Klipper on an Ender 3
— January 11, 2021
This post will take you through the process of getting Klipper up and running from my experience of doing so on an Ender 3 Pro with some mods. I’m going to try to keep this post as up to date as possible while I learn/use new things.
Klipper is a 3d-Printer firmware. It combines the power of a general purpose computer with one or more micro-controllers. — Klipper Website
This means that Klipper will use the Raspberry PI CPU to calculate printer movements and then compress and transmit them to the micro-controller board for execution.
Installation Through Fluidd
Installing Klipper through Fluidd is an easy task. To install it you’ll need to download FluiddPI, a Raspbian based distro for Fluidd that comes with Klipper and everything you need pre-installed.
The following instructions will guide you through the process of putting the OS in the Raspberry PI.
Now on the Raspberry PI we need to build the software for the micro-controller.
For this follow the steps in Building and flashing the
micro-controller. In my case Flashing via USB
did not worked and I had to manually by
.bin build file out of the
Raspberry PI into my computer for then to pasted it into the SD Card and rename
flash.bin that the micro-controller recognize it and flash it.
For the final installation step we need to create the
printer.cfg file. This
file will contain details details on the printer such as pins, stepper motor
directions, drivers, probe, etc… We will talk about this in the Configuration
FluiddPI is not the only way to install Klipper. In fact there are other more popular ones. Like MainsailOS, KIAUH, and there’s always the manual approach. I haven’t experimented with any of these but MainsailOS seems to be very similar to what we did with Fluidd. KIAUH seems to be a script that will allow for custom and different setups.
My configuration file aka
printer.cfg is based on a SKR 1.4 Turbo
micro-controller with TMC 2209 drivers with sensorless homing, an original
BL-Touch v3 and a BMG extruder clone.
There are a couple of things that I should mention.
- Fluidd does require a couple of things to be added to that configuration file
!in front of a pin number will flip/reverse the functionality of said pin
step_distanceas the latter is deprecated and will be removed
- Verify that the endstops are not in
TRIGGEREDstate if they are not being triggered. Use
QUERY_ENDSTOPSfor this. You can read more about this in the verify endstops section
- Use the
STEPPER_BUZZcommand to verify the direction of your motors. For example:
STEPPER_BUZZ STEPPER=stepper_x. You can read more about this in the verify stepper motors section
Marlin for port mappings
While I was working on the mappings for my setup and wasn’t sure about something I used Marlin as the source of truth. This because I had a working configuration there.
For example for the SKR 1.4 I used this Marlin PIN mappings to look for probe pins and ensuring others were correct.
Proper Coordinates and Homing
At first I thought that by setting up
position_max: 235 on X and Y was more
than enough but in reality it was different.
Things I had to account for and measure to get proper homing:
- As I have a probe I added
[safe_z_home]. This is typically done near the center of the bed so that the probe has a safe surface to land. What I did here was to ensure that the nozzle landed in the correct coordinates I set. The bed is
117.5and ensured nozzle was in the middle (it didn’t at first, I explain why later in this section)
- Move the nozzle to each corner, meaning:
235,0and see where the nozzle lands
- In my case this didn’t worked for X correctly and I had to tweak the
homing_retract_distand set it to
0for it to gather 0 right where the end stop is. After that X started working as expected
- In my case this didn’t worked for X correctly and I had to tweak the
- I had to flip the
dir_pinso that the
position_endstopreflected the correct end stop position (
After these changes homing was working as expected.
In my case as I’ve mentioned before I have a BL-Touch. This type of probe even
though it’s very popular it might be more delicate
problematic than others.
There are a couple of things we need to do with the probe to make it work as intended:
- Test that the it works. Read the following BL-Touch section
- Calibrate the probe X, Y, and Z offsets. Read the following on probe
- I recommend to Home the printer before attempting anything
- You need to set
position_minto be able to complete the calibration in your Z axis to a negative number something like
Before you start ensure that your bed and or hotend is at room temperature.
This is the command to calibrate the hotend/extruder:
PID_CALIBRATE HEATER=extruder TARGET=200
This is the command to calibrate the heated bed:
PID_CALIBRATE HEATER=heater_bed TARGET=60
Once any of the above command run
SAVE_CONFIG for it to save the values to the
There are multiple ways to do bed leveling. As I have a probe I used the following two methods. Screw tilt Adjust and then Mesh Bed Leveling. Keep in mind that the former will throw the latter off-board so my recommendation is to do it in such order.
