Tag Archives: Marlin

Misc: MKS Monster8 Board Configuration with Marlin for Ashtar K & C

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Update:

  • 2022/11/20: Linux DFU upload details added
  • 2022/09/19: adding Ashtar C M503 dump beside Ashtar K
  • 2022/08/24: extending with part cooler fan and extruder fan connection
  • 2022/08/14: starting with the notes

Introduction

MKS Monster8 V1.0 board

These are just my notes for configuring Makerbase (MKS) Monster8 V1.0 for Ashtar K and Ashtar C:

  • STM32M407VET6 (ARM Cortex M4), 168MHz, 512KB Flash, 192KB RAM
  • 8 stepper drivers TMC2209, configured in UART mode
  • MKS MINI 12864 V3 display (the “V3” is relevant)
  • 12V power in/out
  • 3 hotends & bed heating
  • Price ~EUR 55 (2022/08) incl. 8 stepper drivers TMC 2209 and 12864 display

Pros:

  • cost effective, EUR 55 (2022/08) incl. 8x TMC 2209 stepper drivers and 12864 display
  • 8 stepper drivers: e.g. X, Y, Z1/Z2 (on-board splitter) and 5 extruders (e.g. E0, E1, E2, E3, E4 – but only 3 hotends possible)
  • TMC 2208 or TMC 2209 silent drivers
  • good connectors on board, clean setup
  • github with Marlin source (partially preconfigured) for Arduino*) & PlatformIO

Cons:

  • no RepRapFirmware
  • no Wifi (the V2.0 version has optional Wifi board to attach)
  • no Ethernet
  • requires Marlin with PlatformIO (tedious to configure, recompiling required, reupload)
  • limited documentation: actual details are scattered around

Stepper Motor UART Mode

As first putting in the jumpers on all the driver sockets, in my case I choose UART mode for each one of the 8 drivers:

Marlin with Arduino vs PlatformIO

As of 2022/08, it seems Arduino is no longer able to compile Marlin-2.x (various compile errors within Arduino), at least with this board and everybody moved on the PlatformIO, which really surprised me.

PlatformIO CLI

As of 2022/08 there is no Linux GUI for PlatformIO but only PlatformIO CLI, but it’s simple enough:

pip3 install platformio

Download

As next download the firmware, Marlin 2.0.x source from github:

git clone https://github.com/makerbase-mks/MKS-Monster8/

Building

By default the board is configured for Voron 2.4 CoreXY, with 3x Z motors and Z probing in the midst of the bed and other things, so I had to edit Marlin/Configuration.h:

  • #define MACHINE_UUID "..." (use online generator to generate one)
  • #define CUSTOM_MACHINE_NAME "Ashtar K #x L8", given Lead 8×8 are used
  • #define LINEAR_AXES 3
  • #define EXTRUDERS 1 (or 2, 3 max)
  • comment out //#define PREVENT_COLD_EXTRUSION needed for calibration
  • comment out //define COREXY
  • define [XYZ]_DRIVER_TYPE and E[012]_DRIVER_TYPE
  • #define DEFAULT_AXIS_STEPS_PER_UNIT aren’t that important, as one can define it with M92 and M500 saving to EEPROM
  • comment out //#define Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN
  • test motors regarding #define INVERT_[XYZ]_DIR true or false
  • test motors regarding #define INVERT_E[012]_DIR true or false
  • #define [XYZ]_HOME_DIR -1
  • #define X_BED_SIZE 380
  • #define Y_BED_SIZE 300
  • #define Z_MAX_POS 330

and Configuration_adv.h:

  • #define NUM_Z_STEPPER_DRIVERS 1 even when two Z-stepper motors are attached
  • if you want an automatic E0 fan which turns on only when nozzle is heated: #define E0_AUTO_FAN_PIN PA1 and attach extruder fan (watch polarity) on FAN1/J12 connector

once those changes are made, build the firmware:

cd marlin\ firmware/MKS_MONSTER_Marlin-2.0.x/Marlin-2.0.x/
platformio run

After a short while (~1min) it should finish successfully (if not, edit files).

Firmware Installation

SD Card Firmware Update

Use a SD card, e.g. 8GB with simple FAT filesytem, and copy .pio/build/mks_monster8_usb_flash_drive/firmware.bin and mks_monster8.bin on the SDcard.

