Mixing and Switching Extruders

[thinkyhead]

Combined #3655 Mixing Extruder and #3994 Switching Extruder. [concise diff].

Mixing Extruder

Most of the email I receive about Marlin concerns this feature. So here is the implementation built on top of the current RCBugFix for those interested parties.

• New feature option MIXING_EXTRUDER_FEATURE
• Support for M163, M164 as in Repetier Host
• Additional command M165 to set the mix in one line
• Optional support for ABCDHI mixing parameters in G1 commands (reference implementation)

Concise diff: https://github.com/MarlinFirmware/Marlin/pull/3655/files?w=1

Switching Extruder

As requested by Peter Stoneham.

This PR adds support for an extruder with:

• A single stepper motor
• Two nozzles
• Two pinch-wheels, either side of the drive-gear
• A servo to switch the pinch-wheel
• Reversed stepper direction for T1

As with other funky extruders, this maintains a single E axis at the stepper level. The E stepper direction is reversed automagically —transparently at the stepper level— whenever the tool changes.

[emartinez167]

Brilliant! This would also apply to the E3D-MAX that is collecting dust in my lab!

[thinkyhead]

@emartinez167 And this sure could use the testing to gain some confidence. It would be nice to have this included, if only as experimental code, in the new release, because there's an increasing demand.

[thinkyhead]

I'm merging this PR with the features disabled, as this includes some helpful improvements, beginning with separation of the E_STEPPERS from EXTRUDERS (similar to how SINGLENOZZLE separated HOTENDS from EXTRUDERS). This PR makes sense to include now (before renaming many feedrate variables). The code that these features augments have been stable for a while. Specifically, the stepper-indirection macros, Stepper class, and the ADVANCE and LIN_ADVANCE handling.

I'm not sure if the ADVANCE handling is exactly right for the mixing extruder. It "feels right" but needs more testing. At the stepper level, the switching extruder is a lot simpler.

[lavato]

Can somebody help me out on following:

• where can I connect the servo on RAMPS?
• what is SWITCHING_EXTRUDER_SERVO_NR 0 used for?

Also, can more angles be added to SWITCHING_EXTRUDER_SERVO_ANGLES for e.g. T2...?

[thinkyhead]

where can I connect the servo on RAMPS?

Try one of the plugs labeled "Servos." Google for the RAMPS schematic if you're not sure where they are.

what is SWITCHING_EXTRUDER_SERVO_NR 0 used for?

SWITCHING_EXTRUDER_SERVO_NR is the index of the servo that you're using to switch the idler orientation on your fancy new switching extruder.

can more angles be added to SWITCHING_EXTRUDER_SERVO_ANGLES

Your switching extruder sure is fancy! But seriously, no. These extruders only have two states, either driving the left filament, or driving the right filament. The E stepper also switches direction based on which side of the drive gear is being used to push the filament.

[lavato]

@thinkyhead Thank you!

Huh, let's wait and see if the "fancy" new extruder will work - as it is still just in my head,
I just started the project and will probably have to modify Marlin to support the feature, which I will share once I see it working.

If it is reasonable, I will raise a PR for it to be reviewed aldough I am still far from this, possibly a month or so, and my CPP is rusty.

[thinkyhead]

No better way to polish up your cpp than picking a project and going for it!

[rjbalsi]

Hi - I'm having issues with mixing extruder enabled (M163,M164 commands don't seem to work) - raised issue #5853 to document.

G1 A1 E10 works but other commands do not....

[rjbalsi]

T0, T1, T2 don't work either...

[guysoft]

Is there a way to make it so T1 and T2 are interpreted as:

M163 S0 P1
M163 S1 P0
M164 S0

And

M163 S0 P0
M163 S1 P1
M164 S0

That would be super helpful, otherwise its needed to search and replace each gcode uploaded to the printer.
I can modify the CPP, but pointing me in the right direction would help a lot!

[thinkyhead]

@guysoft MIXING_VIRTUAL_TOOLS

/**
 * "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 Host 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 2        // Number of steppers in your mixing extruder
  #define MIXING_VIRTUAL_TOOLS 16  // Use the Virtual Tool method with M163 and M164
  //#define DIRECT_MIXING_IN_G1    // Allow ABCDHI mix factors in G1 movement commands
#endif

You use M163 to set the channel values, then you use M164 to store the channel values as a virtual tool. For example, M164 S0 sets the color mix to use when you issue T0 and M164 S1 sets the mix that will be used when you issue T1.

[guysoft]

@thinkyhead I think you just solved another mystery with this, I just got now

Recv: Error:MAXTEMP triggered, system stopped! Heater_ID: 0
Changing monitoring state from 'Printing' to 'Error: MAXTEMP triggered, system stopped! Heater_ID: 0\x0a'
Recv: Error:Printer halted. kill() called!```

I was wondering  how ``Heater_ID: 0\x0a'`` got there, its 16!

[thinkyhead]

@guysoft The "Changing monitoring state" message comes from your host software. The string "0\x0a" represents the single character 0 —which is correct— followed by a hexadecimal representation of the newline character (10 decimal, \x0A hex). The host software should ignore that character instead of including it in its "monitoring state." But it probably does no harm.

So that may be a valid MAXTEMP error. Do you get that error consistently?