing it, and every 10 passes or so I tweak the z-adjust.
  Be sure to write down the z settings for each area/section.
  Then when done you can easily see the setting that gives you the best fill.

• To adjust live-z during a print:
  menu ... live-z adjust ...
  turn knob CW to adj z more pos (less squish)
  turn knob CCW to adj z more neg (more squish)
• Reduce globbing:
• (link to:) Simplify3d tutorial on blobs
• Put a negative value in Print > Extruder > Retraction: "Extra length on restart"
• Increase jerk/retraction speed
• Turn on "Coasting" (available in Cura, but perhaps also called "Linear Advance")
  May be similar to "Wipe while Retracting" (Printer Settings > Extruder)
  Also may be similar to "Pressure Advance" [where?]
  Esp good for filaments that ooze, eg. PETG
  "Coasting stops extruding early in a move so that the string itself [and the pressure in the extruder] will finish the layer."
Prusa says ((link to:) here) that Linear Advance is 'built in' to the firmware. It's set in PS: Filament Settings > Custom G-code: Start G-code.
The code is: M900 K..., where the K value given is "the parameter affecting how much Linear Advance affects the print"
From pictures on link above, low values make sides concave, high values convex.
• Perhaps also try PS: Filament Settings > Filament Settings > Filament: Extrusion Multiplier
• Use "Combing" ???
  "Combing reduces the need to retract during travel moves by making sure that the nozzle oozes where you want it to on the way to the next point."
• Lower extruder temperature
• Use same speeds for all movements
• Clean nozzle with atomic/cold pull
• Get good first layer PETG adhesion:
• Slow down:
  Print > Speed > First Layer Speed: 20%
• Increase height of first layer:
  Print > Layers & Perimeters > First Layer Height: 0.3mm
• Reduce warping on print bed:
• Disable cooling fans
• Make supports easy to remove:
  In PrusaSlicer: Print Settings > Support material > Options
  Set Contact Z distance to 0.25 (default is 0.1)

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