Insert the SD card into the Monster8 board next to the USB connector, and turn off and on the board (power cycle) – wait 5-10 seconds so the new firmware is installed, then the display should show the Marlin splashscreen eventually, and the board becomes available as USB device, in my case as /dev/ttyACM0 on Linux Ubuntu 20.04 LTS.

DFU Util Firmware Update

  • connect board with USB cable and optionally select POWER USB (via jumper)
  • power cycle board (e.g. via USB cable) while you push BOOT 0 button in the center of the board briefly (~2 secs)
  • the device will appear as a new USB device

Linux: install apt install dfu-util and then

% sudo dfu-util -a 0 -s 0x0800C000:leave -D .pio/build/mks_monster8_usb_flash_drive/mks_monster8.bin -d 0483:df11
dfu-util 0.9

Copyright 2005-2009 Weston Schmidt, Harald Welte and OpenMoko Inc.
Copyright 2010-2016 Tormod Volden and Stefan Schmidt
This program is Free Software and has ABSOLUTELY NO WARRANTY
Please report bugs to http://sourceforge.net/p/dfu-util/tickets/

dfu-util: Invalid DFU suffix signature
dfu-util: A valid DFU suffix will be required in a future dfu-util release!!!
Opening DFU capable USB device...
ID 0483:df11
Run-time device DFU version 011a
Claiming USB DFU Interface...
Setting Alternate Setting #0 ...
Determining device status: state = dfuERROR, status = 10
dfuERROR, clearing status
Determining device status: state = dfuIDLE, status = 0
dfuIDLE, continuing
DFU mode device DFU version 011a
Device returned transfer size 2048
DfuSe interface name: "Internal Flash  "
Downloading to address = 0x0800c000, size = 178820
Download        [=========================] 100%       178820 bytes
Download done.
File downloaded successfully
Transitioning to dfuMANIFEST state
%

M503 Dump for Ashtar K

Ashtar K with 300×300 bed, single extruder:

> M503
-----
echo:  G21    ; Units in mm (mm)
echo:  M149 C ; Units in Celsius

echo:; Filament settings: Disabled
echo:  M200 S0 D1.75
echo:; Steps per unit:
echo: M92 X100.00 Y100.00 Z400.00 E95.00
echo:; Maximum feedrates (units/s):
echo:  M203 X300.00 Y300.00 Z5.00 E25.00
echo:; Maximum Acceleration (units/s2):
echo:  M201 X2500.00 Y2500.00 Z100.00 E5000.00
echo:; Acceleration (units/s2): P<print_accel> R<retract_accel> T<travel_accel>
echo:  M204 P3000.00 R3000.00 T3000.00
echo:; Advanced: B<min_segment_time_us> S<min_feedrate> T<min_travel_feedrate> X<max_x_jerk> Y<max_y_jerk> Z<max_z_jerk> E<max_e_jerk>
echo:  M205 B20000.00 S0.00 T0.00 X10.00 Y10.00 Z0.30 E5.00
echo:; Home offset:
echo:  M206 X-35.00 Y-3.00 Z0.15
echo:; Material heatup parameters:
echo:  M145 S0 H180.00 B70.00 F0
echo:  M145 S1 H240.00 B110.00 F0
echo:; PID settings:
echo:  M301 P22.20 I1.08 D114.00
echo:; LCD Contrast:
echo:  M250 C255  
echo:; Power-Loss Recovery:
echo:  M413 S1
echo:; Stepper driver current:
echo:  M906 X500 Y500 Z700
echo:  M906 T0 E500

echo:; Driver stepping mode:
echo:  M569 S1 X Y Z
echo:  M569 S1 T0 E
ok
>

M503 Dump for Ashtar C

Ashtar C with 400×400 bed, 3 extruders with single nozzle:

