Posted on

Setup E3D Chimera/Dual Head on Duet WiFi/RepRapFirmware – and watercooling intro

Some time ago I bought the, at the time, new E3D Chimera+ Watercooled hotend and some extra stuff for it.


(sorry, misplaced photo of unpacked new Chimera+. I’ll see about digging some up!)

I’ve had a bit of issues getting it up and running as the first pump/Reservoir combo I bought from China didn’t work.

A reservoir is just a container where extra water is stored to make sure the system doesn’t run low. It also makes it easier to fill up and maintain, and catch the air/bubbles the bubbles you always have in a new watercooled setup. All of these things can be done without a reservoir, but it makes it a lot easier to get going and easier to maintain and keep a look on waterlevel.

I’ve done a lot of custom watercooling on computers, servers and rack equipment (yes, you can watercool a switch and U1 server), so went into the basement to find some spare equipment.

So, why did I buy a Chinese pump when I allready had a lot of watercooling equiptment the smart reader might ask, and the answer is simply that I figured my pumps were far too powerfull, and yes, they were still too powerfull when I looked at them again, hehe.

My tubings also didn’t match precisely, which I could have worked around and I needed to print some Nylon barbs to work as an adapter from E3Ds bowden solution to the tubes – You can now buy a Water-cooling barbed adapter kit seperately from E3D, which you couldn’t at the time of my purchase… I could do all this, but I still needed a new pump and reservoir.

I could buy a new pump/reservoir combo from China and wait one more month and hope it worked this time…

Or I could buy the Watercooling kit from E3D and get going. This would also make it possible for me to get a look at their new stuff and document it for you in the form of STEP files on GrabCad.

  1. Prelude
  2. Configure RepRapFirmware
  3. Tool Definition
    1. Tool0
    2. Tool1
    3. Tool definition section code
  4. BLTouch offset from Nozzle0
    1. Mesh Grid
    2. The combined section code is like this
  5. Calibrate BLTouch for Z-offset
    1. Find Z-Offset
  6. Define Leadscrew coordinates for Autolevel
      1. How to use it
      2. X coordinates for M671
      3. Y Coordinate for M671
      4. The combined section code is like this
  7. Setup probe coordinates in bed.g

2) Configure RepRapFirmware

Since I’m using my new xBot Chimera+ Watercooled Carriage I need to both setup a new Tool (the second nozzle) which encludes configuring nozzle distance from each other, configure BLTouch placement in regards to my Nozzle, and reset my Z-offset of my BLTouch. Finally I’ll need to redo the coordinates used to do my probing sequce to autolevel my bed.. yes, it’s a lot actually, but taking it one step at a time, and it’s usually not really that hard.

I’ll recommend writing down what you do, if you are like me and work well with having documented what you do and what to do. 
Regardless of the details of your documentation I’ll strongly recommend you do not delete or change existing setup lines, but instead comment them out using ; and create a new line of code, for your new setup.

3) Tool Definition

Lets first add a new tool using M563 for our second nozzle by editing the config.g file. This includes defining which heater and extruder we are going to be using as well as the relative position it has to the first nozzle.

You can name the Tools if you like, which will show up in your web display. I’ve named them Nozzle1 and Nozzle2 respectively.

3.1) Tool0

First tool is Tool 0 (P0), using Extruder 0 (D0) and Heater 1 (H1)
M563 S"Nozzle1" P0 D0 H1 ; Define tool 0
The Tool ofset is defined using G10 and in relation to the origin of the head. I might have used the point between the two nozzles as the origin and defined offset as -10 and +10 on the X axis respectively, but I’m going to be using Nozzle 1 as the origin. This means the offset coordinates for Tool0 are all just 0.
G10 P0 X0 Y0 Z0 ; Set tool 0 axis offsets

3.2) Tool1

The second nozzle looks like: Tool 1 (P1), using Extruder 1 (D1) and Heater 2 (H2)
M563 S"Nozzle2" P1 D1 H2 ; Define tool
The offset of the second nozzle to the first one is +20 on the X axis, so it will look like this:
G10 P1 X20 Y0 Z0 ; Set tool 1 axis offsets

Note on Fans: If you use the default recommend fan0 as print object cooling fan, you do not need to define a fan.

