FLSUN Delta 3D Printer

My modified FLSUN Kossel Delta


I have a modified FLSUN Delta printer that I purchased through Aliexpress. Currently I have it connected to a Raspberry Pi 3 that is running Octoprint, so that I can manage the printer wirelessly.


You can find the FLSUN Kossel Delta on Aliexpress here.

I’ve upgraded the hotend to a volcano kit from Aliexpress. You can read about the hotend here.

I’ve added a 50mm blower fan to the effector, instead of the stock 40mm fan. You can read about the fan here.



My printer runs the developers branch of Marlin, available here. To modify and upload Marlin, I use the Arduino IDE which is available here.


To get it working properly with my FLSUN delta that does not use a heated bed, I had to do the following steps:

  • Obtain the latest Marlin firmware and Arduino IDE
  • Open Marlin.h using the Arduino IDE
  • Search for #define TEMP_SENSOR_BED
    • Change it from 5 to 0, to disable heated bed
  • Search for #define Z_MIN_ENDSTOP_INVERTING
    • Change it to false
  • Search for #define Z_MIN_PROBE_ENDSTOP_INVERTING
    • Change it to false
  • Save, upload to printer

When the updated firmware was uploaded to the printer, I connected using Octoprint. I configured the Z-Offset and extruder steps using the terminal. You could also use Pronterface or Repetier Host as alternatives. I simply set my Z-Offset to 0.3, since that is what I’ve always had good success with. To do that, I just sent the commands

  • G33 p1
  • G33
  • M851 Z0.3
  • M500

G33 is the autocalibration procedure.

M851 sets the Z-offset to 0.3.

M500 saves the information into the EEPROM.

My extruder was out of calibration, so I had to fix that. To calibrate my extruder steps, I did the following:

  • Preheat printer to PLA
  • Remove filament from hotend
  • Mark location on filament
  • Extrude 100mm of filament
  • Measure the length that was extruded ( in my case, 66.9mm )
  • Calculate new e-steps using the following formula
    • 100/66.9*100 = 149.477
  • M92 E149.477
  • M500

The M92 command sets the extruder steps/mm to the desired value, and then it’s saved using M500.

To get higher maximum speeds for extrusion and retraction, I did the following:

  • M203 X200 Y200 Z200 E100
  • M500

The M203 command sets the maximum speeds for the X, Y, Z and extruder motors. Using a higher maximum extruder speed lets you retract faster, which can help with stringing.


Simplify3D Settings

I use S3D to slice the files that I want to print with my FLSUN. These are the settings that I used prior to upgrading to the volcano kit. Infill amount depends on the part, but I usually use rectilinear infill at around 25%. My print speeds are usually between 60mm/s and 120mm/s. It really depends on the object that’s being printed and the layer height. I find that printing above 80mm/s can cause some banding issues, so I’ve mounted the top of my printer to a bookshelf to add rigidity to the frame.


I’ll update this later with my current settings when I have dialed in my volcano settings a bit more.


Automatic Leveling


It can be tricky to get reliable measurements using the old effector design and a physical limit switch. To get the limit switch as sensitive as possible, tighten the adjustment screw until the switch clicks, and then slowly back the screw out until the switch releases by itself.


Hotend Cooling

The volcano kit that I’m currently using has a dedicated 30mm fan for the heat break. The single stock 40mm fan on is unimpressive, so I attached a 50mm blower fan to the stock effector. I made a simple nozzle attachment using Fusion 360 to better direct air towards a printed part. You can read about it here.


The frame of my printer wasn’t very rigid without modification. Using braces, I was able to increase print quality significantly. My preferred brace is made by Stonedge, and is available on Thingiverse here.


Extruder Cooling

I’ve increased the current to the extrusion motor slightly in order to achieve higher maximum speeds and rates of acceleration. I salvaged a heatsink from an old desktop computer, and attached it to the extruder motor to compensate for the heat.

Heatink On Extruder Motor
Heatink On Extruder Motor