> M503
-----
echo:  G21    ; Units in mm (mm)
echo:  M149 C ; Units in Celsius

echo:; Filament settings: Disabled
echo:  M200 T0 D1.75
echo:  M200 T1 D1.75
echo:  M200 T2 D1.75
echo:  M200 S0
echo:; Steps per unit:
echo: M92 X100.00 Y100.00 Z3200.00 E102.00
echo:; Maximum feedrates (units/s):
echo:  M203 X500.00 Y500.00 Z2.00 E120.00
echo:; Maximum Acceleration (units/s2):
echo:  M201 X9000.00 Y9000.00 Z50.00 E10000.00
echo:; Acceleration (units/s2): P<print_accel> R<retract_accel> T<travel_accel>
echo:  M204 P1500.00 R1500.00 T1500.00
echo:; Advanced: B<min_segment_time_us> S<min_feedrate> T<min_travel_feedrate> X<max_x_jerk> Y<max_y_jerk> Z<max_z_jerk> E<max_e_jerk>
echo:  M205 B20000.00 S0.00 T0.00 X10.00 Y10.00 Z0.20 E2.50
echo:; Home offset:
echo:  M206 X0.00 Y-5.00 Z0.15
echo:; Material heatup parameters:
echo:  M145 S0 H180.00 B70.00 F0
echo:  M145 S1 H240.00 B110.00 F0
echo:; PID settings:
echo:  M301 P22.20 I1.08 D114.00
echo:; LCD Contrast:
echo:  M250 C255
echo:; Power-Loss Recovery:
echo:  M413 S1
echo:; Stepper driver current:
echo:  M906 X700 Y700 Z1000
echo:  M906 T0 E700
echo:  M906 T1 E700
echo:  M906 T2 E700

echo:; Driver stepping mode:
echo:  M569 S1 X Y Z
echo:  M569 S1 T0 E
echo:  M569 S1 T1 E
echo:  M569 S1 T2 E
echo:; Tool-changing:
echo: Z2.00
ok
>

Fans

Part cooler fan is plugged into FAN0/J11, and if you enabled extruder fan (temperature dependent), plug it in FAN1/J12.

Part Cooler Fan (FAN0/J11) and Extruder Fan (temperature sensitive) FAN1/J12
  • Part Cooler Fan (FAN0): cools the extruded filament, the filament which becomes the part you print
  • Extruder Fan (FAN1): cools the heatsink near the heatbreak, when attached to FAN1/J12 it only runs when the hotend is hotter than 50C° as defined in Marlin.

The jumpers are needed next to the fan connectors to define the voltage, either Vin (left) which is 12V-24V depending on the power input of the board, or 12V (middle) or 5V (right).

MKS Monster8 V1.0 Pins
MKS Monster8 V2.0 Pins

Multiple Materials/Colors

With 8 stepper drivers one is able to run:

  • 3+1x motors for X, Y, Z(2)
  • 5x extruders (colors or materials), the board supports 3 hotends (3 different temperatures)

Monster8 V1.0 vs V2.0

The boards differ in physical layout such as connectors, but the firmware is the same, incl. the pin for the hotend cooler fan (which switches on conditionally when hotend heats up).

Update V2.0

Board Comparison 2022

As of 2022 (I intend to update this) following boards are suitable for my cases:

MKS Monster8 V1.0/V2.0 & 12864 displayMellow Fly Super8 V1.2 & 12864 displayDuet 3 Mini 5+ & Duet 3 Mini 2+Duet 3 MB 6HC & Duet 3 Expansion 3HC
Price55 EUR80 EUR155 EUR (120+35)385 EUR (255+130)
Stepper Drivers887 (5+2)9 (6+3)
Stepper Connectors9 (dual Z)879
Hotends345 (2+3)6 (3+3)
USBYES (USB-C)YES (USB-C)YES (MicroUSB)YES (MicroUSB)
WIFI– / YES3)YESYES1)YES1)
Ethernet––YES1)YES1)
FirmwareMarlin 2.xMarlin 2.x
RepRapFirmware 3.4.x		RepRapFirmwareRepRapFirmware

Alternatively, there are Duet 2 & 3 clones available on the market:

Duet 2 WIFI CloneDuet 2 WIFI OriginalDuet 3 6HC FYSETC Clone with Duet 3 3HCDuet 3 6HC Original with Duet 3 3HC
Price30-50 EUR2)175-185 EUR1) 225 EUR (150+75)385 EUR (255+130)
Stepper Drivers559 (6+3)9 (6+3)
Stepper Connectors6699
Hotends227 (4+3)6 (3+3)
USBYES (MicroUSB)YES (MicroUSB)YES (MicroUSB)YES (MicroUSB)
WIFIYESYES1)–YES1)
Ethernet–YES1)
YES
YES1)
FirmwareRepRapFirmwareRepRapFirmwareRepRapFirmwareRepRapFirmware
  1. either WIFI or Ethernet
  2. without or with display
  3. MKS Monster8 V2.0 has Wifi module option