Screw Tilt Adjust
For this we need to do 4 things:
- Measure the screw diameter (Mine is M4)
- Know your probe offsets for X and Y
- Measure where are the screws located in the bed (both X and Y references)
- Once you know your screws location add your probe offsets
G28and then run
SCREWS_TILT_CALCULATEand repeat the tilt calculate procedure until flat
For example based on the above my configuration ended like this:
[screws_tilt_adjust] screw1: 74,47 screw1_name: front left screw screw2: 245, 47 screw2_name: front right screw screw3: 245, 217 screw3_name: rear right screw screw4: 74,217 screw4_name: rear left screw screw_thread: CW-M4
screw3X coordinate is
245after adding (sum) the X position with X probe offset; this forced me to change
245to be able to reach that coordinate.
Interpreting the output is simple.
CW 00:15 Turn clockwise 1/4 of a turn.
CCW 00:45 counter clockwise 3/4 of a turn.
For more information check adjusting bed leveling screws using the bed probe.
Mesh Bed Leveling
Mesh bed leveling is simpler than the Screw Tilt Adjust. The most important thing is knowing what are the mesh limits and the amount of probe points you’ll want. For example:
[bed_mesh] speed: 80 horizontal_move_z: 5 mesh_min: 18,18 mesh_max: 175,202 probe_count: 5,5 algorithm: bicubic
After this run
BED_MESH_CALIBRATE and wait for the results, then
to keep those numbers in the configuration file.
For more information check bed mesh configuration.
Calibrating Rotation Distance
For X, Y, and Z I “Obtained rotation_distance by inspecting the hardware” as this is the simplest way to do so. For E I went with the usual way e-steps calibration, but I recommend following this guide.
As I have a BMG extruder clone with a 3:1 gear ration I added this value to the configuration and ended with the following:
[extruder] step_pin: P2.13 dir_pin: !P0.11 enable_pin: !P2.12 rotation_distance: 22.95 # Calculated distance microsteps: 16 gear_ratio: 3:1 # BMG gear ratio ...
For more information check extruder configuration.
Pressure Advance in Klipper is the same as Marlin’s Linear Advance but the tuning part is different, and it seems to work better in Klipper (maybe it’s the way of tuning it).
Note: the calculated pressure advance value is dependent on the extruder, the nozzle, and the filament spool.
Steps for doing so can be found here, but in short:
- Download the square tower STL file
- Slice the STL using:
- Speed of 100mm/s of higher in internal and external perimeters
- ZERO infill
- ZERO to very low retraction (even if bowden tube)
- 0.28mm layer height (or higher).
SET_VELOCITY_LIMIT SQUARE_CORNER_VELOCITY=1 ACCEL=500
TUNING_TOWER COMMAND=SET_PRESSURE_ADVANCE PARAMETER=ADVANCE START=0 FACTOR=.020
- Start printing
Once the print is done, we proceed to the next step, measuring and doing the math to get our Pressure Advance value. Follow the official tuning pressure advance guide for how to measure and calculate the value.
I’ll explain how to set the Pressure Advance value within the slicer in a per filament basis in the Slicers section.
Macros are what you’ll think they are; a set of commands that are called from a single invocation.
These are the macros I currently have:
G29Load the default bed mesh profile
PAUSEPause the print (macro suggested by Fluidd)
RESUMEResume the print (macro suggested by Fluidd)
CANCEL_PRINTCancel the print (macro suggested by Fluidd)
PRIME_EXTRUDERMacro created to prime the extruder on start print
START_PRINTSet of instructions required at the start of every print (accepts parameters)
END_PRINTSet of instructions required at the end of every print
LOAD_FILAMENTMacro for loading filament on the BMG extruder clone
UNLOAD_FILAMENTRequired unloading filament on the BMG extruder clone based on the official BMG scripts
Check the macros in my printer.cfg file.
There are some Slicer requirements from Klipper. Most of the things are related to slicer features you should not use to avoid issues. Other than those I’m going to use this section to explain how to use Macros in you slicer.
For PrusaSlicer for example:
START_PRINT macro and passing whatever first layer temp to it:
START_PRINT BED_TEMP="M140 S[first_layer_bed_temperature]" EXTRUDER_TEMP="M104 S[first_layer_temperature]" ;
Add the Pressure Advance command to a filament:
SET_PRESSURE_ADVANCE ADVANCE=0.544 ;
That’s how a macro is used from within the slicer.