 

3.3) Tool definition section code:


; Tools
; P = Tool Nr
; D = Extruder Drive nr
; H = Heater used
M563 S"Nozzle1" P0 D0 H1 ; Define tool 0
G10 P0 X0 Y0 Z0 ; Set tool 0 axis offsets
;
M563 S"Nozzle2" P1 D1 H2 ; Define tool 1
G10 P1 X20 Y0 Z0 ; Set tool 1 axis offsets

4) BLTouch offset from Nozzle0

Next up we need to modify the BLTouch position in relation to the Head Origin, which in our case is the first nozzle Tool0.

It is our G31 in the config.g we need to modify. Just leave the Pnnn value as is.

The BLTouch is placed 10mm to the right of the nozzle, which is X10 and 24,26mm in front of the nozzle, which translates to Y-24.26.

Important: Do not use , as normal in metric systems when denoting decimals when defining the gcode.

We are going to set Z offset to 0, and setup this again later to match our new carriage.

This means our (base) G31 looks like this:
G31 P600 X10 Y-24.26 Z0 ; BLTouch offset in relation to Tool0

4.1) Mesh Grid

My Mesh grid is spanning the area from X5,Y5 up to X205,Y165 and probing every 10mm.

Tip: When doing initial setup of the Bed I like to make the probing distance larger, at 20mm to get a rough map to use for manual adjustment.

It means my M557 looks like this:
M557 X5:205 Y5:165 S10 ; Define mesh grid

4.2) The combined section code is like this:

; ## Nozzle Distance from BED - Offset. Higher value, closer to bed.
; Set Z probe trigger value, offset in realtion to nozzle and trigger height adjustment
G31 P600 X10 Y-24.26 Z0 ; Zero offset
M557 X5:205 Y5:165 S10 ; Define mesh grid

5) Calibrate BLTouch for Z-offset

Previously we reset the Z offset using G31 to Z, so it now looks like this:
; ## Nozzle Distance from BED - Offset. Higher value, closer to bed.
; Set Z probe trigger value, offset in realtion to nozzle and trigger height adjustment
G31 P600 X10 Y-24.26 Z0 ; BLTouch offset in relation to Tool0

So, lets go find the proper Z offset:

5.1) Find Z-Offset

  1. Move your sensor to around the middle of the bed. You might even want to make a Macro for this, as it can be usefull for many different cases.
    1. Herer’s a simply macro I named Move to Centerbed, where I home X and Y first:
      G28 XY
      G1 X97 Y120 F4000 ; Move probe to middle of bed
      G28 Z

      We need to home Z before we can continue, or it fails to test properly after firmware 1.21
  2. Move Z untill your nozzle is about 10cm (4 inches) from the bed.
    1. Be ready to click the Emergency Stop in case the probe misbehaves.
    2. Now issue G30 command.
    3. Your BLTouch should now send the Pin Down and your bed should now move up (or nozzle down) untill the BLTouch is triggered.
    4. Hit the Emergency Stop if it didn’t stop or the Pin didn’t drop down.
      1. Go through your deployprobe.g if the Pin didn’t drop down.
  3. With #2 successfull you put your sensor over the middle of the bed and jog Z axis untill your nozzle is touching the bed.
    1. Note: If it refuses to move as it has reached Z-minima you can type in G92 Z5 to tell it, that you are 5mm from Z=0.
  4. Once your nozzle just touched the bed tell the machine we are at Z=0 by issuing:
    G92 Z0
  5. Move Z 10mm away from nozzle
    G1 Z10
  6. Now send G30 S-1 at which point the Pin drops down and the z-axis closes the gap until the BLTouch is triggered.
    1. Z now stops moving and reports the current position without changing anything. Note down the reported value.
  7. You might want to repeat the steps 4-6 a few times to insure consistency. I personally just did it 2 times and later did final adjust by looking at print starts.
  8. Mine reported the following:
    G30 S-1
    Stopped at height 2.4mm
  9. I should insert 2,4mm now, but I’ll detract 0,2 as a safety margin, so I’ll change the Z parameters in the G31 line from 0 to 2.2.
    G31 P600 X10 Y-24.26 Z2.2
    Important: The higher Z value the closer you move the nozzle and bed to each other! It’s better to have a value too low here than too high to avoid the nozzle and bed doing a mating game when homing.
    Important: If you later redo the offset method you should reset the offset to Z0 before starting or it might lead to strange results I’ve found on some occasions.