As of 2022, RepRapFirmware has become quasi standard in professional level 3D printing; while a lot of people run Klipper & Marlin together I can’t see the point doing this*) but rather have a more capable microcontroller like the Duet boards have to run the printer and manage WIFI / Ethernet at the same time. The only reason to run Klipper on a Single Board Computer (SBC) setup like Raspberry Pi is cost and enhance simple microcontrollers functionality this way.

MarlinKlipper & MarlinRepRapFirmware with Duet
CPUs1x Simple Microntroller1x SBC + 1x Simple Microcontroller1x Capable Microcontroller
ConnectivityUSB onlyUSB, Ethernet and/or WIFIUSB and Ethernet or WIFI
Configuration3x .h files, recompiling requiredsingle .cfg filesingle .g file**)
Boot Time3sKlipper 30s, Marlin 3s3s

*) running different kinematics on the SBC converting G-code on the fly might be a reason
**) multiple .g file can be used optionally

If you are cheap, buy the Duet clones, if you want to support Open Source and Open Hardware community, buy from Duet3d.com direct, pricing is +45% of the clone prices, whereas the Duet resellers add another +15% (Clone: EUR 150, Duet3d.com: 220 EUR, Reseller 255 EUR)

RepRapFirmware: Mind the SD Card

Whether to run an original Duet board or a clone, one thing though one might pay attention to is the SD card, it is the weakest link as far I can tell:

  • SD card needs to be present at all time to provide configuration
  • SD card is not written regularly to unless the logging is enabled

After power-cycling the board, as it was in a strange state no longer responding to G-code properly, the display remained blank, no response to G0/G1 – after investigation it turned out, a single file vanished from the SD card: config.g – the main configuration file, and that is bizarre. The board appeared to be broken, when in truth, the SD card came to its end of life of operating reliably already after only ~1.5 years. The SD card was the one originally shipped with. In this light, a Marlin-based board requiring no SD card being present operates more reliable, unless one uses an industrial grade SD card.

References

3D Printing: Ashtar K #2 with Diamond Hotend (Multi-Color) with RAMPS 1.4

by · published Technology , , ,

Updates:

  • 2019/04/17: more photos of examples incl. macro closeups
  • 2019/04/15: 16 palette mixed colors from cyan, yellow and glowing magenta (CMY) photo added, best result of mixing colors
  • 2019/04/12: added Firmware Retraction changes in Marlin, updated Trinary Color Palette
  • 2019/04/10: initial post

I print with Ashtar K #1 and #2 since a couple of months and since about 4 months with Ashtar C #1 successfully, and thought to convert Ashtar K #2 (300×300 build-plate) with a Diamond Hotend with 3 colors/extruders, renamed to “Ashtar K E3“:

20190411_063229

Producing stuff like this:

20190410_221650

20190415_174333

Cyan, Yellow, Glowing Magenta, Cyan Z-transition

Firmware (Marlin) & Hardware (RAMPS 1.4)

In the Marlin following settings are required:

Configuration.h

#define EXTRUDERS 1

Counter intuitively using 3 extruders with single nozzle in mixing operations, keep EXTRUDERS 1 and do not enable SINGLENOZZLE but leave is disabled.

Enable MIXING_EXTRUDER:

/**
 * "Mixing Extruder"
 *   - Adds a new code, M165, to set the current mix factors.
 *   - Extends the stepping routines to move multiple steppers in proportion to the mix.
 *   - Optional support for Repetier Firmware M163, M164, and virtual extruder.
 *   - This implementation supports only a single extruder.
 *   - Enable DIRECT_MIXING_IN_G1 for Pia Taubert's reference implementation
 */
#define MIXING_EXTRUDER
#if ENABLED(MIXING_EXTRUDER)
  #define MIXING_STEPPERS 3        // Number of steppers in your mixing extruder
  #define MIXING_VIRTUAL_TOOLS 32  // Use the Virtual Tool method with M163 and M164
  #define DIRECT_MIXING_IN_G1    // Allow ABCDHI mix factors in G1 movement commands
#endif

