Hi guys !
First, I hope you are fine and your family too.

I dropped a few 3d printed parts to volunteers assembling face shields for people fighting the coronavirus.
I am pretty amazed how fast the 3d printing community reacted and how big it is becoming.

How to print "quickly and reliably" ?

I put quickly in bracket, because of the speed and the throughput. Yes for the throughput, speed matters but at what risk: reliability of the print and reliability of the machine. Quality must be good also, I do not only mean only aestethic but strong parts. In this context, we are dealing with technical parts.

Safe Slicer settings:

  • Larger Extrusion Width (Nozzle: 0.4mm -> 0.5mm, 0.6mm -> 0.72mm, 0.8mm -> 1mm): the geometry of the tip of your nozzle and the geometry of the part to print is the limiting factor.
  • Larger Layer Height but not overdo it ( Nozzle: 0.4mm -> 0.28 to 0.32mm, 0.6mm -> 0.4mm): some tuning is needed, the part can become too weak (see cooling/temperature parameters)
  • Tune number of perimeters/insets: given the geometry and the extrusion width you can manage to reduce the number of passes made and reduce/avoid the slow shaking movement of the top/bottom or the gap filling (overlap setting is your friend)
  • Use Concentric infill for Top/Bottom layers : linear infill or zigzag infill will just take more time
  • Cooling parameters: No fan on PETG print for instance, try to reduce it, it makes stronger parts and you can print faster. Set the print time per layer down to 5 or less seconds.
  • Keep the same print speed all around: if there is a bit of ringing it does not really matter for functional parts, always start with the print speed you are used to.
  • Keep a safe margin on the extrusion throughput , go to max 75% to 80% of the theoretical limit.
    • PTFE Short Block: 10 mm^3/sec
    • Full Metal Short Block: 15 mm^3/sec
    • Volcano Block: 30 mm^3/sec
    • Super Volcano Block: 80 mm^3/sec
    This is a basic rule of thumb, it depends on the material and the temperature used.
  • Print with higher temperature but do not overdo it , retraction can become ineffective after a threshold and other issues can come around

Extrusion Throughput Calculator

  • Extrusion Width (mm):
  • Extrusion Flow (%):
  • Print Speed (mm/s):
  • Layer Height (mm):
  • Extrusion Throughput (mm^3/s): {{throughput}}

Example printing a single part on PETG at 230C on an Ender 3

  • Standard Print Speed 40mm/sec, Retraction speed 25mm/s with 6mm
  • Layer Height 0.2mm with 0.4mm extrusion width, base line 2h22m
  • Same speed with larger extrusion width + cooling settings + concentric top/bottom infill: 0.4mm to 0.5mm with 0.2mm layer height: 1h52m (-20% on time)
  • Same speed with larger layer height (0.5mm extrusion width instead of 0.4mm):
    • 0.24mm layer height 1h33m (-33% on time)
    • 0.28mm 1h22m part good (-42% on time)
    • 0.32mm 1h12m part correct (-49% on time), extrusion flow about 6.4 mm^3/s
  • Increasing speed from 40mm/sec to 50mm/sec
    • 0.32mm 1h05m (part too weak, start to have under extrusion after short retractions sequences)
    • 0.28mm 1h12m part correct (-49% on time), extrusion flow about 7 mm^3/s

What about reliability ?

2 minor failures only caused by me ^^
Same quality of the prints over and over, print start and you go.

As you can see I did not increase the print speed and the move speed:

  • only a major change on the extrusion flow
  • a slight reduction in the number of moves performed by the printer due to the increased layer height, extrusion layer width
  • few tweaks here and there to keep the same print speed
  • reduce the number of small moves made by the printer using the concentric infill for top/bottom

Happy 3D Printing !

If you want to go further, faster and deeper:

  • First priority: Larger nozzle but geometry constraints on the model, and extrusion throughput limitations...
    • 0.6mm extrusion width, 40 mm/s, 0.4mm layer height will max out a PTFE Short Block (10 mm^3/s)
    • 0.8mm extrusion width, 40 mm/s, 0.5mm layer height will max out a Full Metal Short Block (16 mm^3/s)
    • 1.2mm extrusion width, 40 mm/s, 0.6mm layer height will max out a Volcano Block (28.8 mm^3/s)
  • Second limitation: Longer heat zone: Volcano, Super Volcano and even bigger (prevent overheating and damage the material)
  • Third issue: Extruder Torque, Bite and Speed
  • Tuning Speed, Acceleration, Jerk, Junction Deviation
  • Tuning Linear Advance Parameters and Retraction settings
  • Modification of the part to print faster

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