6) Define Leadscrew coordinates for Autolevel

Since the xBot is using 3x independent motors for our Z axis we need to define the coordinates of the leadscres in relation to the hotend and carriage combination we are using.

This can be a bit harry, but lets start by looking at the xBot Probe Point Helper Drawing I made for this purpose:


The Drawing is not made specifically for the my current xBot Carriage Chimera+ Watercooled but instead lising the dimensions in relation to the rear center manual finger screw. I did it this way to make it easier for people to use their own favorite carriage and hotend solution.

If you want indepth explanation on what I’m doing here, you should read the section on Z-Leadscrew Placement.

6.1) How to use it:

Before starting you should check if your X and Y -maxima coordinates should be changed. I needed to change mine.

Now home your X and Y axes, then move your carriage to the center rear, so BLTouch is lined up to the rear fingerscrew.
The position reads as X97 and I measure the BLTouch to be placed 20mm in front of fingerscrew, meaning my nozzles are actually placed exactly at my Y-Maxima, which is Y215.

6.2) X coordinates for M671

First leadscrew

Front right is placed 153,6mm to the right of the center rear fingerscrew.

Since my center is X97 it amounts to: 97+153,6 = 250,6 for first X coordinate.

Second leadscrew

Front left is placed 153,6mm to the left of center.

So 97-153,6 = -56,6 for second X coordinate.

Third leadscrew

Rear center is placed at the center, so we use 97 for our third X coordinate.

This adds up to the first part of the M671 line, which looks like this so far:
M671 X250.6:-56.6:97

6.3) Y Coordinate for M671

First Leadscrew

Front right is placed 241,1mm in front of the rear center leadscrew, which has the coordinate Y215 since my Nozzles are exactly on top of it and it corresponds to my Y-Maxima

So we take the Y position 215 and detract 241,1, which gives us 215-241,1 = -26,1 for our first Y coordinate

Second Leadscrew

This is placed at the same point on the Y axis as the first leadscrw, so -26,1 for our second Y coordinate

Third Leadscrew

This on is placed 63,5mm further out the Y axis, so:

215 + 63,5 = 278,5 for our third Y coordinate

When adding the Y coordinates to our M671 codeline we get the following:
M671 X250.6:-56.6:97 Y-26.1:-26.1:278.5 S3

The trailing S3 defines maximum correction the leadscrews can do. Default is 1.

6.4) The combined section code is like this:

; Define the X and Y coordinates of the leadscrews.
; Must come after M584, M667 and M669
; S = Maximum correction
; Motor order: Front right, front left, rear center.
; Snn Maximum correction to apply to each leadscrew in mm (optional, default 1.0)
M671 X250.6:-56.6:97 Y-26.1:-26.1:278.5 S3

7) Setup probe coordinates in bed.g for G32

Now its sime to review our bed.g file to see if it’s still valid.

It’s not really crucial where you probe, but you should try to make the probe points as close to each leadscrews as possible.

I set all mine to 2mm from min and max for each axis.. just in case a wire or something got between my carriage and the printer edges.

The Third point needs to take into account how BLTouch is placed 20mm in front of the nozzles, as it wouldn’t be able to probe at Y215 but at best at Y190. I’ve deducted the extra 2mm and landed on Y188.

It might be a bit fiddly to figure it out, as the actual probing coordinates is for the nozzle, so can be confusing when looking at it.

; bed.g
; Called using G32
; Called to perform Autolevel using 3-point probe
;
M561 ; clear any bed transform
; Made allowances for BLTouch being up to 30mm in front of nozzle. Typical is 27mm+/-
Probe 3-point
M401 ; Deploy probe - deployprobe.g
G30 P0 X207 Y2 Z-9999 ; Front Right
G30 P1 X2 Y2 Z-9999 ; Front Left
G30 P2 X97 Y188 Z-9999 S3 ; Center Rear
M402 ; Retract Probe - retractprobe.g