Use E0 for Extruder #1, E1 for Extruder #2, and use an Stepper Extender for Extruder #3:

diamond-hotend-ramps14

Configuration_adv.h

Enable FWRETRACT:

#define FWRETRACT // ONLY PARTIALLY TESTED
#if ENABLED(FWRETRACT)
#define MIN_AUTORETRACT 0.1 // When auto-retract is on, convert E moves of this length and over
#define MAX_AUTORETRACT 10.0 // Upper limit for auto-retract conversion
#define RETRACT_LENGTH 3 // Default retract length (positive mm)
#define RETRACT_LENGTH_SWAP 13 // Default swap retract length (positive mm), for extruder change
#define RETRACT_FEEDRATE 45 // Default feedrate for retracting (mm/s)
#define RETRACT_ZLIFT 0 // Default retract Z-lift
#define RETRACT_RECOVER_LENGTH 0 // Default additional recover length (mm, added to retract length when recovering)
#define RETRACT_RECOVER_LENGTH_SWAP 0 // Default additional swap recover length (mm, added to retract length when recovering from extruder change)
#define RETRACT_RECOVER_FEEDRATE 8 // Default feedrate for recovering from retraction (mm/s)
#define RETRACT_RECOVER_FEEDRATE_SWAP 8 // Default feedrate for recovering from swap retraction (mm/s)
#endif

​​pins_RAMPS.h

Add following lines below E1_CS_PIN:

#define E2_STEP_PIN 58
#define E2_DIR_PIN 57
#define E2_ENABLE_PIN 59
#define E2_CS_PIN -1

In case the Extruder #3 (E2) runs reverse, invert it in Configuration.h:

#define INVERT_E2_DIR true

Mixed Colors Prints

Two ways to print mixed colors:

  • M163/M164: define mixing ratio palette and define a virtual tool per mixing ratio which can be used as “T<n>” in Gcode later
  • M165: define mixing ratio right away

Virtual Tools Color Palette

Within ~/.config/print3r/printer/ashtar-k-2-e3.ini I added in start_gcode different palettes:

Trinary Palette

A general palette of 19 mixed colors using 3 colors defined in Gcode:

M163 S0 P1 
M163 S1 P0 
M163 S2 P0 
M164 S0

M163 S0 P0 
M163 S1 P1 
M163 S2 P0
M164 S1

M163 S0 P0 
M163 S1 P0 
M163 S2 P1
M164 S2

M163 S0 P1 
M163 S1 P1 
M163 S2 P0
M164 S3

M163 S0 P0 
M163 S1 P1 
M163 S2 P1
M164 S4

M163 S0 P1 
M163 S1 P0 
M163 S2 P1
M164 S5

M163 S0 P1 
M163 S1 P1 
M163 S2 P1
M164 S6

M163 S0 P2 
M163 S1 P1 
M163 S2 P0
M164 S7

M163 S0 P2 
M163 S1 P0 
M163 S2 P1
M164 S8

M163 S0 P2 
M163 S1 P1 
M163 S2 P1
M164 S9

M163 S0 P1 
M163 S1 P2 
M163 S2 P0
M164 S10

M163 S0 P0 
M163 S1 P2 
M163 S2 P1
M164 S11

M163 S0 P1 
M163 S1 P2 
M163 S2 P1
M164 S12

M163 S0 P1 
M163 S1 P0 
M163 S2 P2
M164 S13

M163 S0 P0 
M163 S1 P1 
M163 S2 P2
M164 S14

M163 S0 P1 
M163 S1 P1 
M163 S2 P2
M164 S15

M163 S0 P2 
M163 S1 P2 
M163 S2 P1
M164 S16

M163 S0 P2 
M163 S1 P1 
M163 S2 P2
M164 S17

M163 S0 P1 
M163 S1 P2 
M163 S2 P2
M164 S18

After that, the virtual tools T0 – T18 are available, printing different mix ratios.

Full Saturated True Color (Hue) Palette

The following (source) defines 16 different mix ratios of common colors with Cyan, Yellow and Magenta:

; Cyan
M163 S0 P1
M163 S1 P0
M163 S2 P0
M164 S0

; Ocean
M163 S0 P5
M163 S1 P1
M163 S2 P0
M164 S1

; Blue
M163 S0 P1
M163 S1 P1
M163 S2 P0
M164 S2

; Violet
M163 S0 P1
M163 S1 P5
M163 S2 P0
M164 S3

; Magenta
M163 S0 P0
M163 S1 P1
M163 S2 P0
M164 S4

; Raspberry
M163 S0 P0
M163 S1 P5
M163 S2 P1
M164 S5

; Red
M163 S0 P0
M163 S1 P5
M163 S2 P1
M164 S6

; Orange
M163 S0 P0
M163 S1 P1
M163 S2 P1
M164 S7

; Yellow
M163 S0 P0
M163 S1 P0
M163 S2 P1
M164 S8

; Spring Green
M163 S0 P1
M163 S1 P0
M163 S2 P5
M164 S9

; Green
M163 S0 P1
M163 S1 P0
M163 S2 P1
M164 S10

; Turquoise
M163 S0 P5
M163 S1 P0
M163 S2 P1
M164 S11

; Cyan-Brown
M163 S0 P2
M163 S1 P1
M163 S2 P1
M164 S12

; Magenta-Brown
M163 S0 P1
M163 S1 P2
M163 S2 P1
M164 S13

; Yellow-Brown
M163 S0 P1
M163 S1 P1
M163 S2 P2
M164 S14

; Brown
M163 S0 P1
M163 S1 P1
M163 S2 P1
M164 S15

After that, the virtual tools T0 – T15 are available, printing different mix ratios.

I used following code to purge 30mm (10+10+10mm) filament from all 3 colors at once at the very beginning (start_gcode):

M165 A0.33 B0.33 C0.33  ; 1/3 for each filament
G92 E0
G1 E30 F100     ; extrude 30mm
G92 E0

Additionally, define the firmware retraction:

M207 F3000 S4 Z0.3   ; set firmware retraction 50mm/s 4mm, 0.3mm zhop
M209               ; use firmware retraction

Printing

For test purpose I have:

  • Extruder 1 (E0 or A): glowing magenta PLA
  • Extruder 2 (E1 or B): violett PLA
  • Extruder 3 (E2 or C): white PLA

As such I prepared 16x 20×20 plates with 1 layer height:

print3r --printer=ashtar-k-2-e3 --slicer=cura --random-placement --scad --multiply-part=16 --output=plates-16.gcode slice 'cube([20,20,0.2])'

which gave me plates-16.gcode which I edited and inserted the “16 colors palette” Gcode, and after each “WALL-INNER” lines I added T0, T1 etc. T15 to switch to another tool (mixing colors ratios) for each plate:

There is no purge block, but I wanted to see how fast the switch is possible. Some issues are once the mix changes the first 10-20mm extrusion may come out under-extruded.

20190410_150238

16 mixed colors from 3 colors (Glowing Magenta, Violet, White)

20190415_110908

16 mixed colors from 3 colors (Light Blue/Cyan, Yellow and Glowing Magenta)

With light-blue/cyan, yellow and glowing magenta gave decent results: the green turned out well, the orange as well, even the violet and darker blue came out well.

And finally some cubes with 2- and 3-color transitions in the Z axis:

20190410_221650

where I used print3r directly, using --layer-gcode=... feature (I just added 2019/04/10):

2-color 2 phases: use variables a2 (fades 1..0), and b2(fades 0..1):

  • fade A->B: '--layer-gcode=M165 A${a2} B${b2}'
  • fade B->C: '--layer-gcode=M165 B${a2} C${b2}'
  • fade A->C: '--layer-gcode=M165 A${a2} C${b2}'

20190415_174447

Violet to White, Glowing Magenta to White Z-transition

3-color 3 phases: use variables a3 (fades 1..0 first half), b3 (fades 0..1..0), and c3 (fades 0..1 for second half):

  • fade A->B->C: '--layer-gcode=M165 A${a3} B${b3} C${c3}'
  • fade A->C->B: '--layer-gcode=M165 A${a3} B${c3} C${b3}'

20190415_174910

Glowing Magenta, White, Violet and Cyan, Yellow, Glowing Magenta Z-transition

3-color 4 phases: use variable a34 (1..0..0..1), b34 (fades 0..1..0..0) and c34 (fades 0..0..1..0)

  • fade A->B->C->A: '--layer-gcode=M165 A${a34} B${b34} C${c34}'
  • fade A->C->B->A: '--layer-gcode=M165 A${a34} B${c34} C${b34}'

20190415_174333

Cyan, Yellow, Glowing Magenta, Cyan Z-transition

20190415_192732

Cyan, Yellow, Magenta, Cyan Z-transition: Cyan, Green, Yellow, Orange, Pink/Magenta, Violet, Blue

Partial Mixing

20190410_200839At closer inspection, the Diamond Hotend doesn’t perfectly mix the filament:

  • left/back: white PLA
  • front/center: glowing magenta PLA
  • right/back: violet PLA

 

Now, let’s rotate the XYZ Hollow Cube around the Z axis:

In front with “X” the violet prominently comes soon, the “Y” (right-hand side) looks OK, whereas the back side the white/violet transition is not smooth, the same for the left-hand side.

Jamming

Quickly after trying more complex and longer prints, I experienced filament jamming:

20190411_150126

I chose Violet -> Magenta -> White Z-axis transition, and the jamming occured with the Magenta PLA about 5-6min after the start, not always the same height; I tried several things like feeding a minimum of 5% of each filament, but then lower the print temperature from 205C to 198C, and things worked:

20190411_151429

LowRes-Minecraft and LowRes-LowPoly Easter Eggs (35mm height, 0% infill, no support)

I print with first layer (layer 0) 210C usually on cold bed, and dropping to 195C for the rest usually let the nozzle temperature sink below 190C, sometimes even 185C before reaching 195C again due the thermal mass of the Diamond Hotend, and below 190C risk of under extrusion is high (layer 2-3), therefore I now use 195-198C to limit that risk.

It’s recommended to increase printing temperature with Diamond Hotend to achieve better mixing of the filament, yet, it seems also increases the risk of clogging/jamming of filament as in my case. Although, I currently use an 40mm fan on top of the Diamond Hotend instead of 50mm fan – the heatsinks left/back and right/back are warm, whereas the center/front (with magenta) is cooler. So, I might use a bigger fan and see how things behave then.

That’s it.

3D Printing: Ashtar C Printer: CoreXY Belt Routing

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After some delay of parts, I finally was able to finalize the belt routing and configure the firmware for Ashtar C #1:

Belt Routing

belt-routing

CoreXY belt routing of Ashtar C

Early on I decided to separate belts of motors A and B in the Z axis, so they would not cross as such, and also hoped one axis of the carriage holding the X beam would allow some idlers to redirect the belts – to save space and keep frame dimension and build (or printable space) dimension close.

The Bowden tube and the wires of the hotend are preliminary arranged:

20190101_170842

Firmware

To configure the Marlin firmware turned out not that simple, as CoreXY has its own interdependencies of A & B motors: first X axis was reversed, whereas Y axis worked correctly, the INVERT_X_DIR setting on Configuration.h of Marlin did not help, it reversed the stepper motor direction, but not the actual X axis direction. After many attempts to use COREYX instead of COREXY I ended up

  • swap cables of A & B stepper motors
  • keep #define COREXY
  • #define INVERT_X_DIR = true and #define INVERT_Y_DIR = true

and X and Y direction worked correctly.

Preflight (no extrusion, just X & Y axis movement testing):

The stepper drivers still need some tuning, as I saw or rather heard a few missed steps at fast movement.

X & Y Endstops

The preliminary positions of the endstop are:

  • X endstop resides on the X beam left-hand side (USE_XMIN_PLUG)
  • Y endstop resides on the right-hand backside, (USE_YMAX_PLUG and HOME_DIR_Y 1)

Z Axis

I postponed the actual details of the Z axis, as my main concern of the design was to have a good CoreXY setup and then see how I would achieve the Z axis.

In order to use 625ZZ bearings I started to use them as idlers directly (after cleaning the grease off their surfaces) and also use them to increase contact surface when driving a closed belt which drives 3 or 4 threaded rods M6 x 500mm:

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Since the surface of the threaded rods is rough, I realized I need dedicated bearings to hold the rods at the bottom, otherwise the friction would wear on the mounts and increase its diameter. So, the Z axis isn’t finalized yet, but close.